Background: Cancer care costs are rising, creating concerns about affordability. As a result, delivery systems are creating alternative payment structures to lower costs while maintaining or improving quality. As cancer care delivery often involves multiple provider systems, measuring cost may be difficult. In response, using commercial insurance claims linked to cancer registry records, we constructed broadly applicable, reproducible, clinically relevant episodes to measure costs. Methods: Cancer registry records for patients diagnosed in Western Washington from January 2007-June 2016 were linked with claims from two regional commercial insurers. Patients are age 18+, diagnosed with breast, colorectal (CRC), or non-small cell lung cancer (NSCLC) and enrolled with a single insurance plan. With oncologist input, we constructed three care phases: diagnosis (30 days before diagnosis to first treatment), initial treatment (first treatment through first 4 month treatment gap), and end of life (last 30 days). Costs include all claims paid within the phase (2016 inflation adjusted). Supportive care includes colony-stimulating factors, blood transfusions, antibiotics, antivirals, antifungals, and antiemetics. Results: This study included 8,727 patients at diagnosis, 7,686 during treatment, and 1,736 at end of life. Diagnosis phase averaged 54 days and cost $6,936 (SD $11,761, median $4,021). Treatment averaged 126 days, with costs of $61,148 (SD $75,432, median $35,750). Average end-of-life costs were $15,829 (SD $30,222, median $2,347). The table below provides an example of the variation in costs during the treatment phase using local-stage tumors. Conclusions: Clinically relevant episodes of care and cost measures can be constructed using claims-registry data. This allows for identification of high-cost care categories and areas with large-cost variability, which may be helpful when designing value-based reimbursement programs or identifying areas for potential cost-reduction.