Cancer as a cause of back pain: frequency, clinical presentation, and diagnostic strategies.

Back pain is very common. Rarely, it may be the first manifestation of cancer. Although many advocate selective use of laboratory and x-ray tests for back pain patients, the early detection of cancer may be an important reason to obtain such tests. To develop a diagnostic approach that would identify malignancies while remaining parsimonious, the authors evaluated 1,975 walk-in patients with a chief complaint of back pain. Thirteen patients (0.66%) proved to have underlying cancer. Findings significantly associated with underlying cancer (p less than 0.05) were: age greater than or equal to 50 years, previous history of cancer, duration of pain greater than 1 month, failure to improve with conservative therapy, elevated erythrocyte sedimentation rate (ESR), and anemia. Combining historical features and ESR results led to an algorithm that would have limited x-ray utilization to just 22% of subjects while recommending an x-ray for every cancer patient. It would further suggest which patients with negative x-ray findings require further work-up.