Chemotherapy-induced peripheral neuropathy events resulted in limiting the dosing of chemotherapy in a significant proportion of women with nonmetastatic breast cancer being treated with paclitaxel, and those who had their dose reduced or discontinued received significantly less cumulative drug, according to a retrospective cohort study.
Reported in the Journal of Oncology Practice, the study reviewed electronic medical records for 488 women with nonmetastatic breast cancer who received docetaxel or paclitaxel at a single center. A total of 56 dose-limiting events (dose delay, dose reduction, or treatment discontinuation) attributed to chemotherapy-induced peripheral neuropathy occurred in 50 women (10.2%) and “accounted for more than one third (37.3%) of all the [dose-limiting] decisions oncologists made in this clinical practice population during nonmetastatic paclitaxel or docetaxel chemotherapy,” the researchers stated.
The incidence of dose-limiting chemotherapy-induced peripheral neuropathy “differed significantly by agent,” the investigators reported, occurring in 16.1% of patients receiving paclitaxel vs 2.4% of those receiving docetaxel (P < .001), “and occurred most frequently in the paclitaxel regimen of 80 mg/m2 weekly for 12 cycles (24.5%).” Dose-limiting neuropathy occurred in 14.4% of women receiving the paclitaxel regimen of 175 mg/m2 biweekly for four cycles.
Lower Cumulative Dose
“On average, women who had their paclitaxel dose reduced because of [chemotherapy-induced peripheral neuropathy] (n = 9) received 9.4% less chemotherapy than what they would have received cumulatively according to their planned dose and regimen. The cumulative dose these individuals actually received differed significantly from the cumulative dose they would have received [1,065 mg/m2 vs 1,174.7 mg/m2; P < .001],” the researchers reported.
“Similarly, among women who had their treatment discontinued (n = 26), the cumulative dose actually received was significantly lower than their planned cumulative dose [968 mg/m2 vs 1,355.5 mg/m2; P < .001]. On average these women received 28.4% less cumulative chemotherapy, and the percent difference did not differ by regimen,” the authors added.
“Treatment modification events such as dose delays, dose reductions, and treatment discontinuation are clinically relevant and thus avoided in practice whenever possible. Therefore, it is somewhat surprising that of women who had a [dose-limiting chemotherapy-induced peripheral neuropathy] event, more than half (26 of 50) had their treatment discontinued,” the investigators noted. “Interestingly, only two of those 26 women had had a prior dose delay or dose reduction before the discontinuation. Factors leading to this decision by oncologists and patients are likely to be complex and multifactorial. Whether delaying or reducing the dose earlier in the course of treatment may have prevented the discontinuation of therapy … is unknown; this area would benefit from further study.” ■
Speck RM, et al: J Oncol Pract. May 14, 2013 (early release online).