Case report: grade 4 radiation-induced colitis following conventional reirradiation to a hip metastasis.

Palliative radiation therapy has been widely used for treatment of pain from metastatic bone disease. However, reirradiation is required in approximately 20% of patients initially treated with single fraction conventional palliative radiotherapy. There is a paucity of literature as to toxicities associated with reirradiation, and a lack of knowledge overall as to the cumulative dose limits for the organs at risk. We describe an uncommon late grade 4 adverse event of large bowel colitis in a patient initially radiated with 8 Gy in a single fraction, and reirradiated to the same area 3 months later with 20 Gy in 5 fractions due to pain progression.