Timing of neoadjuvant therapy and surgical treatment in rectal cancer

ABSTRACT Study objectives: To evaluate the ideal timing between neoadjuvant therapy and surgical treatment of rectal cancer, as well as the influence on treatment outcomes. Methods: Using PubMed, a systematic literature search was made on the influence of surgery timing after chemoradiotherapy in treating rectal cancer. Results and discussion: A total of 34 articles published until April 2017 were analyzed. Nine of them were randomized clinical trials, one was a non-randomized trial, 23 were retrospective studies, and one was a meta-analysis. These studies compared treatment intervals varying between two and 19 weeks. Intervals of nine to 14 weeks showed increased tumor downstaging and higher rates of complete pathological response. These intervals shown safety for patients. Nonetheless, few studies showed differences in overall survival. The most used intervals between neoadjuvant chemoradiotherapy are six to eight weeks. Despite that, intervals longer than these show potential benefits for patients without putting them at risk of disease progression. Studies evaluating the effect of overall survival and long-term recurrence are scarce. Conclusion: Programming surgery more than eight weeks after chemoradiotherapy seems preferable to the six to eight weeks most recently practiced, increasing tumor downstaging and having higher complete pathological response rates