Squamous Cell Cancer of an Unknown Primary Head and Neck Site: Is Upfront Neck Dissection Still Relevant in the Era of Chemoradiation?

Abstract

(NPM) is commonly used but often results in incomplete pain control and is associated with its own side effects. Single-institution retrospective reports have provided evidence that prophylactic gabapentin (GP) may reduce the need for NPM in patients undergoing RT, however the ideal dosing schedule is unknown. The purpose of this study was to evaluate whether the use of 300 mg 3 times daily (TID) of GP in a community oncology center will result in reduced need for NPM or reduced weight loss (WL) in patients undergoing RT with or without chemotherapy for oropharyngeal cancer. Materials/Methods: We performed a retrospective chart review of all patients treated with RT for oropharyngeal cancer in our clinic over the last 33 months. From these data, we stratified patients by the use of GP and compared the amount of NPM, the time to initiation of NPM, and the amount of WL between patients who did and did not receive GP. Two-tailed t tests were used to determine significance with a for significance set at P .05. Results: From November 2012 through July 2015, 64 patients with oropharyngeal cancer completed their prescribed RT course and at least 1 month of post-RT follow-up at our institution. Thirty-one patients received GP (at least 300 mg TID) within the first 2 weeks of RT. Patients who received GP had less unintentional WL (9.03 vs 15.82 lbs, PZ.004) and initiated NPM later in their RT course (34.6 vs 22.3 days, P<.001). On subset analysis, patients who underwent upfront surgery and patients with p16-positive disease had less unintentional WL with the use of GP. Oropharyngeal subsite did not influence the effect of GP. No adverse effects were attributed to GP. Conclusion: Patients who initiated at least 300 mg TID of GP within the first 2 weeks of RT for oropharyngeal cancer experienced less WL and a longer time to initiation of NPM compared to those that did not initiate GP. These differences were independent of oropharyngeal subsite. No adverse effects were attributed to GP. Patients who underwent upfront surgery and patients with p16-positive disease derived the greatest benefit from the use of GP. These data support continued exploration of GP use in this patient population. Our institution intends to continue to explore the effect of higher GP dosing in future patients to elucidate potential dose-response relationships. Author Disclosure: T. Dong: None. A. Reed: None. G.C. Jones: None. D. Scoble: None. J. Deeken: None. G.K. Bajaj: None.