Colon cancer has undergone significant changes and has seen increasing treatment options. With more and more drugs available and approved for colon cancer we are facing difficult decisions deciding what is the right treatment at the right time.
For patients with newly diagnosed colon cancer we have two chemotherapeutic regimens: a combination of infusional 5-FU with irinotecan (FOLFIRI) or with oxaliplatin (FOLFOX). Both regimens have shown similar efficacy and similar extent of toxicity however there are differences in the quality of toxicity. More often FOLFOX has to be stopped because of its neurotoxicity than because it stopped working.
Dependiing where you are treated in the USA or somewhere else in the world, some prefer FOLFOX and some prefer FOLFIRI for many different reasons. In the USA FOLFOX is more common because of the North American CALGB 9741 study showing significantly more efficacy of FOLFOX compared to bolus 5-FU combined with irinotecan (IFL). However when FOLFIRI and FOLFOX were compared side by sidesite, there was no difference at all.
FOLFOX is sometimes prefered in patients with possible liver resection because of a study that showed less liver toxicity with FOLFOX compared to FOLFIRI.
In addition to FOLFOX and FOLFIRI we have antibodies, one against VEGF and two against EGFR. Since last year we have genetic tests available which can tell us if the antibodies against EGFR will work or not. We have no established markers for Avastin or the chemo cocktails. We have no promising candidates which are tested in clinical trials.
At the University of Southern California we are using biomarkers to decide whether FOLFOX or FOLFIRI are better therapies for an individual. Since both therapies are equal effective, we want to make the decision more rational rather than empiric. We also test the tumor for markers of angiogenesis to better understand what makes the tumor grow and metastasize. We are now testing tumors for all patients with metastatic colon and gastric cancer to make smarter treatment decisions.
One of the markers called ERCC-1 is now being part of the National Comprehensive Cancer Network (NCCN) guidelines for the treatment of non-small cell lung cancer. We are running two clinical trials to validate these findings with the Southwest Oncology Group (SWOG). These tests are available for all patients and oncologists at ResponseGenetics.com and they will bill your insurance. Take advantage of this cutting edge technology.
Disclosure: Dr. Lenz is a consultant for Response Genetics.