Questions about lower inner zone tumors in early-stage breast cancer

摘要

I want to congratulate Yang and colleagues [1] for their investigation of the prognostic significance of tumor location of the lower inner zone (LIZ) on the survival of patients with early-stage breast cancer. They reported that tumors in LIZ resulted in a significantly worse prognosis for DFS in patients with HER-2-negative, high ki-67 expression breast cancers, those who received neoadjuvant chemotherapy, axillary nodal negative patients, and patients with lymphovascular invasion. I want to make two comments on this study. First of all, the authors stated that among 838 breast cancer patients, the percentage of HER2-positive patients was reported to be 15.1%. However, they noted that the frequency of HER2-enriched molecular subtype was 7.4%. The authors did not mention whether hormone receptor and HER2-positive patients were assigned as luminal B molecular subtype that may affect the survival outcome of molecular subtype tumors located in LIZ. Secondly, the authors hypothesized that tumors in LIZ were more likely to harbor disease in the internal mammary lymph nodes, partly explaining worse DFS outcomes. Although it is not commonly recommended for staging, radiological imaging including computed tomography or positron-emission tomography may show internal mammary lymph node involvement in early-stage breast cancer patients. Therefore, I wonder about the rate of internal mammary lymph node involvement in LIZ and non-LIZ tumors, if these patients had undergone this type of imaging analysis in the current study.