Quality of surgery and surgical reporting for patients with primary gastrointestinal stromal tumours participating in the EORTC STBSG 62024 adjuvant imatinib study.

•Surgeons reviewed the primary tumor resection of patients in the EORTC 62024 study.•Only 56% of the patients had been operated on under the correct diagnosis.•91% of the data on the surgery form used the letter of discharge after surgery.•18% of the patients are questionable whether they should have entered the trial.•The inconsistencies might influence the study results in an adjuvant trial.