For patients with rectal cancer, total neoadjuvant therapy with long-course chemoradiation (LCRT) led to a numerically higher rate of organ preservation compared with short-course radiation therapy (SCRT), according to results of a study.

Results from this study were presented on Saturday, January 21, 2023, at the American Society of Clinical Oncologists Gastrointestinal Cancers Symposium in San Francisco, CA, by Byung Kwan Park, MD, Chung-Ang University Hospital, Seoul, South Korea

Lead author Paul Bernard Romesser, MD, Memorial Sloan Kettering Cancer Center, New York, NY, stated there was an “institutional SCRT mandate with no exceptions” established during the COVID-19 pandemic. For this study patients with rectal cancer treated with LCRT immediately before and after that mandate were compared to patients treated within the mandate period.

There were 332 patients with rectal cancer treated with total neoadjuvant therapy included, 256 who received LCRT and 76 who received SCRT, between January 2018 and January 2021. The most common treatment order was induction chemotherapy, followed by consolidative radiation. For patients who achieved a clinical complete response (cCR), a watch-and-wait approach was recommended while non-responders were recommended to total mesorectal excision. Analyses were performed for local regrowth rate, organ preservation, disease-free survival (DFS), and overall survival (OS).

The median follow-up duration was 32 months for the LCRT group and 28 months for the SCRT group. The 2-year organ preservation rate of all patients in the LCRT group was 40%, compared with 29% in the SCRT group. Both cohorts had a cCR rate of 46%, though this rate was numerically higher in the patients who received radiation first, as compared to those who received chemotherapy first. In patients managed via watch-and-wait, the 2-year local regrowth rate was 20% in the LCRT group and 36% in the SCRT group. The 2-year OS, DFS, and distance recurrence rates were similar across the 2 cohorts.

Dr Romesser et al concluded, “while cCR rates were similar, we observed a numerically higher [organ preservation] rate with LCRT [total neoadjuvant therapy] than with SCRT [total neoadjuvant therapy]. The ongoing ACO/ARO/AIO-18.1 trial, hypothesizing that LCRT [total neoadjuvant therapy] will increase [organ preservation] rates relative to SCRT [total neoadjuvant therapy], should definitively answer this question.”

Source:

Romesser PB, Park BK, Nemirovsky, et al. Organ preservation and total neoadjuvant therapy for rectal cancer: Investigating long-course chemoradiation versus short-course radiation therapy. Presented at 2023 ASCO Gastrointestinal Cancers Symposium; January 19-21, 2023; San Francisco, CA. Abstract 10