Association of opioid requirement and cancer pain with survival in advanced non-small cell lung cancer

Abstract

Background: Pain is associated with shorter survival in non-small cell lung cancer (NSCLC). Lung cancer cells express opioid receptors. Opioids promote angiogenesis, tumor growth and metastases, and shorten survival in animal models. Methods: To examine if long-term opioid requirement, independently of chronic pain, is associated with survival, we studied 209 patients treated with chemotherapy for stage IIIB/IV NSCLC. Pain was stratified by proportion of time patients reported specific levels of pain. Opioids were converted to oral morphine equivalents (OME) for comparison. The effects of pain, opioid requirement, and known prognostic variables on survival were analyzed in univariable and multivariable models. Results: Both severity of pain and greater opioid requirement in first 90 days after starting chemotherapy were strongly predictive of shorter survival on univariable analysis. Patients with no/mild chronic pain and requiring <5 mg/day OME during first 90 days had nearly 12 months longer median survival compared to patients requiring ≥5 mg/day OME and/or experiencing more pain. Differences in survival remained remarkably similar when chronic pain and opioid requirement were assessed over the entire clinical course (until death or last follow-up). In multivariable models, both opioid requirement and chronic pain remained independent predictors of survival, after adjustment for age, stage and performance status. Conclusions: Severity of chronic cancer-related pain or greater opioid requirement are associated with shorter survival in advanced NSCLC, independently of known prognostic factors. While pain adversely influences prognosis, controlling it with opioids does not improve survival. Prospective studies should determine if achieving pain control using opioid-sparing approaches improves outcomes.