Real-World Outcomes Among Older Mexican Women with Breast Cancer Treated with Neoadjuvant Chemotherapy.

ABSTRACT

BACKGROUND: Older patients with breast cancer treated in high-income countries often present with early-stage disease, leading to a lack of information on the use of neoadjuvant chemotherapy in this population. We analyzed the real-world outcomes of older women with breast cancer treated with neoadjuvant chemotherapy at a single institution in Mexico. MATERIALS AND METHODS: The study included 2,216 patients treated with neoadjuvant chemotherapy. Regarding achievement of pathologic complete response (defined as no invasive residual tumor in the breast and lymph nodes), 243 patients aged ≥65 years were compared with 1,973 patients aged <65 years. Disease-free survival and overall survival were compared between groups according to pathologic complete response and subtype, defined by hormone receptor and human epidermal growth receptor 2 (HER2) status. RESULTS: Older women were less likely to have a pathologic complete response than their younger counterparts (26.3 vs. 35.3%, p < .001). When response rates by subtype were analyzed, this difference was significant only for women with triple-negative tumors. Achieving less than a pathologic complete response was associated with a greater chance of recurrence, but age was not an independent factor for recurrence for any subtype. Reaching a pathologic complete response was significantly associated with improved survival among older women with breast cancer, with the exception of those with hormone receptor-positive, HER2- disease. CONCLUSION: Although older women have fewer pathological complete responses, their outcomes after neoadjuvant chemotherapy are comparable to those of younger patients. This is particularly relevant for the treatment of older adults with breast cancer in developing countries, who present in advanced stages and more often need neoadjuvant therapy. IMPLICATIONS FOR PRACTICE The majority of older patients with breast cancer in high-income countries present with early-stage disease, leading to a lack of information regarding the use of neoadjuvant chemotherapy in real-world settings. This article reports the outcomes of older Mexican women with breast cancer who received neoadjuvant chemotherapy compared with their younger counterparts. Although older women (particularly those with triple-negative tumors) were less likely to have a pathologic complete response after neoadjuvant treatment, age was not an independent factor for recurrence. Achieving a pathologic complete response was associated with improved survival, regardless of age.