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Comment by weavejester | Hacker News Reader

Isn't the evolution of cancer cells rather more constrained than your average pathogen? A normal pathogen can infect many thousands or millions of hosts, and can evolve immunities over many years, decades or centuries. A cancer is limited to a single host, and cannot pass on any of its tricks; it must start from scratch each time.

If we had medicine as potent as penicillin that could attack or inhibit certain cancer cells, it might be that the cancer simply wouldn't have the time to fight back before it's removed entirely.

Cancer cells are rather more difficult to distinguish from normal cells than bacteria, of course, but it seems reasonable to assume we'd have less problems with cancer cells evolving defences.

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One big difference between typical pathogens and cancer cells is that cancer cells have much more unstable genomes. Cancer cells divide rapidly and when they do, all sorts of mutations occur.

Even for someone with a diagnosed cancer (i.e. ovarian cancer), there are typically hundreds if not thousands of different types of cancer cells. This is what makes treating cancer so difficult. A drug may knock down 95% of your cancer, but the cells it didn't kill have no problem coming back and are now treatment-resistant.

There are plenty of drugs that work for cancer type A, B, C etc. Unfortunately, there are billions of people in the world all randomly generating Cancer's so all possible mutations are going to show up eventually in somebody.

Which presents the problem, let's say the most common 50% of all cancers are easily cured by drug X. Well the other 50% are all less common and moving to 100% is only going to get harder as you progress.

>>>Which presents the problem, let's say the most common 50% of all cancers are easily cured by drug X. Well the other 50% are all less common and moving to 100% is only going to get harder as you progress.

But for those who are in the 50% who can be cured in the first wave...

... and maybe one of them will go on to develop the cure that helps the remaining 50%.

But keep in mind each of those cancers is developing and evolving independently. Wiping out one type of cancer doesn't make it more likely for the other to proliferate on a population-wide scale. Sure, this treatment might not end up working for everyone, because some people's cancers might have developed chance resistance, but a whole bunch of people are going to be helped and cured without any ill evolutionary consequences.

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