TNT vs Conventional Radiotherapy for Locally Advanced Rectal Cancer

New York, New York—During a lively debate session at the 2019 Great Debates and Updates in Gastrointestinal (GI) Malignancies meeting, Christopher H. Crane, MD, Vice Chair and Director, GI Section, Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, went head to head with Noam VanderWalde, MD, MS, Director of Clinical Research, Department of Radiation Oncology, West Cancer Center and Research Institute, on the use of total neoadjuvant therapy (TNT) versus conventional preoperative chemoradiotherapy in the treatment of patients with locally advanced rectal cancer.

Dr Crane opened the discussion by stating that although rectal cancer is now highly curable thanks to modern modality therapy, it still yields long-term morbidity risks. He then directed attendees to a visual slide he was presenting which featured a single-panel cartoon.

“For those in the back who can’t see it, there’s a General talking at a cocktail party saying, ‘Look, I like to avoid overkill but not at the risk of underkill.’ So, if we can avoid the more toxic treatments then, potentially, we can have the same oncologic outcomes with less long-term morbidity,” he said.

Ultimately, Dr Crane’s stance was that TNT is beneficial and worth keeping around for patients with locally advanced rectal cancer. Citing decades of research, he posited that TNT reduced the need for surgery in higher-risk patients, addressed the distant metastatic risk, and increased patient compliance with chemotherapy.

“The cons might be that if there’s a nonresponse to chemotherapy it could be detrimental, but this is fairly uncommon,” said Dr Crane, who asserted more than once that radical surgery is not ideal in this patient population, and encouraged the use of TNT to deflect this invasive procedure.

Although Dr VanderWalde saw fit to reiterate some of the pros in favor of TNT described by his predecessor, he ultimately stood his ground on the advantages of conventional preoperative radiotherapy over TNT.

“There have been multiple preoperative chemoradiation therapy studies; there have been thousands of patients treated on these clinical trials, really kind of establishing this as the standard of care,” he told attendees, although he did also mention that the partial complete response rates seen with this approach are still fairly low.

Not surprisingly, his arguments against TNT use surpassed those of Dr Crane.

According to Dr VanderWalde, potential pitfalls of TNT include that it extends the treatment process by adding time before surgery.

“In my experience, when patients have rectal cancer they often want it out, so having to wait a significant amount of time for that is sometimes a little bit of debate with the patients,” he said.

In addition, TNT allows for concerns regarding whether or not the disease is progressing, and whether chemotherapy related toxicity could hinder a patient’s ability to undergo surgery or receive radiotherapy, Dr VanderWalde stated.

Although his ultimate arguments were that TNT is not as well-established as standard chemoradiation therapy and that the latter should remain the standard of care, Dr VanderWalde extended an olive branch to Dr Crane’s camp, referring to both treatment approaches as “reasonable.”—Hina Khaliq