Development and multicenter validation of an immunoinflammatory marker-MRI model for pathological complete response after neoadjuvant chemotherapy in invasive breast cancer
Original Article

Development and multicenter validation of an immunoinflammatory marker-MRI model for pathological complete response after neoadjuvant chemotherapy in invasive breast cancer

Fan Meng1,2#, Yanfang Deng3#, Junhui Yuan1#, Shaobo Fang4, Hongkai Zhang1, Tiandong Chen5, Renzhi Zhang6, Yunjing Xue2, Xuejun Chen1, Jinrong Qu1

1Department of Medical Imaging, The Affiliated Cancer Hospital of Zhengzhou University & Henan Cancer Hospital, Zhengzhou, China; 2Department of Radiology, Fujian Medical University Union Hospital, Fuzhou, China; 3Department of Radiology, Longyan First Affiliated Hospital of Fujian Medical University, Longyan, China; 4Department of Radiology, Zhengzhou University People’s Hospital & Henan Provincial People’s Hospital, Academy of Medical Sciences, Zhengzhou University, Zhengzhou, China; 5Department of Pathology, The Affiliated Cancer Hospital of Zhengzhou University & Henan Cancer Hospital, Zhengzhou, China; 6National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China

Contributions: (I) Conception and design: F Meng, Y Deng, J Yuan; (II) Administrative support: X Chen, J Qu; (III) Provision of study materials or patients: S Fang, H Zhang; (IV) Collection and assembly of data: T Chen; (V) Data analysis and interpretation: R Zhang, Y Xue; (VI) Manuscript writing: All authors; (VII) Final approval of manuscript: All authors.

#These authors contributed equally to this work.

Correspondence to: Yunjing Xue, MD. Department of Radiology, Fujian Medical University Union Hospital, Xinquan Road, Gulou District, Fuzhou 350005, China. Email: xueyunjing@126.com; Xuejun Chen, MD; Jinrong Qu, MD. Department of Medical Imaging, The Affiliated Cancer Hospital of Zhengzhou University & Henan Cancer Hospital, Dongming Road, Zhengzhou 450008, China. Email: chenxuejun1967@163.com; qjryq@126.com.

Background: Accurate noninvasive prediction of pathological complete response (pCR) after neoadjuvant chemotherapy (NAC) in invasive breast cancer (BC) remains challenging. This study aimed to develop and validate a multivariable prediction model integrating clinicopathological variables, immunoinflammatory markers, and multiparametric magnetic resonance imaging (MRI) features for predicting pCR after NAC.

Methods: In this retrospective multicenter study, 345 women with invasive BC who underwent pre-treatment breast MRI and NAC were included. pCR was defined as the absence of residual invasive cancer in the breast and axillary lymph nodes at surgery. Patients were divided into training and internal validation cohorts, with an independent external cohort used for validation. Clinicopathological variables, immunoinflammatory markers, and MRI features, including mean apparent diffusion coefficient (ADCmean), were collected. Predictor selection was performed using the least absolute shrinkage and selection operator and multivariable logistic regression. Model performance was assessed using receiver operating characteristic analysis.

Results: Among the 345 patients, 116 (33.62%) achieved pCR. Clinical T stage, lymphocyte-to-monocyte ratio (LMR), systemic immune-inflammation index (SII), enhancement pattern, and ADCmean were independent predictors. The combined model showed the best performance, with area under the curves of 0.820, 0.810, and 0.799 in the training, internal validation, and external validation cohorts, outperforming the clinical and MRI models.

Conclusions: The combined model integrating clinicopathological variables, immunoinflammatory markers, and multiparametric MRI features may help predict pCR after NAC and support individualized treatment planning and potential surgical de-escalation.

Keywords: Invasive breast cancer (invasive BC); neoadjuvant chemotherapy (NAC); pathological complete response (pCR); immunoinflammatory markers; magnetic resonance imaging (MRI)


Submitted Dec 22, 2025. Accepted for publication Mar 11, 2026. Published online Apr 24, 2026.

doi: 10.21037/tcr-2025-1-2841


Highlight box

Key findings

• This multicenter study developed and validated a combined predictive model integrating pre-treatment clinicopathological variables, immunoinflammatory markers, and multiparametric magnetic resonance imaging (MRI) features to predict pathological complete response (pCR) after neoadjuvant chemotherapy (NAC) in invasive breast cancer (BC).

• Clinical T stage, systemic immune-inflammation index, lymphocyte-to-monocyte ratio (LMR), MRI enhancement pattern, and mean apparent diffusion coefficient (ADCmean) were independent predictors of pCR.

• The combined model shows superior performance compared with clinical-only or MRI-only models, with consistent area under the curve values across training, internal validation, and external validation cohorts.

What is known and what is new?

• pCR after NAC is strongly associated with improved survival in BC. Previous studies show that clinicopathological factors, blood-derived inflammatory markers, and imaging features—particularly MRI—can individually predict NAC response, but their accuracy varies and remains limited when used alone.

• This study is among the first multicenter investigations integrating immunoinflammatory markers with multiparametric MRI features and clinical variables into a unified model. The approach improves pCR prediction accuracy compared with single-modality models and demonstrates good generalizability across independent cohorts.

What is the implication, and what should change now?

• The combined model provides a noninvasive, readily available, and clinically applicable tool for individualized pCR prediction before NAC.

• Its use may assist clinicians in optimizing patient selection for NAC, tailoring treatment strategies, and supporting personalized decision-making in invasive BC.

• Future prospective studies and clinical implementation could further refine risk stratification and support precision oncology in BC care.


Introduction

Breast cancer (BC) is one of the most diagnosed malignant tumors and a leading cause of cancer-related death in women (1). Due to the heterogeneity of BC, patients with different subtypes exhibit varying rates of recurrence and metastasis, resulting in significant differences in survival outcomes (2). Neoadjuvant chemotherapy (NAC) is now widely adopted as a routine therapeutic strategy for patients with high-risk BC (3). This approach provides multiple clinical benefits, including reduction of tumor burden, facilitation of disease downstaging, improvement in surgical feasibility and breast-conserving rates, as well as the opportunity to assess tumor responsiveness to systemic treatment at an early stage (4,5). Pathological complete response (pCR) is characterized by the absence of residual invasive carcinoma in both the excised breast tissue and all evaluated regional lymph nodes following neoadjuvant systemic therapy (ypT0/Tis ypN0) (6,7). Studies have shown that pCR is closely related to disease-free survival (DFS) and overall survival (OS) (4,5) and is widely used as a surrogate endpoint in patients with BC who received NAC, with the aim of accelerating the evaluation of new treatment strategies. Therefore, it is necessary to identify a method to accurately predict which patients are likely to achieve a pCR and consequently derive the greatest benefit from NAC.

Several studies have incorporated inflammatory indicators into predictive models for pCR. For instance, Pu et al. constructed a nomogram including lymphovascular invasion, anemia, estrogen receptor (ER) status, Ki-67 expression, and NAC regimen, which achieved an area under the curve (AUC) of 0.758 for predicting pCR after NAC (8). Other studies have also evaluated inflammatory markers such as neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), lymphocyte-to-monocyte ratio (LMR), and systemic immune-inflammation index (SII) as predictors of treatment response in BC (6,9,10). Although these markers are easily obtained from routine blood tests and reflect the host immune-inflammatory status, their predictive performance varies considerably across studies, and models relying primarily on systemic markers often show only moderate discrimination.

Imaging-based approaches have also been explored for predicting pCR after NAC. Among available imaging techniques, breast magnetic resonance imaging (MRI) is considered the most informative modality for treatment response assessment because of its high soft-tissue resolution and functional imaging capability. Multiparametric MRI techniques, particularly dynamic contrast-enhanced MRI (DCE-MRI) and diffusion-weighted imaging (DWI), can provide parameters reflecting tumor vascularity and cellularity. Li et al. (11) reported that a pretreatment DCE-MRI-based nomogram incorporating tumor volume, time-to-peak enhancement, and androgen receptor status achieved AUCs of 0.84 and 0.79 in the training and validation cohorts, respectively. In addition, a systematic review evaluating diffusion-weighted MRI for predicting pCR showed that reported AUC values ranged from 0.50 to 0.92, indicating substantial variability among studies (12). These findings suggest that imaging features can provide valuable information on tumor morphology and microstructure, but their predictive accuracy remains heterogeneous.

One possible explanation is that each modality reflects different aspects of tumor biology. Systemic inflammatory markers mainly represent host immune and inflammatory responses (6,13), whereas MRI features primarily describe local tumor morphology, perfusion, and cellular density. Because response to chemotherapy is influenced by both tumor-intrinsic characteristics and host biological factors, reliance on a single modality may not sufficiently capture the complexity of treatment response (14,15). Integrating systemic immunoinflammatory markers with multiparametric MRI features may therefore provide complementary information and improve predictive performance. However, studies evaluating such combined approaches remain limited.

The objective of the current study was to construct a combined model based on clinicopathological variables, immunoinflammatory markers, and multiparameter MRI features at baseline to predict the probability of pCR in BC patients receiving NAC. We present this article in accordance with the TRIPOD reporting checklist (available at https://tcr.amegroups.com/article/view/10.21037/tcr-2025-1-2841/rc).


Methods

This was a multicenter study. The study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. This study was approved by the Ethics Committees of Henan Cancer Hospital (No. 2024-170-001) and Longyan First Affiliated Hospital of Fujian Medical University (No. LYREC2025-k105-01). Informed consent was waived in this retrospective study. A total of 376 patients with suspected invasive BC who underwent NAC followed by surgery at center 1 (Henan Cancer Hospital) between January 2018 and June 2020 were retrospectively collected as the training cohort. Inclusion criteria: (I) all patients underwent MRI scanning before treatment, including DWI and DCE sequences; (II) invasive BC with clinical stages T1–4, NX, and M0; and (III) complete clinical data and immunoinflammatory markers before treatment were available. Exclusion criteria: (I) a history of other malignancies (n=13); (II) poor image quality (n=16); and (III) missing data were excluded (n=2).

Patients who met the same inclusion and exclusion criteria were prospectively enrolled at center 1 (Henan Cancer Hospital) between June 2023 and June 2024 to form the internal validation cohort. In addition, patients treated at center 2 (Longyan First Affiliated Hospital of Fujian Medical University) between November 2022 and March 2024 were retrospectively collected as the external validation cohort to provide an independent dataset for model validation. The study flowchart is shown in Figure 1. Regarding sample size considerations, the development of the prediction model followed the commonly recommended events-per-variable (EPV ≥10) principle to ensure model stability. The number of outcome events in the training cohort satisfied this requirement. For the validation cohorts, no formal sample size calculation was performed; instead, all eligible patients available during the study period were included.

Figure 1 Flowchart in this study. Center 1, Henan Cancer Hospital; center 2, Longyan First Affiliated Hospital of Fujian Medical University. BC, breast cancer; DCE, dynamic contrast-enhanced; DWI, diffusion-weighted imaging; M, metastasis; MRI, magnetic resonance imaging; N, node; NAC, neoadjuvant chemotherapy; pCR, pathological complete response; T, tumor.

Clinicopathological data

Complete clinicopathological information was obtained from the integrated medical record system of our hospital, including age, menopausal status, clinical T stage, clinical N stage, molecular subtype, ER, progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2), and Ki-67 expression. Clinical staging was determined according to the 8th edition of the American Joint Committee on Cancer (AJCC) staging system. NAC regimens were selected in accordance with the prevailing clinical guidelines at the time, with anthracycline- and taxane-based therapies constituting the principal treatment strategies. pCR is characterized by the absence of residual invasive carcinoma in both the excised breast tissue and all evaluated regional lymph nodes following neoadjuvant systemic therapy (ypT0/Tis ypN0), pCR was defined as Miller-Payne grade 5, while grades 1–4 were classified as non-pCR (7,16). Pathological evaluation criteria: Immunohistochemical positivity for ER and PR was defined as nuclear staining rates of ≥1%, respectively. HER2 was considered negative with scores of 0, 1+, and 2+ [without fluorescence in situ hybridization (FISH) amplification] and positive with scores of 3+ and 2+ (with FISH amplification). Ki-67 was categorized as negative (<20%) and positive (≥20%). BC was classified into four molecular subtypes based on the expression of ER, PR, HER2, and Ki-67: luminal A, luminal B, HER2-enriched, and triple-negative.

Standard hematology assessments and complete blood count analyses were conducted within 2 weeks before therapy. Fasting blood samples were obtained, including 2 mL of ethylenediaminetetraacetic acid (EDTA)-anticoagulated peripheral blood, 2 mL of plasma collected using sodium citrate as an anticoagulant, along with serum specimens. The inflammatory markers were calculated based on the following formulas: systemic inflammation response index (SIRI) was calculated as ratio of neutrophil count × monocyte count to lymphocyte count, pan-immune-inflammation value (PIV) was calculated as the ratio of platelet count × neutrophil count × monocyte count to lymphocyte count, NLR, PLR, and LMR were computed as the ratios of neutrophils to lymphocytes, platelets to lymphocytes, and lymphocytes to monocytes, respectively. The SII was derived according to the following formula: SII = platelet count × neutrophil count/lymphocyte count.

MRI scanning

Center 1: MRI scans were performed using a Skyra 3.0-T and Prisma 3.0-T MRI scanner (Siemens Healthineers, Erlangen, Germany) with a 16-channel breast phased-array coil, in a prone position with feet first. The sequences included T2-weighted imaging (T2WI) [repetition time (TR), 3,500 ms; echo time (TE), 81 ms; slice thickness, 4 mm; field of view (FOV), 384 mm × 360 mm], T1-weighted imaging (T1WI) (TR, 5.36 ms; TE, 2.41 ms; slice thickness, 1.5 mm; FOV, 416 mm × 416 mm), DWI (TR, 6,460 ms; TE, 57 ms; slice thickness, 4 mm; FOV, 112 mm × 224 mm; b-value, 50, 1,000 s/mm2), and DCE- T1WI (TR, 4.18 ms; TE, 1.31 ms; slice thickness, 2 mm; FOV, 640 mm × 560 mm). DCE-T1WI was performed using the TWIST-VIBE sequence, with dynamic acquisition initiated 21.1 seconds after intravenous injection of gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA) at a flow rate of 2.5 mL/s via a high-pressure injector, for a total dose of 0.2 mmol/kg, capturing 40 phases of enhanced images.

Center 2: MRI scans were performed using an Ingenia 3.0-T and an Achive 3.0-T MRI scanner (Philips Healthcare, Andover, MA, USA) with a 7-channel breast phased-array coil, in a prone position with feet first. The sequences included T2WI (TR, 3,772 ms; TE, 70 ms; slice thickness, 4 mm; FOV, 280 mm × 340 mm), T1WI (TR, 542 ms; TE, 8 ms; slice thickness, 4 mm; FOV, 280 mm × 339 mm), DWI (TR, 6,391 ms; TE, 77 ms; slice thickness, 4 mm; FOV, 280 mm × 341 mm; b-value 0, 800 s/mm2), and DCE-T1WI (TR, 4.4 ms; TE, 2.1 ms; slice thickness, 1.2 mm; FOV, 240 mm × 379 mm). DCE-T1WI was performed using the dyn-eTHRIVE sequence, with dynamic acquisition initiated 48.8 seconds after intravenous injection of Gd-DTPA at a flow rate of 2.5 mL/s via a high-pressure injector, for a total dose of 0.2 mmol/kg, capturing 8 phases of enhanced images.

MRI image analysis

MRI characteristics: two radiologists (F.M. and J.Y.) with over 10 years of experience in breast MRI diagnosis analyzed the images based on the 2013 5th edition of the Breast Imaging Reporting and Data System (BI-RADS). Both radiologists were blinded to the pathological results and clinical outcomes during image evaluation to minimize potential bias. In case of discrepancies, consensus was reached through discussion. For multiple lesions, the largest lesion was evaluated. The MRI characteristics recorded included the amount of fibro glandular tissue (FGT), background parenchymal enhancement (BPE), lesion location, number, maximum diameter, shape, margin, enhancement pattern, time-intensity curve (TIC) type, and peritumoral edema. Mean apparent diffusion coefficient (ADCmean) values were measured using Syngo.Via software (Siemens Healthineers) and IntelliSpace Portal (Philips Healthcare). The same two radiologists independently performed the measurements in a blinded manner. Three circular regions of interest (ROI) were selected from the solid part of the tumor, avoiding large vessels and visibly cystic or necrotic areas with an area of 10–40 mm2 at the largest tumor section and the adjacent upper and lower layers, and then the average value was calculated.

Statistical analysis

Data were analyzed using MedCalc 20.1.0 and R 4.0.2 software. In center 1, the minimum sample size of the internal validation was calculated according to the method of test diagnosis in the reference (17). Assuming a null hypothesis AUC of 0.50 and an alternative AUC of 0.70, with an anticipated distribution of 70% non-pCR and 30% pCR cases and a statistical power of 90%, the minimum sample size required for the internal validation cohort was estimated to be 100 patients. Receiver operating characteristic (ROC) curve analysis was applied in the training cohort to identify optimal cutoff values for inflammatory biomarkers, with the threshold corresponding to the maximum Youden index selected as the optimal cutoff. Interobserver agreement between the two radiologists was assessed using the intraclass correlation coefficient (ICC), and an ICC value greater than 0.75 was considered indicative of good agreement. Independent sample t-test was performed the measurement data with normal distribution between groups. Mann-Whitney U test was used to compare the non-normal distribution measurement data and categorical data between groups. Chi-squared test or Fisher’s exact test was used for comparison of non-categorical data. Feature selection was conducted using the least absolute shrinkage and selection operator (LASSO) regression algorithm, with 10-fold cross-validation employed to select the most informative variables. Multivariate logistic regression analysis was used to screen the independent factors for predicting pCR of invasive BC, and then models were constructed and visualized as a nomogram. The ROC curve and the AUC were used to evaluate the performance of the three prediction models in predicting pCR, and the DeLong test was used for comparison. An AUC value between 0.70 and 0.80 was considered acceptable discrimination, 0.80–0.90 was considered good discrimination, and values above 0.90 were considered excellent performance in the context of clinical prediction models (18). All statistical tests were two-sided, and a P value <0.05 was considered statistically significant. LASSO regression analysis was operated with the “glmnet” package.


Results

Patient features

Overall, a total of 345 female patients, with 116 (33.62%) pCR and 229 (66.38%) non-pCR; including 187 patients (pCR group: 65; non-pCR group: 122; a mean age of 46.82±9.65 years) in the training set, 104 patients (pCR group: 33; non-pCR group: 71; a mean age of 46.77±9.30 years) in the internal validation set, and 54 patients (pCR group: 18; non-pCR group: 36; a mean age of 49.02±8.87 years) in the external validation set.

Using the training set data, the Youden index was used to calculate the best cut-off values of SIRI, PIV, PLR, LMR, NLR, and SII, which were 0.461, 303.774, 156.039, 4.656, 1.304, and 946.470, respectively.

Table 1 presents the comparison of clinicopathological variables between patients with and without pCR across the different cohorts. In the training set, clinical T stage, clinical N stage, molecular subtype, ER status, PR status, Ki-67 index, PLR, LMR, and SII differed significantly between the pCR and non-pCR groups (P<0.05). In the internal validation set, significant between-group differences were identified for clinical T stage, molecular subtype, ER status, PR status, and PLR (P<0.05). In the external validation set, only clinical T stage, Ki-67 expression, and PLR demonstrated statistically significant differences between the two groups (P<0.05). No significant differences were observed for other features in the three sets.

Table 1

Comparison of clinicopathological features between pCR and non-pCR groups in the training set, internal validation set, and external validation set

Characteristics Training set Internal validation set External validation set
pCR (n=65) Non-pCR (n=122) P value pCR (n=33) Non-pCR (n=71) P value pCR (n=18) Non-pCR (n=36) P value
Age (years) 0.93 0.85 0.85
   ≤50 26 48 22 46 8 15
   >50 39 74 11 25 10 21
Menopausal status 0.71 0.84 0.85
   Post-menopausal 18 37 24 53 9 19
   Premenopausal 47 85 9 18 9 17
Clinical T stage 0.002 <0.001 0.01
   1 12 6 5 1 0 3
   2 38 68 23 35 7 24
   3 14 33 5 27 9 4
   4 1 15 0 8 2 5
Clinical N stage 0.03 0.24 0.17
   0 16 48 10 26 4 10
   1 24 40 8 21 12 14
   2 19 29 11 21 1 10
   3 6 5 4 3 1 2
Molecular subtypes 0.004 0.003 0.10
   Luminal A 4 18 3 14 2 6
   Luminal B 22 63 7 35 12 12
   HER2-enriched 21 26 13 12 1 10
   Triple negative 18 15 10 10 3 8
ER% <0.001 0.004 0.57
   Negative 40 41 21 24 7 10
   Positive 25 81 12 47 11 26
PR% 0.001 0.003 0.03
   Negative 43 50 22 25 13 15
   Positive 22 72 11 46 5 21
HER2 0.53 0.06 0.34
   Negative 32 66 14 44 7 19
   Positive 33 56 19 27 11 17
Ki-67 0.01 0.21 0.001
   ≤20% 18 16 4 16 5 0
   >20% 47 106 29 55 13 36
SIRI 0.13 0.28 0.23
   ≤0.461 27 65 13 36 2 9
   >0.461 38 57 20 35 16 27
PIV 0.68 0.81 0.37
   ≤303.774 45 88 22 49 15 26
   >303.774 20 34 11 22 3 10
PLR 0.008 0.03 0.03
   ≤156.039 51 72 26 40 14 17
   >156.039 14 50 7 31 4 19
LMR 0.001 0.16 0.22
   ≤4.656 2 25 4 17 8 10
   >4.656 63 97 29 54 10 26
NLR 0.16 0.23 0.54
   ≤1.304 8 25 3 13 0 3
   >1.304 57 97 30 58 18 33
SII <0.001 0.43 0.02
   ≤946.47 63 94 29 58 16 21
   >946.47 2 28 4 13 2 15

Data are presented as number. ER, estrogen receptor; HER2, human epidermal growth factor receptor 2; LMR, lymphocyte-to-monocyte ratio; N, node; NLR, neutrophil-to-lymphocyte ratio; pCR, pathological complete response; PIV, pan-immune-inflammation value; PLR, platelet-to-lymphocyte ratio; PR, progesterone receptor; SII, systemic immune-inflammation index; SIRI, systemic inflammation response index; T, tumor.

MRI features

Comparison of MRI features between the pCR and non-pCR groups is shown in Table 2. Enhancement pattern, maximum diameter, shape, TIC type, and ADCmean were significantly associated with pCR in the training set (P<0.05). In the internal validation set, enhancement pattern, TIC type, and ADCmean have significant differences between the pCR and non-pCR groups (P<0.05). In the external validation set, enhancement pattern, maximum diameter, and ADCmean have significant differences between the pCR and non-pCR groups (P<0.05) (Figures 2,3).

Table 2

Comparison of MRI features between pCR and non-pCR groups in the training set, internal validation set and external validation set

Characteristics Training set Internal validation set External validation set
pCR (n=65) Non-pCR (n=122) P value pCR (n=33) Non-pCR (n=71) P value pCR (n=18) Non-pCR (n=36) P value
Lesion location 0.42 0.70 0.26
   SIQ 5 18 3 14 1 4
   LIQ 3 3 1 1 1 2
   LLQ 7 15 3 7 1 8
   SLQ 42 63 20 35 3 10
   Central 2 8 2 3 1 2
   Cross quadrant 6 15 4 11 11 10
FGT 0.98 0.48 0.58
   a 3 7 2 2 0 0
   b 11 20 3 13 9 12
   c 35 67 17 38 7 18
   d 16 28 11 18 2 6
Number of lesions 0.52 0.68 0.15
   Single 42 73 10 46 10 27
   Multiple 23 49 13 25 8 9
Maximum diameter (cm) 0.03 0.23 0.01
   <2 13 11 7 8 7 3
   ≥2 52 111 26 63 11 33
Shape 0.04 0.43 0.10
   Regular 17 17 4 13 5 3
   Irregular 48 105 29 58 13 33
Margin 0.76 0.46 0.03
   Circumscribed 6 13 4 5 5 2
   Non-circumscribed 59 109 29 66 13 34
Peritumoral edema 0.63 0.59 0.73
   Yes 48 86 11 20 3 8
   No 17 36 22 51 15 28
BPE 0.63 0.95 0.77
   <25% 61 110 31 67 15 29
   25–50% 4 9 2 3 2 3
   51–75% 0 1 0 0 1 4
   >75% 0 2 0 1 0 0
Enhancement pattern 0.01 0.006 0.02
   Homogeneous 11 13 2 16 4 1
   Heterogeneous 51 84 31 47 9 30
   Rim enhancement 3 25 0 8 5 5
TIC type 0.03 0.01 0.21
   Washin 0 0 2 1 0 1
   Plateau pattern 23 64 8 37 9 10
   Washout 42 58 23 33 9 25
ADCmean (×10−6 mm2/s) 842.774±110.638 806.893±107.783 0.03 867.151±125.643 818.305±117.437 0.056 1,136.111±330.884 984.444±133.040 0.02

Data are presented as number or mean ± standard deviation. ADCmean, mean apparent diffusion coefficient; BPE, background parenchymal enhancement; FGT, fibroglandular tissue; LIQ, lower inner quadrant; LLQ, lower lateral quadrant; MRI, magnetic resonance imaging; pCR, pathological complete response; SIQ, superior inner quadrant; SLQ, superior lateral quadrant; TIC, time-intensity curve.

Figure 2 A 60-year-old female patient with invasive BC in the left breast achieved a pCR after NAC. (A) Axial fat-suppressed T1WI shows an equal signal with relatively clear boundaries. (B) Axial fat-suppressed T2WI shows a slightly high signal with surrounding peritumoral edema. (C) Axial apparent diffusion coefficient map shows an uneven low signal, ADCmean =988×10−6 mm2/s. (D,E) Axial and sagittal enhanced T1WI show marked enhancement of the lesion. (F) Photomicrograph (H&E, ×200) of histologic specimen shows no clear residual cancer in the tumor bed area (MP, level 5). ADCmean, mean apparent diffusion coefficient; BC, breast cancer; H&E, hematoxylin and eosin; MP, Miller-Payne grading system; NAC, neoadjuvant chemotherapy; pCR, pathological complete response; T1WI, T1-weighted imaging; T2WI, T2-weighted imaging.
Figure 3 A 33-year-old female patient with invasive BC in the left breast did not achieve a pCR after NAC. (A) Axial fat-suppressed T1WI shows an equal and low signal. (B) Axial fat-suppressed T2WI shows a slightly high signal with surrounding peritumoral edema, central necrosis. (C) Axial apparent diffusion coefficient map shows an uneven low signal, ADCmean =820×10−6 mm2/s. (D,E) Axial and sagittal enhanced T1WI show rim enhancement of the lesion with relatively clear boundaries. (F) Photomicrograph (H&E, ×200) of histologic specimen shows residual cancer (MP, level 3). ADCmean, mean apparent diffusion coefficient; BC, breast cancer; H&E, hematoxylin and eosin; MP, Miller-Payne grading system; NAC, neoadjuvant chemotherapy; pCR, pathological complete response; T1WI, T1-weighted imaging; T2WI, T2-weighted imaging.

Feature selection and prediction model establishment

In the training set, the univariate analysis showed that clinical T stage, clinical N stage, molecular subtypes, PLR, LMR, SII, ER, PR, Ki-67, enhancement pattern, maximum diameter, shape, TIC type, and ADCmean were significantly associated with pCR (P<0.05). Then, LASSO regression analysis showed that clinical T stage, clinical N stage, PLR, LMR, SII, ER, PR, Ki-67, enhancement pattern, maximum diameter, TIC type, and ADCmean were important in predicting pCR after NAC in invasive BC patients (Figure 4). Subsequently, the results of multivariable logistic regression analysis showed that clinical T stage, LMR, SII, enhancement pattern, and ADCmean were the independent factors (Table 3).

Figure 4 Feature selection with the LASSO method in the training set. (A) The tuning parameter (λ) selection in the LASSO model used 10-fold cross-validation with minimum criteria. The optimal λ value was 0.0009932. (B) LASSO coefficient profiles of texture features could predict pCR in invasive BC, yielding 12 best coefficients at the selected logarithm (λ). BC, breast cancer; LASSO, least absolute shrinkage and selection operator; pCR, pathological complete response.

Table 3

Results of multivariable logistic regression analysis in the training set

Characteristics OR 95% CI P value
Clinical T stage
   T4
   T1 43.413 2.805–671.993 0.007
   T2 11.577 1.014–132.173 0.049
   T3 5.720 0.467–70.058 0.17
LMR
   >4.656
   ≤4.656 0.174 0.031–0.985 0.048
SII
   >428.049
   ≤428.049 6.661 1.064–41.695 0.04
ADCmean 1.006 1.002–1.010 0.002
Enhancement pattern
   Rim
   Homogeneous 15.193 2.401–96.144 0.004
   Heterogeneous 7.195 1.657–31.232 0.008

ADCmean, mean apparent diffusion coefficient; CI, confidence interval; LMR, lymphocyte-to-monocyte ratio; OR, odds ratio; SII, systemic immune-inflammation index; T, tumor.

Based on the features identified above, three prediction models were developed: one of which was a clinical model (clinical T stage + LMR + SII), the MRI model (enhancement pattern + ADCmean), and the combined model (clinical + MRI model).

To facilitate independent validation and future clinical application, the final logistic regression model was defined as follows:

Logit(p)=10.814+3.771×(Tstage1)+2.449×(Tstage2)+1.744×(Tstage3)1.750×(LMR)+1.896×(SII)+2.721×(enhancementpattern1)+1.973×(enhancementpattern2)+0.006×(ADCmean)

where p represents the predicted probability of achieving pCR after NAC.

The predicted probability was calculated using the logistic transformation:

p=11+elogit(p)

Evaluation of the performance of different models

In the training set, AUC [95% confidence interval (CI)] for the combined model in predicting pCR was 0.820 (0.758–0.873), which was higher than that for clinical model [0.731 (0.661–0.793)] and MRI model 0.708 (0.637–0.772) (Z=3.326 and 3.491, P<0.05) (Table 4, Figure 5). In the internal validation set, AUC (95% CI) for the combined model [0.810 (0.722–0.881)] was also higher than that for the clinical model [0.756 (0.662–0.835)] and the MRI model [0.691 (0.593–0.778)] (Z=2.052 and 2.379, P<0.05). In the external validation set, AUC (95% CI) for the combined model [0.799 (0.668–0.896)] was also higher than that for the clinical model [0.754 (0.608–0.854)] and the MRI model [0.645 (0.503–0.771)] (Z=1.194 and 1.957, P=0.23 and 0.050) (Table 4, Figure 5).

Table 4

Diagnostic performance of different models in the training and validation sets

Dataset AUC (95% CI) Sensitivity (%) Specificity (%)
Training set
   Clinical model 0.731 (0.661–0.793) 93.85 43.44
   MRI model 0.708 (0.637–0.772) 84.62 51.64
   Combined model 0.820 (0.758–0.873) 78.46 72.13
Internal validation set
   Clinical model 0.756 (0.662–0.835) 69.70 71.83
   MRI model 0.691 (0.593–0.778) 90.91 52.11
   Combined model 0.810 (0.722–0.881) 75.76 78.87
External validation set
   Clinical model 0.754 (0.608–0.854) 66.67 72.22
   MRI model 0.645 (0.503–0.771) 44.44 97.22
   Combined model 0.799 (0.668–0.896) 72.22 80.56

AUC, area under the curve; CI, confidence interval; MRI, magnetic resonance imaging.

Figure 5 ROC curves of the prediction models in the training (A), internal validation (B), and external validation (C) cohorts. MRI, magnetic resonance imaging; ROC, receiver operating characteristic.

Discussion

This study showed that clinical T stage, LMR, SII, enhancement pattern, and ADCmean were the independent factors for predicting pCR of invasive BC, and they can effectively distinguish pCR from non-pCR in invasive BC patients. A combined model based on clinicopathological variables, immunoinflammatory markers, and MRI characteristics can predict post-NAC pCR in invasive BC patients preoperatively, with the combined model (clinical + MRI model) achieving the highest diagnostic efficiency in the training, internal validation, and external validation sets.

Clinicopathological features and immunoinflammatory markers have been previously shown to predict pCR after NAC in invasive BC (6-10). Wang et al. (4) showed that lower clinical T stage, higher LMR, and lower SII were associated with a higher likelihood of achieving pCR. Mosalem et al. (19) reported that high NLR and LMR were associated with a higher likelihood of pCR. According to the research results of Dong et al. (20), clinical T and N stages, SIRI, and NLR are independent prognostic factors for pCR in invasive BC patients, and a low clinical stage is a favorable factor for pCR. In this study, low clinical T stage, high LMR, and low SII were favorable factors for pCR in invasive BC, which was consistent with the results of the appeal study. However, the results of some studies are inconsistent with the present study, such as Peng et al. (21), who suggested that lower LMR is a favorable predictor of the efficacy of NAC in invasive BC patients. The possible reasons are the large difference in patient sample size between the two studies, and related to the inconsistency of LMR cut-off values.

Previous studies have shown that MRI features and parameters can be used for noninvasive prediction of pCR after NAC in invasive BC, and all have good diagnostic efficacy (17,22,23). ADC value can be used to quantitatively evaluate the diffusion of water molecules in tumors, which is widely used. Partridge et al. (22) reported that DWI can reflect the cytotoxic effect of chemotherapy, and mid-treatment ADC is a predictive marker for pCR. Han et al. (17) showed that the maximum diameter and enhancement pattern of DCE-MRI were independently associated with pCR after NAC. Li et al. (24) reported that both DWI and DCE-MRI can well predict the pathological response of invasive BC to NAC, and there is no significant difference in diagnostic performance between them. Tang et al. (25) showed that early clinical staging was associated with pCR in invasive BC. Choi et al. (26) used the pre-treatment ADC value to predict the response of invasive BC to NAC, and the results showed that a high pre-treatment ADC value could better predict pCR. Consistent with the results of this study, ADCmean, enhancement pattern, and clinical T stage were favorable factors for pCR in invasive BC in this study.

Based on the analyses described above, three predictive models were developed: a clinical model, an MRI-based model, and a combined model. In the training cohort, both the clinical and MRI models demonstrated moderate predictive performance, with AUC values of 0.731 and 0.708, respectively. By contrast, the combined model achieved superior discrimination, yielding an AUC of 0.820 in the training set, 0.810 in the internal validation set, and 0.799 in the external validation set, outperforming both the clinical and MRI models. Wang et al. (4) developed a nomogram to predict pCR in invasive BC based on systemic immune-inflammatory markers before and after treatment, with an AUC of 0.754. Partridge et al. (22) used ADC values to assess the response to NAC for invasive BC and showed an AUC of 0.63 for the entire cohort. Wu et al. (27) showed that the AUC of the combination of clinicopathological features and pretreatment systemic inflammatory response index for predicting pCR to NAC in HER2-positive invasive BC was 0.74. Chen et al. (28) showed that the AUC of the MRI model in predicting pCR to NAC for invasive BC was 0.769. The results of this study showed that the AUC of the combined model in the training and validation groups was higher than those of the above studies. This indicated that clinicopathological features combined with inflammatory markers and MRI characteristics can effectively predict pCR in invasive BC.

There are limitations in this study. Firstly, the relatively small size of the external validation cohort (n=54) represents a notable limitation and may affect the precision and generalizability of the model performance. Further studies with larger sample sizes are needed to confirm our findings. Second, differences in patient characteristics were noted between the training and external validation sets; however, these discrepancies may mirror real-world clinical conditions and contribute to a more conservative and realistic assessment of model performance. Thirdly, MRI scans were acquired using machines from two different vendors across two centers, which may have introduced measurement biases.


Conclusions

This study demonstrated that clinical T stage, LMR, SII, enhancement pattern, and ADCmean were the independent factors for predicting pCR of invasive BC, a combined model based on clinicopathological features, combined with inflammatory markers and MRI characteristics, can effectively predict pCR in invasive BC.


Acknowledgments

None.


Footnote

Reporting Checklist: The authors have completed the TRIPOD reporting checklist. Available at https://tcr.amegroups.com/article/view/10.21037/tcr-2025-1-2841/rc

Data Sharing Statement: Available at https://tcr.amegroups.com/article/view/10.21037/tcr-2025-1-2841/dss

Peer Review File: Available at https://tcr.amegroups.com/article/view/10.21037/tcr-2025-1-2841/prf

Funding: This work was supported by Henan Medical Science and Technology Research Project (No. LHGJ20240123).

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://tcr.amegroups.com/article/view/10.21037/tcr-2025-1-2841/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. The study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. This study was approved by the Ethics Committees of Henan Cancer Hospital (No. 2024-170-001) and Longyan First Affiliated Hospital of Fujian Medical University (No. LYREC2025-k105-01). Informed consent was waived in this retrospective study.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.


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Cite this article as: Meng F, Deng Y, Yuan J, Fang S, Zhang H, Chen T, Zhang R, Xue Y, Chen X, Qu J. Development and multicenter validation of an immunoinflammatory marker-MRI model for pathological complete response after neoadjuvant chemotherapy in invasive breast cancer. Transl Cancer Res 2026;15(4):263. doi: 10.21037/tcr-2025-1-2841

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