Risk for dose-limiting chemotherapy-induced peripheral neuropathy in black women with breast cancer.

Abstract

6560 Background: Chemotherapy induced peripheral neuropathy (CIPN) is a potentially dose-limiting toxicity. Recent data from early stage breast cancer clinical trials has suggested that black women are at increased risk for CIPN. We examined whether black race was a risk factor for dose-limiting CIPN events in a general academic practice. Methods: This retrospective cohort study included 260 women, (27.3% black) that received neoadjuvant or adjuvant paclitaxel for non-metastatic breast cancer. The primary outcome was a dose-limiting (DL) event (dose delay, dose reduction, or treatment discontinuation) attributed to CIPN (DL-CIPN). Cox proportional hazards models were used to analyze patient level and treatment level factors related to DL-CIPN. Survival time was represented by cumulative dose in milligrams of paclitaxel received. The final model included independent risk factors (p<0.05) of DL-CIPN and confounders that when adjusted for altered the crude estimate by 10% or more. Results: There were 39 DL-CIPN events; 5 were excluded from analyses for being a subsequent event. For the 34 DL-CIPN events, the median cumulative dose received at time of DL-CIPN event was 925 mg (range=256-1520 mg), which differed significantly (p<0.001) from the 188 women who had no dose-limiting event of any cause (median=1272, range=928-2136 mg). Black race was the only statistically significant independent risk factor for DL-CIPN. Compared to whites, black women had a greater than two-fold increased risk of DL-CIPN (HR=2.29, 95%CI=1.17-4.50). After adjusting for oncologist, menopausal status, obesity (BMI≥30), and regimen (80mg/m2 weekly for 12 cycles vs. 175mg/m2 bi-weekly for 4 cycles) the risk of DL-CIPN for blacks compared to whites was HR=3.35 (95%CI=1.54-7.28). Conclusions: Our findings contribute to the growing body of evidence that black race is associated with CIPN symptom onset and severity. Efforts to elucidate mechanisms, increase clinicians’ awareness of the greater susceptibility of black women to CIPN, and the development of symptom management strategies, effective in ensuring adequate adherence to chemotherapy, are crucial.