Toxicity of high-dose interferon for high-risk melanoma in Ontario: A population-based study of health services use.

Abstract

31 Background: While High-Dose Interferon (HDIFN) is the sole approved adjuvant systemic treatment for melanoma in Ontario and many other jurisdictions, it is toxic, of modest benefit, and costly. We sought to assess the population-level impact of toxicity, particularly neuro-psychiatric toxicity. This can inform value assessment for the adjuvant treatment of melanoma. Methods: This was a retrospective population-based registry study of all patients with melanoma receiving adjuvant HDIFN in Ontario 2008-2012. HDIFN receipt was determined from provincial drug-funding data. Toxicity was investigated through health services use compatible with HDIFN toxicity (e.g. mental health physician billings). Associations between early HDIFN discontinuation and health services use were examined. Using stage data reported from cancer centers on a subset of patients, propensity matched analysis compared utilization in stage IIB-IIIC patients that did and did not receive HDIFN. Results: Of 718 patients receiving HDIFN, 12% were ≥65 years, 83% had little or no comorbidity. One third had ≥1 toxicity-associated utilization within one year of starting HDIFN. 364/420 (87%) of utilization was mental health-related: 54% were family practitioner visits, 39% psychiatrist visits. Early drug discontinuation was more likely with pre-existing mental health issues in multivariable analysis (OR 2.0 (1.1,3.4)). In propensity matched analysis, HDIFN patients were more likely than untreated matched controls to have mental health utilization (51% vs. 42%, p=0.01) between 1 year pre-melanoma diagnosis to 2 years post. Conclusions: Mental health services use is common among stage IIB-IIIC patients with melanoma, especially with HDIFN. This emphasizes an important survivorship issue for these patients, and for those receiving HDIFN, and impacts the value of care. Pre-treatment mental health services use is associated with treatment discontinuation. This is important when contemplating the value of HDIFN use for individual patients. For those receiving HDIFN, optimal support must include mental health care.