As a primary care practitioner, I have a handful of ‘special’ patients diagnosed with a rare disorder called dermatomyositis, which predisposes them to ovarian cancer risk. Dermatomyositis (DM) is defined as an autoimmune disease that attacks skeletal muscles throughout the body causing proximal muscle weakness, rashes, elevated CPK levels and predisposition primarily to ovarian, breast, and colon cancers as well as non-Hodgkin’s Lymphoma. As practitioners we relate these cancers in our patients to having a high suffering index. My love of medicine and caring for my patients precludes a knowledge gap to desire to do everything within medicine not to miss a diagnosis of both DM and ovarian cancer.
The incidence of dermatomyositis is hypothesized to be 0.5 to 0.85 per 100, 000 persons. My voice cries, “But what about the yet-to-be-diagnosed and the undiagnosed-for-decades patients?” Have I already missed the mark? How many patients in my practice have DM yet are undiagnosed, or who may develop this disabling disease? We all know our twenty- and thirty-something year old patients whom we refer to rheumatology — often with no concrete diagnosis — may have been having genomic DNA molecular changes that eventually test positive for DM. I adamantly echo the importance for primary care providers to appropriately screen for cancer in our patients with DM, but I believe that the jury is still out on the official compilation of guidelines for myself and my primary care colleagues.
Shockingly, studies conclude that ovarian cancer rates in DM are as high as 8.3%. As a practitioner I found it confusing at first to understand that DM mimics the century-long question of which came first, “the chicken or the egg.” The experts declare that an undiagnosed underlying cancer may trigger DM, and in their next sentence propose that DM can trigger these specific cancers — but, interestingly enough, only usually in the first five years after diagnosis. So, does DM or cancer come first?
The lexicographic dilemma of knowing to screen for ovarian cancer specifically in our DM patients is mindboggling to my colleagues. Studies refute that our patients with DM who are at greatest risk for the development of cancer in their lifetime are those with the positive antibodies transcription intermediary factor (TIF); 1 gamma (anti-p155/140), and antibodies to nuclear matrix protein (NPX-2; anti-MJ or anti-p140). On the other hand, as in a matrix-like dilemma the antibodies anti-SRP; anti-synthetase; anti-MI-2; anti-SRP; anti-RNP; anti-KU; and anti-PM-Scl evidence a lower risk association to the development of cancers. Even more mind-tapping is the theory that those with ILD (usually possessing the anti-Jo-1 antisynthetase antibodies) have even less cancer risk. However, not all evidence is positive, and experts released the risk relationship to developing cancer to be high in those patients with a prior history of cancer, cutaneous necrosis, leukoclastic vasculitis, and myositis treatment resistance.
As a practitioner, I look to following consensus guidelines and recommendations for all of my patients with a rare disease but now particularly with those diagnosed with DM. I will order a yearly pelvic exam and a transvaginal u/s with a possible CA-125 based on risk at the onset of the diagnosis and follow the recommendations to consider a PET scan in high-risk patients. I will now consider doing a pelvic exam, CA-125, and a transvaginal u/s at 6–12 months for the first two years after diagnosis.
My personal dilemma is for how many years my patient has had DM prior to the actual diagnosis as symptoms mimic other conditions. My top question for the oncology expert is that a high Ca-125 often occurs in our patients with inflammation, and in DM the entire muscular system is inflamed, so are we screening too many false positives?
I am very cautious as well to not preclude omitting the transvaginal ultrasound as we need to know the thickness of the endometrial stripe dictated as endometrial cancer may often be the precursor to ovarian cancer and to diagnose ovarian masses.
During my midnight reading time I further realize that despite the ultrasound, pelvic exam, Ca-125, cbc, and urinalysis recommended as screening, I needed to further consider doing a CT of my DM patient’s abdomen and pelvis to rule out a missed DLBCL retroperitoneal cancer. My midnight thought frenzy further enlightened my research to conclude that a stool colon cancer screening, a colonoscopy, chest X-ray, Pap test, and mammogram age-appropriate will complete the cancer screening requirements in my female patient with DM. My next question is, what to do after the five-year risk period?
I mention my frenzied reading at midnight at the end of a long day in the clinic because I find that screening guidelines for my patients with autoimmune diseases is not easy to find; it is not well organized into a single document or guidelines. I am unable to rest knowing that I may miss screening my patient for ovarian cancer properly. The investigation for answers envelopes cross-coverage from rheumatology and immunology journals and guidelines finely interwoven with the consensus guidelines from the US Preventative Taskforce and American Cancer Society. The “egg or the chicken?” also pops up when I ponder the relationship between using radiation, such as the high-resolution CT scan, to screen for cancer when repeated radiation will also increase cancer risks. I believe there is much need for well-developed consensus guidelines that will at least initiate the specific screening requirement for ovarian cancers in our patients diagnosed with the rare inflammatory muscle disease called DM.