- Dermatomyositis (DM) and polymyositis (PM) are both associated with malignancy with the association being stronger for DM >> PM.
- Incidence of cancer for patients with DM is increased 5- to 7-fold compared to the general population.
- Cancer can be diagnosed before, simulataneously with, or after the diagnosis of DM and PM though (as Rabih mentioned) the peak incidence of a cancer diagnosis in DM and PM occurs simultaneously with/during the first five years after diagnosis.
- Types of malignancies = adenocarcinoma of the cervix, lung, ovaries, pancreas, bladder, and stomach accounts for 70% of cases.
- With a new diagnosis of DM, the following labs are routinely performed:
- CBC, LFTs, U/A
- FIT versus colonoscopy for colon cancer screening
- For women: pap, mammo, transvaginal U/S and CA-125 levels for ovarian cancer screening
- Of note, there is no consensus on frequency of ovarian screening. Pap smears should be performed annually for patients with immunosuppression.