From the Guidelines
Dermatomyositis patients should undergo CT scans as part of 'enhanced cancer screening' at the time of diagnosis, with the frequency of subsequent scans depending on their risk category and clinical features, as recommended by the international guideline for idiopathic inflammatory myopathy-associated cancer screening 1.
Cancer Screening in Dermatomyositis
The risk of cancer in dermatomyositis patients is a significant concern, with an increased risk of malignancy, particularly in the first few years after diagnosis.
- The initial comprehensive screening should include CT scans of the neck, thorax, abdomen, and pelvis, as well as other investigations such as cervical screening, mammography, prostate-specific antigen blood test, CA-125 blood test, pelvic or transvaginal ultrasonography for ovarian cancer, and faecal occult blood test, as outlined in the international guideline 1.
- Patients with adult-onset dermatomyositis at 'high risk of IIM-related cancer' should undergo 'enhanced cancer screening' at the time of diagnosis and 'basic cancer screening' annually for 3 years, according to the guideline 1.
- Clinicians should consider carrying out an 18F-FDG PET–CT scan for patients with adult-onset dermatomyositis at a 'high risk of IIM-related cancer', where underlying cancer has not been detected by investigations at the time of diagnosis, as recommended by the guideline 1.
Individualized Approach
The frequency and type of cancer screening for dermatomyositis patients should be individualized based on their risk factors, clinical features, and geographic location.
- Patients with 'red flag' symptoms or clinical features, such as unintentional weight loss, family history of cancer, smoking, unexplained fever, or night sweats, should undergo cancer screening regardless of their risk category, as recommended by the guideline 1.
- The rationale for this approach is that dermatomyositis can be a paraneoplastic syndrome, with the immune response against the cancer cross-reacting with skin and muscle tissues, and early detection of associated malignancies is crucial as treating the underlying cancer often improves the dermatomyositis symptoms 1.
From the Research
Dermatomyositis and Cancer Screening
- Dermatomyositis is an autoimmune disease associated with an increased risk of underlying malignancy in a subset of patients 2.
- The risk of malignancy in dermatomyositis patients is well-established, but the subset of patients in whom the benefits of malignancy screening outweigh the risks of harm is unknown 2.
Frequency of CT Scans for Cancer Screening
- There is no consensus on the frequency of CT scans for cancer screening in dermatomyositis patients, and the optimal screening protocol has not been extensively studied 2, 3.
- A retrospective analysis of 2 large US dermatomyositis cohorts found that CT scans were the most common studies to reveal a cancer, and that 59% of these cancers were asymptomatic 3.
- The study suggests that effective malignancy screening of dermatomyositis patients often requires evaluation beyond a history, physical examination, and "age-appropriate" cancer screening 3.
Risk Factors and Cancer Screening
- Risk stratification for cancer in patients with myositis is based on clinical risk factors, myositis clinical subtypes, and myositis-specific autoantibodies 4.
- Clinical risk factors include older age at disease onset, male gender, dysphagia, acute onset/refractory myositis, cutaneous ulceration, necrosis/vasculitis, and elevated inflammatory markers 4.
- Appropriate screening strategies are based on the risk level, but further studies are warranted to determine the role of advanced imaging and comprehensive cancer screening 4.
Patient Perspective and Indirect Costs
- A survey of patients recently diagnosed with dermatomyositis found that patient values and indirect costs need to be considered in choosing a screening modality 5.
- The study contributes to a greater understanding of patients' experience of cancer screening in dermatomyositis, which should be taken into consideration when developing consensus guidelines for cancer screening 5.