EP563 - The Role of Neoadjuvant Immunotherapy in Clinical T4 Colon Cancer - A National Cancer Database Review

Sunday, May 11, 2025

4:39 PM – 4:44 PM PT

Location: Monitor 3, Sails Pavilion, Upper Level

ePoster Presenter(s)

Majed El Hechi, MD

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

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Author(s)

Jacob M. Broome, MD

Resident Physician
MedStar Georgetown-Washington Hospital Center
Georgetown Washington Hospital Center
Washington, DC, United States

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Jacob Neary, MD

Resident Physician
MedStar Georgetown-Washington Hospital Center
Medstar Washington Hospital Center-Georgetown University Hospital
Washington, District of Columbia, United States

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Anyelin Almanzar, MD

Colorectal Surgeon
NYU Langone Health

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ZS

Zhifei (Jeff) Sun, MD

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

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Anne Fabrizio, MD (she/her/hers)

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

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SB

Sara Berkey, MD

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

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Erin Teeple, MD

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

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BB

Brian Bello, MD

Regional Chief of Colorectal Surgery
MedStar Health

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Senior Author(s)

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.

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

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

Jacob M. Broome, MD: This individual has no financial relationships with ineligible companies.

Jacob Neary, MD: This individual has no financial relationships with ineligible companies.

Anyelin Almanzar, MD: This individual has no financial relationships with ineligible companies.

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

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

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

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

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

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

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Purpose/Background: The Food and Drug Administration approved immunotherapy for the treatment of MSI-high colorectal cancer in 2017. While the use of neoadjuvant chemotherapy and radiotherapy to improve the resectability of nonmetastatic T4 colon cancer has been described, data on the effect of neoadjuvant immunotherapy on resectability and survival remain limited. We aimed to describe the nationwide use and outcomes of patients treated with neoadjuvant immunotherapy (NeoIO) for clinical T4 colon cancer.

Methods/Interventions: The 2017-2021 National Cancer Database (NCDB) was queried for patients with clinical nonmetastatic T4 colon cancer. Patients who underwent surgery with palliative intent were excluded. Patients were divided into two groups: NeoIO and No NeoIO, based on whether they received neoadjuvant immunotherapy. Patients in the NeoIO group were further stratified and compared based on MSI-High vs. MSI-Low status. Outcomes included margin positivity (R0 vs. R1/R2), multivisceral resection rates, and overall survival. Kaplan-Meier and hazard ratio survival analyses were performed.

Results/Outcomes: A total of 5,377 patients were included, of which 134 (2.5%) underwent NeoIO. On univariable analysis, as compared to the No NeoIO group, NeoIO patients were more likely to be younger than 65 years (34.3% vs. 55.8%, p< 0.001), have T4b tumors (66.4% vs. 48.2%, p< 0.001), have node positivity (47.5% vs. 37.6%, p=0.029), MSI-high status (64.4% vs. 45.9%, p< 0.001), and have received neoadjuvant chemotherapy (73.9% vs. 12.9%, p< 0.001). NeoIO patients were more likely to have an R0 resection (91% vs. 84.6%, p=0.041) and more likely to undergo multivisceral resection (48.5% vs. 28.8%, p< 0.001). After adjustment for patient and disease characteristics, NeoIO patients showed a trend towards improved overall survival compared to No NeoIO patients (HR 0.5, CI 0.25-1.07, p=0.076). Within the NeoIO cohort, MSI-High patients had significantly improved overall survival compared to MSI-Low patients (HR 0.083, CI 0.013-0.51, p=0.007).

Conclusion/Discussion: In the early years of its FDA approval for colorectal cancer, immunotherapy was not frequently used as neoadjuvant therapy for nonmetastatic T4 colon cancer nationwide. Neoadjuvant immunotherapy use was associated with decreased rates of margin positivity, albeit with increased rates of multivisceral resection, and demonstrated increased odds of overall survival in patients with MSI-high tumors.