However, as a result of the GOG 165 study, which was closed prematurely because an interim analysis found that patients in the 5-FU treatment group were not likely to achieve a better outcome, the role of 5-FU (previously popularly included in clinical trials) as a radiosensitizer became subject to debate. Furthermore, a clinical trial performed by the NCI in Canada comparing pelvic RT alone with weekly cisplatin 40 mg/m2 concurrent to RT failed to show improvement of progression free and 5-year survival. While the authors suggested several possible reasons for why their study failed to demonstrate a survival benefit with concurrent weekly cisplatin 40 mg/m2 chemotherapy, other investigators have tried to find another optimal dose and dosing schedule for cisplatin administration.