Ramathibodi Hospital, Mahidol University, Ratchathewi, Thailand
Teerada Siripoon , Conor O'Donnell , Nikolas Naleid , Patrick Starlinger , Thomas D. Atwell , Cornelius A Thiels , Susanne Warner , Jessica L. Mitchell , Krishan Jethwa , Christopher Leigh Hallemeier , Kellie Leanne Mathis , Sherief Shawki , Amit Mahipal , Zhaohui Jin
Background: Local therapies potentially offer a curative approach for patients with oligometastatic colorectal cancer (CRC). The effectiveness of systemic chemotherapy following definitive local treatment in this setting is not well-defined. Tumor-informed circulating tumor DNA (ctDNA) might guide management strategies after curative-intent local treatment. Methods: This is a single institution retrospective study of patients with CRC who underwent curative-intent local therapy to an isolated site of metastatic disease and had post-intervention tumor-informed ctDNA (Signatera) testing. The study was approved by the institutional review board. Clinical characteristics, including ctDNA results, were collected and evaluated. Kaplan-Meier method and log-rank test were used to calculate and compare disease-free survival (DFS). Factors associated with DFS were analyzed using multivariate Cox proportional hazards model. Results: 45 patients were included with median age of 59 years, 62% being male, 91% white, and 53% with stage IV disease at diagnosis. 37% of the patients had RAS mutations, no patient had BRAF mutation, and 2.2% patient had mismatch repair deficient disease. Isolated liver metastases were present in 80% of patients, lung metastases in 11% and other sites in 9%. 44 patients received chemotherapy prior to definitive treatment, with a median treatment duration of 16 weeks. ctDNA tests were done prior to local therapy in 23 patients, with 14 cases (61%) testing positive. Definitive treatment included resection (58%), ablation (13%), radiotherapy (4%), and multimodality (25%). Post-definitive treatment chemotherapy was administered to 24 (53%) patients. ctDNA positivity following definitive therapy was observed in 10 patients (22%), which was associated with a poorer prognosis, with a median DFS of 5.3 months compared to 21.3 months for the ctDNA-negative group (p<0.001). These findings were confirmed on multivariate analysis. In patients who had negative ctDNA after definitive local treatment, median DFS was 14.9 months for those who received post-intervention chemotherapy versus 21.3 months for those without post-intervention chemotherapy (p=0.835). Conclusions: Patients with negative ctDNA results following definitive local therapy for isolated metastatic CRC have better prognosis. Post-intervention chemotherapy in this group of patients was not associated with improved DFS. ctDNA guided omission of post-intervention chemotherapy following curative-intent local treatment of oligometastatic CRC warrants further study.
Recurrence | Median DFS (months) | P value | Hazard ratio (univariate analysis) | |
---|---|---|---|---|
No additional chemotherapy (N=16) | 8 (50%) | 21.3 (12.3-NR) | ||
With additional chemotherapy (N=19) | 9 (47.4%) | 14.9 (8.4-NR) | 0.835 | 1.11 (0.42-2.89) |
Disclaimer
This material on this page is ©2024 American Society of Clinical Oncology, all rights reserved. Licensing available upon request. For more information, please contact licensing@asco.org
Abstract Disclosures
2024 ASCO Gastrointestinal Cancers Symposium
First Author: Conor O'Donnell
2024 ASCO Genitourinary Cancers Symposium
First Author: Young Suk Suk Kwon
2024 ASCO Gastrointestinal Cancers Symposium
First Author: Hendrik-Tobias Arkenau
2023 ASCO Annual Meeting
First Author: Anne Hansen Ree