Selection of patients for randomised trials: a study based on the MACOP-B vs CHOP in NHL study

Abstract

Background: Selection of patients for a clinical trial is affected by awareness of the existence of the trial, interest in the study question and clinical practices and views of the clinicians.

Aims: To investigate the selectivity that may have occurred at Peter MacCallum Cancer Institute (PMCI) during the ANZ Lymphoma Group trial of MACOP-B vs CHOP in non-Hodgkin's lymphoma (NHL).

Methods: NHL patients at PMCI in the study period were assessed against the trial's eligibility criteria. Comparisons were made between eligible (except for consent) non-trial patients and all patients actually randomised into the trial.

Results: Of 497 patients presenting during the trial period, 320 (64%) did not meet the specified eligibility criteria, 102 (21%) were unsuitable on other grounds (age and medical) and 75 (15%) were eligible. Of those eligible, 43 (57%) were entered into the trial and 32 (43%) were not. Four non-trial patients had inappropriate application of eligibility criteria and 13 unknown reason. Eligible non-trial patients were similar to trial patients in most patient and tumour characteristics and overall survival. Significantly more non-trial patients had higher stage disease (p = 0.02). More non-trial patients had lower grade histology, but this was not significant.

Conclusions: Physician selectivity occurred with respect to patient entry, but trial and non-trial patients were similar in most characteristics. Eligibility criteria should specify that patients can withstand all trial drugs and patient availability for treatment and follow-up. PMCI trial accural could have been up to 33% greater. These results suggest the trial accrual period could have been 25% shorter. Patient entry into this trial by PMCI clinicians compared favourably with other centres.