Tumor lysis syndrome following hemi-body irradiation for metastatic breast cancer.

Tumor lysis syndrome (TLS) is a rare serious acute complication of cancer therapy, reported mainly following chemotherapy in patients with large tumor load and chemosensitive disease. These are mainly patients with non-Hodgkin's lymphoma, leukemia and rarely in solid tumors. It is less frequently described after radiotherapy for lymphoid and hematological malignancies. TLS following radiotherapy for solid tumors is a very rare complication. In this report/review we describe a seventy-three-year-old male patient with progressive metastatic carcinoma of the breast to the lungs, liver and bone. He was referred for radiotherapy because of generalized bony pains. The patient was planned for sequential hemi-body irradiation starting with the more symptomatic upper half body. After premedication, he was given 8.5 Gy to the mid point at the maximum chest separation with anterior lung attenuator limiting uncorrected lung dose to 6.15 Gy. A further 3.5 Gy electron boost to the fungating breast tumor was given to the 100%. Forty-eight hours after irradiation he developed hyperkalemia, hyperphosphatemia, hyperuricemia, hypocalcemia and renal failure. These clinical and biochemical changes are typical of tumor lysis syndrome (TLS). Despite hydration, and treating the hyperuricemia, the patient developed coma and died eight days after irradiation. The prophylaxis and management of TLS and in high-risk patients are described to avoid this frequently fatal complication.