Prevalence of paraneoplastic rheumatic syndromes and their antibody profile among patients with solid tumours

The aims of this study were to assess the prevalence of paraneoplastic rheumatic syndromes in a cohort of patients with newly diagnosed solid tumours and to describe their autoimmune profile, comparing it to the controls. Screening questionnaires (3,770) were distributed, and during a three-step study, 94 patients were confirmed to have both paraneoplastic syndrome and oncology diagnoses. Three control groups–patients with undifferentiated arthritis, Raynaud's phenomenon for non-malignant causes and solid tumours only–were designed to compare with the paraneoplastic cases and their immunology profile. The prevalence of paraneoplastic rheumatic syndromes was 2.65% (95% CI 0.21–3.20). The group of patients with arthritis and the group of patients with Raynaud's syndrome were found to prevail among other clinical presentations of paraneoplastic rheumatic syndromes. Both paraneoplastic syndromes were linked to malignancies of the urogenital system. Antinuclear antibodies were found to be similarly frequent in the paraneoplastic arthritis, paraneoplastic Raynaud's phenomenon and the solid tumour groups. No differences were observed when comparing paraneoplastic arthritis and undifferentiated arthritis, except that the patients with paraneoplastic arthritis were older. Comparing paraneoplastic Raynaud's to Raynaud's phenomenon, male preponderance in the paraneoplastic Raynaud's phenomenon group was observed, and the patients were obviously older. Paraneoplastic rheumatic syndromes are rare and more often occur in older patients. Among them, paraneoplastic arthritis and Raynaud's syndrome were the most frequent. The immunology profile does not help in discriminating between arthritis and paraneoplastic arthritis patients and is of limited use in Raynaud's differential diagnosis.