title: Postoperative (Chemo)Radiotherapy for Oral Cavity Squamous Cell Carcinomas: Outcomes and Patterns of Failure.
abstract: To determine outcomes after adjuvant radiotherapy for squamous cell carcinoma of the oral cavity and to correlate locoregional recurrence patterns with radiotherapy target volumes.
  
  
  
  All patients receiving adjuvant radiotherapy±chemotherapy after surgery with curative intent for oral cavity squamous cell carcinoma between 2007 and 2012 were retrospectively analysed. Locoregional recurrences were reconstructed on the planning computed tomography scan by both deformable image co-registration and by visual assessment. Recurrences were categorised as in-field, marginal or out-of-field if >95%, 20-95%, and <20% of the recurrence volume was encompassed by 95% of the prescription isodose, respectively.
  
  
  
  In total, 106 patients with a median follow-up of 42 months were included. Oral cavity subsites included oral tongue (54%) and floor of mouth (32%). Thirty (28%) patients received concurrent chemotherapy. Fifty-five (52%) patients received bilateral neck radiotherapy. Two year overall, disease-free, local disease-free, regional disease-free and distant metastases-free survival were 72, 83, 92, 89, 94%, respectively. On multivariate analysis, extracapsular nodal spread was the only factor significantly associated with inferior overall survival. Fourteen (13%) patients have experienced locoregional failure. Of the eight local recurrences at the primary tumour site, four, three and one were classified as in-field, marginal and out-of-field, respectively. Of 10 regional recurrences, one, one and eight were in-field, marginal and out-of-field. There were 7/21 (33%) contralateral regional recurrences in patients with pN2a/b disease who did not receive contralateral neck irradiation; there were 0/21 (0%) and 0/9 (0%) contralateral regional recurrences in patients with pN0 or pN1 disease, respectively, who did not receive contralateral neck irradiation.
  
  
  
  Marginal recurrences highlight the need for generous target volume delineation. Based upon rates of contralateral regional recurrences, a comprehensive approach to target volume selection should be advised for tumour subsites with bilateral lymphatic drainage in the presence of pN2a/b disease.
authors.affiliation: Department of Clinical Oncology, Leeds Cancer Centre, Leeds, UK; Department of Radiation Oncology, Eskisehir Osmangazi University Medical Faculty, Eskisehir, Turkey.
authors.forename: E
authors.initials: E
authors.lastname: Metcalfe
authors.affiliation: Department of Medical Physics, Leeds Cancer Centre, Leeds, UK.
authors.forename: L
authors.initials: L
authors.lastname: Aspin
authors.affiliation: Department of Medical Physics, Leeds Cancer Centre, Leeds, UK.
authors.forename: R
authors.initials: R
authors.lastname: Speight
authors.affiliation: Department of Clinical Oncology, Leeds Cancer Centre, Leeds, UK.
authors.forename: E
authors.initials: E
authors.lastname: Ermiş
authors.affiliation: Department of Clinical Oncology, Leeds Cancer Centre, Leeds, UK.
authors.forename: S
authors.initials: S
authors.lastname: Ramasamy
authors.affiliation: Department of Clinical Oncology, Leeds Cancer Centre, Leeds, UK.
authors.forename: K
authors.initials: K
authors.lastname: Cardale
authors.affiliation: Department of Clinical Oncology, Leeds Cancer Centre, Leeds, UK.
authors.forename: K E
authors.initials: KE
authors.lastname: Dyker
authors.affiliation: Department of Clinical Oncology, Leeds Cancer Centre, Leeds, UK.
authors.forename: M
authors.initials: M
authors.lastname: Sen
authors.affiliation: Department of Clinical Oncology, Leeds Cancer Centre, Leeds, UK. Electronic address: Robin.Prestwich@nhs.net.
authors.forename: R J D
authors.initials: RJ
authors.lastname: Prestwich
mesh_terms: D000328:Adult; D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy / Q000473:pathology / Q000532:radiotherapy*; D059186:Chemoradiotherapy, Adjuvant / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000188:drug therapy / Q000473:pathology / Q000532:radiotherapy*; D009364:Neoplasm Recurrence, Local / Q000453:epidemiology / Q000473:pathology*; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D017211:Treatment Failure
keywords: Chemotherapy; deformable image registration; oral cavity cancer; radiotherapy; recurrence