Nonmelanoma skin cancer risk awareness in azathioprine-treated myasthenia gravis patients

Objectives: Increased rates of NMSC (nonmelanoma skin cancer) have recently been reported in people with MG (myasthenia gravis) receiving azathioprine treatment. Guidelines on azathioprine for patients with dermatological and gastrointestinal disorders stress the importance of NMSC risk awareness and prevention. The aim of this study is to assess whether MG patients are being informed of this risk. Methods: Clinical records of patients with MG attending a university hospital neurology clinic were reviewed. Data on patient demographics, clinical presentation, diagnostic tests, azathioprine treatment, development of NMSC, and counseling regarding NMSC risk were recorded. Results: Sixty-nine MG cases were identified, median age 58years (range 20-90). Forty-two (60.9%) had received azathioprine at some point with a mean cumulative dose of 235.5g (range 9.1-972.8g). Skin cancer risk and prevention advice provision was documented in 3 (7.1%) azathioprine-treated patients. Five patients developed histologically confirmed NMSC of whom all were treated with azathioprine (incidence rate of 24.9 per 1000, 16 times higher than expected). Documented advice on other safety issues such as regular blood test monitoring was found in 33 (78.8%) azathioprine-treated cases. Conclusions: Preventative measures such as daily sunscreen use have been shown to reduce the incidence of NMSC in the general population. The results of this study demonstrate a very low rate of advice provision about NMSC risk in azathioprine-treated MG patients and the need for increased awareness among treating neurologists and patients.