Reduced-Volume Irradiation of Uninvolved Neck in Patients With Nasopharyngeal Cancer: Updated Results From an Open-Label, Noninferiority, Multicenter, Randomized Phase III Trial.

Abstract

<i>Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the primary end point, may be published when key planned co-primary or secondary analyses are not yet available. Clinical Trial Updates provide an opportunity to disseminate additional results from studies, published in</i> JCO <i>or elsewhere, for which the primary end point has already been reported.</i>We previously reported comparable 3-year regional relapse-free survival (RRFS) using elective upper-neck irradiation (UNI) in N0-1 nasopharyngeal carcinoma (NPC) compared with standard whole-neck irradiation (WNI). Here, we present the prespecified 5-year overall survival (OS), RRFS, late toxicity, and additional analyses. In this randomized trial, patients received UNI (n = 224) or WNI (n = 222) for an uninvolved neck. After a median follow-up of 74 months, the UNI and WNI groups had similar 5-year OS (95.9% <i>v</i> 93.1%, hazard ratio [HR], 0.63 [95% CI, 0.30 to 1.35]; <i>P</i> = .24) and RRFS (95.0% <i>v</i> 94.9%, HR, 0.96 [95% CI, 0.43 to 2.13]; <i>P</i> = .91) rates. The 5-year disease-free survivors in the UNI group had a lower frequency of hypothyroidism (34% <i>v</i> 48%; <i>P</i> = .004), neck tissue damage (29% <i>v</i> 46%; <i>P</i> < .001), dysphagia (14% <i>v</i> 27%; <i>P</i> = .002), and lower-neck common carotid artery stenosis (15% <i>v</i> 26%; <i>P</i> = .043). The UNI group had higher postradiotherapy circulating lymphocyte counts than the WNI group (median: 400 cells/μL <i>v</i> 335 cells/μL, <i>P</i> = .007). In conclusion, these updated data confirmed that UNI of the uninvolved neck is a standard of care in N0-1 NPC, providing outstanding efficacy and reduced long-term toxicity, and might retain more immune function.