Clinical features and risk factors of lung cancer in elderly patients with dermatomyositis

BACKGROUND: Although there are concerns about the association between dermatomyositis (DM) and malignancy, the clinical features in elderly DM patients with lung cancer are largely unknown. Here, we elucidated the clinical features and risk factors of lung cancer in elderly DM patients. METHODS: The data of elderly DM patients (≥65 years old) with or without lung cancer admitted to the Second Xiangya Hospital, Central South University from January 2016 to November 2022 were retrospectively analyzed. RESULTS: Male patients with elderly onset DM (EODM) symptoms were found to be prone to lung cancer (p < 0.001). Elderly DM patients with lung cancer had a higher ratio of a history of smoking and were more likely to present with heliotrope rash, V sign and dysphasia and elevated monocyte‐to‐lymphocyte ratio (MLR) and there was a higher ratio of anti‐TIF1‐γ‐Ab‐positive patients (all p < 0.05). Occurrence of interstitial lung disease (ILD), elevated aspartate aminotransferase (AST) and anti‐aminoacyl‐tRNA synthetase (anti‐ARS)‐antibody positive rates were less common in elderly DM patients with lung cancer than those without lung cancer (all p < 0.05). Multivariate logistic regression analysis showed smoking history (p = 0.011, OR = 4.532), elevated MLR (p = 0.018, OR = 1.159) and anti‐TIF1‐γ‐Ab‐positive status (p = 0.034, OR = 8.529) were independently associated with the presence of lung cancer, while ILD might be a protective factor (p = 0.024, OR = 0.179) for lung cancer in elderly patients with DM. CONCLUSIONS: Lung cancer is more common in male patients with EODM symptoms. Smoking, elevated MLR and being anti‐TIF1‐γ‐Ab‐positive were associated with higher frequencies of lung cancer in elderly DM patients. It is necessary to screen lung cancer in elderly DM patients with a history of smoking, elevated MLR or being anti‐TIF1‐γ‐Ab‐positive.