ORIGINAL RESEARCH article
Front. Oncol.
Sec. Gastrointestinal Cancers: Colorectal Cancer
Volume 15 - 2025 | doi: 10.3389/fonc.2025.1573819
Pathologic complete response after neoadjuvant therapy for locally advanced rectal cancer in a real-world setting -a population-based study
Provisionally accepted
Lina Cadili*
Jonathan M LoreeMichael Peacock
Kimberly DevriesAmandeep GhumanAhmer A KarimuddinTerry PhangManoj J Raval
Carl Brown- University of British Columbia, Vancouver, Canada
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Aim: To determine the impact of time from neoadjuvant therapy (NAT) to surgery on complete pathologic response (pCR) rate in patients with locally advanced rectal cancer. NAT decreases local recurrence of rectal cancer. Some patients achieve pCR. The optimal time between NAT and surgery to maximize pCR remains uncertain. Method: We identified adults with Tany, Nany, M0 rectal adenocarcinoma treated with short-course radiation therapy (SCRT) or long-course chemoradiotherapy (LCRT) followed by total mesorectal excision. Multivariable logistic regression examined characteristics associated with pCR and survival. Results: Between 2000-2017, 3476 patients were included. Of these, 1554 (44.7%) received LCRT and 1796 (51.7%) SCRT. The pCR rate was 13.2% (181/1373) among the LCRT group and 1.5% (26/1770) among the SCRT group. pCR among the SCRT group was positively associated with weeks from SCRT to surgery (OR 1.45, 95% CI 1.13,1.86; p=0.003), tumor grade (grade 1 OR 5.72, 95% CI 1.70, 19.30, p=0.005), and stage (stage 1 OR 7.07, 95% CI 2.49, 20.08, p=<0.001). pCR rate among the LCRT group was not associated with weeks from LCRT to surgery but was associated with sex and stage. Median follow-up was 9.5 years, and median overall survival (OS) was 9.7 years. Among patients receiving LCRT, the 5-year OS rate was higher (69.8%) when surgery followed LCRT by 6-10 weeks compared to those undergoing surgery <6 weeks or 10+ weeks post-LCRT (p = .003). Conclusion: Among rectal cancers treated with LCRT in a population-based cohort, longer delay to radical resection is associated with increased pCR. However, overall pCR was lower than those reported in trial populations.
Keywords: colorectal cancer, rectal cancer, complete pathologic response (pCR), Neoadjuvant Therapy, Locally advanced rectal cancer, oncology
Received: 09 Feb 2025; Accepted: 05 May 2025.
Copyright: © 2025 Cadili, Loree, Peacock, Devries, Ghuman, Karimuddin, Phang, Raval and Brown. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Lina Cadili, University of British Columbia, Vancouver, Canada
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