Timing of quality of life (QoL) assessments as a source of error in oncological trials
AIM OF THE STUDY: To produce an empirical estimate of the nature and magnitude of the error produced by incorrect timing quality of life (QoL) measurements in patients receiving chemotherapy.DESIGN: In a multicentre trial, 283 patients were randomized to receive either docetaxel (T) or sequential methotrexate and 5-fluorouracil (MF). The QoL was assessed at baseline and before each treatment using