Incidence and Risk of Occult Cancer in Advanced-Stage Mandibular Osteoradionecrosis

Advanced mandibular osteoradionecrosis (ORN) often requires segmental resection and reconstruction. Although ORN has distinct clinical and radiographic features, detecting occult cancer preoperatively remains challenging. The goal of this study was to determine the incidence and risk factors of occult cancer in patients undergoing surgery for advanced mandibular ORN.

Medical records of mandibular ORN patients who underwent compound or composite segmental mandibulectomy with flap reconstruction between 2010 and 2022 were reviewed. Data on demographics, ORN presentation, and surgical details were collected. The primary outcome was the incidence of occult cancer in resected specimens, and secondary outcomes included associated risk factors, cancer characteristics, and survival outcomes. Univariable and multivariable logistic regression analyses were used to identify factors associated with occult cancer. Overall survival (OS) and disease-specific survival (DSS) were assessed using Kaplan-Meier analysis.

Among 267 patients included in the study, 24 (9.0%) were found to have occult cancer. Multivariable analysis revealed that bleeding (OR, 4.76; 95% CI, 1.30 to 17.42; P = 0.018), surgery within 6 months of diagnosis (OR, 5.51; 95% CI, 2.02 to 14.99; P = 0.001), and disease extension greater than 4 cm (OR, 6.33; 95% CI, 2.30 to 17.46; P < 0.001) were significant risk factors. Occult cancer was associated with lower 5-year DSS and OS compared with pure ORN (DSS, 50.2% versus 81.3%; OS, 47.4% versus 77.5%; P < 0.001).

Occult cancer was present in a notable proportion of advanced ORN cases. Clinical bleeding, early surgery, and extensive disease were significant risk factors, underscoring the need for diagnostic vigilance and guiding preoperative counseling.