Time interval between neoadjuvant radio-chemotherapy and surgery in rectal cancer: is the long interval correct for all patients?

Background: Optimal time between neoadjuvant radio-chemotherapy period and surgery remains controversial in patients with rectal cancer: an increasing number of studies show results in favor of a long interval.

Methods: We conducted a retrospective analysis of the cases of low-middle rectal adenocarcinoma undergoing neoadjuvant RT-CT and surgery: the primary endpoint was the complete pathological response rate and the secondary endpoint the rate of complications. We analyzed cases from 1/01/2003 to 31/12/2018 divided in two periods: from 2003 to 2010 (23 pts) and from 2011 to 2018 (23 pts). The two periods were characterized by two different surgical teams which use different time intervals (≤ vs. >8 weeks).

Results: The pCR rate is 21.7% in both groups; as regards the complications, the difference between the two groups is in grade IIIb: 8.7% in the first group and 17.4% in the second group (P=0.66).

Conclusions: Although our study is based on a small number of patients, it shows the same rate of pCR with respect to two different time intervals; this suggests the need for studies based on the division of patients into subgroups and the evaluation of different time intervals in order to reach the best oncological outcomes.