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Session: ePoster: Rectal Cancer 1 (Sun8)

EP385 - Total Neoadjuvant Treatment for Locally Advanced Rectal Cancer: Real world outcomes

Sunday, May 11, 2025
9:38 AM – 9:43 AM PT
Location: Monitor 10, Sails Pavilion, Upper Level

    ePoster Presenter(s)

  • Christine Wang, BSc Honors, MD

    Resident
    University of Calgary
    Calgary, AB, Canada

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

    • Senior Author(s)

  • TG

    Tamara I. Gimon, FRCSC, MD, MSc

    General and Colorectal Surgeon
    University of Calgary
    Calgary, Alberta, Canada

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

    • Author(s)

  • AM

    Anthony MacLean, MD, FRCSC

    Clinical Professor of Surgery
    University of Calgary
    Calgary, Alberta, Canada

    Disclosure information not submitted.

  • WB

    William Donald Buie, MD MSc FRCSC FACS FASCRS

    Professor of Surgery and Oncology
    University of Calgary
    Calgary, Alberta, Canada

    Disclosure information not submitted.

All of the relevant financial relationships listed below have been mitigated.
Christine Wang, BSc Honors, MD: This individual has no financial relationships with ineligible companies.
Tamara I. Gimon, FRCSC, MD, MSc: This individual has no financial relationships with ineligible companies.
Image or Table (Do Not add text here):

Purpose/Background: The goal of total neoadjuvant treatment (TNT) for locally advanced rectal cancer is to improve survival and organ preservation. Induction and consolidation chemotherapy regimens are utilized; however, real-world outcomes are needed. Our aim was to review the early use of TNT in one healthcare region, and the associated surgical and oncological outcomes.

Methods/Interventions: A retrospective chart review was performed on adults treated with TNT for rectal cancer in the province of Alberta, Canada between 2021-2022. Patients with metastatic disease at diagnosis were excluded. Patient demographics, disease staging, treatment, surgical and oncologic outcomes were collected and analyzed.

Results/Outcomes: 151 patients met inclusion with a median age of 59 years, 65% male (table 1), and median follow-up of 29 months. On staging MRI, tumor stage was T2 (3%), T3 (58%), and T4 (39%), 47% low tumors ( < 5cm from anal verge). High risk features included: threatened circumferential resection margin (CRM) (66%), extramural venous invasion (66%) and positive nodes (89%; 45% extra-mesorectal). Consolidation TNT was used in 132/151 patients (87%) of which 94% received short course RT. Induction TNT was used in 19/151 patients (13%) of which 89% received long course RT. 57% had chemotherapy adjustments. On clinical/radiographic re-staging, 18% had a complete clinical response, 28% near-complete, 50% incomplete, and 4% progression of the primary. 7% had metastatic disease at re-staging (7% in consolidation, 11% in induction). Surgery with total mesorectal excision (TME) was performed in 133 patients (88%), 12 (8%) underwent non-operative management with close surveillance, 4 (3%) had unresectable metastases, and 2 (1%) died. Of those undergoing surgery, 59% had a low anterior resection, 34% abdominoperineal resection, 4% low Hartmanns and 3% proctocolectomy. 17% included multivisceral resections. R0 resection was 90% (90% consolidation, 94% induction), and 10% overall R1 resection was due to positive CRMs. Pathological complete response was seen in 26% of those who had surgery (25% consolidation, 31% induction). There may be more incomplete TMEs in the consolidation group (14% vs 6%). Post operative complications and readmissions were more common after consolidation. All 8 anastomotic leaks occurred after consolidation. During follow-up, there were 9 locoregional recurrences after primary surgery, 2 local re-growths after non-op management, 32 (21%) distant metastases and 13 deaths (9%).

Conclusion/Discussion: Following TNT, patients have a low risk of progression of the primary tumor and 26% have a complete pathologic response. The rate of incomplete TME is concerning and long-term follow-up is needed to determine the effect on local recurrence. Although non operative management in our cohort was small, a majority maintain complete response. Clinicians should be thoughtful on who is selected for consolidation in light of the higher post operative complications and readmissions.