Ten-year follow-up of patients from EORTC trial 22921 confirmed that fluorouracil-based chemotherapy after preoperative radiotherapy did not affect survival in patients with rectal cancer, according to researchers.
The results were the same whether or not patients also received preoperative chemotherapy, reported Jean-François Bosset of Besançon University Hospital J Minjoz, France, and his associates.
EORTC trial 22921 enrolled 1,011 patients with resectable T3 or T4 M0 rectal adenocarcinoma. Investigators randomized patients to four treatment arms – preoperative radiotherapy alone, preoperative radiotherapy and chemotherapy, preoperative radiotherapy followed by adjuvant chemotherapy, and preoperative radiotherapy plus chemotherapy followed by adjuvant chemotherapy (Lancet Oncol. 2014;15:184-90).
The chemotherapy course included fluorouracil (350 mg/m2 per day IV) and leucovorin (20 mg/m2 per day IV). For preoperative chemotherapy, two courses were given (during weeks 1 and 5 of radiotherapy). Adjuvant chemotherapy was given in four cycles, every 3 weeks. Radiotherapy lasted 5 weeks and consisted of 45 Gy to the posterior pelvis in 1.8-Gy fractions.
After a median follow-up of 10.4 years, overall survival did not differ significantly among the four treatment groups, ranging from 48.4% to 51.9%. Disease-free survival rates also did not differ significantly, ranging from 44.2% to 47.0%. Most recurrences occurred within 5 years, with no significant differences in frequencies of distal metastases and long-term side effects.
Only 43% of patients randomized to adjuvant chemotherapy received the planned dose within the allocated time period, the investigators reported. Such poor adherence might have hampered the ability to assess the value of adjuvant chemotherapy in rectal cancer, they said, adding that "adherence to adjuvant chemotherapy and a preserved dose-intensity over all the cycles will be the crucial issue that will potentially determine the success of these approaches."
The study was supported by EORTC, the National Cancer Institute, Programme Hospitalier de Recherche Clinique, and Ligue contre le Cancer Comité du Doubs. The authors reported that they had no conflicts of interest.
