12 Chemo Cycles: More Toxicity Than Therapy?

John L. Marshall, MD


July 25, 2016

Editorial Collaboration

Medscape &

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John Marshall for Medscape. Something's been bugging me lately and I want to share it with you. It is this concept that 12 cycles is somehow a magic number, that if I don't give patients, particularly with colon cancer, 12 cycles of chemotherapy—I guess that's 6 months of chemotherapy in the metastatic setting—that somehow I've cut them short. We've been talking a lot about this. I see it in patients' referral charts. The patients even have this concept that they've got to get a certain number of cycles.

I think all this really does for most of our patients with metastatic disease is deliver toxicity. We know that most patients benefit from maximum tumor regression somewhere around 3 months, maybe 4 months, and then it levels out. Very rarely would you see continued regression in those patients. Now we have, at least in colorectal cancer, this concept of maintenance therapy where you drop some of the chemo and give a lighter version going forward. There's really no reason for us to get to this magic 12 cycles.

Most clinical trials let you, at 3 or 6 months, begin backing off. We're hurting our patients when we seek to get to some magic 12 cycles. There's nothing magic about it at all. Go to optimum benefit and then back off.

Be a better coach on the sideline. Use the drug until maximum benefit, then back off.

Neuropathy and other side effects are our fault, not our patients'. Be a better coach on the sideline. Use the drug until maximum benefit, then back off and do some sort of maintenance approach. And remember: There is nothing, nothing, nothing magic about 12 cycles.


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