A new study found that the tumor location within the colon predicts a patient’s survival. Researchers of this recent study — the largest of its kind — suggest that the location of the tumors may also help physicians in choosing the correct treatment options for patients suffering with colon cancer.
Tumor Location Significance
A team of researchers embarked on a retrospective analysis of data from a large clinical trial. The analysis was designed to compare the effectiveness of two drugs for treating metastatic colorectal cancer.
Lead author of the study, Alan P. Venook, a professor of medicine at the University of California San Francisco (UCSF), explains the analysis shows that patients whose primary tumor is on the left of the colon have a significantly longer survival than patients whose primary tumor is on the right side.
Data for the central analysis consisted of 293 patients with right-sided primary tumors and 732 patients with left-sided primary tumors.
The results of the analysis found that patients with left-sided primary tumors had a median overall survival of 33.3 months, compared with 19.4 months in patients with right-sided primary tumors.
An American Society of Clinical Oncology, (ASCO) news release added that among patients treated with cetuximab — a drug used to treat head, neck, and colon cancers — those with left-sided primary tumors lived 36 months; whereas, patients with right-sided primary tumors lived 16.7 months.
The analysis also showed a similar pattern for patients treated with the cancer treatment drug bevacizumab. Patients who were treated with bevacizumab lived 31.4 months overall for those with left-sided tumors and 24.2 months for those with right-sided tumors.
Colon Cancer Treatment Options
The researchers conclude that whether the primary tumor was on the left or the right likely influenced the effectiveness of the treatments the patients received in the clinical trial.
Researchers are now looking into the molecular biology mechanisms that might clarify the differences.
ASCO President, Julie M. Vose, MD, MBA, and FASCO, offered the following comment about the study’s findings:
“This is the largest study to date of tumor location in colorectal cancer, and it strongly suggests that this unexpected factor could answer some long-standing questions about why certain patients do better than others. It is also an important reminder, in this exciting era of precision medicine, that genomics is not the only source of insight into how cancers should be studied and treated.”
This groundbreaking study on colorectal cancer tumor locations will be presented at the American Society of Clinical Oncology (ASCO) annual meeting in Chicago, Illinois on June 3-7, 2016.