Low Vit D Linked to Paclitaxel-Induced Peripheral Neuropathy

TOPLINE:

Patients with breast cancer who have low levels of vitamin D when they begin treatment with paclitaxel are more likely to develop peripheral neuropathy, suggesting that correcting levels before treatment might help prevent the condition.

METHODOLOGY:

• Past studies have suggested an association between vitamin D insufficiency and paclitaxel-induced peripheral neuropathy, a largely untreatable and sometimes permanent side effect of chemotherapy.

• To confirm the association, investigators reviewed data and samples from 1191 women in the phase 3 SWOG S0221 trial, which compared weekly and biweekly paclitaxel regimens for early-stage breast cancer.

• Using serum samples collected at baseline, the team evaluated the relationship between insufficient vitamin D levels (20 ng/mL or less) before treatment and grade 3 or higher sensory chemotherapy-induced peripheral neuropathy.

TAKEAWAY:

• Overall, 33.3% of the women had insufficient vitamin D levels at baseline, and 16.4% developed grade 3 or worse sensory chemotherapy-induced peripheral neuropathy.

• The incidence of peripheral neuropathy of grade 3 or greater was higher among patients with pretreatment vitamin D insufficiency (20.7% vs 14.2%; odds ratio [OR], 1.57; P = .005).

• The association grew stronger after adjusting for age and paclitaxel schedule (adjusted OR, 1.65; P = .003), but not after adjusting for race (adjusted OR, 1.39; P = .066).

IN PRACTICE:

• The study “confirms that patients with pretreatment vitamin D insufficiency have a higher incidence of [chemotherapy-induced peripheral neuropathy],” the authors concluded. These results also “suggest that vitamin D supplementation in patients with lower levels of vitamin D may reduce peripheral neuropathy, and particularly high-grade peripheral neuropathy, which would improve these patients’ long-term quality of life,” senior researcher Daniel L. Hertz, PharmD, PhD, University of Michigan College of Pharmacy, Ann Arbor, said in a press release.

SOURCE:

The study, led by Ciao-Sin Chen, PharmD, of the University of Michigan College of Pharmacy, Ann Arbor, was published November 7 in the Journal of the National Comprehensive Cancer Network.

LIMITATIONS:

The trial did not collect data on other peripheral neuropathy risk factors, including preexisting peripheral neuropathy and diabetes. The study included a limited number of non-White participants (16%); larger numbers are needed to elucidate a potential interplay between race, vitamin D, and chemotherapy-induced peripheral neuropathy. The researchers also did not collect data on grade 1 and 2 chemotherapy-induced peripheral neuropathy.

DISCLOSURES:

The study was funded by Amgen, the American Cancer Society, and others. The investigators disclosed no relevant financial relationships.

M. Alexander Otto is a physician assistant with a master’s degree in medical science and a journalism degree from Newhouse. He is an award-winning medical journalist who worked for several major news outlets before joining Medscape. Alex is also an MIT Knight Science Journalism fellow. Email: [email protected]