Analysis of Pathologic Complete Response Rates Between Different Neoadjuvant Radiation Treatment Regimens for Rectal Cancer
Abstract/Contents
- Abstract
- The standard of care for rectal cancer is long or short course radiation followed by surgery with or without adjuvant chemotherapy. Recently, total neoadjuvant therapy (TNT), an approach consisting of giving all chemotherapy and radiotherapy prior to definitive surgery, has been demonstrated to be a promising alternative. This study aims to assess the pathologic complete response (pCR) rates among different neoadjuvant treatment regimens and determine if neoadjuvant chemotherapy improves pCR rates. Electronic medical databases were queried to identify rectal cancer patients treated with neoadjuvant therapy at one institution from 2006-2019. Patients were grouped accordingly: long-course chemoradiation (CRT), long-course chemoradiation with chemotherapy (CRT TNT), short-course radiation (SCRT), and short-course radiation with chemotherapy (SCRT TNT). Patients without follow-up data or surgical pathology reports were excluded. pCR was defined as no evidence of disease at surgery. pCR rates were compared using descriptive statistics and Chi-square analysis. 249 patients were analyzed. There were 200 (80.3%) patients who received CRT, 26 (10.4%) who received CRT TNT, 13 (5.2%) patients who received SCRT, and 10 (4%) patients who received SCRT TNT. Initial stage was different between groups, with metastatic patients more likely to receive SCRT TNT (p<0.001). The median time to surgery were significantly different between groups (p<0.001). 11 (42.3%) and 6 (60%) patients received FOLFOX, and 13 (50%) and 4 (40%) of the patients received XELOX for CRT TNT and SCRT TNT, respectively. The remaining patients (7.7%) in the CRT TNT group received Capecitabine. For CRT, 53 (26.5%) patients achieved pCR, 3 (11.5%) in CRT TNT, 1 (7.7%) in SCRT, and 2 (20%) in SCRT TNT. None of these differences were statistically different (p=0.19). On univariate analysis, age (p=0.13), clinical T stage (p=0.13), clinical N stage (p=0.95), time to surgery (p=0.82), and presence of chemotherapy in the neoadjuvant regimen (p=0.22) were not significant predictors for pCR. Surprisingly, in this analysis, total neoadjuvant treatment for rectal cancer did not improve pCR rates over CRT or SCRT alone. Because of the relatively small numbers of patients in the TNT and SCRT groups, interpretation of these data should be considered preliminary. These data indicate that given the high pCR rates achievable with standard of care CRT, additional gains in pCR rates may require a more intensive TNT approach. Future studies are needed to further investigate this hypothesis prospectively.
Description
| Type of resource | text |
|---|---|
| Date created | June 2021 |
| Date modified | December 5, 2022 |
| Publication date | May 4, 2022 |
Creators/Contributors
| Author | Koong, Amanda J. |
|---|---|
| Degree granting institution | Stanford University, Department of Biology, 2021 |
| Thesis advisor | Le, Quynh |
| Thesis advisor | Morrison, Ashby |
Subjects
| Subject | Biology |
|---|---|
| Subject | rectal cancer |
| Subject | total neoadjuvant therapy |
| Genre | Text |
| Genre | Thesis |
Bibliographic information
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- This work is licensed under a Creative Commons Attribution Share Alike 3.0 Unported license (CC BY-SA).
Preferred citation
- Preferred citation
- Koong, Amanda J.; Le, Quynh; Morrison, Ashby. (2021). Analysis of Pathologic Complete Response Rates Between Different Neoadjuvant Radiation Treatment Regimens for Rectal Cancer. Stanford Digital Repository. Available at: https://purl.stanford.edu/rb091nr7015
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Undergraduate Theses, Department of Biology, 2020-2021
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- ajkoong@stanford.edu
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