Prognostic Nutritional Index Prior to Rectal Cancer Resection Predicts Overall Survival

Prognostic nutritional index (PNI) correlates with postoperative complications and survival in colorectal cancers. Separate studies for rectal cancers are not available where the majority have preoperative radiation, operated by minimally invasive approaches and have diverting ostomies.Consecutive rectal resections between October 2014 and December 2017 from a single center were included. PNI was calculated as 10 x (serum Albumin) + 0.005 x TLC (per mm³) before operation. Multivariate cox regression was used with overall survival (OS) as the dependent variable. Interaction terms of PNI with neoadjuvant therapy, surgical approach and postoperative complications were used to assess specific subgroups.Three-hundred forty elective rectal resections were included with a mean PNI of 46.711 (SD - 6.692), and a median follow up of 44 mo. In multivariable regression, PNI predicted OS (HR - 0.943; p-0.001). Interaction of PNI with preoperative radiation or surgical approach (open, laparoscopic, or robotic) did not change its influence on survival. PNI predicted survival with similar hazard even in patients without major postoperative complicationsDespite routine diversion after rectal resections, PNI predicted OS with an absolute survival benefit of 1.2% at 3-year for every unit increase in PNI irrespective of preoperative therapy or surgical approach.