Determinants of Pain Severity Changes in Ambulatory Patients With Cancer: An Analysis From Eastern Cooperative Oncology Group Trial E2Z02

Purpose To understand changes in pain severity over time and to explore the factors associated with pain changes in ambulatory patients with solid tumors. Patients and Methods We enrolled 3,106 patients with invasive cancer of the breast, prostate, colon/rectum, or lung from multiple sites. At baseline and 4 to 5 weeks later, patients rated their pain level on a 0 to 10 numerical rating scale. A 2-point change in pain score was defined as a clinically significant change in pain. Multivariable logistic models were fitted to examine the effects of pain management and demographic and clinical factors on change in pain severity. Results We analyzed 2,761 patients for changes in pain severity. At initial assessment, 53.0% had no pain, 23.5% had mild pain, 10.3% had moderate pain, and 13.2% had severe pain. Overall, one third of patients with initial pain had pain reduction within 1 month of follow-up, and one fifth had an increase, and the improvement and worsening of pain varied by baseline pain score. Of the patients without pain at initial assessment, 28.4% had pain (8.9% moderate to severe) at the follow-up assessment. Logistic regression analysis showed that inadequate pain management was significantly associated with pain deterioration, as were lower baseline pain level, younger age, and poor health status. Conclusion One third of patients have pain improvement and one fifth experience pain deterioration within 1 month after initial assessment. Inadequate pain management, baseline pain severity, and certain patient demographic and disease characteristics are associated with pain deterioration.