Risk Factors for Malignancy in Dermatomyositis

Dermatomyositis (DM) may be associated with underlying malignancies. This potential link is important to establish, as treatment of the precipitating cancer is crucial for remission of myositis. However, there are no standardized guidelines regarding screening for cancers in DM patients.

Dr. Fred Miller addressed this topic in his ACR session, "MoreThan Skin Deep: Topics in Dermatomyositis" on November 14, 2016. Certain types of cancers are more commonly associated with DM; these include lung, ovarian, non-Hodgkin's lymphoma, bladder, breast, cervical, endometrial, colorectal and nasopharyngeal. The presence of cancer increases mortality risk in patientswith DM. Certain factors may be associated with underlying malignancies, including male sex, age > 45 years, lower CK, rapid onset of disease (< 4 weeks), dysphagia, high ESR, cutaneous necrosis, and the presence of anti-p155/140 autoantibody or NXP-2 autoantibody. Interestingly, the presence of Jo-1 autoantibody may be protective, as well as the existence of concomitant ILD. The presence of arthritis and arthralgia, as well as Raynaud's, may also be protective.

In terms of screening, Dr. Miller suggests dividing DM patients into risk categories. He defines the higher risk category as patients who have many of the risk factors listed above for higher association with cancers, and adds a family history of cancer, smoking history, and history of excessive alcohol use. He recommends that the higher risk category warrants additional testing, including a low-dose chest CT, transvaginal US and Ca-125 screening for ovarian cancer, colonoscopy, serum and urine protein electrophoresis, as well as additional tests based on abnormalities above.

Certain questions still remain, however, such as when, if ever, to repeat cancer screening? Should cancer screens be more extensive at baseline if they are never being repeated again?

As a general rule, I tend to screen my myositis patients quite extensively at diagnosis; this includes CT scans of the chest, abdomen and pelvis, as well as colonoscopy and testicular ultrasound in men. I do not repeat unless the myositis is refractory to treatment, or relapses despite remission, suggesting possible recurrence or onset of malignancy.

What do you offer your myositis patients? How often do you screen? And since the risk is higher with DM patients, should the same screens be offered to patients with polymyositis? It will be interesting to see, as ourmyositis cohorts grow, if any standard clinical guidelines become available. Other autoimmune diseases (e.g. scleroderma) may also be associated with cancer, so this issue is by no means relegated to inflammatory myopathies alone!

More reports from ACR 2016