Taxane‐based chemotherapy regimens are used as first‐line treatment for breast cancer. Neurotoxicity, mainly taxane‐induced peripheral neuropathy (TIPN), remains the most important dose‐limiting adverse event. Multiple genes may be associated with TIPN; however, the strength and direction of the association remain unclear. For this reason, we systematically reviewed observational studies of TIPN pharmacogenetic markers in breast cancer treatment. We conducted a systematic search of terms alluding to breast cancer, genetic markers, taxanes, and neurotoxicity in Ovid, ProQuest, PubMed, Scopus, Virtual Health, and Web of Science. We assessed the quality of evidence and bias profile. We extracted relevant variables and effect measures. Whenever possible, we performed random‐effects gene meta‐analyses and examined interstudy heterogeneity with meta‐regression models and subgroup analyses. This study follows the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA) and STrengthening the REporting of Genetic Association Studies (STREGA) reporting guidance. A total of 42 studies with 19,431 participants were included. These evaluated 262 single‐nucleotide polymorphisms (SNPs) across 121 genes. We conducted meta‐analyses on 23 genes with 60 SNPs (19 studies and 6246 participants). Thirteen individual SNPs (ABCB1‐rs2032582, ABCB1‐rs3213619, BCL6/‐rs1903216, /CAND1‐rs17781082, CYP1B1‐rs1056836, CYP2C8‐rs10509681, CYP2C8‐rs11572080, EPHA5‐rs7349683, EPHA6‐rs301927, FZD3‐rs7001034, GSTP1‐rs1138272, TUBB2A‐rs9501929, and XKR4‐rs4737264) and the overall SNPs' effect in four genes (CYP3A4, EphA5, GSTP1, and SLCO1B1) were statistically significantly associated with TIPN through meta‐analysis. In conclusion, through systematic review and meta‐analysis, we found that polymorphisms, and particularly 13 SNPs, are associated with TIPN, suggesting that genetics does play a role in interindividual predisposition. Further studies could potentially use these findings to develop individual risk profiles and guide decision making.

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.