Newly issued guidelines for cancer screening in patients with dermatomyositis had 100% sensitivity in a single institution’s cohort, though most of the cancers found would have been detected with standard cancer screenings recommended for the general population, according to a research letter published in JAMA Dermatology.
“These early results emphasize the continued need to refine risk assessment and cancer screening for patients with dermatomyositis while balancing resource use and outcomes,” concluded Caroline J. Stone and her colleagues at the Department of Dermatology, Perelman School of Medicine, University of Pennsylvania, Philadelphia.
dermatology.cdlib.org/CC BY-SA 3.0/wikimedia
Patients with dermatomyositis have approximately a 4.7 times greater risk for cancer than those without it, according to a 2016 meta-analysis. Despite the well-established link between cancer and dermatomyositis, cancer in people with idiopathic inflammatory myopathies is commonly diagnosed at a later stage and is the leading cause of death in people with these conditions.
Guidelines First Presented in 2022 and Published in 2023
A wide variability in screening practices eventually led the International Myositis Assessment & Clinical Studies Group (IMACS) to present the first evidence-based and consensus-based guidelines for cancer screening of patients with idiopathic inflammatory myopathies, including those with dermatomyositis, at the 2022 annual meeting of the American College of Rheumatology and publish them in 2023 in Nature Reviews Rheumatology. The guidelines advise low-risk patients to undergo basic cancer screening with routine blood and urine studies, liver function tests, plain chest radiography, and age- and sex-appropriate cancer screening.
Intermediate- and high-risk patients are recommended to undergo enhanced screening that can include mammography, Pap tests, endoscopy/colonoscopy, pelvic and transvaginal ultrasonography, prostate-specific antigen or cancer antigen 125 blood tests, fecal occult blood tests, and CT of the neck, thorax, abdomen, and pelvis.
But because the guidelines are new, little evidence exists regarding their validation in real-world cohorts. Researchers, therefore, assessed the IMACS guidelines in 370 patients, aged 18-80 years, who visited the University of Pennsylvania rheumatology-dermatology specialty clinic between July 2008 and January 2024. All participants had dermatomyositis and at least 3 years of follow-up and were an average 48 years old. The vast majority were women (87%) and White participants (89%).
Most (68.6%) had myositis-specific autoantibody test results, one of the factors included in the guidelines for determining whether the patient should be classified as low, intermediate, or high risk. Other factors for risk stratification included myositis subtype, age at disease onset, and clinical features. About half (49.2%) had classic dermatomyositis, 42.4% had amyopathic dermatomyositis, 3.8% had juvenile dermatomyositis, 3.2% had hypomyopathic dermatomyositis, 0.8% had antisynthetase syndrome, and 0.5% had immune-mediated necrotizing myopathy.
Just over half the patients (54%) were classified as high risk, while 37.3% were classified as intermediate risk and 8.9% as low risk using the guidelines. Among the 18 patients (4.9%) with paraneoplastic dermatomyositis, 15 were classified as high risk and 3 as intermediate risk.
Of the patients diagnosed with cancer, 55% of cases were diagnosed about a year before their dermatomyositis diagnosis. In three patients, symptoms “suggestive of cancer at the time of dermatomyositis diagnosis, including lymphadenopathy and unexplained weight loss,” led to diagnostic testing that found an underlying cancer.
In the eight patients diagnosed with cancer after their dermatomyositis diagnosis, 75% of the cancers were identified during the first year of follow-up and 25% in the second year. Five were identified based on basic cancer screening and three on enhanced screening.
A total of 11 patients (3%) developed intravenous contrast allergies, and no other adverse events were reported to be associated with cancer screening, but the study was not designed to capture other types of adverse screening effects, such as cost, quality of life, or risk from radiation exposure.
The most common neoplasm identified was breast cancer, found in nine (50%) of the patients using mammography. Two patients had lung cancer identified with chest radiography and two had ovarian cancer identified with abdominal radiography and CT. The remaining five patients included one each with bladder cancer, papillary thyroid cancer, renal cell carcinoma, non-Hodgkin lymphoma, and adenocarcinoma with unknown primary.
The sensitivity of the guidelines in detecting cancer related to dermatomyositis was 100%, though the authors noted that the “IMACS risk-stratification scheme may overestimate cancer risk and encourage enhanced screening protocols of unclear benefit.” Most of the cancers found after dermatomyositis diagnosis were detected with routine age- and sex-related screening that already falls under basic cancer screening recommendations for the general population. Nonetheless, 90% of the participants fell into the intermediate- and high-risk groups, warranting a more comprehensive and costly enhanced screening protocol.