EGFR in Metastatic Colon Cancer

Dr. Johanna Bendell from the Sarah Cannon Research Institute discusses the role of EGFR in the treatment of metastatic colon cancer.

Q: Welcome to Understanding Cancer.  Today we’re visiting with Dr. Bendell from the Sarah Cannon Research Institute in Nashville, Tennessee.  Welcome to the show.

A: Thank you so much.

Q: So what role do the EGFR receptors play in the management of metastatic colon cancer?

A: So EGFR receptor antagonists, or antibodies, are a new type of targeted agent that go after what I call are almost like TV antenna that are on the outside of colon cancer cells.  And what these drugs do is they attach to those TV antenna and tell the cell to stop growing or tell the cell to die.  And we’ve seen that the use of EGFR receptor inhibitors have actually prolonged survival for patients with colon cancer.

And their role is becoming even more important now because we’re starting to see that there’s a specific test that we can use of a patient’s tumor to see whether or not they’re going to benefit from EGFR inhibitors, and that test is called a KRAS mutation analysis.  And patients don’t have to have new biopsies to get this test done.  It can be done on their original surgical colon tumor that was taken out however long ago when they had their original diagnosis of colon cancer.

And pathologists can run this test, and if you are somebody who has what we call wild type KRAS, you are very likely to benefit from EGFR inhibitors, and if you are somebody who has a mutation in their KRAS, the whole – the use of EGFR inhibitors in those particular patients is not worth it.  It’s shown that the patients who have this mutation get no benefit from EGFR inhibitors.  So if you do have the wild type KRAS and EGFR inhibitors can be a benefit to you – and some people are suggesting now that we could even use EGFR inhibitors earlier in therapy, like in initial therapy for patients with colon cancer.

And trials to that extent are still being done and studied to know what to optimally do, and as of yet the FDA has not approved their use as such.  But you might see some oncologists that discuss that with their patients, or some trials that are looking at that for patients.

Q: So you can assess and tailor therapy in this particular case?

A: Yes.  This is what’s very exciting about colon cancer now, is that we’re able to start to tailor therapy to the patient specifically.  And hopefully, within the next few years, we’re going to see even more markers start to come up that are going to help us tailor therapy even better.  Even with EGFR receptor inhibitors we’ve seen other tests such as amphiregulin and epiregulin, P10 mutations, PI-3 kinase mutations, that are all start – and B-RAF mutations – which are all starting to give us some suggestion as to who might – may or may not respond to EGFR inhibitors and who might be the optimal patient to receive an EGFR inhibitor.

And we’re going to start to see more of those tests coming for other targeted agents, including Bevacizumab and other targeted agents that are coming in clinical trial down the road.

Q: I’ve noticed that you’ve mentioned EGFR receptor inhibitors.  Is there more than one?

A: Yes, there are two EGFR receptor inhibitors that are approved for the treatment of metastatic colon cancer.  The first is a drug called Cetuximab and the second is a drug called Panitumumab, and they’ve very, very similar except their side effect profile is a little bit different.  Patients who receive Cetuximab have a little bit more of a chance of having an allergic reaction to the Cetuximab than  patients who receive Panitumumab.

Q: In summing up, is there anything in particular you’d like to tell cancer patients with metastatic colon cancer that they should really think about when they’re diagnosed?

A: Don’t give up hope.  Never suffer in silence.  Always tell your doctor if something’s going on, ‘cause there’s oftentimes something people can do about it.  And try clinical trials, because there’s so many good trials that are out there that are going to be the way that we find the cure to treating metastatic colon cancer.

Q: Well, it sounds like very good advice, and I really want to thank you for joining us today.

A: Thank you.

Q: And I do hope you’ll come back and visit with us again sometime.

A: Thank you so much.

[End of recording.]