Abstract and Introduction
Abstract
Patients with systemic autoimmune rheumatic diseases, particularly RA, SLE, SS and idiopathic inflammatory myopathies, are at increased risk of developing malignancies. Cancer occurrence adds to the disease burden in these patients, adversely affecting quality of life and life expectancy. This risk is related to the pathobiology of the underlying rheumatic disease including the inflammatory burden, immunological defects, and personal and environmental exposure such as smoking and some viral infections. Immunomodulatory therapies, especially chemotherapeutic agents, are also associated with an increased risk of cancer in these conditions. The decision to use immunomodulating therapies in patients with rheumatic disease must take into account the disease severity, expectations for disease control, comorbidities and host and environmental risk factors for cancer. Effective screening and monitoring strategies are important in reducing the risk of cancer in these patients.
Introduction
Malignancy is an important part of the burden of comorbidities associated with rheumatic diseases. Patients with systemic inflammatory rheumatic disorders generally have an increased risk of developing malignancy, with certain malignant tumours being increased in particular subsets of patients. This increased risk is the result both of fundamental underlying immunological effects of autoimmunity on cancer risk and the risk of cancers associated with drug treatments of rheumatic diseases. In some cases, common environmental risk factors for chronic inflammatory diseases and malignancy contribute to increased comorbidity.
Cancer may also constitute a major diagnostic challenge in patients with rheumatic symptoms. Musculoskeletal complaints may be manifestations of paraneoplastic processes, and some patients with a tentative diagnosis of a chronic rheumatic disorder at presentation actually have an underlying malignancy. In patients with established rheumatic disease, it is sometimes difficult to distinguish symptoms related to the tumour from worsening of the rheumatic condition. In addition, the development of cancer, or a history of malignancy in the past, may have a major impact on long-term management of rheumatic diseases. The purpose of this review is to discuss what is currently known about comorbidity from malignancy in rheumatic diseases, including recent developments relevant to the management of patients with chronic inflammatory disease.