Pharyngeal-sparing radiation for head and neck carcinoma of unknown primary following TORS assisted work-up.

Abstract

In patients with head and neck carcinoma of unknown primary (HNCUP;pT0) following TORS-assisted workup, we have adopted a pharyngeal-sparing radiation therapy (PSRT) approach targeting only the at-risk neck and omitting treatment of the pharynx. We report outcomes following PSRT, and compare to institutional historical control subjects who received pharyngeal-targeted RT (PRT). Between 2009 and 2018, 172 patients underwent TORS-assisted endoscopy as part of their workup for HNCUP. Following TORS, 54 patients had pT0 disease, of which 45 received RT. Forty-nine percent received PSRT and 51% received PRT. No statistically significant differences existed between the PSRT and PRT groups with respect to overall nodal distribution, p16 positivity (55% vs. 43%, P = .12), neck dissection rates (77% vs. 65%, P = .51), and administration of chemotherapy (55% vs. 65%, P = .55). Median follow-up for PSRT and PRT groups were 24 and 28 months, respectively (P = .04). Two-year RFS was 86% and 74% for PSRT and PRT patients, respectively (log-rank P = .30). Three and six patients recurred after PSRT and PRT, respectively. Two-year OS for PSRT and PRT patients was 91% and 74%, respectively (log-rank P = .31). Compared to PRT, PSRT was associated with statistically significantly less: grade 2+ mucositis (18% vs. 91%, P < .01), new opioid requirement (27% vs. 91%, P < .01), mean weight loss during RT (6.2 lbs vs. 17.4 lbs, P < .01), feeding tube placement during RT (5% vs. 43%, P < .01), and treatment-related unplanned hospitalizations (9% vs. 39%, P = .04). Following TORS-assisted management of patients with pT0 HNCUP, we observed reduced toxicity following PSRT compared to PRT without apparent compromise of disease cure. Level 3 evidence, retrospective review comparing cases and controls Laryngoscope, 130:691-697, 2020.