Abstract
PurposeSeveral methods are used to assess the pathologic response of breast cancer after neoadjuvant chemotherapy (NAC) to predict clinical outcome. However, the clinical utility of these systems for each molecular subtype of breast cancer is unclear. Therefore, we applied six pathologic response assessment systems to specific subtypes of breast cancer and compared the results.Patients and MethodsFive hundred and eighty eight breast cancer patients treated with anthracycline with/without taxane-based NAC were retrospectively analyzed, and the ypTNM stage, residual cancer burden (RCB), residual disease in breast and nodes (RDBN), tumor response ratio, Sataloff’s classification, and Miller—Payne grading system were evaluated. The results obtained for each assessment system were analyzed in terms of patient survival.ResultsIn triple-negative tumors, all systems were significantly associated with disease-free survival and Kaplan-Meier survival curves for disease-free survival were clearly separated by all assessment methods. For HR+/HER2- tumors, systems assessing the residual tumor (ypTNM stage, RCB, and RDBN) had prognostic significance. However, for HER2+ tumors, the association between patient survival and the pathologic response assessment results varied according to the system used, and none resulted in distinct Kaplan—Meier curves.ConclusionMost of the currently available pathologic assessment systems used after anthracycline with/without taxane-based NAC effectively classified triple-negative breast cancers into groups showing different prognoses. The pathologic assessment systems evaluating residual tumors only also had prognostic significance in HR+/HER2- tumors. However, new assessment methods are required to effectively evaluate the pathologic response of HR+/HER2+ and HR-/HER2+ tumors to anthracycline with/without taxane-based NAC.
Highlights
Neoadjuvant chemotherapy (NAC) is often used to treat three categories of patient: those with locally advanced breast cancer; those with operable breast cancer who are not candidates for breast-conserving surgery; and those with proven lymph node metastases [1, 2]
Five hundred and eighty eight breast cancer patients treated with anthracycline with/without taxane-based NAC were retrospectively analyzed, and the ypTNM stage, residual cancer burden (RCB), residual disease in breast and nodes (RDBN), tumor response ratio, Sataloff’s classification, and Miller—Payne grading system were evaluated
For HER2+ tumors, the association between patient survival and the pathologic response assessment results varied according to the system used, and none resulted in distinct Kaplan—Meier curves
Summary
Neoadjuvant chemotherapy (NAC) is often used to treat three categories of patient: those with locally advanced breast cancer; those with operable breast cancer who are not candidates for breast-conserving surgery; and those with proven lymph node metastases [1, 2]. Several pathologic response evaluation systems for residual cancer have been proposed These evaluation systems can be roughly divided into two categories: absolute assessment of the residual tumor and relative assessment of the treatment response (comparing the cellularity or tumor size of post-NAC specimens with those of pre-NAC specimens or images)[9,10,11,12,13,14]. Parameters such as ypTNM stage, residual disease in breast and nodes (RDBN), and residual cancer burden (RCB) evaluate only residual tumor in the breast parenchyma and lymph nodes [6, 13, 15]. Recent studies compared several of these classification systems and found that they yielded different predictive values.[16, 17] no standardized and/or superior pathologic response evaluation system exists at the present time
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