Years after completing cancer treatment, 45% of women cancer survivors still have chemotherapy-induced peripheral neuropathy symptoms, according to new research.

PT_news-01In the study, CIPN was associated with worse physical functioning, poorer mobility and a nearly two-fold higher risk of falls. While more research is needed, the investigators said these findings might inform rehabilitation and fall prevention interventions tailored to people with CIPN.

Findings were presented at the 2016 Cancer Survivorship Symposium, which took place Jan. 15-16 in San Francisco.

“We can’t dismiss neuropathy as a treatment side effect that goes away, because symptoms persist for years in nearly half of women,” lead author Kerri M. Winters-Stone, PhD, a research professor at Oregon Health and Science University in Portland, said in a news release. “While there are no effective treatments for this side effect, rehabilitative exercise programs may preserve physical functioning and mobility in the presence of neuropathy to help prevent falls and resulting injuries.”

Depending of the type of chemotherapy they received, an estimated 57% to 83% of patients will have signs of CIPN at some point during or after their care. It is not possible to predict which patient will develop CIPN or how long the symptoms will last, according to the release. And because there are no reliable tools for early detection of CIPN in routine cancer care, it often is not found until the symptoms become severe.

According to the authors, this is one of the first studies to explore the relationship between CIPN and physical functioning, including risk of falls. The researchers assessed data from 462 women enrolled in exercise intervention trials designed to address fractures and falls in women cancer survivors. The majority (71%) of the women had breast cancer, and others had lung, colorectal, ovarian or blood cancers.

At an average of six years since cancer diagnosis, 45% of the women still reported some symptoms of CIPN, such as loss of feeling in their hands and feet, results showed. Researchers found having CIPN symptoms was associated with significantly poorer physical functioning and more self-reported difficulty doing activities of daily living.

Findings also showed women with CIPN had altered gait patterns and nearly twice the risk of falling, compared with women without CIPN symptoms.

The researchers found the falls risk for women with CIPN is linked to specific underlying impairments, which may be different from those occurring with other conditions or aging. For example, CIPN does not cause muscle weakness but rather has a distinct effect on movement and gait patterns. In this study, women with CIPN had difficulty rising from a chair, possibly because their brains do not get enough information from their feet about how quickly or forcefully to stand up.

Based on these findings, the authors argue commonly recommended exercise, such as walking, might be safer for women with CIPN when done on a treadmill with handrails instead of outdoors because their altered gait puts them at increased risk of falling. Machine-based resistance training also might not be beneficial because neuropathy does not decrease leg strength, according to the release. Instead, the authors wrote, rehab efforts should focus on improving balance during upright movement and specific gait training.

If symptoms of CIPN are detected early, cancer treatments potentially could be changed to prevent these problems from occurring, or early rehabilitation interventions can be started, according to the researchers. Winters-Stone and her team are developing a portable, smartphone-driven device that patients can use to detect and quantify symptoms of neuropathy such as gait and balance impairments, according to the release.

Men with cancer are as likely to experience CIPN as women, according to the release; however, there are less research data on CIPN and physical functioning specifically in men.

This study was supported by the National Cancer Institute, American Cancer Society and Susan G. Komen for a Cure Foundation.

“Chemotherapy-induced peripheral neuropathy is a common and often under-recognized symptom among the thousands of cancer survivors in the U.S. and worldwide,” Merry-Jennifer Markham, MD, ASCO spokeswoman, said while moderating a Jan. 11 presscast. “Studies like this shed new light on the fact that CIPN has significant, measurable implications for a patient’s physical function and long-term health. This knowledge will allow us to improve and tailor rehabilitation as needed.”