Incidence and impact of dysplasia at final resection margins in cancers of the oral cavity.

Background: The literature often cites margin status as being free, close or involved by tumor but there is very sparse evidence of the relevance of dysplasia at resection margin. To compare the impact of dysplasia at final resection margin (D-FRM) and other margin statuses on overall survival (OS) and disease free survival (DFS).

Methods: This is a retrospective review of 1700 treatment naïve oral squamous carcinoma patients who underwent surgery between January 2012 and December 2015. The study arm consisted of patients with dysplasia at final resection margin (D-FRM). Each of these patients were double propensity matched to obtain positive (P-FRM), close (C-FRM) and free final resection margins (F-FRM).

Results: There was no hazard discrimination in survival among the D-FRM and C-FRM (vs F-FRM; p-0.597, HR-1.207 (0.621-2.346) and p-0.075, HR-1.594 (0.947-2.684), respectively). A decreasing survival trend was observed as the grade and number of D-FRM margins increased. Although not significant, the addition of adjuvant therapy for D-FRM showed a trend towards improved survival outcomes compared to C-FRM, especially with chemotherapy. The presence of D-FRM, irrespective of grade, had a similar impact on survival as C-FRM and underscores the possible need for treatment intensification.