PO:25:075 | Cancer occurence in patients with idiopathic inflammatory myopathies: new insights from the analysis of a monocentric cohort

Michele Diomedi¹, Federico Fattorini¹, Simone Barsotti², Chiara Cardelli^1|3, Elenia Laurino⁴, Alessandra Tripoli⁴, Linda Carli⁴, Marta Mosca^1|4. | ¹Rheumatology Unit, Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy; ²Rheumatology, Versilia Hospital, Viareggio, Italy; ³Department of Medical Biotechnologies, University of Siena, Siena, Italy; ⁴Rheumatology Unit, AOUP, Pisa, Italy.

Background. Idiopathic inflammatory myopathies (IIMs) are rare systemic autoimmune disorders, associated with an increased risk of cancer. Data from International Guideline for IIMs-Associated Cancer Screening identified the following conditions as a risk factor for cancer development: Dermatomyositis (DM), Anti-TIF1-gamma and Anti-NXP2 positivity, age >40 years at onset, persistent high disease activity despite therapy, dysphagia and cutaneous necrosis. The objective of the study was to assess the prevalence of cancer in a single-centre cohort of patients with IIMs, exploring possible correlations among cancer development, demographic and clinical parameters.

Materials and Methods. We retrospectively analysed the medical records of consecutive patients diagnosed with IIMs according to the 2017 EULAR classification criteria and followed at our Unit. Data about demography, autoantibody profile, organ involvement and comorbidities were collected. Intergroups comparisons were assessed by using Chi- square, t-test and ANOVA. P values <0.05 were considered significant.

Results. A total of 220 IIMs patients [mean age 66.5±14.3, 77 men (35%)] were enrolled. Among them, 30 (15.8%) had a diagnosis of cancer: 5 prostate, 5 breast, 3 endometrium, 3 lung, 3 larynx, 2 melanoma, 2 colon, 1 nasopharyngeal, 1 thyroid, 1 liver, 1 basal cell carcinoma, 1 squamous cell carcinoma, 1 MALT and 1 osteosarcoma. In this subgroup of patients, the mean age was 74.5± 9.4 years and 16 patients were men (53.3%). An older age and male sex were risk factors for neoplasms (respectively p <0.001 and p=0.03). No IIM phenotype appeared to significantly influence tumor risk, however, some differences emerged. Indeed,no patients with Clinically Amyopathic DM (CADM) and Immune-Mediated Necrotizing Myositis (IMNM) developed cancer. On the contrary, in the subgroup of Anti-synthetase syndrome (ASS) we found that 7 on 30 patients (23%) developed a cancer. Autoantibodies positivity for anti-Ro52 and anti-TIF1-gamma was associated with a higher number of neoplasms (p=0.01 and p=0.02, respectively). Among organ involvement, oesophageal dysmotility was associated with cancer (p=0.04). None of the patients with calcinosis had malignancies. Among the different comorbidities, dysthymia, dyslipidemia, hypertension (p<=0.04), stroke (p=0.02) and hypothyroidism (p=0.03) were more frequent in IIMs patients with cancer.

Conclusions. More than 15% of IIMs patients of our cohort had a diagnosis of cancer. Although this association is known from previous works, our analysis has allowed us to identify additional factors that may be associated with the development of neoplasia, such as antiRo52 positivity. Furthermore, cancer is not rare in ASS, showing a prevalence that is comparable to that already observed in DM. Finally, our results suggest that IIMs patients with cancer could have more frequently cardiovascular, psychiatric and endocrinological comorbidities. These preliminary data could help rheumatologists in the clinical profiling of this subgroup of patients and could be useful to optimize cancer screening in the assessment of IIMs patients, aiming at improving their management.