A woman, aged 56, was diagnosed with an inadequately segregated cecal adenocarcinoma with metastases to ovaries, omentum, and sigmoid colon. After undergoing 12 cycles of infusional 5-fluorouracil, leucovorin, and oxaliplatin (FOLFOX-4 regimen), she entered into remission. A pelvic recurrence was diagnosed by physicians after thirteen months. As such, the old lady was administered with 9 cycles of FOLFOX-6 plus bevacizumab. While a clinical complete response was attained through the treatment, an occurrence of pancytopenia was detected. The biopsy of her bone marrow was congruous with therapy-related acute myelogenous leukemia. The analysis of her chromosome showed structural rearrangements. These included fractional deletion of the long arms of chromosomes 5, 7, 20, and 21, plus trisomy of chromosome 8 and losses of chromosomes 3 and 11. Remission was achieved due to induction chemotherapy. However, the woman passed away two months later after the progress in her colon cancer caused complications. It is probable that the administration of oxaliplatin was linked to leukemia.