Dermatomyositis among high risk factors for cancer in idiopathic inflammatory myopathy

PHILADELPHIA — High risk factors for cancer in patients with idiopathic inflammatory myopathy include dermatomyositis, anti-TIF1-gamma positivity, anti-NXP2 positivity and age 40 or older at onset, said a speaker here.

Alexander Oldroyd, MD, of the University of Manchester, in the United Kingdom, presented the first recommendations for cancer screening in patients with idiopathic inflammatory myopathy (IIM), drafted and approved by the International Myositis Assessment and Clinical Studies Group, at ACR Convergence 2022.

Other high-risk factors listed in the recommendation document include dysphagia, cutaneous necrosis and features of persistent high disease activity despite immunosuppressive therapy, including relapse of previously controlled disease. According to the recommendations, adult patients with IIM who demonstrate two or more of these factors should be considered to be at high risk for IIM-related cancer.

“There are no guidelines for myositis cancer screening ,” Oldroyd told attendees. “That is what I wanted to remedy.”

Oldroyd suggested that adult-onset idiopathic inflammatory myopathy (IIM) previously has been associated with an increased risk for malignancy, including lung, ovarian, colorectal, breast and naso-pharyngeal cancer, as well as lymphoma. These incidents frequently occur 3 years before or after IIM onset.

Ultimately, one in four patients with myositis will develop cancer, according to Oldroyd.

“Cancer is the leading cause of death for patients with myositis,” he said, adding that these cancers are generally identified “at late stage,” which suggests that earlier recognition and screening is essential.

Oldroyd reported that the International Myositis Assessment and Clinical Studies Group (IMACS) formed a steering group to develop a set of recommendations for IIM-associated cancer screening. The group reviewed 117 data sets to determine their recommendations.

“Some were observational, some were screening trial studies,” Oldroyd said.

An initial draft of the document was sent to 75 experts in 22 countries worldwide. In addition, patient partners provided “invaluable input,” according to Oldroyd.

Recommendations were assigned as “strong” or “conditional” based on the extent to which the benefits outweighed the risk. In addition, the level of evidence supporting each recommendation was assigned a value of high, moderate, low or very low. Voting members were asked to provide a numerical rating scale for each recommendation.

Ultimately, Oldroyd and colleagues drafted and approved 18 recommendations, of which 13 were deemed strong while five were conditional.

“By strong I mean that the clinician should do something,” Oldroyd said. “By [conditional] I mean the clinician should consider doing something.”

None of the recommendations were backed by strong evidence, according to Oldroyd. Moderate evidence supported eight of the recommendations, while there was low evidence for four and very low evidence for three recommendations. Three other recommendations had no evidence supporting them, but were formed using expert consensus.

Regarding risk factors, the group included those associated with myositis subtype, myositis-specific antibodies (MSA) and myositis-associated antibodies (MAA), along with clinical risk factors. High-risk patients include those with dermatomyositis, those with TIF1-gamma or NXP2 and those aged 40 years or older.

For screening investigations, Oldroyd recommended several approaches including clinical exam, full patient history, blood count, liver function tests, erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP), urinalysis and chest X-ray.

“This is all in addition to any age- and sex-appropriate cancer screening programs in any country,” he said.

Screening frequency should be based on the risk factors in any given patient. Some patients will simply need basic screening at the time of myositis diagnosis, while others may require PET or other imaging analyses.

Additional recommendations state that PET or CT scan may be considered if a patient has a high risk for myositis at initial exam or diagnosis. Upper or lower gastrointestinal endoscopy may also be used in patients with a high number of risk factors for myositis-associated cancer. In addition, naso-endoscopy may be considered in patients with a high risk for nasopharyngeal carcinoma.

The recommendations also state that clinicians should consider cancer screening for all patients who demonstrate “red flags” such as unintentional weight loss, a family history of cancer, smoking, unexplained fever and night sweats.

Oldroyd acknowledged that evidence supporting these recommendations is insufficient, and that the document is likely to be updated in the coming years.

“This is a foundation for future evidence and future amendments to this guideline,” he said.