Consistency of phase III clinical trial abstracts presented at an annual meeting of the American Society of Clinical Oncology compared with their subsequent full-text publications

Purpose This study aimed to determine the consistency of phase III clinical trial abstracts presented at American Society of Clinical Oncology (ASCO) Annual Meetings compared with their subsequent full-text publications. Methods We identified abstracts describing phase III clinical trials of chemotherapy, chemoradiotherapy, immunotherapy, and hormone therapy presented at the 36th ASCO Annual Meeting in May 2000. We searched MEDLINE and PubMed for all corresponding publications. Data were extracted from the abstracts and publications that met our inclusion criteria. Results A total of 192 abstracts were identified. Seventy-four abstracts met our inclusion criteria. Six years after the 2000 ASCO Meeting, 74% of abstracts had corresponding publications. The primary end point was stated in 34% of abstracts and 100% of published papers. The primary end point result differed by more than 5% between the abstract and publication in 42% of comparisons. The statistical significance of the primary end point and study conclusions were consistent between abstracts and subsequent publications in 89% and 91% of the comparisons, respectively. Abstracts selected as plenary or oral presentations were significantly more likely to be published. No factors predicted consistency for primary end point significance and overall conclusion between ASCO abstracts and their journal publications. Conclusion When carefully selected, ASCO Annual Meeting abstracts of phase III trials consistently reflect final published results, but some differences were observed that warrant caution in using abstract results to shape treatment decisions before full publication.