In a nutshell
This study looked at whether the original location of tumors which have spread can predict how the cancer may progress.
Some background
Despite many advances in the field of colorectal cancer, relatively few markers have been found which help predict patient survival. Some factors, such as whether there is a mutation (abnormality) in the BRAF or KRAS genes, have been linked with a poorer patient outcome. Other factors, such as original tumor location, have also been examined. Colorectal cancer can be classified as occuring on the left or right. Left/right tumors often have unique genetic characteristics. However, studies examining whether the location of the original tumor can predict survival have been small and relatively inaccurate.
Methods & findings
This study reviewed three previous trials. Trial A included 200 patients, Trial B included 559 patients and Trial C included 1268 patients. All patients received FOLFIRI chemotherapy and bevacizumab (Avastin) to treat their cancer.
In Trial A, patients who had left-sided tumors had an average survival time of 42 months. In comparison, patients with right sided tumors had a survival time of 24.8 months. Trials B and C also reported improved survival times for left-sided tumors.
Progression free survival is the time following treatment before the disease progresses. Patients with left-sided tumors had a progression free survival time of 12.1 months, compared to 9.9 months for right-sided tumors. Trials B and C saw similar trends, but the difference was not significant in Trial C.
Patients with BRAF mutations were 48% more likely to survive if they had left-sided tumors.
The effectiveness of the treatment bevacizumab did not depend on tumor location.
The bottom line
This study concluded that the original tumor location is a strong predictor of survival in patients with colorectal cancer that has spread.
Published By :
Journal of the National Cancer Institute (JNCI)
Date :
Mar 01, 2015
