ASCO Perspective Quote

"Testing patients with stage III colon cancer for ctDNA following surgery is a low-risk procedure that is fairly simple to complete. Many patients may be interested in this procedure if given the opportunity. It's important for oncologists to be aware of these findings so that they can have risk-benefit conversations with their patients," said Laura Vater, MD, MPH, Indiana University Simon Cancer Center.

Study at-a-Glance

Focus	Stage III colon cancer that has been removed with surgery
Population	1,011 patients
Main Takeaway	For patients with stage III colon cancer that was surgically removed, a blood test to find circulating tumor DNA (ctDNA) can help determine prognosis and treatment benefit.
Significance	When colon cancer has spread to nearby lymph nodes but not to distant parts of the body, it is considered stage III. One out of three patients with colon cancer are diagnosed at stage III. The conventional initial treatment for stage III colon cancer is surgery to remove as much of the tumor as possible followed by treatment with one of several chemotherapy regimens, including FOLFOX chemotherapy. Previous research has shown that non-steroid anti-inflammatory drugs (NSAIDs), including aspirin and COX-2 inhibitors, can reduce the risk of developing colon cancer. COX-2 inhibitors are a type of NSAID that specifically block COX-2, a cyclooxygenase enzyme that causes inflammation. The randomized, phase 3 CALGB/SWOG 80702 clinical trial was designed to see if the COX-2 inhibitor celecoxib could also improve disease-free survival (DFS) in patients with stage III colon cancer for patients with stage III colon cancer that has previously been surgically removed and who received FOLFOX chemotherapy. The initial results showed that celecoxib did not significantly improve DFS in patients with stage III colon cancer. This is a new analysis of a subset of the patients from CALGB/SWOG 80702 that was designed to identify patients who were more likely to have a recurrence of cancer and determine whether these patients may also benefit from the addition of celecoxib to their treatment.

ALEXANDRIA, Va. - A new study found that adding celecoxib to FOLFOX chemotherapy improved disease-free survival in patients with stage III colon cancer who tested positive for ctDNA after surgery. The research will be presented at the 2025 American Society of Clinical Oncology (ASCO) Gastrointestinal Cancers Symposium, taking place January 23-25 in San Francisco, California.

About the Study

This analysis of a subset of the patients from CALGB/SWOG 80702 was conducted to learn if a blood test to detect ctDNA could identify patients who were more likely to have a recurrence of cancer. This analysis also tested whether celecoxib was a helpful treatment for patients whose blood tested positive for ctDNA.

Key Findings

• Of the 1,011 patients who had ctDNA testing done, 189 (18.7%) had blood samples that tested positive for ctDNA.
• After three years, 86.6% of patients who were ctDNA negative had no cancer growth. In comparison, only 36.8% of patients who were ctDNA positive had no cancer growth.
• Patients who were ctDNA negative who took celecoxib did not have a statistically significant improvement in disease-free survival, or the amount of time after treatment ends before cancer grows back, when compared to a placebo. However, in patients who were ctDNA positive, celecoxib significantly improved disease-free survival when compared to a placebo.
  • After 3 years, 44.1% of patients who were ctDNA positive and who took celecoxib had no cancer growth. In comparison, 26.6% of patients who were ctDNA positive who took a placebo had no cancer growth.
• Patients who were ctDNA positive who took celecoxib had a 37% lower risk of dying from any cause than ctDNA positive patients who took a placebo.

"Our results suggest that a blood-based biomarker test looking at ctDNA to see if any tumor cells remain right after a patient has surgery to remove their primary colon cancer could help determine whether they should take an oral drug that would help prevent cancer recurrence. Our study provides a compelling demonstration that identifying patients with residual ctDNA doesn't just provide prognostic information but also provides information that can help select an accessible therapy that may help patients live longer," said lead study author Jonathan Nowak, MD, PhD, Molecular and Gastrointestinal Pathologist at the Dana-Farber Cancer Institute.

Next Steps

Researchers will continue to study additional biomarkers that may help select patients that will benefit from celecoxib and will also study whether longer chemotherapy use is better for ctDNA-positive patients. They will also continue to study the biology of how reducing inflammation by COX-2 inhibition helps to prevent colon cancer from recurring.

The CALGB/SWOG 80702 study was funded by the National Cancer Institute, Alliance Foundation, and Natera.

View the full embargoed abstract (author disclosures included in the abstract)

View the News Planning Team disclosures

ATTRIBUTION TO THE AMERICAN SOCIETY OF CLINICAL ONCOLOGY GASTROINTESTINAL CANCERS SYMPOSIUM IS REQUESTED IN ALL COVERAGE.

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Founded in 1964, the American Society of Clinical Oncology, Inc. (ASCO®) is committed to the principle that knowledge conquers cancer. Together with the Association for Clinical Oncology, ASCO represents more than 50,000 oncology professionals who care for people living with cancer. Through research, education, and promotion of high quality, equitable patient care, ASCO works to conquer cancer and create a world where cancer is prevented or cured, and every survivor is healthy. Conquer Cancer, the ASCO Foundation, supports ASCO by funding groundbreaking research and education across cancer's full continuum. Learn more at www.ASCO.org, and follow us on Facebook, X, LinkedIn, Instagram, and YouTube.