HealthDay News — Survival odds for colorectal cancer may depend on which side of the colon the primary tumor develops, according to a study released Wednesday during a media briefing that previewed some of the research to be presented at the upcoming annual meeting of the American Society of Clinical Oncology, held from June 3 to 7 in Chicago.
In a study of 1,025 men and women with metastatic colorectal cancer, those with left-sided tumors survived 33.3 months, while those with right-sided tumors survived only 19.4 months.
The researchers also found that patients with tumors on the left side of the colon lived an average of 36 months after cetuximab (Erbitux) was added to their treatment. However, patients treated with cetuximab whose tumor was on the right side of the colon survived 16.7 months. The researchers found a similar pattern among patients who were on bevacizumab (Avastin): Overall survival was 31.4 months for those with left-sided tumors and 24.2 months for those with right-sided tumors.
“It’s a stunning and surprising finding, and the difference is dramatic,” lead researcher Alan Venook, MD, a professor of medicine at the University of California, San Francisco, told HealthDay. “Now that we are aware of this, there’s a whole lot more to learn and a lot of digging to do. People don’t just have colon cancer, they have a particular brand of colon cancer, much as we see with breast cancer.”
The study received funding from Bristol-Myers Squibb, Genentech, and Imclone.