“A critical takeaway message for clinicians who are determining which individual patient might benefit from a less intensive regimen to treat locally advanced rectal cancer is to first have a multidisciplinary consensus which should encompass review of a rectal MRI, pathology, chest and abdominal imaging, colonoscopy, as well as the patient’s clinical status including comorbidities,” said Dr. Benson, who served as chair of the NCCN Guidelines Panel for Colon/Rectal/Anal Cancers and Small Intestine Adenocarcinoma.
“The location of the rectal tumor (distal versus proximal) and clinical TNM stage also will inform the discussion as to which of the potential total neoadjuvant therapy regimens would be most optimal to reduce the risk of local recurrence and maintain long-term quality of life for the individual patient,” explained Dr. Benson, professor of medicine at Robert H. Lurie Comprehensive Cancer Center of Northwestern University in Chicago.
The effectiveness of less intense treatment for rectal cancer remains a work in progress, Dr. Benson said in an interview. “There is much we still do not know, such as the optimal selection of patients and the durability of this approach over time.”
Patients who undergo watch and wait require intensive follow-up, including sigmoidoscopy, digital rectal exam, and rectal MRI, to detect any evidence of local recurrence that would warrant further intervention, including possible radiation and surgery, he said. A highly skilled multidisciplinary team is a must for individuals who are potential candidates for a less intense treatment regimen, he emphasized.
The treatment of locally advanced rectal cancer continues to evolve, but there is no question that TNT has transformed patient outcomes, including the ability to deintensify treatment for select patients, Dr. Benson said.
However, many research gaps remain, Dr. Benson said in an interview. “For the MSI/dMMR patient who has achieved a complete response from immunotherapy we will need more long-term data to determine the durability of a complete clinical response and long-term avoidance of other interventions including radiation, chemotherapy and surgery.
“The wait and watch strategy for the much more common MSS patient also will require much longer follow-up to determine which patients are destined to recur and which are not,” he added.
“The introduction of monitoring with ctDNA determination over time offers an opportunity to streamline surveillance of patients who have completed combination therapy and for those undergoing watch and wait; however, much more information is required to determine which of the various ctDNA assays are most optimal, and the frequency and duration of ctDNA determination that will lend this approach as a standard of care,” Dr. Benson said.
Dr. Willett and Dr. Benson had no financial conflicts to disclose.
