Standardization of pathologic evaluation and reporting of postneoadjuvant specimens in clinical trials of breast cancer: recommendations from an international working group

Research trends of neoadjuvant therapy for breast cancer: A bibliometric analysis

The approach of neoadjuvant therapy for breast cancer, which involves administering systemic treatment prior to primary surgery, has undergone substantial advancements in recent decades. This strategy is intended to reduce tumor size, thereby enabling less invasive surgical procedures and enhancing patient outcomes. This study presents a comprehensive bibliometric analysis of research trends in neoadjuvant therapy for breast cancer from 2009 to 2024. Using data extracted from the Web of Science Core Collection, a total of 3,674 articles were analyzed to map the research landscape in this field. The analysis reveals a steady increase in publication output, peaking in 2022, with the United States and China identified as the leading contributors. Key institutions, such as the University of Texas System and MD Anderson Cancer Center, have been instrumental in advancing the research on neoadjuvant therapy. The study also highlights the contributions of influential authors like Sibylle Loibl and Gunter von Minckwitz, as well as major journals such as the Journal of Clinical Oncology. Emerging research topics, including immunotherapy, liquid biopsy, and artificial intelligence, are gaining prominence and represent potential future directions for clinical applications. This bibliometric analysis provides critical insights into global research trends, key contributors, and future developments in the field of neoadjuvant therapy for breast cancer, offering a foundation for future research and clinical practice advancements.

The prevalence and clinical significance of residual occult breast cancer after neoadjuvant chemotherapy: reassessing surgical pathology in cases initially described as pathological complete response

AIMS

Evaluation of pathological complete response (pCR) [no residual invasive carcinoma in the breast (RIC) or lymph node metastases (LNM) in surgical specimens following therapy] is typically based on evaluation of one level of haematoxylin and eosin (H&E) section. Not achieving pCR is associated with worse outcomes, and additional therapy may ensue. This study of patients with triple-negative (TNBC) or human epidermal growth factor receptor 2 (HER2)-positive (HER2+) breast cancer who underwent neoadjuvant therapy aims to assess whether occult residual disease (ORD) can be identified in deeper sections of tumour beds and lymph nodes in cases originally reported as pCR and whether ORD is associated with worse outcomes.

METHODS AND RESULTS

In 84 cases of pCR (2009-17) at our institution, deeper-level recuts were assessed for ORD. Oncological and survival outcomes were compared. ORD was identified in seven of 40 TNBC (17.5%; five RIC; one LMN; one RIC and LMN) and four of 44 HER2+ (9.1%; three RIC; one LMN) cases (all residual cancer burden I). Median follow-up was 46.7 months for TNBC (one local recurrence, four distant metastases and two deaths) and 86.8 months for HER2+ (no local recurrence, three distant metastases and two deaths). All recurrence and death events occurred in patients with pCR without ORD, with no recurrence events in patients with ORD.

CONCLUSIONS

In patients with TNBC and HER2+ breast cancer with pCR by standard pathological assessment, occult residual disease is not uncommon. Occult disease was not associated with worse oncological or survival outcomes, suggesting standard pathological assessment is sufficient to identify clinically meaningful disease.

Predictors of Pathologic Complete Response with Neoadjuvant Chemo-Immunotherapy in Early-Stage Triple-Negative Breast Cancer

BACKGROUND

The combination of pembrolizumab with neoadjuvant chemotherapy (NAC) for triple-negative breast cancer (TNBC) improves pathologic complete response (pCR) rates and event-free survival. Yet it is unclear which patients benefit most from the addition of immunotherapy. This study aims to identify predictive factors for pCR in patients with TNBC receiving chemo-immunotherapy (chemo-IO).

PATIENTS AND METHODS

This single-institution retrospective analysis included 283 consecutive patients with TNBC treated with neoadjuvant chemo-IO from 1 June 2021 to 20 January 2023. The primary outcome was overall pCR; secondary outcomes were breast pCR and nodal pCR. Univariate and multivariable logistic regression models assessed for characteristics associated with overall, breast, or nodal pCR.

RESULTS

Most patients presented with cT2 (71%) cN0 (54%) disease. The overall pCR rate was 57%, breast pCR was 58%, and axillary pCR was 67% among biopsy-proven cN+ patients. Race, pathogenic BRCA mutations, backbone chemotherapy regimen, immune-related adverse events, and disruptions in immunotherapy were not associated with pCR. Univariate associations with overall pCR were younger age (p = 0.04), lower clinical T stage (p = 0.01), ductal histology (p < 0.001), poor differentiation (p < 0.001), and unifocality (p < 0.001). Breast and axillary pCR had similar associations. Nodal pCR also had univariate associations with normal body mass index (BMI) (p = 0.04) and absence of lymphovascular invasion (LVI) (p = 0.04). On multivariable analyses, ductal histology and unifocality remained independently associated with overall and breast pCR.

CONCLUSIONS

This analysis showed few clinical variables to be independently associated with pCR after neoadjuvant chemo-IO for TNBC. Thus, predicting chemo-IO response to personalize treatment and minimize morbidity may instead lie in ongoing basic and translational research to assess for useful biomarkers.

Gross Evaluation of Breast Carcinomas Post-Neoadjuvant Chemotherapy Without Radio-opaque Clip Insertion: An Alternative Option

CONTEXT.—

Gross evaluation of post-neoadjuvant chemotherapy breast carcinoma is challenging when the primary tumor is not localized before therapy with a radio-opaque wire/clip, a situation common in resource-constrained settings.

OBJECTIVE.—

To compare 2 grossing approaches in post-neoadjuvant chemotherapy breast carcinoma specimens to evaluate the sampling adequacy.

DESIGN.—

Fifty breast carcinoma specimens were grossed in a 2-step manner. The tumor bed was identified using clinico-radiologic and gross correlation, and 1 slice was selected as the most representative (sample I). Subsequently, the entire tumor bed was submitted in grids of multiple slices (sample II). Agreement between methods was assessed using κ values.

RESULTS.—

Sample I resulted in an average of 8 blocks per case, while sample II resulted in 26 blocks. Pathologic complete response (pCR) by both methods was calculated. Sample I documented 23 cases with pCR, of which 21 were confirmed by sample II. The 2 cases missed by sample I had less than 5% residual tumor (residual cancer burden class I). Both cases were human epidermal growth factor receptor 2 (HER2)-positive, and residual tumor was seen in the slices adjacent to the selected slice. The concordance between the 2 methods was 94%, with a κ value of 0.915 for sample I, indicating excellent correlation with sample II.

CONCLUSIONS.—

The average cost of sample I was 33% of that of sample II and helped calculate the residual cancer burden with similar accuracy. However, in HER2-positive cases, pCR may be overestimated. Hence, we recommend sampling slices adjacent to the selected tumor slice. Further study using this method is essential due to its limited sample size and single-center design before considering implementation in the general population.

Biomarker alteration following chemotherapy-based systemic therapy in de novo metastatic breast cancer

INTRODUCTION

It is unclear whether the expression of biomarkers such as estrogen receptor (ER), progesterone receptor(PR), human epidermal growth factor receptor-2(HER2), and Ki-67 proliferation index changes following chemotherapy-based systemic therapy(CST) in patients with de novo metastatic breast cancer(dnMBC). The study aimed to investigate the expression of the biomarkers before and after CST and its impact on the prognosis of dnMBC patients.

METHODS

Using hospital-based database, we conducted a retrospective cohort study on dnMBC patients who received CST between February 2010 and December 2017. Based on clinicopathological data, changes in pathological findings(ER,PR,HER-2,Ki-67) following CST were examined. The effect of biomarker conversion on prognosis was evaluated. The primary outcome was overall survival(OS). Kaplan-Meier method and log-rank test was used for survival analyses.

RESULTS

The study included 192 female patients. The change rates of ER,PR,HER-2 and Ki-67 before and after CST were 9.9 %,17.2 %,6.2 % and 25.5 % respectively. Among them, the change in negative-to-positive expression of Ki-67 was the most common type of discordance observed. There was no statistical difference in OS between patients with changes in the four biomarkers and patients with no changes in the biomarkers(all p > 0.05). Interestingly, positive conversion of ER and PR, as well as persistent positive HER2 and Ki-67, were significantly associated with poor prognosis(p < 0.001,p < 0.001; p = 0.029,p < 0.001). Family history, initial metastatic site, and tumor grade were independent variables related to survival(p = 0.002,p < 0.001,p < 0.001).

CONCLUSIONS

Changes in ER, PR, HER2, and Ki-67 status were observed in patients following CST. Positive conversion of ER and PR, and persistent positive expression of HER2 and Ki-67 may indicate a poor prognosis. Further research is needed to determine whether biomarker expression investigations are needed following CST to optimize treatment options and improve survival.

Histopathologic Grading of Residual Tumor Predicts Survival of Intrahepatic Cholangiocarcinoma Patients Treated With Neoadjuvant Therapy: Major Pathologic Response and Its Clinical Significance

Neoadjuvant therapy (NAT) is increasingly used to treat patients with initially unresectable intrahepatic cholangiocarcinoma (iCCA). A histopathologic grading system for residual tumors that can predict patient survival is lacking in the literature. This retrospective study enrolled 151 iCCA patients who received NAT. The percentage of residual viable tumor (%RVT) extent was calculated by RVT surface area/total tumor bed area ×100 and scored in 5% increments. Kaplan-Meier and Cox regression analyses were used to investigate its correlations with recurrence-free survival (RFS) and overall survival (OS). Tumor regression grading by the College of American Pathologists (CAP) and MD Anderson (MDA) methodologies were also validated. A 10% RVT-based tumor regression score (TRS) showed a significant correlation with both OS and RFS. TRS and major pathologic response (mPR) were therefore defined as follows: TRS 1/mPR, tumor with 0 to 10% RVT; TRS 2, more than 10% RVT. Patients graded as TRS 1/mPR had superior OS ( P =0.006) and RFS ( P <0.001) compared with those with TRS 2 in univariate analysis. In a multivariate analysis including ypTNM stages, lymphovascular invasion, and perineural invasion, TRS 1/mPR was also found to be an independent prognostic factor for both OS (hazard ratio [HR]: 0.226; 95% CI: 0.053-0.966, P =0.045) and RFS (HR: 0.474; 95% CI: 0.231-0.974, P =0.042). As for the CAP and MDA grading methodologies, they were found to correlate with RFS (CAP: P =0.002; MDA: P =0.001), but not with OS (CAP: P =0.181; MDA: P =0.09). Our study revealed that a TRS of ≤10% RVT significantly correlates with longer OS and RFS and can be suggested as an mPR in iCCA. This indicator is easily applicable, prognostically relevant, and could be further validated in future prospective clinical trials.

Personalizing Neoadjuvant Chemotherapy: The Impact of BRCA Variants on Pathologic Complete Response in Luminal B Breast Cancer

Background: Neoadjuvant chemotherapy (NACT) is effective in downstaging locally advanced breast cancer, improving surgical and oncological outcomes. However, luminal B breast cancer typically exhibits a poorer response to NACT, with only 10-15% of patients achieving a pathologic complete response (pCR). This study investigates whether BRCA pathogenic variants (BRCA PVs) influence pCR rates in luminal B breast cancer patients, aiming to identify potential predictors for personalized treatment strategies. Materials and Methods: This retrospective study included luminal B breast cancer patients who underwent NACT at the Fondazione Policlinico Universitario Agostino Gemelli IRCCS between January 2014 and June 2023. Patients were stratified according to BRCA status: BRCA PVs and BRCA wild-type (WT). Primary endpoint was to evaluate pCR rates, while secondary endpoints included locoregional disease-free survival (LR-DFS), distant disease-free survival (DDFS), and overall survival (OS). Results: In total, 495 patients were enrolled, of whom 442 (89.3%) carried BRCA WT and 53 (10.7%) BRCA PVs. The pCR rate was significantly higher in the BRCA PVs group (20.8% PVs vs. 10.9% WT; p = 0.044). Specifically, the breast pCR rate was 28.3% in BRCA PVs versus 15.4% in BRCA WT (p = 0.030). BRCA WT patients had better 5-year LR-DFS (91.1% WT vs. 79.5% PVs; p = 0.003), while no significant differences were observed in 5-year DDFS or OS. Conclusions: BRCA PVs are associated with a higher pCR rate in luminal B breast cancer patients receiving NACT, suggesting a potential predictive role in tailoring treatment strategies.

Real-World Outcomes of Combination Anthracycline and Taxane Adjuvant Therapies in Early Triple-Negative Breast Cancer: A Moroccan Retrospective Analysis

PURPOSE

Neoadjuvant chemoimmunotherapy followed by adjuvant immunotherapy is the gold standard for treating patients with higher risk early triple-negative breast cancer (TNBC); however, in some cases, these patients undergo surgery followed by chemotherapy-based anthracyclines and taxanes without adhering to the guidelines.

METHODS

Patients with previously untreated stage I, II, and III TNBC who received adjuvant therapy with either doxorubicin and cyclophosphamide (AC) + docetaxel (AC-D), AC + weekly paclitaxel (AC-WP), epirubicin and cyclophosphamide (EC) + docetaxel (EC-D), or EC + WP (EC-WP); older than 18 years; and diagnosed between January 1st, 2011, and December 31st, 2022, were eligible for the study. Disease-free survival (DFS) is the primary reported end point. Overall survival (OS) and safety were the secondary end points.

RESULTS

We included 272 female patients. At a prespecified event-driven data cutoff, with a median follow-up of 26.3 months, the 5-year DFS was 49% (95% CI, 38 to 63) in the AC-D group, 45% (95% CI, 29 to 70) in the AC-WP group, 73% (95% CI, 61 to 100) in the EC-D group, and 72% (95% CI, 44 to 100) in the EC-WP group (hazard ratio [HR], 0.2 [95% CI, 0.06 to 0.67]; P = .08). The 7-year OS was 52% (95% CI, 32 to 83) in the AC-D group, 88% (95% CI, 78 to 99) in the AC-WP group, 95% (95% CI, 88 to 100) in the EC-D group, and 83% (95% CI, 58 to 100) in the EC-WP group (HR, 0.19 [95% CI, 0.06 to 0.66]; P = .03). Most of the grade 3-4 adverse events occurred in the AC-D group, primarily neutropenia, nausea-vomiting, and alopecia.

CONCLUSION

EC-D was linked to a slightly longer survival free of invasive, noninvasive, or distant disease and a significantly longer OS with fewer adverse events. Further studies are needed to confirm and establish long-term clinical benefits.

Molecular shifts in breast cancer following neoadjuvant chemotherapy: a prospective study and review of literature

BACKGROUND

Standard clinical guidelines recommend evaluating Estrogen & progesterone Receptor (ER, PR), Human epidermal growth factor receptor-2 (HER-2), and Ki-67 in breast cancer biopsy samples. This study investigates the changes in molecular subtype following neoadjuvant chemotherapy (NACT) in breast cancer patients.

METHODS

Patients aged 18 to 65 years who underwent core needle biopsy before NACT and received at least four chemotherapy cycles were included in the study. Patients with inflammatory breast cancer, de novo metastatic or bilateral breast cancer, pregnancy, lactation, prior endocrine/radiation therapy, or achieved pathological complete response (pCR) were excluded. Molecular profiles (ER, PR, HER-2, Ki-67) were analyzed pre- and post-NACT.

RESULTS

The study involved 100 breast cancer patients with a median age of 51.78 years. 47% of patients underwent breast-conserving surgery (BCS), while 53% underwent modified radical mastectomy (MRM). Seventy-six percent of patients had tumors larger than 5 cm, and 72% presented with axillary lymph node metastasis. Initially, 90% and 89% of patients were ER, and PR positive, respectively, which decreased to 81% and 75% post-surgery. Ki67 expression showed a significant reduction following chemotherapy. Larger tumors and lymph node-positivity had significant changes in molecular subtypes.

CONCLUSION

The study revealed significant alterations in ER, PR, HER-2, and Ki-67 levels post-NACT, prompting reassessment for tailored therapy.

A pooled analysis evaluating prognostic significance of Residual Cancer Burden in invasive lobular breast cancer

Residual Cancer Burden (RCB) after neoadjuvant chemotherapy (NAC) is validated to predict event-free survival (EFS) in breast cancer but has not been studied for invasive lobular carcinoma (ILC). We studied patient-level data from a pooled cohort across 12 institutions. Associations between RCB index, class, and EFS were assessed in ILC and non-ILC with mixed effect Cox models and multivariable analyses. Recursive partitioning was used in an exploratory model to stratify prognosis by RCB components. Of 5106 patients, the diagnosis was ILC in 216 and non-ILC in 4890. Increased RCB index was associated with worse EFS in both ILC and non-ILC (p = 0.002 and p < 0.001, respectively) and remained prognostic when stratified by receptor subtype and adjusted for age, grade, T category, and nodal status. Recursive partitioning demonstrated residual invasive cancer cellularity as most prognostic in ILC. These results underscore the utility of RCB for evaluating NAC response in those with ILC.

Influence of Multiband Technique on Temporal Diffusion Spectroscopy and Its Diagnostic Value in Breast Tumors

BACKGROUND

Temporal diffusion spectroscopy (TDS) is a noninvasive diffusion imaging technique used to characterizing cellular microstructures. The influence of multiband (MB) on TDS, particularly in breast tumor imaging remain unknown.

PURPOSE

To investigate the influence of MB on TDS in terms of scanning time, image quality, and quantitative parameters and to assess the diagnostic value of TDS with MB in breast tumors.

STUDY TYPE

Prospective.

POPULATION

Seventy-one women with 71 confirmed lesions.

FIELD STRENGTH/SEQUENCE

3.0 T; oscillating gradient spin-echo (OGSE), OGSE with MB, and pulsed gradient spin-echo, and routine magnetic resonance imaging squences.

ASSESSMENT

TDS with MB was used to assess diagnostic efficacy in differentiating benign and malignant tumors. A comparison of scanning time and image quality was performed in 17 patients. Imaging parameters were analyzed using limited spectrally edited diffusion (IMPULSED) and apparent diffusion coefficient (ADC) values were compared between MB and non-MB protocols. The cell diameter from TDS was compared with histopathological measurements in 21 patients.

STATISTICAL TESTS

Bland-Altman plot, paired t test, Mann-Whitney U test, kappa test, DeLong's test, intraclass correlation coefficient agreement, receiver operating characteristic curve, area under the curve (AUC), and simple linear regression, with statistical significance set at P < 0.05.

RESULTS

The TDS with MB protocol had a shorter average scanning time than that without MB protocol (7 minutes 22 seconds vs. 12 minutes 28 seconds); image quality was improved by reducing image artifacts. Most IMPULSED parameters and ADC values did not significantly differ between the MB and non-MB protocols (P = 0.23, P = 0.17). The IMPULSED parameters of cellularity and intracellular volume fraction achieved the highest AUC values for distinguishing breast tumors (0.865 and 0.821, respectively), surpassing the diagnostic efficiency of conventional ADC-1000 (0.776). The correlation between IMPULSED parameters and microscopic cell size was strong (r = 0.842).

DATA CONCLUSION

The MB technique improved the TDS protocol's efficiency and reduced the image artifacts. TDS parameters correlated with pathological findings and showed good performance in differentiating benign from malignant breast tumors.

PLAIN LANGUAGE SUMMARY

We explored the impact of simultaneous multislice acquisition technology on temporal diffusion spectroscopy (TDS) and whether combining this method could help distinguish benign from malignant breast tumors. Our findings showed that simultaneous multislice acquisition technology shortened the scanning time and improved image quality by reducing motion-related issues. Additionally, measurements of cell size using simultaneous multislice acquisition technology matched well with results from pathology tests. Overall, our study suggests that simultaneous multislice acquisition enhanced TDS could make breast cancer diagnosis more accurate and efficient, offering good advantages compared to conventional imaging methods.

LEVEL OF EVIDENCE

2 TECHNICAL EFFICACY: Stage 2.

Predictive factors for axillary pathological complete response to neoadjuvant therapy in elderly breast cancer patients

PURPOSE

This study explores the predictive factors for axillary pathological complete response(apCR) during neoadjuvant therapy(NAT) for elderly breast cancer patients to supplement the indications for retaining the axilla.

METHODS

Comprehensive clinical information was gathered from November 2016 to July 2023 from elderly patients with pathology-confirmed invasive breast cancer who underwent NAT and surgery in the Breast Department of Sichuan Cancer Hospital. The relationships between clinicopathological characteristics and apCR were investigated via retrospective analysis. Univariate analysis of the clinicopathological parameters and efficacy was performed via the chi-square test or Fisher's exact test, while multivariate analysis was conducted via binary logistic regression.

RESULTS

This study included 109 elderly patients with breast cancer, with an overall apCR rate of 46.8%. The univariate analysis results showed that the initial clinical lymph nodes negative(cN0) stage, Human Epidermal Growth Factor Receptor 2(HER2) positivity and breast pathological complete response(bpCR) were significantly correlated with high apCR rates(all P < 0.05). Multivariate analysis revealed that apCR exhibited a significant association with initial cN0 stage and HER2 positivity. The apCR rate for HER2-positive elderly patients with initial cN0 disease is 100.0%,whereas the lowest apCR rate is observed in HER2-negative and clinical lymph nodes positive(cN+) patients(36.0%). Subgroup analysis revealed a close relationship between molecular subtypes and apCR.

CONCLUSION

This study indicates that initial cN0 stage and HER2 positivity can serve as independent predictive factors for apCR after NAT in elderly breast cancer patients. HER2-positive elderly patients with initial cN0 stage can be considered exempt from axillary lymph node dissection(ALND) after standard NAT.

The prognostic value of histological grade determined after neoadjuvant chemotherapy of breast cancer

Histological grade is a validated prognostic factor of breast cancer but may show alterations following neoadjuvant chemotherapy (NACT). Its reporting after NACT is recommended by several guidelines, but evidence of its retained prognostic impact is scarce. Patients treated with NACT followed by surgery and having sufficient residual tumour for the determination of grade were analysed for the survival effects of posttreatment grade (yG). Kaplan-Meier analyses and the log-rank test were applied, followed by the univariable and multivariable Cox proportional hazards models. The cohort comprised 355 patients with known yG, and 320 of them had also a pretreatment grade available. Pretreatment grade changed in 99/320 (31 %) cases following NACT, and downgrading was more common (n=78/320, 24 %) than upgrading (21/320, 7 %). Among 355 breast cancer patients, those with yG3 (poorly differentiated) tumours (n=155) had worse 5-year relapse-free and overall survival estimates than those with yG2 (n=169) or yG1 (n=31) tumours. This was also substantiated by univariable analysis; however, yG lost its significance in the multivariable model. Post-NACT histological grade has a prognostic impact, but does not seem to be an independent prognosticator in the post-NACT setting; however, these results lend support for its reporting by pathologists after primary systemic treatment.

Dynamic ultrasound-based modeling predictive of response to neoadjuvant chemotherapy in patients with early breast cancer

Early prediction of patient responses to neoadjuvant chemotherapy (NACT) is essential for the precision treatment of early breast cancer (EBC). Therefore, this study aims to noninvasively and early predict pathological complete response (pCR). We used dynamic ultrasound (US) imaging changes acquired during NACT, along with clinicopathological features, to create a nomogram and construct a machine learning model. This retrospective study included 304 EBC patients recruited from multiple centers. All enrollees had completed NACT regimens, and underwent US examinations at baseline and at each NACT cycle. We subsequently determined that percentage reduction of tumor maximum diameter from baseline to third cycle of NACT serves to independent predictor for pCR, enabling creation of a nomogram ([Formula: see text]). Our predictive accuracy further improved ([Formula: see text]) by combining dynamic US data and clinicopathological features in a machine learning model. Such models may offer a means of accurately predicting NACT responses in this setting, helping to individualize patient therapy. Our study may provide additional insights into the US-based response prediction by focusing on the dynamic changes of the tumor in the early and full NACT cycle.

Tumor Morphology for Prediction of Poor Responses Early in Neoadjuvant Chemotherapy for Breast Cancer: A Multicenter Retrospective Study

BACKGROUND

This multicenter and retrospective study investigated the additive value of tumor morphologic features derived from the functional tumor volume (FTV) tumor mask at pre-treatment (T0) and the early treatment time point (T1) in the prediction of pathologic outcomes for breast cancer patients undergoing neoadjuvant chemotherapy.

METHODS

A total of 910 patients enrolled in the multicenter I-SPY 2 trial were included. FTV and tumor morphologic features were calculated from the dynamic contrast-enhanced (DCE) MRI. A poor response was defined as a residual cancer burden (RCB) class III (RCB-III) at surgical excision. The area under the receiver operating characteristic curve (AUC) was used to evaluate the predictive performance. The analysis was performed in the full cohort and in individual sub-cohorts stratified by hormone receptor (HR) and human epidermal growth factor receptor 2 (HER2) status.

RESULTS

In the full cohort, the AUCs for the use of the FTV ratio and clinicopathologic data were 0.64 ± 0.03 (mean ± SD [standard deviation]). With morphologic features, the AUC increased significantly to 0.76 ± 0.04 (p < 0.001). The ratio of the surface area to volume ratio between T0 and T1 was found to be the most contributing feature. All top contributing features were from T1. An improvement was also observed in the HR+/HER2- and triple-negative sub-cohorts. The AUC increased significantly from 0.56 ± 0.05 to 0.70 ± 0.06 (p < 0.001) and from 0.65 ± 0.06 to 0.73 ± 0.06 (p < 0.001), respectively, when adding morphologic features.

CONCLUSION

Tumor morphologic features can improve the prediction of RCB-III compared to using FTV only at the early treatment time point.

An explainable longitudinal multi-modal fusion model for predicting neoadjuvant therapy response in women with breast cancer

Multi-modal image analysis using deep learning (DL) lays the foundation for neoadjuvant treatment (NAT) response monitoring. However, existing methods prioritize extracting multi-modal features to enhance predictive performance, with limited consideration on real-world clinical applicability, particularly in longitudinal NAT scenarios with multi-modal data. Here, we propose the Multi-modal Response Prediction (MRP) system, designed to mimic real-world physician assessments of NAT responses in breast cancer. To enhance feasibility, MRP integrates cross-modal knowledge mining and temporal information embedding strategy to handle missing modalities and remain less affected by different NAT settings. We validated MRP through multi-center studies and multinational reader studies. MRP exhibited comparable robustness to breast radiologists, outperforming humans in predicting pathological complete response in the Pre-NAT phase (ΔAUROC 14% and 10% on in-house and external datasets, respectively). Furthermore, we assessed MRP's clinical utility impact on treatment decision-making. MRP may have profound implications for enrolment into NAT trials and determining surgery extensiveness.

Comparison of proportions and prognostic impact of pathological complete response between evaluations of representative specimen and total specimen in primary breast cancer after neoadjuvant chemoradiotherapy: an ancillary study of JCOG0306

BACKGROUND

In JCOG0306 trial, a phase II study to examine the efficacy of neoadjuvant chemotherapy followed by radiation therapy (NAC-RT) to primary breast cancer, pathological complete response (pCR) was evaluated from specimens of the representative cross-section including the tumor center that had been accurately marked [representative specimen (RS) method]. In this ancillary study, we examined if the RS method was comparable to the conventional total specimen (TS) method, which is widely employed in Japan, to identify the pCR group showing excellent prognosis.

METHODS

We obtained long-term follow-up data of 103 patients enrolled in JCOG0306 trial. As histological therapeutic effect, pCR (ypT0 and ypT0/is) and quasi-pCR [QpCR, ypT0/is plus Grade 2b (only a few remaining invasive cancer cells)] were evaluated with RS and TS methods. Concordance of pCR between these two methods and associations of the pCR with prognosis were examined.

RESULTS

ypT0, ypT0/is, and QpCR were observed in 28 (27.2%), 39 (37.9%), and 45 (43.7%) patients with RS method, whereas these were 20 (19.4%), 25 (24.3%) and 40 (38.9%) with TS method, respectively. Between RS and TS methods, concordance proportions of ypT0 and ypTis were 92.2% and 86.4%, respectively. Risk of recurrence of ypT0/is group was lower than that of non-ypT0/is group (HR 0.408, 95% CI [0.175-0.946], P = 0.037) and risk of death of ypT0/is group was lower than that of non-ypT0/is group (HR 0.251, 95% CI [0.073-0.857], P = 0.027). The ypT0 and ypT0/is groups with RS method showed excellent prognosis similarly with those with TS method, and RS method was able to differentiate the OS and RFS between pCR and non-pCR than TS method significantly even if pCR was classified ypT0 or ypT0/is. With TS method, QpCR criteria stratified patients into the better and worse prognosis groupsmore clearly than pCR criteria of ypT0 or ypT0/is.

CONCLUSIONS

RS method was comparable to TS method for the evaluation of pCR in the patients who received NAC-RT to primary breast cancer provided the tumor center was accurately marked. As pCR criteria with RS method, ypT0/is appeared more appropriate than ypT0.

Impact of the CPS-EG score as a new prognostic biomarker in triple-negative breast cancer patients who received neoadjuvant chemotherapy

BACKGROUND

This study aimed to establish risk groups on the basis of CPS-EG scores, independent of pCR status, in triple-negative breast cancer (TNBC) patients receiving neoadjuvant chemotherapy (NACT) to identify the prognostic impact of the CPS-EG score.

METHODS

Patient characteristics included age, menopausal status, clinical stage, pathological stage, estrogen receptor (ER) expression, nuclear grade, Ki-67 proliferation index, residual cancer burden (RCB) score, HER2 status, and other tumor characteristics. The CPS-EG scoring system included clinical stage, pathological stage, ER status, and grade. Patients were divided into two groups on the basis of their CPS-EG scores ≤ 3 and > 3.

RESULTS

A total of 148 patients who were diagnosed with TNBC and treated with NACT were included in the study. A total of 52.0% of the patients had a CPS-EG score of ≤ 3, whereas 48.0% had a score of > 3. The rate of patients who achieved pCR was 29.7% (n = 44). CPS-EG score (HR: 2.331; 95%CI; 1.179-4.608; p = 0.015), pCR (HR: 0.348; 95%CI; 0.144-0.844; p = 0.019), pre-treatment mKi-67 proliferation index (HR: 0.467; 95%CI; 0.251-0.871; p = 0.017), and RCB score (HR: 0.401; 95%CI; 0.174-0.923; p = 0.032) were identified as significant prognostic factors for 5-year DFS. For 5-year OS, significant prognostic factors were CPS-EG score (HR: 2.30; 95%CI; 1.036-4.799; p = 0.040) and pre-treatment mKi-67 proliferation index (HR: 0.484; 95%CI; 0.246-0.954; p = 0.036).

CONCLUSIONS

The CPS-EG score, pre-treatment mKi-67 level, and the pCR and RCB score were practical prognostic markers for long-term survival. Conversely, the prognostic significance of pCR status was diminished, particularly in predicting OS. These findings underscore the importance of not only post-treatment pathological staging but also the initial tumor stage and biological characteristics of the tumor in predicting ultimate survival outcomes following neoadjuvant chemotherapy in TNBC patients.

Non-invasive prediction of axillary lymph node dissection exemption in breast cancer patients post-neoadjuvant therapy: A radiomics and deep learning analysis on longitudinal DCE-MRI data

PURPOSE

In breast cancer (BC) patients with clinical axillary lymph node metastasis (cN+) undergoing neoadjuvant therapy (NAT), precise axillary lymph node (ALN) assessment dictates therapeutic strategy. There is a critical demand for a precise method to assess the axillary lymph node (ALN) status in these patients.

MATERIALS AND METHODS

A retrospective analysis was conducted on 160 BC patients undergoing NAT at Fujian Medical University Union Hospital. We analyzed baseline and two-cycle reassessment dynamic contrast-enhanced MRI (DCE-MRI) images, extracting 3668 radiomic and 4096 deep learning features, and computing 1834 delta-radiomic and 2048 delta-deep learning features. Light Gradient Boosting Machine (LightGBM), Support Vector Machine (SVM), RandomForest, and Multilayer Perceptron (MLP) algorithms were employed to develop risk models and were evaluated using 10-fold cross-validation.

RESULTS

Of the patients, 61 (38.13 %) achieved ypN0 status post-NAT. Univariate and multivariable logistic regression analyses revealed molecular subtypes and Ki67 as pivotal predictors of achieving ypN0 post-NAT. The SVM-based "Data Amalgamation" model that integrates radiomic, deep learning features, and clinical data, exhibited an outstanding AUC of 0.986 (95 % CI: 0.954-1.000), surpassing other models.

CONCLUSION

Our study illuminates the challenges and opportunities inherent in breast cancer management post-NAT. By introducing a sophisticated, SVM-based "Data Amalgamation" model, we propose a way towards accurate, dynamic ALN assessments, offering potential for personalized therapeutic strategies in BC.

Tailoring neoadjuvant systemic therapy in breast cancer: "The advent of a personalized approach"-The Breast-Gynecological and Immuno-Oncology International Cancer Conference (BGICC) consensus and recommendations

BACKGROUND

The management of early breast cancer (BC) has witnessed an uprise in the use of neoadjuvant therapy and a remarkable reshaping of the systemic therapy postneoadjuvant treatment in the last few years, with the evolution of many controversial clinical situations that require consensus.

METHODS

During the 14th Breast-Gynecological and Immuno-Oncology International Cancer Conference held in Egypt in 2022, a panel of 44 BC experts from 13 countries voted on statements concerning debatable challenges in the neo/adjuvant treatment setting. The recommendations were subsequently updated based on the most recent data emerging. A modified Delphi approach was used to develop this consensus. A consensus was achieved when ≥75% of voters selected an answer.

RESULTS AND CONCLUSIONS

The consensus recommendations addressed different escalation and de-escalation strategies in the setting of neoadjuvant therapy for early BC. The recommendations recapitulate the available clinical evidence and expert opinion to individualize patient management and optimize therapy outcomes. Consensus was reached in 63% of the statements (52/83), and the rationale behind each statement was clarified.

A multidisciplinary team and patient perspective on omission of surgery after neoadjuvant systemic therapy for early breast cancer: A European Society of Surgical Oncology (ESSO) Research Academy survey

BACKGROUND

Surgical de-escalation aims to reduce morbidity without compromising oncological outcomes. Trials to de-escalate breast cancer (BC) surgery among exceptional responders after neoadjuvant systemic therapy (NST) are ongoing. Combined patient and clinician insights on this strategy are unknown.

METHODS

The European Society of Surgical Oncology Young Surgeons Alumni Club (EYSAC) performed an online survey to evaluate the perspective of multidisciplinary teams (MDTs) on omission of surgery ("no surgery") following complete response to NST for early BC. The aim was to identify MDT considerations and perceived barriers to omission of BC surgery. Patient insights were obtained through a focused group discussion (FGD) with four members of the patient advocacy group, Guiding Researchers and Advocates to Scientific Partnerships (GRASP).

RESULTS

The MDT survey had 248 responses, with 229 included for analysis. Criteria for a "no surgery" approach included: patient's tumor and nodal status before (39.7 %) and after (45.9 %) NST and comorbidities (44.3 %). The majority chose standard surgery for hypothetical cases with a complete response to NST. Barriers for implementation were lack of definitive trials (55.9 %), "no surgery" not being discussed in MDTs (28.8 %) and lack of essential diagnostic or therapeutic options (24 %). Patients expressed communication gaps about BC surgery, lack of trust regarding accuracy of imaging, fear of regret and psychosocial burden of choosing less extensive surgery.

CONCLUSIONS

Before accepting "no surgery" after complete response to NST, MDTs and patients need level 1 evidence from clinical trials, access to standard diagnostic modalities and treatments. Patient's fear of regretting less surgery need to be acknowledged and addressed.

Exploring the synergistic effects of vitamin D and synbiotics on cytokines profile, and treatment response in breast cancer: a pilot randomized clinical trial

This study was designed to investigate the effect of vitamin D and/or synbiotics on the response to treatment, cytokines profile and hormonal biomarkers in breast cancer patients undergoing neoadjuvant therapy. A total of 76 patients were recruited and completed the course of the intervention between 2019 and 2021 in Kerman, Iran. breast cancer patients were randomly enrolled in this study. Patients divided into four groups to receive one of the following regimens: placebo, vitamin D, synbiotics and a combination of vitamin D and synbiotics. clinicopathologic parameters, inflammatory and anti-inflammatory biomarkers and hormonal levels were measured at the baseline and four months after intervention. The study results found no clear link between the interventions and achieving pathological complete response (pCR), and a similar trend was observed in Ki-67 index examination. After neoadjuvant therapy, TNF-α concentrations decreased, with vitamin D supplementation moderating this decline. Vitamin D supplemented groups showed a significant increase in serum IL-6 levels. While IL-10 levels decreased in the placebo group, all intervention groups were protected from this decline. Moreover, there was a notable increase in the anti-inflammatory index, particularly in the group receiving both vitamin D and synbiotic supplementation, suggesting potential synergistic anti-inflammatory effects from their combined administration. The outcomes suggest a potential anti-inflammatory function of this combination. Consequently, more extensive studies with prolonged follow-up periods and substantial sample sizes are warranted to thoroughly evaluate their potential benefits for breast cancer patients.

Pathology of Surgically Resected Lung Cancers Following Neoadjuvant Therapy

In around 30% of patients, non-small cell lung cancer is diagnosed at an advanced but resectable stage. Adding systemic therapy has shown clear benefit over surgery alone in locally advanced disease, and currently, chemo-immunotherapy in the adjuvant or neoadjuvant setting is the new standard for patients without targetable mutations. One major advantage of the neoadjuvant approach is the possibility of an immediate evaluation of the treatment effect, highlighting the role of pathology as an important contributor at the forefront of clinical decision-making and research. This review provides a summary and an update on current guidelines for histological evaluation of treatment effect after neoadjuvant therapy, also known as regression grading, and discusses newer data focusing on areas of evolving questions and controversies, such as the gross examination of the tumor and tumor bed, weighted versus unweighted evaluation approaches, discussion of histologic tumor type-specific cut-offs for major pathologic response, assessment of lymph nodes and regression grading after immunotherapy and targeted therapy. As no data or recommendations exist on regression grading of multiple tumor nodules, a practical approach is recommended. Lastly, we will touch on additional tissue biomarkers and summarize recent advances in the ardently discussed field of using circulating tumor DNA for the evaluation of treatment response.

Contrast-enhanced mammography and preoperative magnetic seed placement in breast cancer patients for the detection of residual disease following neoadjuvant systemic therapy

PURPOSE

Assess whether contrast-enhanced mammography (CEM) enables an evaluation of the residual size of breast tumours following neoadjuvant systemic therapy (NAST) in patients initially marked with magnetic seed.

MATERIALS AND METHODS

This single-centre prospective study was performed between March 2022 and April 2023 with patients with invasive breast carcinoma and lesional marking with magnetic seed. CEM was performed before and after NAST. The lesion size in CEM after NAST was compared to the pathological examination after surgery. Differences between sizes were evaluated and we determined the diagnostic capability indices.

RESULTS

The breast lesions marked with magnetic seed were successfully localised in the preoperative stage for the 42 patients included in the study and selective surgical excision was also achieved in all cases. Tumour diameter after NAST was determined by comparing enhancement on combined CEM images from before and after NAST. The mean diameter was 13.6 mm while post-surgical pathological examination determined the mean diameter to be 12.9 mm. There were therefore no statistically significant differences between the measurements.

CONCLUSIONS

There is a positive correlation and similarity between CEM and pathological examination with regards to the detection of residual disease after NAST, with high specificity and PPV.

Association of residual ductal carcinoma in situ with breast cancer treatment outcomes after neoadjuvant chemotherapy according to hormone receptor status

PURPOSE

This research aimed to clarify the impact of residual ductal carcinoma in situ(DCIS) in surgical specimens obtained after neoadjuvant chemotherapy(NAC) for breast cancer on the associated prognosis outcomes.

METHODS

This retrospective study was performed on a cohort of 1,009 patients who achieved pCR following NAC for breast cancer and underwent subsequent breast surgery at a single institution between January 2008 and December 2019. Overall survival, local recurrence-free survival, distant metastasis-free survival, and disease-free survival of the residual and non-residual DCIS groups were the outcomes compared, with further subgroup analysis performed according to hormone receptor status.

RESULTS

260 individuals (25.8%) presented with residual DCIS. Based on a median follow-up of 54.0 months, no significant differences in outcomes were observed between the two groups. Patients with residual DCIS and hormone receptor-negative (HR-) breast cancer demonstrated a significant decrease in distant metastasis-free survival (p = 0.030) compared to those without residual DCIS. In the HR + cohort, no significant difference was observed between the two groups. Multivariate analysis of the HR- cohort demonstrated a significant association between residual DCIS and an elevated risk for distant recurrence (hazard ratio = 2.3, 95% confidence interval = 1.01-5.20, p = 0.047).

CONCLUSIONS

Residual DCIS following NAC may impact breast cancer outcomes, particularly with respect to the occurrence of distant metastasis in HR- patients. Therefore, clinicians must vigilantly monitor patients with residual DCIS after NAC, and further research is needed to expand our understanding of the clinical implications of residual DCIS.

Plasma Metabolome Signatures to Predict Responsiveness to Neoadjuvant Chemotherapy in Breast Cancer

BACKGROUND

Neoadjuvant chemotherapy (NACT) has arisen as a treatment option for breast cancer (BC). However, the response to NACT is still unpredictable and dependent on cancer subtype. Metabolomics is a tool for predicting biomarkers and chemotherapy response. We used plasma to verify metabolomic alterations in BC before NACT, relating to clinical data.

METHODS

Liquid chromatography coupled to mass spectrometry (LC-MS) was performed on pre-NACT plasma from patients with BC (n = 75). After data filtering, an SVM model for classification was built and validated with 75%/25% of the data, respectively.

RESULTS

The model composed of 19 identified metabolites effectively predicted NACT response for training/validation sets with high sensitivity (95.4%/93.3%), specificity (91.6%/100.0%), and accuracy (94.6%/94.7%). In both sets, the panel correctly classified 95% of resistant and 94% of sensitive females. Most compounds identified by the model were lipids and amino acids and revealed pathway alterations related to chemoresistance.

CONCLUSION

We developed a model for predicting patient response to NACT. These metabolite panels allow clinical gain by building precision medicine strategies based on tumor stratification.

Breast Cancer Histopathology in the Age of Molecular Oncology

For more than a century, microscopic histology has been the cornerstone for cancer diagnosis, and breast carcinoma is no exception. In recent years, clinical biomarkers, gene expression profiles, and other molecular tests have shown increasing utility for identifying the key biological features that guide prognosis and treatment of breast cancer. Indeed, the most common histologic pattern-invasive ductal carcinoma of no special type-provides relatively little guidance to management beyond triggering grading, biomarker testing, and clinical staging. However, many less common histologic patterns can be recognized by trained pathologists, which in many cases can be linked to characteristic biomarker and gene expression patterns, underlying mutations, prognosis, and therapy. Herein we describe more than a dozen such histomorphologic subtypes (including lobular, metaplastic, salivary analog, and several good prognosis special types of breast cancer) in the context of their molecular and clinical features.

A dedicated structured data set for reporting of invasive carcinoma of the breast in the setting of neoadjuvant therapy: recommendations from the International Collaboration on Cancer Reporting (ICCR)

AIMS

The International Collaboration on Cancer Reporting (ICCR), a global alliance of major (inter-)national pathology and cancer organisations, is an initiative aimed at providing a unified international approach to reporting cancer. ICCR recently published new data sets for the reporting of invasive breast carcinoma, surgically removed lymph nodes for breast tumours and ductal carcinoma in situ, variants of lobular carcinoma in situ and low-grade lesions. The data set in this paper addresses the neoadjuvant setting. The aim is to promote high-quality, standardised reporting of tumour response and residual disease after neoadjuvant treatment that can be used for subsequent management decisions for each patient.

METHODS

The ICCR convened expert panels of breast pathologists with a representative surgeon and oncologist to critically review and discuss current evidence. Feedback from the international public consultation was critical in the development of this data set.

RESULTS

The expert panel concluded that a dedicated data set was required for reporting of breast specimens post-neoadjuvant therapy with inclusion of data elements specific to the neoadjuvant setting as core or non-core elements. This data set proposes a practical approach for handling and reporting breast resection specimens following neoadjuvant therapy. The comments for each data element clarify terminology, discuss available evidence and highlight areas with limited evidence that need further study. This data set overlaps with, and should be used in conjunction with, the data sets for the reporting of invasive breast carcinoma and surgically removed lymph nodes from patients with breast tumours, as appropriate. Key issues specific to the neoadjuvant setting are included in this paper. The entire data set is freely available on the ICCR website.

CONCLUSIONS

High-quality, standardised reporting of tumour response and residual disease after neoadjuvant treatment are critical for subsequent management decisions for each patient.

Pathological response and tumor stroma immunogenic features predict long-term survival in non-small cell lung cancer after neoadjuvant chemotherapy

PURPOSE

Major pathological response (MPR) has become a surrogate endpoint for overall survival (OS) in non-small cell lung cancer (NSCLC) after neoadjuvant therapy, however, the prognostic histologic features and optimal N descriptor after neoadjuvant therapy are poorly defined.

METHODS

We retrospectively analyzed data from 368 NSCLC patients who underwent surgery after neoadjuvant chemotherapy (NAC) from January 2010 to December 2020. The percentage of residual viable tumors in the primary tumor, lymph nodes (LN), and inflammation components within the tumor stroma were comprehensively reviewed. The primary endpoint was OS.

RESULTS

Of the 368 enrolled patients, 12.0% (44/368) achieved MPR in the primary tumor, which was associated with significantly better OS (HR, 0.36 0.17-0.77, p = 0.008) and DFS (HR = 0.59, 0.36-0.92, p = 0.038). In patients who did not have an MPR, we identified an immune-activated phenotype in primary tumors, characterized by intense tumor-infiltrating lymphocyte or multinucleated giant cell infiltration, that was associated with similar OS and DFS as patients who had MPR. Neoadjuvant pathologic grade (NPG), consisting of MPR and immune-activated phenotype, identified 30.7% (113/368) patients that derived significant OS (HR 0.28, 0.17-0.46, p < 0.001) and DFS (HR 0.44, 0.31-0.61, p < 0.001) benefit from NAC. Moreover, the combination of NPG and the number of positive LN stations (nS) in the multivariate analysis had a higher C-index (0.711 vs. 0.663, p < 0.001) than the ypTNM Stage when examining OS.

CONCLUSION

NPG integrated with nS can provide a simple, practical, and robust approach that may allow for better stratification of patients when evaluating neoadjuvant chemotherapy in clinical practice.

Pragmatic guide to the macroscopic evaluation of breast specimens

The pathological assessment of a breast surgical specimen starts with macroscopic evaluation, arguably one of the most critical steps, as only a small percentage of the tissue is examined microscopically. To properly evaluate and select tissue sections from breast specimens, it is essential to correlate radiological findings, prior biopsies, procedures and treatment with the gross findings. Owing to its fatty nature, breast tissue requires special attention for proper fixation to ensure appropriate microscopic evaluation and performance of ancillary studies. In addition, knowledge of the information necessary for patient management will ensure that these data are collected during the macroscopic evaluation, and appropriate sections are taken to obtain the information needed from the microscopic evaluation. Herein, we present a review of the macroscopic evaluation of different breast specimen types, including processing requirements, challenges and recommendations.

Assessment of residual cancer burden and survival in neoadjuvant chemotherapy of inoperable stage III breast cancer: A ten-year follow-up analysis in Vietnam

BACKGROUND

Prognostic scores such as Residual Cancer Burden (RCB), Clinical Pathological Score (CPS), and Neo-Bioscore have been introduced to categorize breast cancer patients into different prognostic risk groups after neoadjuvant chemotherapy (NAC).

PURPOSE

To evaluate the prognostic value of the residual cancer burden index in a large group of Vietnamese breast cancer patients treated with neoadjuvant chemotherapy in real-world settings.

METHODS

126 patients diagnosed with stage III breast cancer received neoadjuvant chemotherapy according to the AP regimes. After operation of BC, pathologic complete response (pCR) and Residual cancer burden (RCB) were evaluated. All breast cancer patients' survival were analyzed by using Kaplan-Meier and Log-Rank models.

RESULTS

The average overall survival (OS) time was 75 months, with 90 (71.4%) recurrence and 82 (65%) mortality. The Kaplan Meier curve between OS and DFS with subgroups RCB indicate that the groups with higher RCB had a lower probability of survival, with statistical significance. Adjusted Cox regression model for age, menstruation, side of breast, clinical respose and overall stage illustrate that patients in RCB group 3 had a 2.7 times higher risk of mortality (95% CI: 1.28-5.67) compared to RCB group 0, p = 0.01. Patients with higher RCB levels had a higher risk of mortality.

CONCLUSION

Stage IIIC, RCB score and RCB group are the independent prognostic factors for predicting survival time of breast cancer patients receiving neoadjuvant treatment.

Pathologic Processing of Lung Cancer Resection Specimens After Neoadjuvant Therapy

Neoadjuvant treatment of non-small cell lung cancer challenges the traditional processing of pathology specimens. Induction therapy before resection allows evaluation of the efficacy of neoadjuvant agents at the time of surgery. Many clinical trials use pathologic tumor response, measured as major pathologic response (MPR, ≤10% residual viable tumor [RVT]) or complete pathologic response (CPR, 0% RVT) as a surrogate of clinical efficacy. Consequently, accurate pathologic evaluation of RVT is crucial. However, pathologic assessment has not been uniform, which is particularly true for sampling of the primary tumor, which instead of the traditional processing, requires different tissue submission because the focus has shifted from tumor typing alone to RVT scoring. Using a simulation study, we analyzed the accuracy rates of %RVT, MPR, and CPR of 31 pretreated primary lung tumors using traditional grossing compared with the gold standard of submitting the entire residual primary tumor and identified the minimum number of tumor sections to be submitted to ensure the most accurate scoring of %RVT, MPR, and CPR. Accurate %RVT, MPR, and CPR calls were achieved in 52%, 87%, and 81% of cases, respectively, using the traditional grossing method. Accuracy rates of at least 90% for these parameters require either submission of all residual primary tumor or at least 20 tumor sections. Accurate %RVT, MPR, and CPR scores cannot be achieved with traditional tumor grossing. Submission of the entire primary tumor, up to a maximum of 20 sections, is required for the most accurate reads.

Pathological response in mucinous carcinoma of breast after neoadjuvant therapy - a multi-institutional study

Although mucinous carcinoma (MC) is considered a favorable histologic subtype of invasive breast cancer (BC), a subset of MC is managed with neoadjuvant therapy (NAT). The clinical and pathologic features of MC following NAT are not well characterized. The aim of this study is to characterize pathologic response in patients with MC treated with NAT, including neoadjuvant endocrine therapy (NET), neoadjuvant chemotherapy (NCT), and Herceptin-targeted NCT (H-NCT). We conducted a retrospective cohort study of 28 patients with MC who received preoperative adjuvant therapy followed by resection from three institutions between 2010 and 2020. Demographic and clinical information were retrieved from the medical records. Pathologic review of the post NAT resection specimens was performed including tumor grading, tumor size, staging, residual tumor cellularity, estrogen receptor (ER) and HER2 status. Nine (32 %) patients with ER+/HER2- MC received NET, 8 (29 %) ER+/HER2- MC were treated with NCT only and 11 (39 %) HER2+ MC received HER2-targeted NCT (H-NCT). The HER2+ MC patients were younger (45 vs. 64 years; p = 0.006). The HER2+ MC were of higher grade (p = 0.03) and more likely to be multifocal (p = 0.008). Only 2 of 28 (7 %) MC (both HER2+) showed complete pathologic response with residual acellular mucin pools. Persistent mass-forming mucin pools were present in 26 (93 %) cases. The residual tumor cellularity was markedly reduced (≤5 %) in H-NCT treated MC (11/11, 100 %), followed by NET group (6/9, 67 %) and NCT only group (4/8, 50 %) (p = 0.011). Similarly, a higher rate of pathologic response (pCR/RCB-I) was observed in H-NCT (7/11, 64 %), followed by NET group (5/9, 56 %), and NCT only group (1/7, 13 %) (p = 0.053). Post-therapy, all HER2+ MC were smaller than 2 cm and ypT size was significantly smaller in H-NCT group (11/11, 100 %) versus combined NET (5/9, 55 %) and NCT only groups (4/8, 50 %) (p = 0.029). We conclude that ER-/HER2+ and ER+/HER2-mucinous carcinomas of the breast show robust pathological response to neoadjuvant HER2 targeted and endocrine therapy, respectively. Our findings suggest that MC may show good response to endocrine therapy.

Expression of Soluble Form of Aurora A as a Predictive Factor for Neoadjuvant Therapy in Breast Cancer Patients: A Single-Center Pilot Study

PURPOSE

To search for new predictive breast cancer biomarkers. We analyzed the serum concentrations of biomarkers involved in carcinogenesis, which can also be targeted by therapy.

METHODS

In a single-center prospective study, the serum levels of Aurora A, thymidine kinase 1, and human epidermal growth factor receptor type 3 (HER3) were determined in 119 women with BC before neoadjuvant treatment using ELISA kits.

RESULTS

The following clinical data were analyzed: age; TNM; the expression of ER, PGR, HER2, and Ki67; histological grade (G); and the response to neoadjuvant treatment (NAT) in the residual tumor burden classification (RCB). A complete pathological response (pCR) was achieved after NAT in 41 patients (34%). The highest proportion of the patients with a confirmed pCR was found for triple negative breast cancer (TNBC) (62.5%); non-luminal HER2-positive (52.6%) cancer subtypes (p = 0.0003); and in the G3 group (50%; p = 0.0078). The patients with higher levels of Aurora A were more likely to achieve pCR (p = 0.039). In the multivariate analysis, the serum Aurora A levels ≥ 4.75 ng/mL correlated with a higher rate of pCR (OR: 3.5; 95% CI: 1.2-10.1; p = 0.023).

CONCLUSIONS

We showed that in a biologically heterogeneous group of BC patients, the pretreatment serum Aurora A levels were of significant value in predicting the response to NAT.

Routine Use of a Standardized Mastectomy Diagram by Surgeons Improves Accuracy and Timeliness of the Final Pathological Report

BACKGROUND

Accurate and timely assessment of pathology specimens is critical for patient care and oncologic management. This study aimed to determine whether a standardized mastectomy diagram would facilitate communication among surgeons and pathologists and improve pathologic processing.

METHODS

A prospective quality improvement study was conducted over a continuous 12-month period. During the first 6 months, usual pathologic processing of mastectomy specimens was performed per standard department protocol. In the second 6 months, a standardized mastectomy diagram was completed at the time of surgery, noting the location and preoperative pathologic diagnosis of all benign and malignant lesions. An analysis of covariance was used to compare the number of breast lesions identified and the number of days between specimen receipt and the date of the final pathology report between each group.

RESULTS

Time from specimen receipt to final pathologic report decreased from a mean (± SE) of 8.3 ± 0.7 days in the usual processing group to 6.1 ± 0.6 days with the use of the standardized mastectomy diagram, for a between-group difference of 2.1 days (95% confidence interval [CI] 0.3-4.0; p = 0.02). The number of lesions identified increased from 1.8 ± 0.2 to 2.6 ± 0.2, for a between-group difference of 0.8 (95% CI 0.1-1.5; p = 0.02).

CONCLUSION

A standardized mastectomy diagram completed at the time of surgery improves the quality of pathologic processing. The diagram, which serves as a mastectomy lesion map, assists lesion localization, enhances accuracy, and reduces time to final pathology report.

International Association for the Study of Lung Cancer Study of Reproducibility in Assessment of Pathologic Response in Resected Lung Cancers After Neoadjuvant Therapy

INTRODUCTION

Pathologic response has been proposed as an early clinical trial end point of survival after neoadjuvant treatment in clinical trials of NSCLC. The International Association for the Study of Lung Cancer (IASLC) published recommendations for pathologic evaluation of resected lung cancers after neoadjuvant therapy. The aim of this study was to assess pathologic response interobserver reproducibility using IASLC criteria.

METHODS

An international panel of 11 pulmonary pathologists reviewed hematoxylin and eosin-stained slides from the lung tumors of resected NSCLC from 84 patients who received neoadjuvant immune checkpoint inhibitors in six clinical trials. Pathologic response was assessed for percent viable tumor, necrosis, and stroma. For each slide, tumor bed area was measured microscopically, and pre-embedded formulas calculated unweighted and weighted major pathologic response (MPR) averages to reflect variable tumor bed proportion.

RESULTS

Unanimous agreement among pathologists for MPR was observed in 68 patients (81%), and inter-rater agreement (IRA) was 0.84 (95% confidence interval [CI]: 0.76-0.92) and 0.86 (95% CI: 0.79-0.93) for unweighted and weighted averages, respectively. Overall, unweighted and weighted methods did not reveal significant differences in the classification of MPR. The highest concordance by both methods was observed for cases with more than 95% viable tumor (IRA = 0.98, 95% CI: 0.96-1) and 0% viable tumor (IRA = 0.94, 95% CI: 0.89-0.98). The most common reasons for discrepancies included interpretations of tumor bed, presence of prominent stromal inflammation, distinction between reactive and neoplastic pneumocytes, and assessment of invasive mucinous adenocarcinoma.

CONCLUSIONS

Our study revealed excellent reliability in cases with no residual viable tumor and good reliability for MPR with the IASLC recommended less than or equal to 10% cutoff for viable tumor after neoadjuvant therapy.

Clinical Utility of Pre-Therapeutic [18F]FDG PET/CT Imaging for Predicting Outcomes in Breast Cancer

BACKGROUND

[18F]FDG PET/CT is used for staging and could also provide information associated with clinical outcomes. The objective of this study was to determine the clinical utility of biomarkers measured using [18F]FDG PET/CT to predict the absence of pathological complete response (no-pCR) and recurrence.

METHODS

In this retrospective study, we included patients with non-special-type breast carcinoma who underwent [18F]FDG PET/CT before neoadjuvant chemotherapy between 2011 and 2019. Clinicopathological data were collected. Tumor SUVmax and total metabolic tumor volume (TMTV) were measured from PET images. The association between biomarkers and no-pCR was studied using logistic regression. The cut-off value was determined using the area under the ROC Curve. To predict 3-year recurrence-free survival (RFS), we used a multivariable Cox model, and the cut-off value was determined using time-dependent ROC and predictiveness curves.

RESULTS

Two hundred and eighty-six patients were included in the analysis. One hundred and twelve patients had a pCR (39.2%). The pCR rate was significantly higher in patients with a high nuclear grade (p < 0.01), HER2+ and TNBC subtypes (p < 0.01), high Ki67 (p < 0.01), and low TMTV (p < 0.01). A high TMTV value (>9.0 cm3) was significantly associated with no-pCR in the whole cohort (OR = 2.4, 95% CI: 1.3-4.2, p < 0.01). After a median follow-up of 4.5 years, 65 patients experienced recurrence and 39 patients died. High TMTV (>13.5 cm3) was associated with shorter RFS (HR = 4.0, 95% CI: 1.9-8.4, p < 0.01).

CONCLUSION

High TMTV in pre-therapeutic imaging is associated with no-pCR and recurrence. It can help in identifying high-risk patients and be considered as an intensified or alternative adjuvant therapy for closely monitoring patients.

Machine Learning-Based Prediction of Distant Recurrence in Invasive Breast Carcinoma Using Clinicopathological Data: A Cross-Institutional Study

Breast cancer is the most common type of cancer worldwide. Alarmingly, approximately 30% of breast cancer cases result in disease recurrence at distant organs after treatment. Distant recurrence is more common in some subtypes such as invasive breast carcinoma (IBC). While clinicians have utilized several clinicopathological measurements to predict distant recurrences in IBC, no studies have predicted distant recurrences by combining clinicopathological evaluations of IBC tumors pre- and post-therapy with machine learning (ML) models. The goal of our study was to determine whether classification-based ML techniques could predict distant recurrences in IBC patients using key clinicopathological measurements, including pathological staging of the tumor and surrounding lymph nodes assessed both pre- and post-neoadjuvant therapy, response to therapy via standard-of-care imaging, and binary status of adjuvant therapy administered to patients. We trained and tested four clinicopathological ML models using a dataset (144 and 17 patients for training and testing, respectively) from Duke University and validated the best-performing model using an external dataset (8 patients) from Dartmouth Hitchcock Medical Center. The random forest model performed better than the C-support vector classifier, multilayer perceptron, and logistic regression models, yielding AUC values of 1.0 in the testing set and 0.75 in the validation set (p < 0.002) across both institutions, thereby demonstrating the cross-institutional portability and validity of ML models in the field of clinical research in cancer. The top-ranking clinicopathological measurement impacting the prediction of distant recurrences in IBC were identified to be tumor response to neoadjuvant therapy as evaluated via SOC imaging and pathology, which included tumor as well as node staging.

Diffuse reflectance spectroscopy for accurate margin assessment in breast-conserving surgeries: importance of an optimal number of fibers

During breast-conserving surgeries, it remains challenging to accomplish adequate surgical margins. We investigated different numbers of fibers for fiber-optic diffuse reflectance spectroscopy to differentiate tumorous breast tissue from healthy tissue ex vivo up to 2 mm from the margin. Using a machine-learning classification model, the optimal performance was obtained using at least three emitting fibers (Matthew's correlation coefficient (MCC) of 0.73), which was significantly higher compared to the performance of using a single-emitting fiber (MCC of 0.48). The percentage of correctly classified tumor locations varied from 75% to 100% depending on the tumor percentage, the tumor-margin distance and the number of fibers.

High expression of MORC2 predicts worse neoadjuvant chemotherapy efficacy in triple negative breast cancer

Tumor infiltrating lymphocytes (TILs) are closely related to the patients' prognosis. Recently, Microrchidia 2 (MORC2) has been documented as a prognostic and predictive biomarker in triple negative breast cancer (TNBC). To compare whether MORC2 is a better predictor than TILs, as well as clinicopathological parameters, in predicting the efficacy of neoadjuvant chemotherapy (NAC) in TNBC, we detected the expression of MORC2 on neoplastic cells through immunohistochemistry and quantified the stromal TILs through Hematoxylin-eosin staining on core biopsies from 50 locally advanced TNBC patients who underwent standard NAC. Among all the 50 patients, 28 (56%) cases had residual tumors, while the other 22 (44%) achieved pathologic complete response (pCR). In these studied patients, age and T-stage showed no correlation with pCR rate, while percentage of TILs, nodal involvement and expression of MORC2 on tumor cells showed significant association with pCR rate. Positive nodal involvement was correlation with worse pathologic response at multivariate analysis (P = .0036), and high TILs levels (≥50%) was positively associated with better NAC efficacy at univariate analysis (P = .002). Whereas high expression of MORC2 was statistically associated with worse pCR rate both at univariate (P < .001) and multivariate (P = .036) analysis. Our results indicate that MORC2 expression has a better predictive role in predicting the efficacy of NAC than TILs in TNBC patients.

Compression OCT-elastography combined with speckle-contrast analysis as an approach to the morphological assessment of breast cancer tissue

Currently, optical biopsy technologies are being developed for rapid and label-free visualization of biological tissue with micrometer-level resolution. They can play an important role in breast-conserving surgery guidance, detection of residual cancer cells, and targeted histological analysis. For solving these problems, compression optical coherence elastography (C-OCE) demonstrated impressive results based on differences in the elasticity of different tissue constituents. However, sometimes straightforward C-OCE-based differentiation is insufficient because of the similar stiffness of certain tissue components. We present a new automated approach to the rapid morphological assessment of human breast cancer based on the combined usage of C-OCE and speckle-contrast (SC) analysis. Using the SC analysis of structural OCT images, the threshold value of the SC coefficient was established to enable the separation of areas of adipose cells from necrotic cancer cells, even if they are highly similar in elastic properties. Consequently, the boundaries of the tumor bed can be reliably identified. The joint analysis of structural and elastographic images enables automated morphological segmentation based on the characteristic ranges of stiffness (Young's modulus) and SC coefficient established for four morphological structures of breast-cancer samples from patients post neoadjuvant chemotherapy (residual cancer cells, cancer stroma, necrotic cancer cells, and mammary adipose cells). This enabled precise automated detection of residual cancer-cell zones within the tumor bed for grading cancer response to chemotherapy. The results of C-OCE/SC morphometry highly correlated with the histology-based results (r =0.96-0.98). The combined C-OCE/SC approach has the potential to be used intraoperatively for achieving clean resection margins in breast cancer surgery and for performing targeted histological analysis of samples, including the evaluation of the efficacy of cancer chemotherapy.

(Common) Data Elements in Radiation Oncology: A Systematic Literature Review

PURPOSE

Structured medical data documentation is highly relevant in a data-driven discipline such as radiation oncology. Defined (common) data elements (CDEs) can be used to record data in clinical trials, health records, or computer systems for improved standardization and data exchange. The International Society for Radiation Oncology Informatics initiated a project for a scientific literature analysis of defined data elements for structured documentation in radiation oncology.

METHODS

We performed a systematic literature review on both PubMed and Scopus to analyze publications relevant to the utilization of specified data elements for the documentation of radiation therapy (RT)-related information. Relevant publications were retrieved as full-text and searched for published data elements. Finally, the extracted data elements were quantitatively analyzed and classified.

RESULTS

We found a total of 452 publications, of which 46 were considered relevant for structured data documentation. Twenty-nine publications addressed defined RT-specific data elements, of which 12 publications provided data elements. Only two publications focused on data elements in radiation oncology. The 29 analyzed publications were heterogeneous regarding the subject and usage of the defined data elements, and different concepts/terms for defined data elements were used.

CONCLUSION

The literature about structured data documentation in radiation oncology using defined data elements is scarce. There is a need for a comprehensive list of RT-specific CDEs the radio-oncologic community can rely on. As it has been done in other medical fields, establishing such a list would be of great value for clinical practice and research as it would promote interoperability and standardization.

Luminal B, Human Epidermal Growth Factor Receptor 2 (HER2/neu), and Triple-Negative Breast Cancers Associated With a Better Chemotherapy Response Than Luminal A Breast Cancers in Postneoadjuvant Settings

Background Breast cancer is a heterogeneous disease with many histological and molecular/intrinsic breast cancer subtypes. Intrinsic breast cancer subtypes include luminal A, luminal B, human epidermal growth factor receptor 2 (HER2/neu), and triple-negative subtypes. The intrinsic breast cancer typing is based on the expression of estrogen receptor (ER), progesterone receptor (PR), HER2/neu, and Ki67-labeling index. One of these patients' foremost prognostic factors upon surgical resection is a response to neoadjuvant chemotherapy. The presence of a pathologically complete response (pCR) indicates a favorable patient outcome compared with a pathologically partial response (pPR). In this study, we compared the neoadjuvant chemotherapy response in breast cancer in different intrinsic breast cancer subtypes. Methodology It was a retrospective cross-sectional study conducted in the Department of Histopathology, Liaquat National Hospital, from January 2019 to December 2022, over three years. A total of 287 post-neoadjuvant chemotherapy cases of breast cancer were included. Anthracyclines and taxanes, coupled with or without anti-HER2/neu therapy, have been used in the neoadjuvant chemotherapy treatment setting contingent upon the patients' HER2/neu status. The post-chemotherapy response was assessed pathologically and categorized into pCR and pPR. Results The mean age of the patients was 47.90 ± 10.34 years, with a mean tumor size and Ki67 index of 5.36 ± 2.59 cm and 36.30 ± 22.14%, respectively. Invasive breast carcinoma of no special type (IBC-NST) made up 88.2% of cases, while grade 2 carcinomas made up 45.5%. The majority of tumors (42.7%) belonged to tumor (T) stage T2, and nodal metastasis was detected in 59.7% of patients. The intrinsic breast cancer subtypes luminal B (40.6%) and triple negative (33.3%) were the most prevalent, followed by luminal A (15.8%) and HER2/neu (10.3%). In 81 cases (24.5%), pCR was detected. The association of post-neoadjuvant chemotherapy response with intrinsic breast cancer subtypes showed a significant difference (P < 0.001). The highest frequency of pCR was noted in HER2/neu cancers (58.8%), followed by luminal B (25.4%) and triple negative (23.6%). Regarding age, T-stage, tumor grade, and histological type of carcinoma, there was no discernible difference between pCR and pPR. Conversely, a significant association was noted for the Ki67 index. A Ki67 index higher than 25% showed a significantly higher frequency of pCR. Conclusions In postchemotherapy specimens, the HER2/neu breast cancer subtype substantially displayed higher pCR, followed by luminal B and triple-negative subtypes. After identifying the patients' subtypes, intrinsic subtyping can help determine the prognosis and anticipated response to chemotherapy. Furthermore, prechemotherapy breast specimens with high Ki67 index values have shown a direct association with neoadjuvant chemotherapy response.

Early-Stage Triple-Negative Breast Cancer Journey: Beginning, End, and Everything in Between

Triple-negative breast cancer (TNBC) is a very heterogeneous and aggressive breast cancer subtype with a high risk of mortality, even if diagnosed early. The mainstay of early-stage breast cancer includes systemic chemotherapy and surgery, with or without radiation therapy. More recently, immunotherapy is approved to treat TNBC, but managing immune-rated adverse events while balancing efficacy is a challenge. The purpose of this review is to highlight the current treatment recommendations for early-stage TNBC and the management of immunotherapy toxicities.

Pathology of Immunotherapy-induced Responses in Cutaneous Melanoma: Current Evidences and Future Perspectives

Over the last years, immune checkpoint inhibitors (ICIs) have demonstrated remarkable anti-tumor activity and beneficial effects in patients with early and advanced melanoma. However, ICIs provide clinical benefit only in a minority of patients due to primary and/or acquired resistance mechanisms. Immunotherapy resistance is a complex phenomenon relying on genetic and epigenetic factors, which ultimately influence the interplay between cancer cells and the tumor microenvironment. Information is accumulating on the cellular and molecular mechanisms underlying the production of resistance and the resulting diminished therapeutic efficacy. In addition, current knowledge on predictors of response and toxicity to immunotherapy and on biomarkers that reliably identify resistant patients is in progress. In this review, we will focus on the tumor microenvironment changes induced by ICIs in melanoma, summarizing the available evidence of clinical trials in the neoadjuvant and metastatic setting. We will also overview the role of potential biomarkers in predicting disease response to ICIs, providing insight into current and future research in this field.

Contrast-enhanced mammography in the assessment of residual disease after neoadjuvant treatment

PURPOSE

To investigate the utility of contrast-enhanced mammography (CEM) as an alternative to breast MRI for the evaluation of residual disease after neoadjuvant treatment (NAT).

METHODS

This prospective study enrolled consecutive women undergoing NAT for breast cancer from July 2017-July 2019. Breast MRI and CEM exams performed after completion of NAT were read independently by two breast radiologists. Residual disease and lesion size on MRI and CEM recombined (RI) and low-energy images (LEI) were compared. Histopathology was considered the reference standard. Statistical analysis was performed using McNemar's and Leisenring's tests. Multiple comparison adjustment was made using Bonferroni procedure. Lesion sizes were correlated using Kendall's tau coefficient.

RESULTS

There were 110 participants with 115 breast cancers. Residual disease (invasive cancer or ductal carcinoma in situ) was detected in 83/115 (72%) lesions on pathology, 71/115 (62%) on MRI, 55/115 (48%) on CEM RI, and 75/115 (65%) on CEM LEI. When using multiple comparison adjustment, no significant differences were detected between MRI combined with CEM LEI and CEM RI combined with CEM LEI, in terms of accuracy (MRI: 77%, CEM: 72%; p ≥ 0.99), sensitivity (MRI: 88%, CEM: 81%; p ≥ 0.99), specificity (MRI: 47%, CEM: 50%; p ≥ 0.99), PPV (MRI: 81%, CEM: 81%; p ≥ 0.99), or NPV (MRI: 60%, CEM: 50%; p ≥ 0.99). Size correlation between pathology and both MRI combined with CEM LEI and CEM RI combined with CEM LEI was moderate: τ = 0. 36 vs 0.33 (p ≥ 0.99).

CONCLUSION

Contrast-enhanced mammography is an acceptable alternative to breast MRI for the detection of residual disease after neoadjuvant treatment.

High Dynamic Range Dual-Modal White Light Imaging Improves the Accuracy of Tumor Bed Sampling After Neoadjuvant Therapy for Breast Cancer

OBJECTIVES

Accurate evaluation of residual cancer burden remains challenging because of the lack of appropriate techniques for tumor bed sampling. This study evaluated the application of a white light imaging system to help pathologists differentiate the components and location of tumor bed in specimens.

METHODS

The high dynamic range dual-mode white light imaging (HDR-DWI) system was developed to capture antiglare reflection and multiexposure HDR transmission images. It was tested in 60 specimens of modified radical mastectomy after neoadjuvant therapy. We observed the differential transmittance among tumor tissue, fibrosis tissue, and adipose tissue.

RESULTS

The sensitivity and specificity of HDR-DWI were compared with x-ray or visual examination to determine whether HDR-DWI was superior in identifying tumor beds. We found that tumor tissue had lower transmittance (0.12 ± 0.03) than fibers (0.15 ± 0.04) and fats (0.27 ± 0.07) (P < .01).

CONCLUSIONS

HDR-DWI was more sensitive in identifying fiber and tumor tissues than cabinet x-ray and visual observation (P < .01). In addition, HDR-DWI could identify more fibrosis areas than the currently used whole slide imaging did in 12 samples (12/60). We have determined that HDR-DWI can provide more in-depth tumor bed information than x-ray and visual examination do, which will help prevent diagnostic errors in tumor bed sampling.

Protective anti-tumor vaccination against glioblastoma expressing the MHC class II transactivator CIITA

Glioblastoma is the most malignant tumor of the central nervous system. Current treatments based on surgery, chemotherapy, and radiotherapy, and more recently on selected immunological approaches, unfortunately produce dismal outcomes, and less than 2% of patients survive after 5 years. Thus, there is an urgent need for new therapeutic strategies. Here, we report unprecedented positive results in terms of protection from glioblastoma growth in an animal experimental system after vaccination with glioblastoma GL261 cells stably expressing the MHC class II transactivator CIITA. Mice injected with GL261-CIITA express de novo MHC class II molecules and reject or strongly retard tumor growth as a consequence of rapid infiltration with CD4+ and CD8+ T cells. Importantly, mice vaccinated with GL261-CIITA cells by injection in the right brain hemisphere strongly reject parental GL261 tumors injected in the opposite brain hemisphere, indicating not only the acquisition of anti-tumor immune memory but also the capacity of immune T cells to migrate within the brain, overcoming the blood–brain barrier. GL261-CIITA cells are a potent anti-glioblastoma vaccine, stimulating a protective adaptive anti-tumor immune response in vivo as a consequence of CIITA-driven MHC class II expression and consequent acquisition of surrogate antigen-presenting function toward tumor-specific CD4+ Th cells. This unprecedented approach for glioblastoma demonstrates the feasibility of novel immunotherapeutic strategies for potential application in the clinical setting.