Fatal tumor lysis syndrome in a patient with metastatic colon cancer after palliative chemotherapy

SummaryTumor lysis syndrome (TLS) is a rare but life-threatening complication of chemotherapy in patients with solid tumors such as colorectal cancer. Combination therapy comprising infusional irinotencan, 5-fluorouracil (5-FU), with folinic acid (FOLFIRI) and bevacizumab is considered the first choice for metastatic colorectal cancer. Reports of TLS after therapy with FOLFIRI and bevacizumab are rare. Here we report a case of TLS in a patient with metastatic colon cancer and peritoneal carcinomatosis, which developed 4 days after FOLFIRI and bevacizumab combination therapy. The patient died of acute renal failure 7 days after chemotherapy despite aggressive medical treatment. The large tumor burden, rapid proliferation of cancer cells, and azotemia prior to chemotherapy indicated a high risk of developing TLS in our patient. Although rare, steps to prevent TLS and to manage it aggressively if it occurs are required, especially for high-risk patients.