This topic is pretty morbid, but it’s something I’ve been curious about for some time.
I have an elementary understanding of what cancer is - an uncontrolled replication of cells somewhere in the body.
However, why is this fatal?
Do the tumors eventually grow so large that they starve the rest of the body of blood, oxygen, and nutrients? Is the actual cause of death usually acute failure of the organ that’s primarily affected by the cancer? Do cancer cells produce large amounts of poisonous waste, overwhelming the systems that dispose of it?
Well, I guess it’s fairly obvious that cancer of a vital organ could kill the victim by causing that organ to fail.
So what about cancer that affects organs that aren’t necessary to life, such as breast cancer, prostate cancer, skin (if only a small patch of skin is affected), testicular cancer, etc.
Are those only fatal once they spread to a vital organ, or can they kill without spreading?
Cancer is many types of diseases of many organs. Some people can lead normal lives almost up to the end. Symptoms ultimately appear. With lung cancer, for example, you eventually have coughing and blood. You can die of lung infection or drowning in your own fluids. They can do surgery, radiation and chemo. Then you can die from the treatment. The treatment is often strong enough to kill before the disease itself kills. If you go on long enough, cancer spreads to other vital organs like the liver or brain. It’s all quite variable. I suspect you’d be better off not even knowing.
Sometimes the tumor grows large enough to obstruct something vital, like important blood vessels or your digestive tract. Sometimes they have more insidious effects; my friend only discovered she had cancer because she had blurred vision … because she had massively high blood pressure … because the tumor cells were actually creating hormones that pumped up her blood pressure! Had they not intervened, I’m sure a stroke, etc., could have been possible.
These usually kill by spreading to other organs. Bits of the tumour break off and float around the bloodstream, eventually lodging in some other organ and growing there.
(Quoting myself from earlier threads on the same subject)
"Cancer kills in many ways. Depending on the specific type, all or some of the following may apply:
Cancer, at its primary site can cause lethal problems eg. lung cancer blocking a bronchus (breathing tube) leading to pneumonia, eg. cancer of the bile ducts blocking off the liver
Cancer can spread locally and kill, eg. a lung tumor that eats it way into a blood vessel or into the heart lining
Cancer can spread far beyond its primary site and do damage there, eg. breast cancer spreading to the liver and causing liver failure, or eg. breast cancer spreading diffusely through the lungs, or eg. lung cancer spreading to the brain
Cancer weakens the body, sometimes in obvious ways such as malnutrition, and sometimes in subtler ways such as inhibiting the immune system. In either case, infections result and are much more severe than in “normal” individuals.
Cancer makes the blood clot more readily. Further, many people with cancer are often relatively immobile and that, too, promotes clots. Blood clots kill. (The association between cancer and clots is quite common but not generally appreciated, IMO, by lay people)
Cancer replaces the bone marrow causing fewer white blood cells and/or platelets to be produced. Infection and/or bleeding results. Infection is also made more likely by the relative immobility of cancer patients (eg. pneumonia, skin break down and infection).
Cancer can leads to bizarre, unpredictable, and sometimes mysterious effects in the body, eg. lung cancer causing “Lou Gehrig’s Disease”, eg. kidney cancer causing high blood calcium levels, eg. myeloma (a type of bone marrow cancer) causing breakdown of the nerves in the body (neuropathy), eg. lymph cancer leading to kidney failure."
BTW, here are some previous threads on the question:
I think your question is basically answered in my earlier post directly above yours.
People with metastatic cancer can die from any of the mechanisms listed. A ‘final common pathway’ is infection, especially pneumonia - people with end-stage cancer are often very malnourished and thus susceptible to infections* in generally. Being bed-bound tends to cause parts of the lungs to collapse and that provides a good “culture medium” for germs causing pneumonia. When added to cancer patients’ general susceptibility to infections, as I say, pneumonia often results. (*and, if they received chemo or radiation, their immune systems may be even weaker).
If I recall correctly from reading “how we Die” virtually all death comes down to a fairly small number of mechanisms failing, theres just a large number of things that cause the small number of things to fail.