Study Examines Factors That Contribute to Peripheral Neuropathy

Certain patients may be more likely to develop chemotherapy-induced peripheral neuropathy (CIPN), according to a recent study presented at the 2016 American Society of Clinical Oncology (ASCO) Annual Meeting, a gathering of more than 30,000 oncology professionals in Chicago.

The study used the SWOG clinical trial database to identify 1,401 patients over the age of 65 who were enrolled in phase 1 or 2 trials that included taxane therapy. Of these patients, 251 (18 percent) had grade 2-4 neuropathy. These data were then linked with corresponding Medicare claims and used to evaluate the likelihood of developing CIPN with the following comorbidities: diabetes, hypothyroid, hypercholesterolemia, hypertension, varicella zoster, peripheral vascular disease and autoimmune disease.

“Through their claims, we were able to figure out what other comorbid conditions they have and then through their clinical trials data, figure out whether or not they developed moderate or severe CIPN,” Dawn L. Hershman, professor of medicine and epidemiology at Columbia University, and lead author of the study, said in an interview with CURE.

Of the seven health-related factors examined, diabetes proved to play a role in the development of CIPN.

“Interestingly, we found that patients with diabetes had about a two-fold increased risk of developing CIPN,” Hershman explained. “For patients who already have neuropathy from their diabetes, we really need to think about the treatments that we’re giving them, especially in the palliative care setting, where they may not be beneficial.”

Age also played a significant factor; the chance of CIPN increased by about 4 percent every year the patients aged.

The third affecting factor was the type of chemotherapy drug a patient was given. Those who received paclitaxel were almost twice as likely to experience CIPN than those who were on docetaxel (25 percent vs 12 percent).

Hershman said that she hopes these results will help develop better treatment plans and interventions for CIPN, for which there is currently no cure.

“Until we understand the mechanisms and risk factors better, we can’t really design good interventions,” she said. “Maybe if we control patients’ glucose level during their treatment … especially diabetic patients, and put them on an exercise intervention, we may be able to reduce the risk by more intensive control of their underlying comorbidity.”

Based on findings from the study, the interventions of older or diabetic patients may look quite different from those who have autoimmune disease, a cohort that actually showed a decrease in CIPN incidents.

“That’s the first time we’ve seen something to be protective. What we don’t know is whether the inflammatory state of autoimmune disease may produce cytokines that protect patients from the chemotherapy toxicities or that being on chronic treatments for autoimmune disease, such as steroids, may prime the patient so they’re less at risk,” Hershman said, noting that that may be a possibility for further research.

Hershman also mentioned that future studies may look at the correlation between obesity and specifically obesity-related diabetes and CIPN.

“So [the study has] given us insight into directions we may want to go from a research perspective,” she said.