ESTRO 36 Abstract Book

S566 ESTRO 36 2017 _______________________________________________________________________________________________

L. Sommers 1 , R. Steenbakkers 1 , H. Bijl 1 , J. Vemer-van den Hoek 1 , J. Roodenburg 2 , S. Oosting 3 , S. De Rooij 4 , J. Langendijk 1 1 UMCG University Medical Center Groningen, Radiation Oncology, Groningen, The Netherlands 2 UMCG University Medical Center Groningen, Oral and Maxillofacial Surgery, Groningen, The Netherlands 3 UMCG University Medical Center Groningen, Medical Oncology, Groningen, The Netherlands 4 UMCG University Medical Center Groningen, University Center for Geriatric Medicine, Groningen, The Netherlands Purpose or Objective To investigate the effect of age on overall survival (OS), cancer-specific survival (CSS) and non-cancer related death (NCRD) in elderly (i.e. ≥70 years) head and neck squamous cell carcinoma (HNSSC) patients treated with definitive radiotherapy compared to younger patients and determine the most important prognostic factors on these survival endpoints. Material and Methods This was a retrospective analysis of prospectively collated data of all consecutive HNSCC patients treated between April 2007 and December 2014 at our department with primary curative radiotherapy (66-70 Gy). Multivariable association models for age were performed as well as a multivariate analysis to identify potential prognostic factors for these endpoints in only the elderly patients. Results The study population was composed of 674 consecutive patients, including 168 elderly patients (24.9%). Three- year OS and NCRD rates in elderly patients were significantly worse, respectively p=0.007 and p<0.001. In the multivariable association analysis on the relation between age and OS, lymph node involvement and worse WHO performance status were found significant confounders. Multivariable association analysis between age and NCRD only identified UICC stage as a significant confounder. Worse WHO performance status, lymph node involvement and specific tumor site were independent prognostic factors for OS and CSS in the elderly patients. Almost half of the elderly patients died during follow-up, of which 45.0% due to index tumor. In elderly patients, treatment with combined modality (radiotherapy with systemic agent) was significantly associated with adverse NCRD.

Conclusion Dose to the anterior mandible could be constrained in most patients. Planned use of this technique will further inform pre-treatment dental assessments and allow greater prospective planning of dental rehabilitation to improve head and neck cancer survivorship. EP-1033 Survival patterns in elderly head & neck squamous cell carcinoma patients treated with definitive RT