Consistent and breakthrough pain in diverse advanced cancer patients: a longitudinal examination.

Although cancer pain, both consistent and breakthrough pain ([BTP]; pain flares interrupting well-controlled baseline pain), is common among cancer patients, its prevalence, characteristics, etiology, and impact on health-related quality of life (HRQOL) are poorly understood. This longitudinal study examined the experience and treatment of cancer-related pain over six months, including an evaluation of ethnic differences. Patients with Stage III or IV breast, prostate, colorectal, or lung cancer, or Stage II-IV multiple myeloma with BTP completed surveys on initial assessment and at three and six months. Each survey assessed consistent pain, BTP, depressed affect, active coping ability, and HRQOL. Among the respondents (n=96), 70% were white, 66% were female, and had a mean age of 56+/-10 years. Nonwhites reported significantly greater severity for consistent pain at its worst (P = 0.009), least (P < or = 0.001), on average (P = 0.004), and upon initial assessment (P = 0.04), and greater severity for BTP at its worst (P = 0.03), least (P = 0.02), and at initial assessment (P = 0.008). Women also had higher levels of some BTP measures. Ethnic disparities persisted when data estimation techniques were used. Examined longitudinally, consistent pain on average and several BTP measures reduced over time, although not greatly, indicating the persistence of pain in the cancer experience. These data provide evidence for the significant toll of cancer pain, while demonstrating further health care disparities in the cancer pain experience.