Patterns of Failure and Cost Analysis for Integrating a Novel Tumor HPV DNA Assay Into HPV-Associated Oropharyngeal Squamous Cell Carcinoma (HPV+OPSCC) Recurrence Surveillance

Abstract

<h3>Purpose/Objective(s)</h3> HPV+OPSCC surveillance is challenging and costly. Given that a liquid biopsy tumor-specific HPV DNA assay, has reported 100% NPV and 94% PPV, it has great promise in cancer recurrence surveillance. We characterized the patterns of failure in HPV+OPSCC patients at our institution and conducted a cost analysis of various surveillance strategies to design an institutional surveillance guideline that may lower healthcare costs while providing better cancer recurrence detection. <h3>Materials/Methods</h3> We performed a retrospective chart review of 214 p16+ patients with OPSCC, 23 of which had recurrence confirmed with biopsy during a 5-year observation period. Efficiencies in detecting recurrence using imaging vs physical exam with flexible laryngoscopy (FL) were also determined. Total number of imaging studies used in these calculations was estimated at 2 scans annually per patient while total exams with FL was 2.8 exams annually per patient. Using specialty-specific CPT codes and associated professional and medical center charges (follow up visits: $437-$472; PET/CT: $10290; chest CT: $4492; neck CT: $4023; FL: $665; liquid biopsy assay: $1800), financial charges were calculated for two 5-year post-treatment follow up strategies. Strategy A, based on current institution-specific guidelines, includes follow up visits quarterly for 2 years then semiannually for 3 years with a total of 14 visits (FL at every visit) plus annual neck and chest CT with one post-treatment PET/CT. Strategy B, our proposed novel strategy, is semiannual follow up visits with FL for 5 years and liquid biopsy assay at every visit plus additional assays during pre-treatment and 4 weeks during treatment. <h3>Results</h3> Of the p16+ OPSCC patients (n=214), 23 had recurrence of disease (10.75%), mostly within the first 2 years post-treatment (18/23 = 78.26%), and 11 had locoregional recurrence (11/23 = 47.83%). Median follow up time was 44 months post-treatment. Efficiency calculations showed that 72 imaging studies and 2198 exams with FL were needed to detect one recurrence. We calculated total charges of $69,298 for Strategy A and $32,795 for Strategy B, resulting in savings of $36,503 for Strategy B. <h3>Conclusion</h3> FL remained a part of our proposed surveillance strategy (Strategy B) despite its low estimated efficiency because of its utility in reassuring patients, identifying thrush and infection, and diagnosing radiation necrosis and aspiration. Implementing this novel tumor-specific HPV DNA assay according to our proposed scheduling would lower costs by omitting imaging and better guiding clinical decisions in HPV+OPSCC surveillance by providing high sensitivity and specificity in recurrence detection.