Association of tumor downstaging after neoadjuvant chemotherapy with survival in patients with locally advanced nasopharyngeal carcinoma: a retrospective cohort study

Assessing the downstaging effects of neoadjuvant chemotherapy (NACT) in patients with locally advanced nasopharyngeal carcinoma (LANPC) and predicting response to treatment remain challenging. The present study aimed to evaluate the long-term prognosis of downstaging after NACT in patients with LANPC and to investigate the prognostic value of post-NACT tumor downstaging on treatment outcomes in the era of concurrent chemoradiotherapy (CCRT). This retrospective study included 226 patients with stage III (n = 188) and IVA (n = 38) NPC admitted to Haikou People’s Hospital between 1 October 2009 and 1 October 2012. The patients were grouped as downstaging or no after NACT. Overall survival (OS), locoregional failure-free survival (LFFS), and distant failure-free survival (DFFS) were analyzed. Among 226 patients, 196 (86.7%) were in the downstaging group and 30 (13.3%) were in the non-downstaging group. The longest follow-up was 76 months, and the median was 45 months. The 3-year OS rates of the downstaging group and non-downstaging group were 91.0% (95% CI 0.89–0.93) and 69.5% (95% CI 0.66–0.72) (P = 0.005). The 5-year OS rates were 81.6% (95% CI 0.78–0.86) and 53.3% (95% CI 0.49–0.61) (P = 0.001). N downstaging (3-year OS, HR 0.491, 95% CI 0.221–0.881, P = 0.022; 5-year OS, HR = 0.597, 95% CI 0.378–0.878, P = 0.021) was independently associated with OS. In the treatment of LANPC, the patients with downstaging after NACT have a better prognosis than those without downstaging. This study suggests that NACT can improve the prognosis for patients with LANPC if there is downstaging.