title: Evaluation of a web-based weight loss intervention in overweight cancer survivors aged 50 years and younger.
abstract: Half of adult cancer survivors under age 50 years are obese. Excess body weight is associated with cancer recurrence, and effective weight loss interventions for younger cancer survivors are needed. Commercially available, online weight loss programmes are readily accessible, but few have been studied in this population. This study employed a single-arm, pre-post intervention (baseline-6 month/baseline-12 month comparisons) to preliminarily explore feasibility, efficacy and safety of an online, commercially available weight loss programme in breast (n= 30) and testicular (n= 16) cancer survivors under age 50 years.
  
  
  
  The intervention included three daily components: exercise, nutritional/behavioural modification strategies and health lessons. Intention-to-treat and completers analyses were conducted. Feasibility was measured by participation (number of participants enrolled/number screened), retention (number of participants attending 6/12 month study visit/number of enrolled) and self-reported adherence rates (average of mean percent adherence to each of the three intervention components). Efficacy was assessed by changes in initial weight (percent weight loss). Safety was assessed by adverse events.
  
  
  
  The mean participation rate was 42%. The retention rate was 59% at 6 and 49% at 12 months. The adherence rate for all participants (completers/dropouts/lost-to-follow-up) was 50.1% at 6 and 44% at 12 months. Completers reported adherence rates of 68% at 12 months. Study participants lost 5.3% body weight at 12 months; completers lost 9%. Only three unexpected adverse events (unrelated to the intervention) were reported.
  
  
  
  Clinically significant weight loss was observed, although retention rates were low. Findings generally support preliminary feasibility, efficacy and safety of this online weight loss programme, and future randomized control trials should be explored.
authors.affiliation: Cancer Prevention and Control Fox Chase Cancer Center Philadelphia PA USA; Center for Clinical Epidemiology and Biostatistics, Department of Biostatistics and Epidemiology University of Pennsylvania Philadelphia PA USA.
authors.forename: S M
authors.initials: SM
authors.lastname: Lynch
authors.affiliation: Abramson Cancer Center University of Pennsylvania Philadelphia PA USA.
authors.forename: C T
authors.initials: CT
authors.lastname: Stricker
authors.affiliation: Center for Clinical Epidemiology and Biostatistics, Department of Biostatistics and Epidemiology University of Pennsylvania Philadelphia PA USA.
authors.forename: J C
authors.initials: JC
authors.lastname: Brown
authors.affiliation: Precision Nutrition Inc Toronto ON Canada.
authors.forename: J M
authors.initials: JM
authors.lastname: Berardi
authors.affiliation: Abramson Cancer Center University of Pennsylvania Philadelphia PA USA.
authors.forename: D
authors.initials: D
authors.lastname: Vaughn
authors.affiliation: Abramson Cancer Center University of Pennsylvania Philadelphia PA USA.
authors.forename: S
authors.initials: S
authors.lastname: Domchek
authors.affiliation: Recruitment, Outreach, and Assessment Resource(ROAR), Abramson Cancer Center University of Pennsylvania Philadelphia PA USA.
authors.forename: S
authors.initials: S
authors.lastname: Filseth
authors.affiliation: Abramson Cancer Center University of Pennsylvania Philadelphia PA USA.
authors.forename: A
authors.initials: A
authors.lastname: Branas
authors.affiliation: Precision Nutrition Inc Toronto ON Canada.
authors.forename: E
authors.initials: E
authors.lastname: Weiss-Trainor
authors.affiliation: Center for Clinical Epidemiology and Biostatistics, Department of Biostatistics and Epidemiology University of Pennsylvania Philadelphia PA USA.
authors.forename: K H
authors.initials: KH
authors.lastname: Schmitz
authors.affiliation: Center for Obesity Research and Education, College of Public Health Temple University Philadelphia PA USA.
authors.forename: D B
authors.initials: DB
authors.lastname: Sarwer
keywords: Weight loss; cancer survivor; internet