Idiopathic inflammatory myositis is characterized by progressive weakness of the proximal muscles. There is a higher risk of malignancy than in the normal population. The aim of this study was to evaluate the frequency of malignancy among 251 myositis patients. We also compared clinical and immunological characteristics of cancer-associated myositis with primary myositis. There were no malignancies among polymyositis, overlap, or juvenile myositis patients. Twenty-two of ninety dermatomyositis patients also had a malignant disease. Patients with cancer-associated dermatomyositis were significantly older than primary myositis patients and had more severe cutaneous and muscle symptoms. Dysphagia and diaphragmatic involvement were more frequent among cancer-associated patients, while extramuscular features were less frequent. After successful treatment of the malignancy, we were able to manage myositis symptoms. One-year survival rate was significantly better in primary dermatomyositis patients. The subset of cancer-associated myositis differs from primary myositis in many aspects of its clinical and immunological features. Prognosis and life expectancy in cancer-associated myositis patients is determined by the underlying malignant disease. Therefore, age- and sex-specific examinations for detection of an underlying malignancy are important in the management of patients with dermatomyositis.

Association between cancer and myositis has been extensively reported and malignancy is a potentially life-threating complication in myositis. In this retrospective study authors give an overview of Hungarian cancer-associated myositis (CAM) patients treated at a single centre managing 450 myositis patients. All patients were diagnosed according to Bohan and Peter. Statistical analysis of disease onset, age, sex, muscle, skin and extramuscular symptoms, muscle enzymes, presence of antibodies, treatment and prognosis was performed. 43 patients could be considered as having CAM. 83.72% had cancer within one year of diagnosis of myositis. Most common localizations were ductal carcinoma of breast and adenocarcinoma of lung. Significant differences were observed between CAM and the non-CAM control patients: DM:PM ratio was 2.31:1 vs. 0.87:1, respectively (p = 0.029), age at diagnosis was 56.60 ± 12.79 vs. 38.88 ± 10.88 years, respectively (p < 0.001). Tumour-treatment was the following: surgical removal in 55.81%, chemotherapy in 51.1%, radiotherapy in 39.53%, hormone treatment in 18.6%, combination therapy in 51.16% of patients. Muscle enzyme levels of patients undergoing surgery were significantly reduced after intervention. 36 patients died (83.72%); 25 DM (83.33%) and 11 PM patients (84.62%); 5 years survival was 15.4% for PM and 27.5% for DM. This study demonstrates that DM, distal muscle weakness, asymmetric Raynaud's phenomenon, older age, ANA-negativity are risk factors for developing malignancy and polymyositis patients have less chance of long-lasting survival. It is very important to think about cancer and follow every single myositis patient in the clinical routine because survival rate of CAM is very poor.

No abstract

No abstract

Cancer-associated myositis differs from primary myositis in many aspects. Prognosis and life-expectancy are determined by the underlying malignancy. Therefore, patient-specific examinations for detection of an underlying cancer are important in the management of patients. Recent clinical findings and new possibilities in immunoserological testing may result in the elaboration of an evidence-based recommendation for cancer screening programs in patients with IIM in the future.