Association of Pain With Mental and Physical Function in Patients With Chemotherapy-Induced Peripheral Neuropathy: A Secondary Analysis From Two Randomized Controlled Trials.

INTRODUCTION/AIMS: Chemotherapy-induced peripheral neuropathy (CIPN) affects 30%-60% of patients who receive neurotoxic chemotherapy. Multiple studies have shown that these symptoms negatively impact patients' quality of life. This study seeks to examine the association of the severity of pain in CIPN and different health outcomes after adjustment for non-painful symptoms.

METHODS

Baseline data from two randomized clinical trials (RCTs) involving 595 participants with painful and non-painful CIPN were used to examine associations between pain severity and mental and physical function using linear regression models. Participants were grouped into four pain severity categories measured via the 0-10 numeric rating scale. The analyses were repeated with adjustment for non-painful symptoms.

RESULTS

The proportions of participants reporting severe pain were similar between trials (41% vs. 48%). Participants with severe CIPN pain in both trials (N = 274) reported worse outcomes across all assessed domains than participants with non-painful CIPN (N = 70) (p < 0.02). However, this was not consistently observed when comparing to other pain groups (mild or moderate pain). When the analyses were repeated with the severity of numbness and tingling included as covariates for a proxy of overall neuropathy severity, the associations between pain and health domains were similar.

DISCUSSION: Participants with CIPN experiencing severe pain have worse health outcomes than participants with non-painful CIPN, regardless of severity of other non-painful neuropathy symptoms. Research should focus on developing effective pharmacological and non-pharmacological interventions that target pain to reduce the symptom burden of CIPN and increase implementation of currently available interventions for pain in the context of CIPN.