Safety of resection margins in CAD/CAM-guided primarily reconstructed oral squamous cell carcinoma-a retrospective case series.

Objectives: After resection of malignancies of the jaws, CAD/CAM procedures have become standard for primary bony reconstruction. Even so, these techniques may limit surgical resection safety. Therefore, the aim of the study was to examine osseous as well as soft tissue resection margins after CAD/CAM-guided tumor resections and reconstructions.

Methods: A retrospective analysis of patients treated with oral squamous cell carcinoma (OSCC) from 2014 to 2019 was performed. Inclusion criteria were CAD/CAM-guided osseous resection and primary reconstruction. Evaluation was performed for histological confirmed resection margins (hard and soft tissue) as well as recurrence of the disease related to the resection status.

Results: In 46 patients, bony resection margins were classified: tumor free (R0 41/46), microscopical invasion (R1 1/46), and close margin (R0 < 4 mm 4/46) respectively for soft tissue 29/46 tumor free (R0), 7/46 close margin (R0 < 4 mm), 5/46 R1, and 4/46 could not be further determined (Rx). Fourteen patients (14/46) showed recurrent disease (2/46 locoregional) without association with the bony resection margin status. Recurrence occurred predominantly (13/46) in high-staged tumor patients. R1/close margin/Rx resection of the soft tissue resulted in a significant earlier recurrence when compared with R0 resection.

Conclusion: CAD/CAM procedure allows safe tumor resection with the profit of a guided and accurate reconstruction. In contrast to positive soft tissue margins, positive bony resection margins did not increase recurrence parameters.