Cancer and benign tumors in myotonic dystrophy, facioscapulohumeral muscular dystrophy, and oculopharyngeal muscular dystrophy: a 23-year, single-center, retrospective study.

Objectives: Some muscular dystrophies, such as myotonic dystrophy type 1 and 2 (DM1 and DM2), facioscapulohumeral muscular dystrophy (FSHD), and oculopharyngeal muscular dystrophy (OPMD), are caused by genetic mutations that may affect the expression and function of various cancer-related genes. We assessed the frequency and type of cancers and benign tumors in patients with DM1, DM2, FSHD, and OPMD.

Methods: We conducted a single-center, retrospective, cross-sectional study on patients with DM1, DM2, FSHD, and OPMD at our institution from January 2000 to September 2023.

Results: Seventy seven (46 female) DM1, 20 (15 female) DM2, 40 (18 female) FSHD, and 46 (22 female) OPMD patients were included, among which 22 (28.57%), 9 (45%), 7 (17.5%), and 15 (32.61%) patients had at least one cancer, respectively. Median age (range) of patients where presence or absence of cancer was ascertained was 65 (18-87), 63.5 (45-86), 61 (27-83), and 71.5 (40-82) years, respectively (P < 0.0001). Overall, non-sex-related cancers were more frequent than sex-related cancers among all patients together. Independent to sex and age, DM1 patients had an increased risk of non-sex-related cancers compared to non-DM cases. Melanoma (P < 0.01) and testicular (P < 0.05) cancers were significantly more frequent in DM2 and OMPD patients, respectively. DM patients had also increased risk of non-sex related benign tumors (including skin and thyroid benign tumors) compared to non-DM patients.

Conclusions: Our study highlights the differences in the prevalence of cancers and benign tumors among patients with DM1, DM2, FSHD, and OPMD, underscoring the potential need for regular screening for specific cancers.