Doctor and patient
Photo courtesy of NIH

SAN FRANCISCO—A study of female cancer survivors indicates that many still have chemotherapy-induced peripheral neuropathy (CIPN) symptoms years after completing cancer treatment.

In addition, CIPN was associated with worse physical functioning, poorer mobility, and a higher risk of falls.

Although more research is needed, investigators believe these findings may inform rehabilitation and fall prevention interventions for people with CIPN.

The findings were presented at the 2016 Cancer Survivorship Symposium (abstract 130*).

“We can’t dismiss neuropathy as a treatment side effect that goes away because symptoms persist for years in nearly half of women,” said Kerri M. Winters-Stone, PhD, of Oregon Health and Science University in Portland.

“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.”

For this study, Dr Winters-Stone and her colleagues assessed data from 512 women enrolled in exercise intervention trials designed to address fractures and falls in female cancer survivors. Most of the women had breast cancer, but there were also cases of lung, colorectal, ovarian, and hematologic cancers.

At an average of 6 years post-cancer diagnosis, 46% of the women (n=238) still reported some symptoms of CIPN, such as loss of feeling in their hands and feet.

The investigators noted significant relationships (P<0.01) between CIPN severity and gait speed, Physical Performance Battery score, self-reported physical functioning, and self-reported disability.

The team also compared measures of physical functioning in the women with CIPN to measures in women without CIPN (n=274). This analysis was adjusted for cancer type and time since diagnosis.

There was a significant difference (P<0.01) between the groups in one measure of lower-extremity fitness but not another. Namely, it took CIPN-positive women significantly longer to rise out of a chair (tested 5 times each). But women in both groups fared similarly on a test measuring maximal leg press strength.

The investigators also tested the women on mobility and physical functioning. The CIPN-positive women fared significantly worse than CIPN-negative women (P<0.01) when it came to walking speed, step number, stride length, percentage of gait cycle in double support, and Physical Performance Battery score. However, there was no significant difference between the groups with regard to base of support.

Finally, CIPN-positive women were significantly more likely than CIPN-negative women to report poor physical function and disability (P<0.01 for both). And CIPN-positive women had a higher rate of falls in the last year (P<0.01).

The investigators said women with CIPN have specific underlying impairments that put them at risk for falls, which may be different from the impairments that occur with other conditions or old age.

For example, CIPN does not cause muscle weakness, but it has a distinct effect on movement and gait patterns.

The team noted that the 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 investigators argued that commonly recommended exercise, such as walking, may be safer for women with CIPN when done on a treadmill with handrails because their altered gait puts them at an increased risk of falling.

The team also said that machine-based resistance training may not be beneficial because neuropathy does not appear to decrease leg strength. Instead, rehabilitation efforts should focus on improving balance during upright movement and specific gait training.

Furthermore, the investigators believe that, if the symptoms of CIPN are detected early, cancer treatments could potentially be changed to prevent these debilitating problems or early rehabilitation interventions could be started.

In addition, Dr Winters-Stone and her research team are developing a smartphone-driven device that patients can use to detect and quantify symptoms of neuropathy, such as gait and balance impairments.

*Data in the abstract differ from the presentation.

CIPN persists in female cancer survivors