Health system costs for cancer medications and radiation treatment in Ontario for the 4 most common cancers: a retrospective cohort study.

BACKGROUND: Previous costing and resource estimates for cancer have not been complete owing to lack of comprehensive data on cancer-related medication and radiation treatment. Our objective was to calculate the mean overall costs per patient of cancer-related medications and radiation, as well as by disease subtype and stage, in the first year after diagnosis for the 4 most prevalent cancers in Ontario. METHODS: We conducted a retrospective cohort study using provincial health administrative databases to identify population health system resources and costs for all patients diagnosed with breast, colorectal, lung or prostate cancer between Jan. 1, 2010, and Dec. 31, 2015 in Ontario. The primary outcome measure was the overall average cost per patient in the 365 days after diagnosis for cancer-related medications and radiation treatment, calculated with the use of 2 novel costing algorithms. We determined the cost by disease, disease subtype and stage as secondary outcomes. RESULTS: There were 168 316 Ontarians diagnosed with cancer during the study period, 50 141 with breast cancer, 38 108 with colorectal cancer, 34 809 with lung cancer and 45 258 with prostate cancer. The mean per-patient cost for cancer-related medications was $8167 (95% confidence interval [CI] $8023-$8311), $6568 (95% CI $6446-$6691), $2900 (95% CI $2816-$2984) and $1211 (95% CI $1175-$1247) for breast, colorectal, lung and prostate cancer, respectively. The corresponding mean radiation treatment costs were $18 529 (95% CI $18 415-$18 643), $15 177 (95% CI $14 899-$15 456), $10 818 (95% CI $10 669-$10 966) and $16 887 (95% CI $16 648-$17 125). In general, stage III and IV cancers were the most expensive stages for both medications and radiation across all 4 disease sites. INTERPRETATION: Our work updates previous costing estimates to help understand costs and resources critical to health care system planning in a single-payer system. More refined costing estimates are useful as inputs to allow for more robust health economic modelling and health care system planning.