MYOTONIC DYSTROPHY: EP.237 A systematic review and meta-analysis of cancer risk in myotonic dystrophy: consistent with a general increased risk of cancer

Abstract

Dystrophia myotonica type 1 (DM; Steinert's disease) is an autosomal dominant, multi-system disease caused by CTG trinucleotide repeats in the DMPK gene. Case reports of pilomatricoma, a rare benign skin cancer, in DM patients have raised questions of excess cancer incidence in these patients. To investigate whether DM patients have an increased risk of developing cancer, we systematically searched three electronic databases from database inception through to 20/08/2019. A random effects meta-analysis was used to produce a pooled risk estimate for cancer risk in DM patients. Nine studies reporting on 3,915 DM patients met the eligibility criteria for inclusion. Four studies reported a risk estimate for all cause cancer. Pooled risk estimate showed DM patients had a statistically significant increased odds of developing cancer (pooled OR 1.72 (95% CI 1.45-1.99)). Elevated odds were observed for 10 cancer sites including endometrial (OR 7.92 (95% CI 4.82-13.05)), melanoma (OR 2.49 (1.29-4.83)), brain (OR 5.66 (3.89-8.23)), bladder (OR 5.60 (2.84-11.01)), thyroid (OR 9.75 (4.73-20.11)), ovarian (OR 5.60 (2.84-11.02)), testicular (OR 6.09 (1.96-18.95)), colon/colorectal (OR 2.45 (1.52-3.95)), non-Hodgkin's lymphoma (OR 2.77 (1.20-6.34)) and pancreatic cancer (OR 3.15 (1.12-8.88)). This data supports that the pathogenic DM1 trinucleotide expansion confers a general increase in cancer risk and raises questions about cancer surveillance in DM patients and trinucleotide repeat instability as a potentially carcinogenic phenomenon.