Enhanced risk of DM1 patients developing benign and malignant cancers has been identified in recent registry-based studies (UK Myotonic Dystrophy Patient Registry and National Registry of Myotonic Dystrophy and Facioscapulohumeral Muscular Dystrophy Patients and Family Members). Although sample size was small, one of these earlier studies (Gadalla et al., 2017a) showed elevated risk of skin tumors with the key risk factor, sun exposure, similar to that of the general population.
New Longitudinal Data on Skin Cancer Risk in DM1
Dr. Shahinaz Gadalla and colleagues at the U.S. National Cancer Institute, UK Medicines and Healthcare Products Regulatory Agency, Queen’s University Belfast, and Newcastle University have published a large electronic medical records study of cancer risks in DM1 that included 1,061 DM1 patients and 15,119 DM-free subjects (Gadazlla et al. 2017b). After controlling for a variety of variables, the research team identified a cohort that included 35 DM1 and 108 DM-free individuals who developed skin cancer; incidence rates were approximately 435/100,000 for DM1 and 131/100,000 for DM-free subjects. DM1 patients had significantly increased risk for developing skin cancer (all types combined), with the highest risk for basal cell carcinoma. A 2-fold increase in risk of melanoma among DM1 patients did not reach significance.
Overall, a DM1 diagnosis was associated with approximately 6-fold excess risk of developing non-melanoma skin cancers and as much as 7-fold excess risk for all skin cancers combined. There were no gender or age at diagnosis differences in skin cancer risk among DM1 patients.
Clinical Care Guidance and Future Studies
Taken together, data from recent registry-based studies suggest an elevated risk of skin cancer in DM1 patients, with an addressable key risk factor—patients should minimize ultraviolet light exposure and seek medical opinion for suspicious skin lesions. This latest study assessed a large cohort, used a longitudinal design and was carefully controlled, lending a high degree of confidence to these findings. Biologic mechanisms underlying the increased cancer risk in DM1 are currently unknown—potential relationships to MBNL depletion or mis-splicing of skin-related genes should be probed.
Pigmentation phenotype, photosensitivity and skin neoplasms in patients with myotonic dystrophy.
Gadalla SM, Hilbert JE, Martens WB, Givens S, Moxley RT 3rd, Greene MH.
Eur J Neurol. 2017a May;24(5):713-718. doi: 10.1111/ene.13276. Epub 2017 Mar 20.
Risk of skin cancer among patients with myotonic dystrophy type 1 based on Primary care physician data from the United Kingdom Clinical Practice Research Datalink.
Wang Y, Pfeiffer RM, Alsaggaf R, Meeraus W, Gage JC, Anderson LA, Bremer RC, Nikolenko N, Lochmuller H, Greene MH, Gadalla SM.
Int J Cancer. 2017b Nov 7. doi: 10.1002/ijc.31143. [Epub ahead of print]