Valero C., Petrovic I., Zanoni D.K., McGill M.R., Ganly I., Patel S.G., Shah Jatin P Segmental mandibulectomy in patients with oral squamous cell carcinoma: Oncological outcomes and selection criteria for fibula free flap reconstruction. Golova i sheya. Rossijskij zhurnal Head and neck Russian Journal. 2019;7(4):8–17 (in Russian).
Purpose: Patients with advanced stage oral cavity squamous cell carcinoma (OSCC) have a poor prognosis despite aggressive multimodal therapy. Segmental mandibulectomy is required in some of these patients to achieve an oncologically complete resection. Patients undergoing segmental mandibulectomy, particularly of the anterior arch and the body of the mandible, will have significant functional and aesthetic morbidity, and therefore, reconstruction of the resected segment of the mandible becomes an integral part of the surgical plan. Patients must be thoroughly assessed preoperatively to decide which type of reconstruction is optimal and feasible in each case. The aim of this study is to describe the clinicopathological characteristics and oncological outcomes of patients with OSCC who underwent segmental mandibulectomy at our institution, and to define our selection criteria for fibula free flap (FFF) reconstruction.
Methods: After receiving approval from our Institutional Review Board, a retrospective analysis was performed on 2082 consecutive patients who had a biopsy-proven invasive squamous cell carcinoma of the oral cavity treated with primary surgery between 1985 and 2015 at our institution. For this study, we selected the patients that required segmental mandibulectomy to form our final cohort of 311 patients. To analyze our selection criteria for FFF reconstruction, patients were grouped according to the type of reconstruction: patients with FFF reconstruction (n=139, 44.7%) vs patients without FFF reconstruction (n=172, 55.3%). The outcomes of interest were overall survival (OS), disease-specific survival (DSS) and local, regional, and distant recurrencefree probability (LRFP, RRFP, DRFP). To compare variables between groups we used Pearson’s chi-squared test. Survival curves were calculated according to the Kaplan–Meier method and differences in survival were compared using the log-rank test. Unadjusted hazard ratios (HR) were calculated using the Cox proportional hazard model.
Results: The mean age was 64 years (range, 28-100), and 61.4% were men. Nearly 90% of patients had stage III–IV tumors. The most common primary tumor site was lower alveolus (52.1%). Bone invasion was present in 69.8% of patients and 6.1% had positive bone margins; these patients had poor prognosis and management was challenging. For the whole cohort (n = 311), median follow-up time was 32 months (range, 11-87). Five-year OS and DSS were 45.2% and 63.9%, respectively. Five-year LRFP, RRFP, and DRFP were 71.3%, 83.5%, and 83.3%, respectively. Patients with FFF reconstruction were younger (p<0.001) and had less comorbidities (p=0.031). Patients with FFF also had a lower percentage of tumors in the buccal mucosa or retromolar trigone compared to patients without FFF (14.4% vs 34.9%, p<0.001). There were no differences in terms of sex (p=0.187) or tobacco and alcohol use (p=0.773 and p=0.931). No differences in clinical or pathological staging between groups were observed (p=0.729 and p=0.543, respectively). When evaluating adjuvant treatment, the group without FFF reconstruction had a higher percentage of patients, with comorbid conditions, who could not receive adjuvant treatment compared to the group of patients with FFF reconstruction (39.5% vs 26.6%, p=0.050). Patients with FFF had a 5-year OS of 59.0%, compared to 34.8% in patients without FFF (HR: 0.473; 95% CI: 0.358-0.623, p<0.001). This clearly shows the selection bias for patients who had FFF reconstruction. The 5-year DSS in the group of patients with FFF was 69.6%, compared to 58.0% in the group without FFF (HR: 0.634; 95% CI: 0.409-0.984, p=0.042). No significant differences were seen when LRFP was analyzed between groups; the 5-year LRFP in the group of patients with FFF was 74.2%, and 68.6% in the group without FFF (HR: 0.742; 95% CI: 0.462-1.189, p=0.215).
Conclusion: Segmental mandibulectomy with FFF reconstruction remains the treatment of choice in properly selected patients with OSCC. In our cohort of 2082 OSCC patients, 15% needed a segmental mandibulectomy and almost half of them had FFF reconstruction. In general, younger patients with less comorbidities and with anterior arch or body of the mandible involvement are the best candidates for FFF reconstruction. This underscores the need for a thorough preoperative assessment and stringent selection criteria. Patients with positive bone margins have a poor prognosis and management is challenging. New techniques that better assess bone margins intraoperatively need to be studied.
Keywords: Oral cavity; Squamous cell carcinoma; Segmental mandibulectomy; Fibula free flap; Reconstruction
Funding: This study was funded by Fundaciо`n Alfonso Martín Escudero and the National Institutes of Health/ National Cancer Institute (NIH/NCI) Cancer Center Support Grant P30 CA008748. Conflict of interest: The authors declare that they have no conflict of interest.
For citation: Valero C., Petrovic I., Zanoni D.K., McGill M.R., Ganly I., Patel S.G., Shah Jatin P Segmental mandibulectomy in patients with oral squamous cell carcinoma: Oncological outcomes and selection criteria for fibula free flap reconstruction. Golova i sheya. Rossijskij zhurnal Head and neck Russian Journal. 2019;7(4):8–17 (in Russian).