Dermatomyositis and colorectal cancer: a systematic review.

BACKGROUND: Dermatomyositis (DM) is an idiopathic inflammatory myositis. The principal characteristics are cutaneous rash, muscle ache, and muscle weakness. In the past, associations have been established between DM and malignancy, including colorectal cancer.

METHODS: A systematic PubMed and Scopus search was conducted.

RESULTS: The median age of the patients was 65 years (range 40-82). The majority were female (17 out of 27, 63%). Adenocarcinoma was the most frequent histological type of colorectal neoplasm. DM manifested before the diagnosis of colorectal cancer in 21 out of 27 patients (77.8%). At the time of the first presentation, creatine kinase was at a median level of 514.5 U/L (range 50-11,744), and serum antibodies were present in 11 out of 27 patients (40.7%). Immediate improvement of DM symptoms after surgery occurred in 14 out of 26 patients (53.8%). Recurrence of cancer in the form of distal metastasis was present in 5 out of 26 patients (19.2%). Cancer recurrence occurred within a median of 7.9 months (range 2-21) after surgery. In 7 out of 26 patients (26.9%), DM symptoms recurred during the post-operative period. Death was reported in 23 out of 27 patients (85.2%).

CONCLUSION: It is of paramount importance to perform a systematic diagnostic workup for malignancy, always including colonoscopy, in DM patients, since there is a high incidence of cancer in DM patients. Surgical treatment of colorectal tumors should precede the treatment of DM, as DM will frequently regress after a successful resection of malignancy.