In a nutshell
This study examined if genetic analysis can predict when FOLFOX or FOLFIRI chemotherapy would be more useful.
Some background
The treatment of choice for colon cancer is surgical resection (removal of part of the intestine). However, if the cancer has spread (metastasized), chemotherapy is often the only option. Two drug regimens are the standard chemotherapy treatments used: FOLFOX and FOLFIRI. FOLFOX involves a combination treatment of 5-fluorouracil (5-FU), leucovorin (folinic acid), and oxaliplatin (Eloxatin). FOLFIRI involves a combination treatment of 5-fluorouracil, leucovorin, and irinotecan (Camptosar). Both treatments are complimentary to each other, meaning if one is not successful the other regime may work.
Currently there is no method for knowing which treatment should be tried first. However, there is some evidence that specific genetic markers may help predict this.
Methods & findings
The aim of this study was to determine if genetic analysis could help physicians decide which regime to begin with for individual patients.
One hundred and thirty five adults (average age 60.9 years), with stage IV colorectal cancer, were included in the study. The cancer had spread to the liver in all 135 patients, and also to further locations in 65 patients. Patients were divided into two groups: an unplanned group (80 patients) and a planned group (55 patients). The patients in the unplanned group were not genetically tested and all patients received the FOLFOX regime, as this was deemed to have the better outcome. For the planned group each patients’ blood was genetically analyzed to determine which treatment they would receive. If they had mutations in one or fewer of the genes related to oxaliplatin response (XPD-751, GSTP-1-105 and XRCC1-399), FOLFOX was chosen (35 patients). If they had mutations in more than one of the genes related to oxaliplatin response and no mutation in the gene associated with irinotecan response (UGT1A1), FOLFIRI was chosen (20 patients).
Overall, 54.8% of patients responded to their drug regime. The planned FOLFOX group had the highest percentage of responders (77.1%), followed by the planned FOLFIRI group (50%), and then the unplanned group (46.3%).
The bottom line
The authors concluded that genetic analysis improved the response rates to FOLFOX chemotherapy in patients with stage IV colon cancer.
The fine print
This is a small study that was only carried out in Korean patients. It may need to be repeated in other patient groups.
Published By :
Surgical oncology
Date :
Dec 07, 2013
