ALB and malnutrition: His preoperative BMI was 31.2, with a serum albumin level of 4.2 g/dL and a PNI of 57.4; however, due to malnutrition induced by parenteral nutrition and inflammation resulting from an anastomotic leak, the serum albumin level declined to 2.1 g/dL, and the PNI decreased to 25.5 by postoperative day 8.