The difference between study recommendations, stated policy, and actual practice in a clinical trial.

Background: We determined whether physicians involved in a clinical trial adhere to the study recommendations or the stated policy of their treatment centre with respect to the administration of boost radiation after breast conserving surgery.

Patients And Methods: Boost radiation treatment policy was determined by survey at 25 oncology centres involved in a randomised trial of breast or breast plus nodal radiation in Canada. Actual practice was compared with stated policy and study recommendations.

Results: Among 248 subjects, 201 (81%) were treated according to stated policy [kappa=0.40, 95% confidence intervals (CI) 0.27-0.52; P<0.0001], indicating only a fair to moderate agreement between stated and actual practice, while 232 (94%) were treated according to study recommendations (kappa=0.59, 95% CI 0.40-0.77; P<0.0001), indicating moderate to near substantial agreement between study recommendations and actual practice (P=0.88 for z-test of difference). In a multivariate analysis, subjects who had invasive disease at a resection margin were more likely to get a boost than those with margins clear of invasive tumour by 2 mm [odds ratio (OR) 49, 95% CI 7.6-322; P<0.0001].

Conclusions: Physicians appear compliant with study recommendations for a non-randomised manoeuvre in a clinical trial, possibly at the expense of compliance with stated local policy. Clinical trial protocols should incorporate standard practice.