18005 Background: The objective of this study was to use a 5% sample of Medicare claims data to estimate health-care utilization and cost for the treatment of melanoma. METHODS Data for this study were obtained from national administrative Medicare files. Adult patients were selected for the analysis if they were newly diagnosed with melanoma between July 1, 1999 and June 30, 2001. Patients with diagnoses of other cancers prior to melanoma as well as those who did not have data available for at least six months of continuous follow-up were excluded from the analysis. Patients were identified as having Stage 0-II or Stage III-IV melanoma based on the absence or receipt, respectively, of lymph node dissection, chemotherapy, and/or radiation therapy. Study measures included the type, cost, and duration of melanoma treatment. RESULTS A total of 1,465 patients were identified for the study, including 1,291 with Stage 0-II melanoma and 174 with Stage III-IV melanoma. The mean age was 73.9 years, 54% were female. Overall, 98.3% of patients underwent a surgical procedure, 3.1% underwent chemotherapy, 2.3% had inpatient treatment, 1.2% received radiation, and 1.5% had home health treatment for melanoma in the first six months after diagnosis. Corresponding percentages by disease stage were 100%, 0%, 1.2%, 0%, and 0.9% for Stage 0-II patients, and 85.6%, 25.9%, 10.9%, 10.3%, and 6.3% for Stage III-IV patients. The average total six-month Medicare cost of care was $2,395 ($2,065 outpatient, $330 inpatient) per patient; the average per-patient cost of care was $1,402 ($1,292 outpatient, $110 inpatient) for Stage 0-II patients and was $9,756 ($7,800 outpatient, $1,956 inpatient) for Stage III-IV patients. CONCLUSIONS Treatment costs for melanoma are substantial in the first six months following diagnosis, especially for those patients with Stage III-IV disease. No significant financial relationships to disclose.