Prospective monitoring of osteoradionecrosis after postoperative radiotherapy for oral cavity cancer.

Rationale: Osteoradionecrosis (ORN) is a severe late toxicity that can occur after radiotherapy. In severe cases, ORN can lead to extensive bone necrosis, spontaneous fractures of the jaw and fistulas, requiring repeated hospital visitation, and in some cases surgical reconstruction. Patients who undergo postoperative radiotherapy (PORT) for oral cavity cancers are at higher risk for developing ORN. A prospective cohort study can help us better understand the development over time and early signs of ORN, as well as predictive and prognostic factors.

Primary objective: To investigate in a prospective setting the incidence of osteoradionecrosis and the development of associated complaints over time including early signs, after PORT for oral cavity cancer.

Study population: Patients (n=120) with oral cavity cancer T1-4 N0-3 M0 referred for postoperative (chemo)radiotherapy at the Erasmus MC as a primary treatment with curative intent after surgery (local excision or extensive).

Intervention: All interventions are according to applicable standard clinical procedures & protocols for oral cavity cancer treatment at the Erasmus MC Cancer Center.

Main study endpoints: osteoradionecrosis (defined as the presence of exposed bone in irradiated tissue without the presence of tumor recurrence), graded over time according to Notani and CTCAE and RTOG/EORTC criteria.

We hypothesize that the incidence of osteoradionecrosis is higher in patients who undergo postoperative radiotherapy for oral cavity cancers, than in other patients who undergo radiotherapy of the head and neck, and that there are clear early signs of osteoradionecrosis that can be helpfull in early detection of osteoradionecrosis.

Measurements and clinical data will be collected during regular clinical appointments and follow up visits. PROMS will be send previous to clinical meeting.