eP218 - Local Excision for T1 Rectal Cancer: A Population-Based Study of Practice Patterns and Oncological Outcomes

Sunday, June 2, 2024

9:30 AM – 9:35 AM ET, USA

Location: Baltimore Convention Center, Room 318-320

ePoster Presenter(s)

Kelly Brennan, MSc, MD

General surgery resident physician
Queen's University
Queen's University
Kingston, ON, Canada

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

Author(s)

MR

Mandip Rai, MD, FRCPC, MSc

Assistant Professor of Medicine
Queen's University
Kingston, Ontario, Canada

Disclosure information not submitted.
AF

Ameer Farooq, MD MPH FRCSC

Assistant Professor (Colorectal Surgeon)
Queen's University
Kingston, Ontario, Canada

Disclosure information not submitted.
Vanessa Wiseman, MD

General Surgery Resident
Queen's University
Queen’s University
Kingston, ON, Canada

All of the relevant financial relationships listed below have been mitigated.
This individual has no financial relationships with ineligible companies.
Tyler McKechnie, MD, MSc (he/him/his)

Resident Physician
McMaster University
McMaster University
Hamilton, ON, Canada

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

General Surgery Resident
Queen's University
Queen's University
Kingston, ON, Canada

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

Senior Author(s)

SP

Sunil Patel, MD

Associate Professor
Queens University
Kingston, Ontario, Canada

Disclosure information not submitted.

Purpose/Background: Background: Local Excision (LE) for T1 rectal cancer may be recommended in those with low-risk disease, while resection is typically recommended in those with high risk of luminal recurrence or presence of lymph node metastasis.

Objective: To assess practice patterns and outcomes of those with T1 rectal cancer in Ontario, Canada.Methods/Interventions:

Methods: All individuals with T1Nx rectal cancer between 2010-2014 in Ontario, Canada were included. Detailed histopathology records were obtained from the Ontario Cancer Registry. Histopathology details (including risk factors), patient characteristics, staging investigations, stage of disease, treatments and long-term outcomes were determined using linked administrative databases.Results/Outcomes:

Results: 719 patients were identified, including 359 who underwent resection only, 113 with LE and immediate resection ( < 90 days) and 247 with LE. The groups were similar in baseline characteristics (sex, age group, socioeconomic status, comorbidities, p>0.10). The majority of LE was performed via colonoscopy. Piecemeal excision (42% vs. 49%, p=0.28) and positive margin (50% vs 77%, p < 0.01) rates were high in both LE groups with the highest rate in those with immediate resection, while poorly differentiated ( < 5%, p=0.70) and lymphovascular invasion (LVI) (14%, p=0.80) were similar and rare across all groups. In those with LE without immediate resection, 21% ultimately underwent resection (median 150 days, IQR 114-181) and 4% received radiation (median 211 days, IQR 174-242). There was no difference in 5-year overall survival between groups (resection 83.2% vs. LE and immediate resection 82.3% vs. LE 83.3%, p=0.33) and this persisted on adjusted analyses (resection vs LE, and resection vs LE and immediate resection, respectively; HR 0.97 [95%CI 0.70-1.35], HR 0.97 [95%CI 0.60-1.45], p=0.98). Differentiation, piecemeal excisions and LVI were not associated with overall survival in the LE or LE with immediate resection groups (p>0.50).Conclusion/

Discussion:

Conclusions: There were no observed differences in overall survival between those who underwent resection, LE and immediate resection and LE only. A lack of survival difference is notable, considering that many in the LE without immediate resection had risk factors (piecemeal excision) for local recurrence. Although this is observational data, these results call into question the practice of routine resection for those with piecemeal excision for T1 rectal cancer.Overall survival of T1 rectal cancer in Ontario Canada in patients from 2010-2014ASCRS abstract submission 2024 photo.tif