Patients with autoimmune disease had a higher incidence of late toxicity compared to those without autoimmune disease.
Types of autoimmune disease prone to more severe toxicity:
(1) systemic lupus erythematosus (SLE, high risk of acute or late toxicity)
(2) scleroderma (higher risk of late toxicity)
Sites prone to increased radiation toxicity:
(1) breast
(2) pelvis (including effects on urinary bladder and colon)
Factors affecting outcome:
(1) activity of the autoimmune disease
(2) dose of radiation therapy
(3) concurrent chemotherapy
(4) history of a previous reaction to radiation therapy
Ways of reducing toxicity:
(1) reduction in the total radiation dose administered
(2) reduction of the dose fraction given at any one time (with smaller doses given more often)
(3) reduction of the dose delivered to a given surface area
(4) changing dose and timing of any chemotherapy
