title: Predictors of weight loss during conformal radiotherapy for head and neck cancers - how important are planning target volumes?
abstract: OBJECTIVE
  Nutritional compromise is common during high dose radiotherapy (RT) or chemoradiotherapy (CRT) for head and neck cancers. We aimed to identify the factors that determine nutritional outcome for head and neck cancer patients during radiotherapy.
  
  
  METHODS
  Data from 103 patients with head and neck cancer treated with highly conformal radiotherapy to doses of 60 Gy or more in 30-33 fractions in the adjuvant or definitive setting was analyzed. All patients received complex 3D conformal radiotherapy (3DCRT) or intensity modulated radiotherapy (IMRT). Patients received regular nutritional counseling and need-based interventions. Their weight was recorded at the beginning and end of radiotherapy. Using univariate and multivariate models we tested possible predictors of weight loss of >5% and NG tube requirement.
  
  
  RESULTS
  The mean weight loss was 3.8%. The incidence of weight loss >5% was 37.9% and NG tube placement was 24.3%. The factors significantly associated with >5% weight loss in the univariate analysis were tumor site (oro-hypopharyngeal vs. others), definitive vs. adjuvant RT; prescription dose of >60 Gy vs. 60 Gy; CRT vs. RT alone; prescription dose planning target volume (PTV) volume >235 cc and total PTV volume >615 cc. Age, sex, T stage, N stage and modality (3DCRT/IMRT) were not significant. In multivariate analysis, the total PTV volume, prescription dose PTV volume and use of chemotherapy were significant after controlling for other factors. Patients could be risk stratified based on the use of CRT and large PTV volumes. Patients with none, one or both factors had a likelihood of >5% weight loss of 0%, 30.3%, and 56.9% (p < 0.001) and likelihood of NG tube placement of 5.3%, 15.2% and 37.3% (p = 0.007).
  
  
  CONCLUSIONS
  It is possible to predict weight loss and NG tube requirements from disease and treatment related factors. PTV volumes are important predictors of nutritional compromise. Risk stratification may enable more focused counseling and identification of patients who require preventive interventions.
authors: Department of Radiation Oncology, Tata Medical Center, Kolkata, India. indranil.mallick@tmckolkata.com
authors: I
authors: I
authors: Mallick
authors: S K
authors: SK
authors: Gupta
authors: R
authors: R
authors: Ray
authors: T
authors: T
authors: Sinha
authors: S
authors: S
authors: Sinha
authors: R
authors: R
authors: Achari
authors: S
authors: S
authors: Chatterjee
mesh_terms: D005260:Female; D006258:Head and Neck Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D020266:Radiotherapy, Conformal / Q000009:adverse effects; D012189:Retrospective Studies; D012307:Risk Factors; D016896:Treatment Outcome; D015431:Weight Loss / Q000528:radiation effects*
keywords: Chemoradiation; PTV; enteral nutrition; head and neck cancer; radiotherapy; weight loss