Grading and prognosis of weight loss before and after treatment with optimal cutoff values in nasopharyngeal carcinoma.

Objectives: Weight loss has been validated as a prognostic predictor of nasopharyngeal carcinoma (NPC); however, no global unitary indicator and criteria exist for the definition of weight loss as a prognostic factor. The aim of this study was to determine the most effective indicator for weight loss, evaluate its effect on the prognosis of NPC, and further propose a cutoff value to identify patients in need of nutritional care.

Methods: This retrospective cohort analysis with a median follow-up of 62.3 mo included 681 newly diagnosed patients with NPC. Principal component analysis was performed to select the best continuous variable including weight loss (kg; value of weight loss [VWL]), percent weight loss (PWL), and body mass index loss (BMIL). Multivariable Cox regression analysis and multiple correspondence analysis were performed to select the best cutoff values by different cutoff methods including the median, receiver operating characteristic curve, and threshold searching.

Results: PWL was the highest contributor to the prognosis of NPC compared with VWL and BMIL. Cutoff values of PWL (6.3 and 12.3%) were confirmed to be more important and were proposed to differentiate patients into low-, medium-, and high-risk NPC groups, with their 5-y progression-free survival (84.5 versus 77.9%, P = 0.046; 77.9 versus 67.3%, P = 0.046). PWL was an independent adverse prognostic factor (P = 0.002) for NPC.

Conclusions: PWL is a promising predictor for NPC, and cutoff values could be validated for nutritional risk grading in patients with NPC. These stratified criteria may help accelerate the extensive application of grading nutritional management in NPC therapy.