Impact of postoperative neck radiotherapy on regional control in pathologically node-negative head and neck cancer: A meta-analysis

Background: the appropriate extent of the radiation field (primary site ± neck) in pathologically node-negative (pn0) head and neck cancer (hnc) with adverse features at the primary site remains controversial. we investigated the effect of adjuvant neck radiotherapy (rt) on regional control and survival in patients with pn0 hnc. materials and methods: a systematic search of databases (medline, embase, and cochrane library) was performed for literature published until january 2021. studies of hnc patients with pn0 neck that reported on the regional recurrence (rr) rate and regional recurrence-free survival (rrfs) with respect to adjuvant neck rt were included. results: five studies comprising 553 patients, with a median follow-up of 50 months, were included. the overall rr rates were 2.0% (3/153) for patients treated with adjuvant neck rt and 6.5% (26/400) for patients treated with neck dissection (nd) only. patients who received adjuvant neck rt had a 0.37-fold (95% confidence interval [ci]=0.13–1.04, p=0.06, i2=0%) lower risk of rr than did patients with nd only. the addition of adjuvant neck rt did not significantly improve rrfs (hazard ratio=0.58, 95% ci=0.16–2.08, p=0.41, i2=0%). conclusions: given the rr rate of 6.5% in the rtnegative group, nd alone appears to be sufficient for treating neck disease in pn0 hnc. however, the neck rt group had a lower rr rate than that of the non-rt group, suggesting that pn0 hnc patients with a high risk of recurrence may benefit from elective neck rt.