Is the whole larger than the sum of the parts? Integrated PET/MRI as a tool for response prediction

3T DCE-MRI Radiomics Improves Predictive Models of Complete Response to Neoadjuvant Chemotherapy in Breast Cancer

OBJECTIVES

To test whether 3T MRI radiomics of breast malignant lesions improves the performance of predictive models of complete response to neoadjuvant chemotherapy when added to other clinical, histological and radiological information.

METHODS

Women who consecutively had pre-neoadjuvant chemotherapy (NAC) 3T DCE-MRI between January 2016 and October 2019 were retrospectively included in the study. 18F-FDG PET-CT and histological information obtained through lesion biopsy were also available. All patients underwent surgery and specimens were analyzed. Subjects were divided between complete responders (Pinder class 1i or 1ii) and non-complete responders to NAC. Geometric, first order or textural (higher order) radiomic features were extracted from pre-NAC MRI and feature reduction was performed. Five radiomic features were added to other available information to build predictive models of complete response to NAC using three different classifiers (logistic regression, support vector machines regression and random forest) and exploring the whole set of possible feature selections.

RESULTS

The study population consisted of 20 complete responders and 40 non-complete responders. Models including MRI radiomic features consistently showed better performance compared to combinations of other clinical, histological and radiological information. The AUC (ROC analysis) of predictors that did not include radiomic features reached up to 0.89, while all three classifiers gave AUC higher than 0.90 with the inclusion of radiomic information (range: 0.91-0.98).

CONCLUSIONS

Radiomic features extracted from 3T DCE-MRI consistently improved predictive models of complete response to neo-adjuvant chemotherapy. However, further investigation is necessary before this information can be used for clinical decision making.

Conversion of immunohistochemical markers and breast density are associated with pathological response and prognosis in very young breast cancer patients who fail to achieve a pathological complete response after neoadjuvant chemotherapy

Purpose

Patients younger than age 35 that fail to achieve a pathologic complete response (pCR) after Neoadjuvant chemotherapy (NACT) tend to have worse long term outcomes. The purpose of our study was to assess the correlation between the conversion of immunohistochemical (IHC) markers and breast density and investigate their association with pathological response and prognosis.

Methods

We included 119 patients younger than age 35 who failed to achieve a pCR after NACT in this analysis. We evaluated the clinical and pathological response to NACT by the Union for International Cancer control (UICC) and the Miller-Payne grading (MPG) systems, respectively. A breast density assessment was applied via mammography examination at the time of diagnosis. MPG and breast density (BD) have been combined to define a specific classification of three risk levels to evaluate the prognosis of these patients.

Results

The diameter changes of the tumors and lymph nodes were negatively associated with hormone receptor conversion and positively correlated with Ki67 conversion. A significantly large size change was observed in the groups demonstrating conversion from HER-2 (+) to (−). The variation level of IHC markers was related to MPG and BD and was associated with the survival rate of the patients. Patients with a high breast density and low Miller-Payne grading after NACT had a higher risk of distant metastases or local recurrences.

Conclusion

ER, PR and Ki67 conversion are closely related to MPG, while PR and Ki67 conversion are closely related to BD. While ER and PR conversion are independent and significant predictors of disease free survival (DFS) and overall survival (OS), HER-2 and Ki67 conversion are only significant for DFS. This risk factor grouping provides a useful index to evaluate the risk of young women with breast cancer who fail to achieve a pCR.

Response to immunohistochemical markers' conversion after neoadjuvant chemotherapy in breast cancer patients: association between imaging and histopathologic analysis

BACKGROUND

Breast ultrasound and mammography were used in the detection of residual tumor after neoadjuvant chemotherapy. The aim of this study was to evaluate the correlation between clinical and pathological responses with breast density and IHC marker conversion to understand how this information might be used in the future to direct treatment.

METHODS

We included 119 patients who underwent CNB and followed NACT. The breast density assessment was based on the mammography examination performed at the time of diagnosis. We evaluated the clinical and pathological responses to NACT by the UICC and Miller-Payne grading systems, respectively.

RESULTS

Of 119 patients who met the inclusion criteria, patients with high pre-treatment IHC markers levels showed higher expression of IHC markers regardless of the post-treatment IHC marker level at baseline. However, breast and node tumor sizes before and after NACT were negatively correlated with hormone receptor conversion and positively correlated with Ki-67 conversion (P < 0.05). Patients with low BD were more likely to have a cCR, pCR, TNBC, and postmenopausal status than those with a high BD (P < 0.05). BD was significantly associated with PR and Ki67 conversion but not ER conversion.

CONCLUSION

Our prospective observational study demonstrated that IHC marker conversion could be used to identify lesion size changes and BD. We also found that a high BD was linked to clinical and pathological responses, molecular subtype, and menopausal status. In the future, additional studies are required to validate the predictive value identified by this research.