Risk profile for osteoradionecrosis of the mandible in the IMRT era.
BACKGROUND
The risk for osteoradionecrosis (ORN) of the mandible is positively related to bone volume exposed to > ~ 60 Gy. We hypothesized that in combined treatment, surgery may also be a risk factor.


METHODS
The impact of mandibular surgery on ORN in locally disease-free IMRT cohorts was retrospectively analyzed.


RESULTS
Between October 2002 and October 2013, 531 of 715 patients with oral cavity cancer (OCC), mesopharyngeal cancer (MC), or salivary gland tumor were treated with the mandible bone exposed to ~ > 60 Gy (mean follow-up, 38 months; 7-143 months). Of the 531 patients, 36 developed ORN (7 %; 1.5 % with grade 3-4). The ORN rate in definitive IMRT MC (16/227) and in postoperative IMRT OCC patients with no mandibular surgery (3/46) was 7 % each; in OCC patients with mandibular surgery the rate was 29 % (15/60, p = 0.002). Marginal or periosteal bone resection was found to be a high risk factor (39 %, vs. 7 % followed by segmental or no resection, p < 0.0001).


CONCLUSIONS
Marginal or periosteal bone resection of the mandible was identified as the highest ORN risk factor in our IMRT cohort.
Department of Radiation Oncology, Head Neck Cancer Center, University Hospital Zurich, Raemistrasse 100, 8091, Zurich, Switzerland. gabriela.studer@usz.ch.
Gabriela
G
Studer
Department of Craniomaxillofacial and Oral Surgery, Head Neck Cancer Center, University Hospital Zurich, Zurich, Switzerland.
Marius
M
Bredell
Department of Craniomaxillofacial and Oral Surgery, Head Neck Cancer Center, University Hospital Zurich, Zurich, Switzerland.
Stephan
S
Studer
Department of Otorhinolaryngology, Head Neck Cancer Center, Head and Neck Surgery, University Hospital Zurich, Zurich, Switzerland.
Gerhard
G
Huber
Department of Radiation Oncology, Head Neck Cancer Center, University Hospital Zurich, Raemistrasse 100, 8091, Zurich, Switzerland.
Christoph
C
Glanzmann
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D003131:Combined Modality Therapy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008334:Mandible / Q000528:radiation effects* / Q000601:surgery; D008875:Middle Aged; D010025:Osteoradionecrosis / Q000209:etiology*; D010039:Otorhinolaryngologic Neoplasms / Q000532:radiotherapy* / Q000601:surgery; D011879:Radiotherapy Dosage; D018714:Radiotherapy, Adjuvant; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects*; D012307:Risk Factors
Osteoradionecrosis, ORN; Postoperative ORN; Preradiation surgery; Risk factors, ORN; Surgery-related ORN