Adverse Events Relating to Radiation Therapy in Patients with Collagen Vascular Disorders

Abstract

To evaluate treatment related toxicity in patients with collagen vascular disorder (CVD) undergoing contemporary radiotherapy. This is a retrospective cohort study of patients with CVD undergoing radiation therapy from 2005 to 2022 at a single institution. CVD evaluated included lupus, scleroderma, rheumatoid arthritis, and Sjogren's syndrome or other nonspecific CVD. Patient characteristics, diagnostic and treatment information were extracted from various institutional EMR systems. This study was designated the status of EXEMPT by the institutional IRB. A total of 40 patients undergoing 44 treatment courses with a minimum follow up of 3 months are included in this study. Among the 40 patients identified, 8 were male and 32 were female, with a median age of 62 (range, 17 to 88). Out of the 40 patients in our study, 30 were diagnosed with lupus, 6 with scleroderma, and 4 with other CVDs. In regard to treatments, 38 were performed for malignant conditions and 6 for benign conditions. Treatment locations included 10 to the head and neck region, 16 to the thorax, 6 to the pelvis, and 11 to the skin, soft tissue, or other locations. Treatment modalities were protons for 6 treatments, photons for 33 treatments, and electrons for 5 treatments. Ten patients also received chemotherapy concurrently. Median follow up time was 33.2 months. Table 1 illustrates the extent of skin and subcutaneous reaction by treatment region and radiation doses. One patient, who had Grade 3 radiation dermatitis, underwent a short break in RT due to severity of symptoms. Three patients experienced severe, painful lupus flares during the course of RT, but were managed by medication; however, one was hospitalized due to severe pain and blistering of the skin. Two patients experienced radiation related dermal thickening and fibrosis of the treatment area skin. Contemporary radiation techniques may allow for the treatment of patients with significant collagen vascular disorders. In general, the treatments are well tolerated with the most common side effects relating to skin and subcutaneous tissue or flare up in generalized symptoms. However, the time to resolution of these symptoms may be longer and requires diligent care. Caution should be used in treating patients with CVD.