GS1 - Neoadjuvant Radiation versus Upfront Surgery for Upper Rectal Cancer: A Meta-Analysis of the Evidence

Sunday, June 2, 2024

10:18 AM – 10:21 AM ET, USA

Location: Room 314-317

Abstract Podium Presenter(s)

AE

Ahmed Eltahir, MD

Resident Physician
Washington University in St. Louis
Washington University in St. Louis
St. Louis, MO, United States

All relevant financial disclosures have been managed and will be listed below.
This individual has no financial relationships with ineligible companies.

Author(s)

Oluseye Oduyale, MD

Resident Physician
Washington University School of Medicine in St. Louis
Washington University School of Medicine in St. Louis
St. Louis, MO, United States

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This individual has no financial relationships with ineligible companies.
VP

Vikram S. Pothuri, BA

Medical Student
Washington University School of Medicine
St. Louis, Missouri, United States

Disclosure information not submitted.
DH

Daniel Hong, MD

Resident Physician
Washington University in St. Louis
St. Louis, Missouri, United States

Disclosure information not submitted.
Hyun Kim, MD

Associate Professor of Radiation Oncology
Washington University in St. Louis
St. Louis, Missouri, United States

Disclosure information not submitted.
MS

Matthew Silviera, MD MS

Assistant Professor of Surgery
Washington University School of Medicine
St Louis, Missouri, United States

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This individual has no relevant relationships with ineligible companies.
Matthew Mutch, MD, FACS, FASCRS

Professor of Surgery
Washington University School of Medicine
Washington University School of Medicine
St Louis, Missouri, United States

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This individual has no financial relationships with ineligible companies.

Senior Author(s)

WC

William Chapman, Jr, MD

Assistant Professor
Washington University in St. Louis
St. Louis, Missouri, United States

Disclosure information not submitted.

Purpose/Background: Neoadjuvant radiation therapy (NRT) in addition to total mesorectal excision is considered the standard of care for locally-advanced rectal cancers. Improved local recurrence has been consistently shown using NRT in patients with low-mid rectal cancers, but not upper rectal cancers. While guidelines in some countries recommend upfront surgery for the treatment of upper rectal cancer, the role of neoadjuvant radiation is unclear. We thus sought to characterize the effect of NRT compared to upfront surgery in treating upper rectal cancer.

Methods/Interventions: A systematic search through February of 2023 was conducted for relevant articles in Ovid MEDLINE, PubMed, Embase, Scopus, Cochrane Central and Clinicaltrials.gov. Search terms included, but were not limited to: upper rectal, high rectal, rectosigmoid, cancer, neoplasms, surgery, resection, mesorectal excision, and neoadjuvant chemoradiation. Studies were included if they contained an NRT group and an upfront surgery group among upper rectal cancer patients. Adhering to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a full-text review and data extraction were performed by two independent researchers for articles that included oncologic outcomes for patients who received NRT and those who received upfront surgery. Studies that did not define the upper rectum or report outcomes specific to the upper rectum were excluded.

Results/Outcomes: There were 2124 unique citations, from which nine articles comprising 2087 total patients met inclusion criteria for analysis. The NRT group included 853 patients while the upfront surgery group 1234 patients. Selected articles were published from 2005 to 2022 and included two RCTs and seven retrospective cohort studies. Across, all studies defined upper rectal cancer as being at least 9 to 11 cm above the anal verge. One study defined upper rectal cancer to be above the peritoneal reflection and under 12 cm. Long-course RT was primarily administered in five studies and short-course RT was primarily administered in three studies. One study did not include NRT regimen. A reduction in local recurrence was seen among NRT recipients compared to upfront surgery (OR 0.54, 95% CI 0.34-0.86). Additionally, a decrease in overall survival was seen among patients receiving upfront surgery compared to patients receiving NRT (OR 0.73, 95% CI 0.55-0.95). No study reported on the adverse effects of radiation.

Conclusion/Discussion: Despite the upper rectum being imprecisely defined, neoadjuvant radiation improved local recurrence and overall survival in patients with upper rectal cancer. While the role of neoadjuvant radiation in upper rectal cancer remains unclear, this study demonstrates possible benefits. The use of neoadjuvant radiation should be considered with factors such as node status, distance from the anal verge, the peritoneal reflection, and circumferential resection margin. Further studies are need to understand the adverse effects of radiation weighed against any favorable effects seen in oncologic outcomes for upper rectal cancer.