GSTM1 and neoplasm: For the risk score for prolonged hospitalization, defined as 0-7 days vs. 8+ days of hospital stay, we assigned each patient 1 point for each of the following factors that have been shown to be significantly associated with the risk of prolonged hospitalization: Hb at admission <11.05 g/dL; tumor localization: right-sided colon; fluid intake intraoperatively >3.75 liters; RAA: absent; number of drainage tubes >/=2; postoperative hematocrit level <29.5%.