I’m educated enough to generally understand that cancer is the result of a gene mutation, which activates rapid cell reproduction, but what about this growing/spreading tumor makes it fatal? Why can’t we just periodically remove the tumor as it continues grow, thereby (almost) completely eliminating any possible death threat from cancer?
***EDIT: thanks for all the responses to my question! Some of them are really great, and perfectly answer my question. Frankly, I was not aware that cancerous cells and tumors have, in so many ways, “a mind of their own”.***
***I’m very lucky to have been of general good health my whole life, but the threat of cancer as I age scares the daylights outta me — it literally keeps me up at night, often. I’m slightly relieved to realize that so much is known about cancer and so many different treatment options exist, depending on the diagnosis and prognosis. And I recognize this wealth of knowledge, understanding, and treatment options is growing almost by the day with modern medicine — and this helps put me at ease a little too.***
***Here’s to ongoing good health for me and you…!***
In: 10
This is a simplified version of a complex topic.
First you are thinking about just a solid mass, say a lump, of cancer. That of course does happen. But cancer spreads setting up new lumps all over, at a simple level. You reach a point where where if you did surgically remove a bunch of these, very shortly there would be a bunch of new ones, maybe even more. There is a limit to how much surgery you can do and this dependent on age, health etc. Cancer is most common in the old. Surgery on the elderly is more risky than a twenty year old. The elderly don’t heal as well or fast, the anesthesia itself can be a problem, greater risk of infections as the immune system is not as robust. You reach a point where the constant surgery would kill the patient or shorten their life more than the cancer, or alternatively you reach a point you have really damaged a person and their quality of life is nothing but suffering from that point on. So there are limits, and when you get really old, those limits are lower for what you body can handle. Then their are issues with cancer in spots you can’t really operate on to remove, or fully remove it.
Another thing is not all cancers are lumps. Some are floating around in the blood like a leukemia. There may be no mass to remove. In these cases, one of the things that can kill you is that the cancer basically replaces your blood marrow which is the stuff that makes your immune system. Thus a person can die from that, lack of immune system, which means you get an infection that drugs and your body together cannot fight off. This is similar to how people with untreated AIDS die, the lack of immunity means you get an infection, it can be lethal. We can’t surgically remove someone’s bone marrow that has cancer in it. What we can do is what is called a bone marrow transplant. In this, we kill off both the patients cancer in the marrow along with the healthy marrow and replace it with new immune cells that repopulate the bone marrow, start growing in the (hopefully cancer free) bone marrow space, basically giving them a new immune system. If we are able to use their own stem cells to do this it is ideal, if not you need bone marrow from a donor which may not match perfectly, which requires immune suppressants to prevent graft vs. host disease where the new immune system attacks the body. While doing this in the most ideal situation with the patient own stem cells the procedure itself can ultimately result in death as there is a period where the patient has no immune system until the new one grows. Getting an opportunistic infection in this period can kill you. If getting bone marrow from a donor, immune suppressants will be required at least for a period, or longer depending, again the patient is immune compromised due to these drugs and can get an opportunistic infection. Transplants like this are often last resort when chemo or drugs fail. Survival for one year after transplant is about 60%, with death resulting from the procedure itself and its noted complications or the cancer or both.
What about chemo? At a simple level, chemo is a poison that just so happens to preferentially kill fast growing cells more so than slow ones. In some chases you are giving the patient as much “poison” as you can that won’t kill them outright, but enough that it kills the cancer. Those lines of too much and enough can be relatively close. As I mentioned this kills fast growing cells, but you have healthy cells in your body that grow fast too and they can be killed along side the cancer putting a lot of stress on the body. Given the toxicity of the drugs it is possible for a small percent of the patient to die from the drug treatment itself. Another way to die with cancer, basically too much poison. Depending on the chemo it can kill some immune cells and thus opportunistic infections may occur, but here you are damaging the immune system not totally destroying it like BMT.
OK you treated the patient with as much surgery as is possible, done chemo, done newer drugs that are less toxic than chemo but the patient still has cancer. Usually by this point, as they are often elderly, physically they are much weakened in a health sense from all this. This may be where decisions need to be made to treat more or stop. In their weakened state more chemo of a different sort may itself be more likely to kill the patient now, and if it doesn’t the outcome may be damaging enough the patient is going to suffer a lot in their remaining time, but probably will still succumb to the cancer. Is it worth it? Patient’s and the docs have two weigh this and everyone is different so there is no one right answer here. If they do another chemo round that may ultimately cause death before the cancer. So the treatments don’t work anymore, can’t do more surgery, but they cancer remains. How does this kill them? Depending cancer type, its location etc. it might be the cancer grows in and destroys an organ needed for survival, or impairs the immune system where infections kill the patient. Also as others mentioned cancer is not just growth of tumors but also may alter bodily functions through its unusual biochemical processes that negatively affect systems in the body needed to live thus killing the patient.
This is all greatly simplified but you can see that the treatment process itself can kill a patient before the cancer does through different means, and the end stage of cancer will kill in different ways. Hope that is helpful.
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