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Session: ePoster: Rectal Cancer 11 (Sat315)

EP168 - Outcomes of MRI-Guided Upfront Surgery in Rectal Cancer: Avoiding Unnecessary Chemoradiotherapy

Saturday, May 10, 2025
3:47 PM – 3:52 PM PT
Location: Monitor 9, Sails Pavilion, Upper Level

    ePoster Presenter(s)

  • Laura M. Fernandez, n/a (she/her/hers)

    Colorectal Surgeon
    Champalimaud Foundation
    Lisbon, Lisboa, Portugal

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

    • Author(s)

  • Jose M. Azevedo, MD (he/him/his)

    Colorectal Surgeon
    Champalimaud Foundation
    Lisbon, Lisboa, Portugal

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

  • RH

    Richard Heald, n/a

    Colorectal Surgeon
    Champalimaud Foundation
    Lisboa, Lisboa, Portugal

    Disclosure information not submitted.

    • Senior Author(s)

  • AP

    Amjad Parvaiz, MD, PhD

    Colorectal Surgery Consultant
    Hamad Medical Corporation-Qatar/ Champalimaud Foundation-Lisbon-Portugal
    Doha, Ad Dawhah, Qatar

    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.
Laura M. Fernandez, n/a: This individual has no financial relationships with ineligible companies.
Jose M. Azevedo, MD: This individual has no financial relationships with ineligible companies.
Amjad Parvaiz, MD, PhD: This individual has no financial relationships with ineligible companies.
Image or Table (Do Not add text here):

Purpose/Background: Rectal cancer management has evolved, with neoadjuvant chemoradiotherapy (nCRT) as the gold standard for locally advanced cases due to its benefits in reducing local recurrences, preserving sphincters, and lower toxicity. However, these advantages have not consistently improved disease-free survival (DFS) or overall survival (OS). Total neoadjuvant therapy (TNT) is now used to reduce metastasis rates and increased organ preservation, but its broad application raises concerns about increased toxicity. Improved MRI staging has become crucial for selecting high risk patients for nCRT. This study analyzes oncological outcomes in rectal cancer patients selected for upfront surgery based on MRI findings at a single institution avoiding unnecessary nCRT.

Methods/Interventions: Consecutive rectal cancer patients from a single tertiary institution who underwent primary resectional surgery for rectal adenocarcinoma between september 2013 and may 2024 were identified from a prospectively maintained database. Institutional policy recommendations to neoadjuvant CRT include the presence of high-risk features considered as threatened or invaded Mesorectal fascia (MRF), positive extramural venous invasion (EMVI+) or “high risk mrLR3-4 lower tumours, regardless of the presence of baseline positive lymph nodes.Local Recurrence, Distant metastasis and Overall Survival rates were described using Kaplan-Meier method with a log rank test

Results/Outcomes: A total of 322 consecutive patients with rectal cancer were identified during the study period. 142 patients meet the inclusion criteria and were included in the analysis. 82 (57.7%) were male with a median age of 63 years. Median distance of the tumour to the anorectal ring was 6 cm. 57% of the patients presented with cT3-4 stage tumour, and 38% as node-positive. EMVI positive in only 7.7% of the patients, while MRF involvement was observed in 1 patient with previous RT due to prostate carcinoma.
Pathological outcomes: Negative circumferential resection margin (CRM) was observed in 99.3% of patients, pEMVI was confirmed in 15.5% of patients, and only 2 patients presented R1 resection.
Local recurrence (LR) occurred in 2 patients, resulting in a 3-year and 5-year LRFS of 99% and 97% respectively. Distant metastasis (DM) was observed in 14 patients leading to a 3-year and 5-year DMFS of 91% and 87% respectively. The overall 3-year and 5-year survival were 97% and 95%, with a median follow-up of 34,5 months.
LRFS at 3 years by subgroups analysis based on final pathological stage were 98%, 100% and 100% for stage I, II and III respectively. For distant metastasis free survival at 3years were 98%, 97% and 80%.

Conclusion/Discussion: our study demonstrates that upfront surgery guided by high-resolution MRI staging can achieve excellent oncological outcomes in rectal cancer patients while significantly reducing the need for neoadjuvant chemoradiotherapy (nCRT) and its associated toxicities.