Critical weight loss predicts poor prognosis in nasopharyngeal carcinoma

BACKGROUND: The impacts of weight loss on prognosis in nasopharyngeal carcinoma (NPC) remain unclear. The present study was therefore undertaken to investigate the association between critical weight loss and long-term survival in NPC patients. METHODS: The eligible 2399 NPC patients were reviewed. Weight change was categorized into critical weight loss (CWL) and non-critical weight loss (Non-CWL). The associations of CWL with long-term survival were analyzed by Cox regression in the entire patient and two subsets. Propensity score matching was performed to reduce the effects of confounding factors. RESULTS: CWL was defined as body weight loss of ≥4.6 %. Compared with patients without CWL, patients with CWL had significantly lower 5-year OS (72.4 vs. 79.3 %, P < 0.001), FFS (71.1 vs. 78.4 %, P <0.001), and LR-FFS (78.1 vs. 84.8 %, P <0.001), respectively. After adjustment for potential confounders, CWL remained an independence prognostic factor for OS (HR = 1.352; 95 % CI 1.160–1.576; P < 0.001), FFS (HR = 3.275; 95 % CI 1.101–9.740; P = 0.033), and LR-FFS (HR = 6.620; 95 % CI 2.990–14.658; P < 0.001), respectively. Furthermore, subgroup analysis in the cohort of patients received concurrent chemoradiotherapy or radiotherapy alone confirmed the results in the entire patient even after the propensity-score matching. In IMRT cohort, CWL was also significantly associated with a lower OS (P = 0.04) and FFS (P = 0.04). CONCLUSIONS: CWL has a significant and independent impact on long-term survival in nasopharyngeal carcinoma patients. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12885-016-2214-4) contains supplementary material, which is available to authorized users.