Does elimination of planned postoperative radiation to the primary bed in p16-positive, transorally-resected oropharyngeal carcinoma associate with poorer outcomes?
The purpose of our study is to compare oncologic and functional outcomes of p16-positive oropharyngeal squamous cell carcinoma (OPSCC) patients, in the presence and absence of planned radiation to the primary bed following transoral surgery (TOS), stratified by T-classification.



Retrospective cohort study of 261, T1-T4, consecutively TOS-treated OPSCC patients.



At a median follow-up of 61months, local recurrence (LR) occurred in 6 (2.3%)patients (3 each in T1-T2 and T3-T4 groups), of which 5 had tumors in the tongue base and one in the tonsil. Of patients not receiving planned primary bed radiation, LR occurred in 3% of T1-T2s versus 17% of T3-T4s. In patients with T1-T2 tumors, Absolute Risk Reduction of LR with primary bed radiation was 3.26% (95% CI: -0.37%, 7%); Number Needed to Treat to prevent one LR was 31 (95% CI: 14.5, 271). Absolute Risk Increase for gastrostomy-tube with primary bed radiation was 34.4% (95% CI: 24%, 45%); Number Needed to Harm was 3 (95% CI: 2.2, 4.2), i.e., for every three patients with T1-T2 tumors receiving primary bed radiation, one had a gastrostomy-tube.



Elimination of primary bed radiation in margin-negative resected, T1-T2 p16-positive OPSCC was not associated with significant compromise of local control, and correlated with superior swallowing preservation, assessed using gastrostomy rate as a surrogate. Lack of primary bed radiation in T3-T4 tumors associated with significantly increased LR rates.
Otolaryngology-Head and Neck Surgery, Washington University School of Medicine, St. Louis, MO, United States.
Parul
P
Sinha
Otolaryngology-Head and Neck Surgery, Washington University School of Medicine, St. Louis, MO, United States.
Patrik
P
Pipkorn
Radiation Oncology, Washington University School of Medicine, St. Louis, MO, United States.
Wade L
WL
Thorstad
Radiation Oncology, Washington University School of Medicine, St. Louis, MO, United States.
Hiram A
HA
Gay
Head and Neck Surgery, Florida Hospital Celebration Health, Celebration, FL, United States; Department of Surgery, University of Auckland Faculty of Medicine and Health Sciences, Auckland, New Zealand. Electronic address: Bruce.Haughey.MD@flhosp.org.
Bruce H
BH
Haughey
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D052685:Alphapapillomavirus / Q000302:isolation & purification*; D002294:Carcinoma, Squamous Cell / Q000235:genetics / Q000532:radiotherapy* / Q000601:surgery / Q000821:virology; D003131:Combined Modality Therapy; D005260:Female; D019942:Genes, p16; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D009959:Oropharyngeal Neoplasms / Q000235:genetics / Q000532:radiotherapy* / Q000601:surgery / Q000821:virology; D012189:Retrospective Studies; D016896:Treatment Outcome
De-escalation; Head and neck cancer; Human papillomavirus; Oropharynx cancer; Postoperative radiation; p16 gene; p16-positive