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Colon Cancer

Elevated CA125, clean PET and CT scans



I was diagnosed with metastatic colon cancer 2 years ago which had spread to my reproductive system. The original diagnosis was ovarian cancer. I had a radical hysterectomy and the pathology proved the original site was the colon. I have been on a regimen of FOLFOX and my CA125 remained normal. I went on Xeloda and had bad side-effects and was off chemo for about 3 months. My CA125 began to rise. It rose to over 200 despite a clean PT and CT scan. I went back on FOLFOX and my CA125 went from 225 to 201. The next month it rose to 211. Does this mean the FOLFOX is not working? Could there be any other explanation for the rise in the CA125 other than a recurrence of the cancer?


We do not typically rely on cancer markers to decide on whether a treatment is working or not. The imaging studies (CT scan, PET scan) and the overall clinical picture is a more useful predictor and indicator of response or progression. There are many factors that can affect changes in cancer marker levels, including normal variations (especially when the changes are within the 5-10% range). 

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Response by:

Tanios   Bekaii-Saab, MD Tanios Bekaii-Saab, MD
Assistant Professor of Medical Oncology
Associate Professor of Pharmacology
College of Medicine
The Ohio State University