Watch-and-wait Therapeutic Approach in Locally Advanced Rectal Cancer: An Innovative or Inevitable Option for Rectal Preservation

Neoadjuvant chemoradiation followed by total mesorectal excision through a low anterior resection (LAR) or abdominoperineal resection (APR) is considered the standard treatment approach in most patients with locally advanced rectal cancer. While LAR allows for anatomic rectal preservation, APR leads to significant morbidity and compromised quality of life in rectal cancer patients. Approximately 10-40% of patients achieve clinical complete response (cCR) following neoadjuvant chemoradiation. Meanwhile, the pathologic complete response (pCR) rate is usually less than the cCR rate. The complete response rate may be improved by escalating the radiation dose and optimizing (total) neoadjuvant chemotherapy. Therefore, at least one-fifth of patients will have the chance of rectal preservation using the watch-and-wait strategy. In this therapeutic strategy, patients should be followed up by an active surveillance protocol to detect early tumor regrowth and undergo salvage radical surgery and will, therefore, provide comparable oncologic outcomes to those achieved in patients who undergo initial radical surgery. This study aimed to review the most recent evidence and guidelines regarding the watch-and-wait therapeutic strategy in patients with rectal cancer.