EP582 - Complete Pathologic Response for Locally Advanced Rectal Cancer in patients undergoing Total Neoadjuvant Therapy vs. Neoadjuvant Chemotherapy NCDB 2018-2021.

Sunday, May 11, 2025

4:00 PM – 4:05 PM PT

Location: Monitor 6, Sails Pavilion, Upper Level

ePoster Presenter(s)

BM

Brian Monahan, MD

Colorectal Fellow
Medstar Health
Washington, DC, DC, United States

All of the relevant financial relationships listed below have been mitigated.
This individual has no financial relationships with ineligible companies.

Author(s)

Anne Fabrizio, MD (she/her/hers)

Assistant Professor of Surgery
MedStar Health
Washington, District of Columbia, United States

All of the relevant financial relationships listed below have been mitigated.
This individual has no financial relationships with ineligible companies.

Senior Author(s)

BB

Brian Bello, MD

Regional Chief of Colorectal Surgery
MedStar Health

All of the relevant financial relationships listed below have been mitigated.
This individual has no financial relationships with ineligible companies.

Author(s)

Erin Teeple, MD

Faculty
MedStar Washington Hospital Center
Washington, District of Columbia, United States

All of the relevant financial relationships listed below have been mitigated.
This individual has no financial relationships with ineligible companies.
PA

Preetha Ali, MD

Assistant Professor of Surgery
MedStar Health
Washington, District of Columbia, United States

All of the relevant financial relationships listed below have been mitigated.
This individual has no financial relationships with ineligible companies.
SB

Sara Berkey, MD

Assistant Professor of Surgery
MedStar Health
Washington, District of Columbia, United States

All of the relevant financial relationships listed below have been mitigated.
This individual has no financial relationships with ineligible companies.
ZS

Zhifei (Jeff) Sun, MD

Assistant Professor of Surgery
MedStar Health
Washington, District of Columbia, United States

All of the relevant financial relationships listed below have been mitigated.
This individual has no financial relationships with ineligible companies.
Majed El Hechi, MD

Surgical Resident
MedStar Georgetown - Washington Hospital Center
MedStar Georgetown University Hospital
Washington, DC, United States

All of the relevant financial relationships listed below have been mitigated.
This individual has no financial relationships with ineligible companies.

All of the relevant financial relationships listed below have been mitigated.

Brian Monahan, MD: This individual has no financial relationships with ineligible companies.

Anne Fabrizio, MD: This individual has no financial relationships with ineligible companies.

Brian Bello, MD: This individual has no financial relationships with ineligible companies.

Erin Teeple, MD: This individual has no financial relationships with ineligible companies.

Preetha Ali, MD: This individual has no financial relationships with ineligible companies.

Sara Berkey, MD: This individual has no financial relationships with ineligible companies.

Zhifei (Jeff) Sun, MD: This individual has no financial relationships with ineligible companies.

Majed El Hechi, MD: This individual has no financial relationships with ineligible companies.

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Purpose/Background: Treatments and survival for locally advanced rectal cancer have significantly improved survival over the past several years. The recent PROSPECT trial showed that neoadjuvant FOLFOX was non inferior to the current standard of care of neoadjuvant chemoradiotherapy. Recent protocols have combined neoadjuvant chemotherapy with chemoradiotherapy for a Total Neoadjuvant Therapy (TNT) approach.

Methods/Interventions: A retrospective review of the National Cancer Database (NCDB) was conducted from 2018-2021 identifying patients with locally advanced rectal cancer (T3+, any N, M0) who received neoadjuvant chemotherapy alone and were able to achieve complete pathologic or clinical response. These were compared to patients who achieved a complete pathologic or clinical response after receiving TNT. Patients who underwent local excision, palliative surgery, intraoperative radiation therapy or adjuvant chemotherapy or radiation were excluded. Patient demographics were also obtained. A Kaplan-Meier survival curve was constructed comparing the two groups.

Results/Outcomes: From 2018-2021, 3085 patients were identified to have achieved a complete pathologic or clinical response after undergoing neoadjuvant TNT or chemotherapy alone. 5.2% received only chemotherapy while 94.8% received TNT. 14.1% of patients receiving chemotherapy alone achieved a complete clinical or pathologic response compared with 19.0% who received TNT. There was no difference between age, sex, and pretreatment tumor staging between those who achieved a complete response after receiving TNT vs. chemotherapy. Additionally, there was no difference in mortality and rates of sphincter preservation between the two groups.

Conclusion/Discussion: While Total Neoadjuvant Therapy is associated with a slightly higher rate of complete pathologic response, a small subset of patients were able to achieve a complete pathologic response with chemotherapy alone. For these subsets of patients, there were no differences in initial tumor stage, node status or age of presentation. Additionally, no differences in survival or rates of sphincter preservation were seen between the two groups. Limitations of this work include possible differences in the drugs and duration of chemotherapy used or whether chemotherapy used in TNT was induction or consolidation. Additional limitations were due to the database unable to identify patients following a “watch and wait” protocol. Future work could be conducted to see if there is specific tumor biology that can predict patients who are able to achieve complete pathologic responses with chemotherapy alone.