Incidence of osteoradionecrosis of the jaws: A retrospective study of 620 head and neck cancer patients treated by radiotherapy

Abstract

Background This study aims to assess systemic and local risk factors influencing the development of osteoradionecrosis of the jaws (ORN) and its incidence in head and neck cancer patients undergoing radiotherapy.Methods This was a retrospective cohort study of 620 adult patients following radiation for a head and neck cancer in 2011 or 2012. Results Of the 181 patients who did not require any extraction, the incidence of ORN was 0.5%. Of the 266 patients with 1491 dental extractions (mean 5.5 teeth per patient) performed before radiotherapy, the incidence of ORN was 3.7%. ORN was always observed in extraction sites located in the field of radiation. No dental extractions were done during radiotherapy. Of the 20 patients with 53 dental extractions (mean 2.7 teeth per patient) performed after radiotherapy, 15 teeth were located in the field of radiation. No case of ORN was reported in that group. For edentulous patients, ORN incidence was 1.7%. Conclusion Within the limitations of this study, the incidence of ORN can be minimized with a meticulous pre-radiotherapy dental examination, a comprehensive treatment plan and diligent post-radiotherapy follow-ups conducted by an experienced multidisciplinary team.

Osteoradionecrosis – an old problem with new consequences

“…Kabir et al stated during RT is the worst time for extractions and best time for post-RT extractions is between 6 weeks and 4 months after RT [11]. However, Liao et al reported that tooth extraction during RT did not significantly increase risk of ORN (HR = 1.303, P = 0.4862) and post-RT extraction after 6 months of RT increase risk of ORN.…”

“…ORN can develop from months to years after RT [3] with Sapienza et al [14] reporting that ORN can develop even 5-10 years post-RT. Multiple studies reported post-RT incidence of ORN was higher in males than females [3,5,11,13,15] because incidence of HNC is higher in males and behavioural factors linked to ORN development and HNC risk being more common in males [16,17].…”

“…This is because floor of mouth, orophyraynx, and tongue cancers are more common than maxillary cancer leading to higher radiation exposure to the mandible [11]. The mandible's compact bone absorbs more radiation making it more susceptible to ORN [2,3,11,13].…”

“…In last three decades, studies have reported that post-RT teeth extraction and number of teeth extracted increased risk of ORN incidence, but the studies varied in sample sizes, associated co-factors, and diagnostic parameters [2,11,42]. According to Sathasivam et al [30] dental alveolar surgery, or dental extractions, performed post-RT have a significantly higher incidence of ORN when compared to dental alveolar surgery pre-RT.…”

“…Most of the studies reported a dose threshold of ≥60 Gy increases risk of ORN [21,54,56,58]. Along with radiation dose threshold the mean dose to the mandible is an important dose factor for ORN incidence [11,32]. Kubota et al reported that V60Gy >14% to the mandible was an independent risk factor for ORN along with the primary site.…”