GP3a - The Influence of Dental Rehabilitation on the Detection and Rate of Cancer Recurrence after Oral Cavity Malignant Tumor Ablation

Abstract: Immediate microvascular tissue reconstruction is the reconstructive modality of choice after head and neck malignant tumor ablation. Although delayed reconstruction allows for definitive analysis of pathologic margins, studies have shown that immediate reconstruction does not yield higher rates of recurrence.1 Immediate reconstruction is associated with less financial burden, decrease in treatment time, and improved quality of life.1 The use of an implant-retained or -supported prosthetics furthers this improvement in quality of life. Although the previously discussed benefits also apply when endosseous implants are placed immediately at the time of reconstruction, there are concerns of their impact on recurrence in the treatment of malignant tumors. It has been hypothesized that immediate implant placement can result in seeding, interference with the efficacy of adjuvant radiation therapy, and delay in the diagnosis of recurrent disease secondary to radiographic artifact and lack of clinical visibility.2 The primary aim of this study was to assess the impact of dental rehabilitation in the diagnosis of disease recurrence in patients with oral cavity malignancies that underwent free flap reconstruction with endosseous implant placement. The secondary aim was to determine the rate of osteoradionecrosis in patients who underwent adjuvant radiation treatment.

This is a retrospective study from a sample of subjects who underwent immediate reconstruction with a free tissue transfer and either immediate or delayed implant placement for treatment of oral cavity malignancies by the Division of Oral and Maxillofacial Surgery at the Mayo Clinic, MN. Descriptive data were collected on patient demographics, diagnosis, number of implants, history of radiation therapy, and type of prosthesis utilized. The tumors were staged according to the AJCC eighth edition tumor-node-metastasis classification. All subjects received an implant-retained or -supported prosthesis and had a minimum follow-up of 24 months. Recurrence was confirmed by incisional biopsy.

A total of 29 patients with an average age of 54.6 years old, including 12 females (41.4%) and 17 males (58.6%), with an oral cavity malignancy met inclusion criteria. Squamous cell carcinoma was the most common malignancy, occurring in 20 patients (69%), followed by 5 subjects (17.2%) with osteosarcoma. Seven patients (24.1%) experienced a local recurrence and, of these, and 5 had an initial pathologic T4a squamous cell carcinoma. Six of the 24 subjects (25.0%) restored with a fixed prosthesis experienced a recurrence. Fifteen patients (51.7%) had implants placed at the time of reconstruction. Of those, 5 (33.3%) experienced recurrence with the average number of days from reconstruction to diagnosis of recurrence being 810.8 days. Two (14.3%) subjects in the delayed implant group experienced recurrence with the average number of days from reconstruction to the diagnosis of recurrence being 4550 days. Fourteen subjects received adjuvant radiation therapy, of which 4 (28.6%) experienced osteoradionecrosis. Timing of implant placement was equally distributed in patients who experienced osteoradionecrosis.

In conclusion, subjects who underwent immediate implant placement had a higher rate of recurrence (33.3%) when compared to those with delayed implant placement (14.3%). None of the recurrences were directly adjacent to the endosseous implants and the clinical diagnosis of local recurrence was not affected by the presence of a prosthesis. The timing of implant placement was not associated with a higher risk of osteoradionecrosis.

1. Hsieh T-Y, Chang K-P, Lee S-S, Chang C-H, Lai C-H, Wu Y-C, Huang S-H, Lai C-S, Lin S-D: Free flap reconstruction in patients with advanced oral squamous cell carcinoma: Analysis of patient survival and cancer recurrence. Microsurgery 32:598, 2012
2. Weckx A, Riekert M, Grandoch A, Schick V, Zöller JE, Kreppel M: Time to recurrence and patient survival in recurrent oral squamous cell carcinoma. Oral Oncology 94:8, 2019