Anatomic Diagram as a Novel Assessment Strategy for Subclinical Local Residual Disease in Sinonasal Squamous Cell Carcinoma and Intestinal-type Adenocarcinoma

Objective: In the last two decades, transnasal endoscopic surgery (TES) has become pivotal in the management of sinonasal tumors. This approach involves a multiblock tumor resection, adding complexity to the interpretation of surgical margins after pathological examination. This study compares different strategies to infer subclinical local residual disease (SLRD), aiming to identify and validate the best available method for assessing SLRD after transnasal endoscopic resection of sinonasal squamous cell carcinoma (SCC) and intestinal-type adenocarcinoma (ITAC). Methods: Three methods to estimate SLRD (as either absent—R0 - or microscopically present—R1) were applied in patients who received negative margins-aimed endoscopic resection: sole-pathologist examination, multidisciplinary evaluation, and anatomic diagram-based assessment. The primary outcome to compare methods was time-to-recurrence (TTR) stratification provided by these methods. Results: 105 patients were included (50 SCC and 55 ITAC). All three methods resulted significantly associated with TTR in both ITAC and SCC populations. In a multivariate model, only SLRD assessed with the anatomical diagram was independently associated with time-to-local-recurrence (TTLR) in SCC and TTR in both ITAC and SCC groups. The concordance index (C-index), the area under the curve (AUC), and the incremental AUC (iAUC) were higher for the anatomical diagram method in the ITAC and SCC cohorts. Conclusion: The anatomic diagram proved to be the best available strategy, yet with limitations, for assessing SLRD, demonstrating superior TTR stratification compared to traditional methods.