Abstract P4-13-01: Racial Disparities in the Incidence of Dose-limiting Chemotherapy Induced Peripheral Neuropathy

Abstract

Objective: To determine the incidence of and risk factors for dose-limiting chemotherapy induced peripheral neuropathy (CIPN) in non-metastatic breast cancer. Methods: This retrospective cohort study included 488 women with an adjuvant or neoadjuvant treatment plan with docetaxel or paclitaxel from June 1, 2009 to December 31, 2011. Exclusion criteria were: metastatic disease, previous neurotoxic chemotherapy, pre-existing neuropathy, pregnant or within 3 months post-partum, and prosthetic limb. The primary outcome was dose-limiting CIPN, defined as a treatment modification event (dose delay, dose reduction, or treatment discontinuation) attributed to CIPN. The primary risk factor of interest was obesity (BMI≥30). Covariates included race, age, menopausal status, diabetes, and other comorbidities, node status, tumor size, regimen, and oncologist. With 80% power and 0.05 type I error rate, the study could detect a risk ratio of 1.8 in the obese versus non-obese. Results: Fifty (10.2%) women had a treatment modification event attributed to CIPN (TM-CIPN). TM-CIPN incidence differed significantly by agent (docetaxel = 2.4% (N = 5/209), paclitaxel=16.1% (N = 45/279); p < 0.001). In analyses restricted to patients treated with paclitaxel with complete covariate data (N = 273), the odds of TM-CIPN did not differ by obesity, OR = 1.17 (95% CI 0.59–2.35). After adjusting for black race, menopausal status, disease severity, and type II diabetes the TM-CIPN and obesity association was attenuated. The attenuation occurred after adjustment for black race, which was a confounder of the obesity and TM-CIPN relationship, and associated with obesity (OR = 3.78, p = <0.001). Post-menopausal status, disease severity, and type II diabetes were associated with obesity, but were not confounders. Compared to whites, and after controlling for disease severity, menopausal status, and oncologist, blacks and other non-whites had significantly increased odds of CIPN-TM (OR = 2.5, p < 0.02; OR = 4.8, p < 0.01; respectively). Tests of homogeneity indicated the race and TM-CIPN association was not modified by oncologist or disease severity. Conclusion: Obese and non-obese women have a comparable likelihood of having their treatment modified due to CIPN. Women of racial minorities had over 2-to 4-fold increased odds of TM-CIPN compared to white women. Investigations addressing the mechanistic explanations for this association are warranted. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P4-13-01.

Impact of Obesity on Cancer Survivorship and the Potential Relevance of Race and Ethnicity

“…Peripheral Neuropathy and Cardiotoxicity. Two studies observed statistically significantly higher incidence of peripheral neuropathy among black cancer patients as compared with non-Hispanic white breast cancer patients treated with taxanes (98,137). By comparison, one other study did not (97).…”

“…Very little information is available regarding the potential relationship between obesity and peripheral neuropathy. In breast cancer, two studies observed no association between obesity and chemotherapy-induced peripheral neuropathy after taxane administration (97,98). Further, a study among multiple myeloma patients found that obesity did not increase the risk of peripheral neuropathy (99).…”