Specimen oriented intraoperative margin assessment in oral cavity and oropharyngeal squamous cell carcinoma

Abstract

Objective Evaluate the oncologic outcomes and cost analysis of transitioning to a specimen oriented intraoperative margin assessment protocol from a tumour bed sampling protocol in oral cavity (OCSCC) and oropharyngeal squamous cell carcinoma (OPSCC). Study design Retrospective case series and subsequent prospective cohort study Setting Tertiary care academic teaching hospital Subjects and methods Retrospective case series of all institutional T1-T2 OCSCC or OPSCC treated with primary surgery between January 1st 2009 – December 31st 2014. Kaplan-Meier survival estimates with log rank tests were used to compare patients based on final margin status. Cost analysis was performed for escalation of therapy due to positive final margins. Following introduction of a specimen derived margin protocol, successive prospective cohort study of T1-T4 OCSCC or OPSCC treated with primary surgery from January 1st 2017 – December 31st 2018. Analysis and comparison of both protocols included review of intraoperative margins, final pathology and treatment cost. Results Analysis of our intra-operative tumour bed frozen section protocol revealed 15 of 116 (12.9%) patients had positive final pathology margins, resulting in post-operative escalation of therapy for 14/15 patients in the form of re-resection (7/14), radiation therapy (6/14) and chemoradiotherapy (1/14). One other patient with positive final margins received escalated therapy for additional negative prognostic factors. Recurrence free survival at 3 years was 88.4 and 50.7% for negative and positive final margins respectively (p = 0.048). Implementation of a specimen oriented frozen section protocol resulted in 1 of 111 patients (0.9%) having positive final pathology margins, a statistically significant decrease (p < 0.001). Utilizing our specimen oriented protocol, there was an absolute risk reduction for having a final positive margin of 12.0% and relative risk reduction of 93.0%. Estimated cost avoidance applying the specimen oriented protocol to our previous cohort was $412,052.812017 CAD. Conclusion Implementation of a specimen oriented intraoperative margin protocol provides a statistically significant decrease in final positive margins. This change in protocol leads to decreased patient morbidity by avoiding therapy escalation attributable only to positive margins, and avoids the economic costs of these treatments. Graphical abstract

Trends in Positive Surgical Margins in cT1‐T2 Oral Cavity Squamous Cell Carcinoma

“…Further, beyond use versus nonuse, the method of intraoperative margin assessment has been found to have a considerable effect on final margin status. Horwich et al report a 93% relative reduction in risk of PSM with utilization of a specimen‐oriented protocol, as compared to a tumor bed frozen section protocol 21 . Trends and between‐group differences in the use of intraoperative margin assessment may have contributed to our findings.…”

“…Horwich et al report a 93% relative reduction in risk of PSM with utilization of a specimen-oriented protocol, as compared to a tumor bed frozen section protocol. 21 Trends and between-group differences in the use of intraoperative margin assessment may have contributed to our findings. However, this data are not included in the NCDB.…”

Transoral Robotic Surgery for Oropharyngeal Squamous Cell Carcinoma of the Tonsil versus Base of Tongue: A Systematic Review and Meta-Analysis

“…In surgical oncological care, positive postoperative margins have been widely accepted as a prognostic factor for increased locoregional recurrence [ 60 ]. This has been endorsed in numerous studies of OPSCC, with patients who had final positive margins experiencing reduced disease-specific survival, recurrence-free survival, and overall survival [ 39 , 61 , 62 , 63 , 64 ]. However, all of these studies did not report HPV tumor status, which has been shown to be a crucial delineator when considering OPSCC outcomes [ 48 ].…”

Image-guided surgery in oral cancer: toward improved margin control

“…First of all, since only a selected amount of the resection specimen is investigated, this lead to sampling error. As a result, sensitivity of frozen section is low (approximately 50%) which could lead up to 12.9% conversion from ‘negative’ margins by frozen section to ‘positive’ final histopathology margins [3,4]. Second, even if positive margins are found by frozen section, revising of initial positive margins to final negative histopathology margins using immediate intraoperative reresection was only achieved in 57.9% in a recent study [4].…”