Predicting complications in elderly patients undergoing oral cancer resection with free flap reconstruction in China: a retrospective cohort study using the modified Frailty Index and Prognostic Nutritional Index.

Objectives: This study aimed to evaluate the predictive abilities of the 5-item modified Frailty Index (5-mFI), Prognostic Nutrition Index (PNI), and their combination in older adult patients undergoing oral cancer resection and free flap reconstruction.

Design: Retrospective cohort study.

Setting: Secondary care involving multiple centres treating older adult patients for oral cancer.

Participants: This study included a total of 1197 patients aged ≥60 years who underwent oral cancer resection with free flap reconstruction between January 2014 and December 2022. The study included patients aged ≥60 years with malignant tumours who underwent selective radical surgery, such as mandibulectomy, maxillectomy, glossectomy or laryngectomy, followed by free flap reconstruction under general anaesthesia. Exclusion criteria included the presence of any inflammatory disease affecting blood test results, incomplete clinical records or missing data for any of the five items in the 5-mFI. Patients were categorised into four groups based on PNI and 5-mFI values: (1) 'Control' (neither frail nor malnourished), (2) 'Frailty' (frail only), (3) 'Malnutrition' (malnourished only) and (4) 'Frailty+Malnutrition' (both frail and malnourished).

Primary And Secondary Outcome Measures: The primary outcome was the rate of complications within 30 days after surgery. Secondary outcomes included unplanned reoperation rates, length of postoperative hospital stay and the predictive performance of PNI, 5-mFI and their combination.

Results: The overall complication rate within 30 days post-surgery was 34.6%. The Frailty+Malnutrition group exhibited the highest risk of complications, longer postoperative hospital stays and increased rates of unplanned reoperation compared with the Control, Frailty and Malnutrition groups. The combined PNI and 5-mFI model significantly improved the predictive value for postoperative complications compared with either PNI or 5-mFI alone.

Conclusions: Older adult patients undergoing oral cancer resection with free flap reconstruction face considerable risk from frailty and malnutrition. Although both 5-mFI and PNI independently demonstrated good predictive abilities for postoperative complications, the combined model provided the best prediction. These findings could help optimise preoperative management in this high-risk population.