Why I’m pessimistic about cancer cures and radical life extension

Epistemic status: idea I got in college biology nearly ten years ago. My memory of the relevant biology may not be perfect.

Recently, Sarah Constantine has been writing some posts on cancer treatments and how we might create better ones. This has reminded me of some thoughts I’ve had for awhile on cancer cures and life-extension, and why I’m quite pessimistic about the prospects for them.

(This is not a direct reply to Sarah–she hasn’t finished her post series yet, so it’s hard to evaluate her arguments.)

Basically, cancer and aging seem to be two sides of one coin. Cancer is typically described as cells growing out of control, but in a sense cancer is more fundamentally about cells not dying when they should. Conversely, a lot of aging involves slow cell death throughout the body. This means trying to solve both problems is a potentially delicate balancing act.

For example, telomeres seem to play an important role in aging. I won’t get in to the technical details, but basically a lot of people think telomere elongation is promising as an aging treatment. Unfortunately, it turns out that willy-nilly telomere elongation causes cancer.

Conversely, well, I probably don’t need to tell you that radiation therapy and chemotherapy often suck. Cancer cells aren’t alien invaders from outside your body, they’re your own cells gone bad, and how exactly they go bad can vary a lot. So it’s hard to kill cancer without killing some cells you don’t want to kill.

In other words, medicine is very broadly about making sure your cells don’t die when you don’t want them to. Cancer, however, is about cells not dying when you want them to (until you and all your cells are killed by the cancer). This is an example of the general problem with false positives vs. false negatives. The hard thing isn’t reducing one or the other–it’s reducing one without increasing the other.

Similarly, there’s nothing actually difficult about killing cancer cells–cyanide should do the trick. And maybe preventing aging-related cell death is just a matter of throwing telomerase at the problem. Doing both at the same time, however…

If this model is right, solving cancer and aging will likely make solving the problem of AIDS look trivial by comparison. For a long time, AIDS was the big scary disease we couldn’t do anything about, but nowadays antiretrovirals are pretty effective and more recently we’ve gotten good AIDS prevention drugs. But AIDS was easy–we never had to worry about making a person’s viral load too low.

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4 thoughts on “Why I’m pessimistic about cancer cures and radical life extension

  1. “Unfortunately, it turns out that willy-nilly telomere elongation causes cancer”

    Lol. It would have been really, really weird if it didn’t right? I mean what other plausible purpose could telomere-shortening have other than cancer control? Did anyone really think will-nilly telomere elongation would work?

    Like

  2. I’m pretty sure very large, long-lived animals (e.g. whales, elephants) are simultaneously (1) capable of more cell divisions than humans, to build their large bodies, and yet also (2) have more effective defenses against cancer. It might be possible to make, say, transgenic humans that have whale anti-cancer genes. I haven’t taken biology since undergrad, so for all I know this might have unintended effects like causing auto-immune disease (maybe the genes code for proteins which turn out to be immunogenic in humans?). But it’s definitely possible to have both longer lifespans and more protection against cancer than baseline humans.

    Liked by 1 person

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