Impact of Chemotherapy-Induced Peripheral Neuropathy on Treatment Delivery in Nonmetastatic Breast Cancer

Purpose: To determine the incidence of dose-limiting (DL) chemotherapy-induced peripheral neuropathy (CIPN) events in clinical practice. Patients and Methods: This retrospective cohort study included 488 women who received docetaxel or paclitaxel. The primary outcome was a DL event (dose delay, dose reduction, or treatment discontinuation) attributed to CIPN (DL CIPN). The paired t test was used to test the difference in received cumulative dose and planned cumulative dose by dose reduction and treatment discontinuation status. Results: A total of 150 unique DL events occurred in 120 women (24.6%). More than one third (37.3%; n = 56) of the events were attributed to CIPN. The 56 DL CIPN events occurred in 50 women (10.2%). DL CIPN incidence differed significantly by agent (docetaxel, 2.4%; n = five of 209; paclitaxel, 16.1%; n = 45 of 279; P < .001). DL CIPN occurred in 24.5% and 14.4% of women who received paclitaxel 80 mg/m(2) weekly for 12 cycles and 175 mg/m(2) biweekly for four cycles, respectively (adjusted odds ratio, 2.11; 95% CI, 0.97 to 4.60; P = .06). The cumulative dose actually received was significantly lower than the planned cumulative dose among women who had a dose reduction or treatment termination attributed to CIPN (9.4% less; P < .001 and 28.4% less; P < .001, respectively). Conclusion: Oncologists limited the dosing of chemotherapy because of CIPN in a significant proportion of paclitaxel recipients, most frequently in those who received a weekly regimen. Patients who had their dose reduced or discontinued received significantly less cumulative chemotherapy than planned. The implications of these DL CIPN events on treatment outcomes must be investigated.