Patients with HPV related oropharyngeal carcinoma tend to have more favorable outcomes after treatment than their HPV negative counterparts. However, a substantial percentage of patients will develop recurrence in the post treatment setting. Furthermore, it has been recognized that patterns of recurrence among HPV related cases can differ greatly between patients and can be unpredictable, especially when occurring at distant sites. Currently, there are no standard guidelines for surveillance, which frequently leads to repeat costly imaging and frequent office visits with procedures. The development of a novel blood test in the form of a tumor specific HPV DNA assay may have the potential to revolutionize the detection of recurrence within HPV related cases, with early studies demonstrating a 100% negative predictive value and 94% positive predictive value. We set out to propose a modified surveillance strategy using this test as the main method of detection to understand the cost implications of potentially avoiding routine imaging and surveillance visits at our institution.
Methods: 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. Based on our retrospective review, we defined two surveillance strategies, the “current” and “proposed” method which utilizes HPV DNA assay. The current strategy was based on our institution’s consensus surveillance paradigm which includes follow up visits quarterly for 2 years then semiannually for 3 years with a total of 14 visits (endoscopy at every visit) plus annual neck and chest CT with one post-treatment PET/CT. The “proposed” strategy modification compromises of semiannual follow up visits with flexible laryngoscopy for 5 years and HPV DNA assay testing at every visit plus additional assays during pre-treatment and 4 weeks during treatment with imaging to be used at the discretion of the physician(s) in cases of high clinical suspicion. We used select patient cases to perform a flow through, comparative cost analysis to get an estimate of potential cost savings on an per case basis.
Results: 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. The standard work flow model determined that 72 imaging studies and 2198 physical examinations with flexible laryngoscopy were needed to detect one recurrence in our cohort. Based on our cost analysis, we determined a potential individual patient cost reduction of 42% in the post-treatment, surveillance period.
Conclusions: The promising performance of plasma circulating tumor HPV DNA to detect recurrence in HPV+ OPSCC is capable of substantial cost savings in the post treatment surveillance period. Our institutional analysis led us to understand the number of imaging studies required to detect a single recurrence and the associated cost savings by implementing a proposed surveillance strategy with HPV DNA assay test in favor of frequent office visits, endoscopic procedures, and routine imaging.