Cancer treatment may cause cancer, FDA warns

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The Susan G. Komen Organization is going to have to start holding events called Race for the Cause.


There are a couple of prescription meds they advertise on TV that I’ve noticed in the disclaimer "side effects may include . . . " and then there among the long list of possible side effects one happens to be the very same thing the drug is supposed to be treating.


Wow, this is a bit confusing. If you give a cancer patient a drug that turns out to cause the same kind of cancer they already have… how can you tell? Does the cancer just accelerate? How can you be sure it was the drug rather than the disease progressing on its own?


[CAR-T] therapy uses a patient’s own immune cells to treat certain blood cancers

Wait, so this is a treatment for blood cancer that causes blood cancer?

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Because the drugs cause new cancers arising from new cells that would be molecularly distinct from the original cancer.


Yes, because it uses immune cells, a type of blood cell, to attack the cancer. If the injected cells start to divide too much, that is a new blood cancer.

Cancer treatments that cause cancer are a common problem, though this example is for a kind of novel reason. In most cases, it is because the cancer treatment, like radiation therapy or drugs that target DNA repair systems, rely on a theory of cancer that cancer cells are in this special window where their DNA is just messed up enough to cause cancer, but not so messed up that the cell just dies. Radiation therapy then damages the DNA even more to push the cancer cells over the edge. However, if healthy cells are also exposed, there is always the risk of creating new damage and new cancers. Overall the tradeoff is usually worth it, because the original cancer is going to kill you right now and the new cancer may still take decades to develop. This happened to a wonderful author that used to be popular on This American Life, David Rakoff.

In this new example, the therapy is actually a genetically modified version of your own immune cells that are designed to better target the type of cell causing your cancer. However, there is always a risk with genetic modifications that you could create an off-target mutation that causes problems, such as driving a new cancer originating from the modified cells. It appears that this has happened at least a few times based on the limited data available for these treatments. It’s still worth it to the patients because anyone getting this treatment has a very dangerous diagnosis, and so far at least the rate of cancer development from the therapy actually appears to be pretty low.


In the world of drug development, ALARP is king. I found a decent explanation on this UK health website.

If you look at most medications, you’ll find that they have at least some side effects. Some of these are quite strange and/or nasty. The idea is that whatever drug you are taking helps more than it hurts. It’s a very careful balance, and not one that every drug manufacturer gets right.

To think of a very personal current example - chemotherapy. Chemotherapy is, at a base level, you having very strong poison put into your body with the hope that it kills the bad cells first, or at least more bad cells than good ones. On paper it looks as insane as McCoy looking at dialysis, but it’s the best we currently have and it works most of the time. Yes, you’re super weak and lose your hair, and so much more…but most of the time you also kill the cancer and the rest comes back.

That’s ALARP.



In the “also ironic cancer treatment news” department: I have a low-grade (i.e. die with, not die from) skin cancer for which one of the treatments is… high-strength UV-B light.


Ugh… no fun!

And of course, many cancers are treated by poisoning the patient and hoping that the treatment kills the cancer first…


I’d obviously rather not have any sort of health issue, but as cancers go, this is sort of a poor cousin that’s not known for being lethal; and standing in front of a glorified tanning bed for 20 minutes every few days in the comfort of my own home is literally painless and actually gives me an excuse to do nothing and listen to podcasts.


Many of those drugs cost $40,000 per year, and are aimed at the “sophisticated” consumer who will then badger their doctor into writing them a prescription. If a drug is a biologic, it will be very expensive.


Yes. I’m slowly working my way through The Emperor of all Maladies, and the history and present state of cancer treatment is and always has been ghastly. It’s about weighing the potential benefits against the risks.

There’s nothing new or even interesting about a cancer treatment provoking new cancers. The only treatment we currently have that probably doesn’t do that is surgery. Unfortunately, most cancers cannot simply be excised by the scalpel.

Reality is messy and complicated and glib “man bites dog” style headlines just encourage the kind of distrust of medical science that saw millions of people taking dewormers for a viral infection.


Reminds me of an ad I saw once for a Non- Drowsy Allergy medication, where the warnings section started “May cause drowsiness, heart attack…” and a long list of things that mainly sounded more unpleasant than allergies. I wish I could remember which medication because I think I’d like to avoid a non- drowsy allergy medication that might still make you drowsy in addition to killing in several ways.


That’s good to hear at least… also, fuck cancer!


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