Clinical impact of postoperative prognostic nutritional index in colorectal cancer patients undergoing adjuvant chemotherapy.

Preoperative Prognostic Nutritional Index (PNI) could be a crucial factor for the prognosis of colorectal cancer (CRC). However, the clinical impact of postoperative PNI is still unclear, and there have been no reports on the significance of postoperative PNI in patients undergoing adjuvant chemotherapy (AC). We retrospectively analysed 227 consecutive patients who underwent AC after radical surgery for high-risk stage II or stage III CRC. PNI value was calculated before radical surgery and before the introduction of AC. In our study, patients with a low PNI value before surgery showed significantly poorer long-term outcomes than those with a high PNI value. Next, we divided the patients into four groups: patients with a high PNI value before surgery and remained after surgery (Group High-High), a high PNI value before surgery but decreased after surgery (Group High-Low), a low PNI value before surgery but recovered after surgery (Group Low-High), and a low PNI value but did not recover after surgery (Group Low-Low). Although the patients in Group Low-Low showed significantly poorer long-term outcomes than those in Group High-High, the prognosis of patients in Group Low-High was the same as that of patients in Group High-High. In addition, in patients with recurrence after AC, those with a high PNI value at the time of recurrence showed a significantly better survival after recurrence than patients with a low PNI value. Postoperative PNI value could be a prognostic biomarker for CRC patients undergoing AC. Even though the PNI value was low before the surgery, recovery of PNI value by the introduction of AC could improve the prognosis of CRC patients.