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

Abstract

Objective 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). Methods 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. Results 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). Conclusion 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 of Evidence Level 3 evidence, retrospective review comparing cases and controls Laryngoscope, 130:691–697, 2020

Locoregional Recurrence in p16‐Positive Oropharyngeal Squamous Cell Carcinoma After TORS

“…The need for adjuvant therapy was determined by the University of Pennsylvania Head and Neck Cancer Multidisciplinary Tumor Board, based on NCCN guidelines 10 . Radiation included intensity‐modulated radiation therapy or proton beam therapy which was administered using a dose‐painting technique as previously described 11–13 . Sixty patients were included who had been enrolled in an institutional phase II clinical trial involving alternative volumes of oropharyngeal irradiation for de‐intensification, which spared radiation to the resected primary tumor site and demonstrated similar locoregional recurrence and survival outcomes compared to standard radiation protocols 13 .…”

“…10 Radiation included intensitymodulated radiation therapy or proton beam therapy which was administered using a dose-painting technique as previously described. [11][12][13] Sixty patients were included who had been enrolled in an institutional phase II clinical trial involving alternative volumes of oropharyngeal irradiation for de-intensification, which spared radiation to the resected primary tumor site and demonstrated similar locoregional recurrence and survival outcomes compared to standard radiation protocols. 13 Chemotherapy was generally given for positive resection margins and lymph nodes with extranodal extension (ENE).…”

Proton Beam Therapy for Head and Neck Carcinoma of Unknown Primary: Toxicity and Quality of Life

“…Although further studies are needed to validate the hypothesis that PRT, particularly IMPT, improves sequelae and QOL relative to IMRT, PRT is entirely compatible with other modern toxicity-reducing techniques, including dose and volume reduction, careful patient selection, and complete diagnostic workup. The PRT seems to be the next natural step in furnishing a patient-centered and toxicity-reducing treatment for HNCUP [ 35 ].…”

Human Papillomavirus and Squamous Cell Carcinoma of Unknown Primary in the Head and Neck Region: A Comprehensive Review on Clinical Implications

“…In one cohort study including p16+ patients and another including >66% HPV+ patients, it has been proposed that the pharyngeal mucosa can be sparred in 44–50% of the patients [ 91 , 102 ], thereby limiting multimodal therapy. Even after a failed primary tumor site identification, there is no difference in overall, local and distant, or regional recurrence-free survival when omitting the pharyngeal mucosa in the RT field for p16+ patients after a thorough diagnostic workup including TORS with clearance of the lymphoid tissue in the oropharynx [ 103 ]. The de-escalation strategy significantly limited grade 2+ mucositis, opioid treatment, weight loss, feeding tube placement, and unplanned hospital admissions [ 103 ].…”