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.

Significance of Pathologic Response in Patients With Early and Locally Advanced Breast Cancer Treated With Neoadjuvant Chemotherapy in a Middle-Income Country. A Real-World Historical Cohort

“…The global ypCR rate in our study was higher compared with rates in other regions (ypCR, 9%-21%), 19,20 but comparable with those described in other Latin American studies. 12 The key distinction between global data and ours is that our population is enriched for HER2 and TNBC, two subgroups that usually have higher ypCR rates. This may also explain why our ypCR data are comparable with the findings by Cabrera Galeana et al 12 There are two Colombian NACT cohorts.…”

“…12 The key distinction between global data and ours is that our population is enriched for HER2 and TNBC, two subgroups that usually have higher ypCR rates. This may also explain why our ypCR data are comparable with the findings by Cabrera Galeana et al 12 There are two Colombian NACT cohorts. Diaz Casas et al 21 described a similar population to our study, but a lower rate of ypCR (14%).…”

“…In our cohort, we observed a higher proportion of TNBC compared with North America, 7,16,17 but similar to other findings in Latin America. 12-14,18 There is no clear explanation for this observation. However, important risk factors such as overweight and obesity are more prevalent among the Hispanic population, which was also observed in our study.…”

“…In comparison with historical NACT trials, 9 we observed an increased number of locally advanced BCs, which aligns with findings from other Latin American trials. [12][13][14] This observation could be attributed to delays in access to medical care. Piñeros et al 15 In our cohort, we observed a higher proportion of TNBC compared with North America, 7,16,17 but similar to other findings in Latin America.…”

“…In comparison with historical NACT trials, 9 we observed an increased number of locally advanced BCs, which aligns with findings from other Latin American trials. 12-14 This observation could be attributed to delays in access to medical care. Piñeros et al 15 described that 81.3% of patients with BC in Colombia had symptoms at diagnosis, with 20.3% of patients seeking medical attention more than 3 months after symptom onset.…”