Here, we’re going to discuss cytotoxic chemotherapy or systemic therapy in colorectal cancer. As a whole, you’re going to hear basically two terms at the first line setting: FOLFOX and FOLFIRI.
They both contain 5FU or fluorouracil as their backbone. Both of these regimens contain fluorouracil because it’s very effective in colorectal cancer. It also has a sister or cousin called capecitabine, which is basically the oral version that you metabolize to get the same effect as the fluorouracil. So that is all the primary backbone of initial management with colorectal cancer. The FOLFOX and FOLFIRI account for the other agent you’re giving with that backbone. And it can be oxaliplatin or irinotecan. And depending on what your personal status is like and what your doctor is worried about with side effects makes you pick between the two in the first-line setting, whether it’s FOLFOX or FOLFIRI, plus some other adjunct drugs we’ll discuss later. Oxaliplatin causes bad neuropathy and tingling in your hands and feet. So people that already have neuropathy may do better with FOLFIRI first. Irinotecan has pretty bad diarrhea. So if somebody had a recurrence or a relapse at stage four and already has trouble with possibly maybe a short gut or short bowel, or having colon problems causing diarrhea at baseline, you may want to avoid the irinotecan. So FOLFOX and FOLFIRI, and when you progress on the one that you do first, oftentimes you’re going to switch to the other one if possible. Whereas FOLFOX eventually may need to stop the oxaliplatin, either because of the neuropathy or your bone marrow counts fall too far down as you get more oxaliplatin. FOLFIRI can actually be continued indefinitely or until tumor progression if you tolerate it well.