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
First, many cancers are not fatal. Usually two things cause the fatal kinds of cancer. It’s in some place inopportune and inoperable for any number of reasons, or it has spread throughout the body (metastasized), or both.
You have to look for cancer at the right time in order to be able to successfully do something about it. Look too early and you won’t find it, its either not there yet or too small to detect. Look too late and its hard/impossible to track it all down and remove it.
So why not look more often? Because looking can cause harm. In false positives (no cancer but the person is told there is which results in anxiety and additional, unnecessary invasive tests and procedures). In cases where the investigative method causes damage itself or carries a risk.
There are also cases where cancers AREN’T fatal. Some develop so slowly you’re likely to die of other causes long before the cancer becomes a problem. But because we can’t be sure, we treat it and you suffer the side effects. If you hadn’t gone looking for it, and you never developed symptoms, you’d never have noticed.
Basically its hard to find cancer in the right window where its treatable and the treatment isn’t worse than the cancer itself.
Cancer cells do not function as normal cells do anymore. They also can prevent proper functioning of organs when they become prevalent enough. For example, once enough lung tissue becomes cancer cells, your lungs stop functioning. They can also disrupt blood flow.
When you surgically removed cancer tissue, you also remove healthy tissue. There is only so much you can remove before the organ no longer functions. Maybe it’s a lung or kidney where you have two, but if the cancer cannot be fully removed, it will keep spreading. Some will eventually spread to other parts of the body. Organ failure isn’t uncommon with cancer.
Frequently, cancer is suspected due to disruption of normal body function. At times, the damage is so widespread by the time it is detected that it is going to be lethal anyway, but we are getting better at catching it earlier and treating it.
Removing some tumors, like neuroendocrine tumors, can make things worse. Cancer tissue starts replacing healthy tissue, and soon enough you don’t have enough healthy tissue left. Not only that, lots of solid tumors create blood supply to themselves so they start stealing nutrients and removing them gets much, much harder.
That said, there are more and more treatments that are making cancer survivable.
Usually it spreads everywhere and starts growing everywhere. On top of that, it somehow gains mutations that allows it to defend itself against the immune system really well so its not as simple as just rapid cell reproduction.
A few reasons
1) tumors don’t like to function normally, some become hyper functional and do way to much of what they normally do (neuroendocrine tumors often produce way to much of the hormone they normally produce to the point where it messes up everything else. An example is a gastrinoma which produces way to much of a hormone that is responsible for telling your stomach to make acid. This excess acid production can lead to peptic ulcers which can be life threatening if they perforate). This hyper function can mess with the bodies normal function and cause harm.
2) tumors can also just do nothing productive other then grow, and they focus on this so much that they recruit extra blood vessels to feed them resources to continue growing, siphoning resources away from healthy tissue in the same organ, causing them to fail eventually, compromising other organs in the body.
3) tumors spread, melanoma can travel to the brain, bowel cancer can spread to the liver etc. when they spread, they continue acting like the original tumor, and like point 2) they start growing and stealing resources from this new organ, so a melanoma from the skin spreading to the brain is bad because not only do u have a weird mass of cells producing skin pigment in the brain, u also have a mass of cells stealing nutrients from the rest of the brain, which can lead to strokes etc.
4) tumors can be weird and suddenly decide they want to do completely different functions to their original function, for example some lung cancers often decide they want to become hormone producing cells instead of lung cells and they can produce hormones like PTH or ADH, which can cause your body to dissolve your bones causing way to much calcium in the blood, leading to things like kidney failure, or the hormones can tell your kidneys to hold onto all the water and not filter any out, making you fluid overloaded and sodium deficient which can lead to seizures, respiratory depression and coma.
5) the cancer diseases mentioned in point 4) are apart of a term called para neo plastic syndromes. These refer to diseases that are associated with a cancer but can not be attritubted to the location of the tumor and where it is invading/compressing. The syndromes mentioned in point 4) are called endocrine paraneoplastic syndromes as these are diseases that involve the cancer cells developing the new ability to produce hormones like endocrine cells do.
Other PNP syndromes can be caused by the immune system trying to attack the cancer but getting confused between cancer cells and healthy cells (and these can be everywhere in the body, not just the same organ the cancer is in), because unfortauntely cancer is your own cells, it’s not some foreign invader, so the immune system can get confused and cause damage elsewhere in the body. An example of this is myasthenia gravis which can cause the immune system to “attack” a specific type of nerve the in body that controls things like muscles. As a result patients may get similar symptoms to strokes like limb weakness, speech issues, facial weekness, double vision. Eventually the syndrome can even affect the nerves that innervate the diaphragm (the breathing muscle), leading to respiratory depression and death
All of these reasons combined can lead to multiple organ failure and death
As to why we can’t just cut them out constantly, it’s because they can grow back very fast, and surgery isn’t without its own risk, and repeated surgeries is just begging for an infection to get in there or the patient to bleed out on the table, just further compromising the patient. Cancers also love to overrun the healthy tissue to the point that removing the cancer will compromise what’s left of the organ and it will likely fail. Cancers also love growing heaps of extra blood vessels to support there desire to grow rapidly, these blood vessels aren’t like normal healthy blood vessels that follow a pattern that we have spent 100’s of years studying and learning there normal paths. As such cutting the tumours out isn’t just like regular surgery where a surgeon can just study anatomy textbooks to know where the blood vessels go and what is what and what they need to cut, instead the tumor is unique and will have a very inefficient but dense jungle of blood vessels which have to be sorted through to know what is supplying the healthy tissue and what is supplying the tumor, otherwise the surgeon may accidentally cut the wrong vessel and send the healthy part of the organ into organ failure or cause massive blood loss… killing the patient
Our bodies only function based on the premise that we are comprised of many individual parts (organs and cells) that work together to keep the system alive (the body). Cells are basically cooperative, working together to provide services/benefits to those around them or throughout the body. Cancer cells are essentially parasitic, they act at their own benefit at the cost of the overall system. They draw nutrients needed for body function and us it to grow, allowing them to overtake healthy cells. If the cells composing your kidney are only 2% cancer, your kidney can still function relatively normally. However as the cancer grows and replaces the healthy cells, your kidney will lose some of its function, and could eventually shut down, which greatly affects your overall health. Some cancers can even spread throughout the body using the natural transport systems in your body, allowing them to be planted anywhere and spread. One spot of cancer is manageable, 10 growing at the same rate is 10 times the cancer in the same amount of time.
TL,DR: Cancer cells are parasitic, meaning once a cell becomes cancerous it effectively is no longer a part of your body and will take everything in your body until you die or it dies.
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.
Cancerous tumors are basically rapidly replicating cells that have no “guidance”. Normally our cells replicate with a given blueprint on our DNA, which determines what cells they’ll become, what they’ll do, and when they’ll die and start the cycle anew. Cancer cells have no blueprint, and just rapidly expand and multiply as they slowly take over. The tumors not only grow larger but they also spread, which is called metastasis, which means that more tumors start developing around our bodies in exponential rates. What can start out as a single tumor can become dozens or hundreds of tumors all over the body. The main issues they cause are:
1. Resource hogs. Tumors sap a lot of nutrients that would normally be used to sustain the host in order to grow itself. In fact, cancer cells use up a disproportionate amount of energy compared to healthy cells. It’s one of the reasons (but not the only one) why one of the first noticeable symptoms of cancer is seemingly unexplained weight loss.
2. They interfere with the normal operation of our organs. Cancerous tumors rarely just sit there growing bigger minding their own business. As a cancerous tumor grows it starts affecting the organ it is attached to, which means that whatever job that organ has suddenly stops being done right until ultimately the organ fails. This is why some cancers are much more fatal than others. Lung, liver and pancreas cancers are much more fatal compared to other cancers because when those organs stop being able to do their job our overall health takes a nosedive very quickly.
3. It’s not just their size, a lot of the times they’re actively attacking us. Cancerous tumors don’t just sit there sucking in nutrients and taking up real estate. They release chemicals into our bloodstream and interfere with normal bodily functions. In many ways they’re outright attacking us.
These are just some generalised aspects of cancer. The reality is that there’s a ton of different kinds of cancers and a ton of different effects they can have on people. There are tumors that seemingly don’t do anything and just sit there and grow and they’re called benign tumors but those are usually very small. Very rarely will a huge tumor be benign but it is possible.
Surgical removal is not always an option because cancers have their own blood supply and may be large in size. Completely removing a tumor is difficult and it’s even more difficult to patch up the empty space left behind. As a cancer takes its toll on the patient it makes it much more risky to put them through major surgery, or multiple major surgeries. Depending on the stage of the cancer surgery may not be feasible as the cancer may have metastasized and gone to the entire body. Doesn’t matter if you remove the bigger tumors if there’s still a bunch of smaller tumors in your body. That’s why chemotherapy and radiotherapy are the most prevalent forms of treatment as they attack all the cancer in the body. Surgery is usually opted when the cancer is caught at an early stage. Chemotherapy and radiotherapy are always included in cancer treatment but surgery isn’t always part of treatment.
Your body is like a ship where everyone has their own job. It can be to clean the decks, navigate the ship or fix parts of the ship. Everyone gets their fair share of food dependent on how much energy they need to carry out their job.
Say if a couple on the ship decided they no longer want to do their job and started to have parties and babies all day. The babies grow and mature fast, just like their parents they refuse to do work and continue to have parties and more babies. These rebels hog all the food, take up space in their department/compartment and interrupt their colleagues from working.
They might eventually start to wonder to other people’s workstation and prevent them from working as well. So if these rebels make their way into the engine room and prevent the workers from the engine room to then the ship is not gonna be able to move. Eventually the ship is gonna become too chaotic and things are gonna break down since people cannot do their job and repair the ship and it will just become stranded and decay.
When you decide to remove these rebels, you may be able to identify them by maybe a tattoo that they all have. However, when they are mixed in with the normal workers you might be unable to separate the rebels from the workers and end up culling a bunch of the good workers as collateral damage. Then it would mean that department would no longer be able to carry their job out properly. If you’re able to get rid of rebels and the collateral damage is small, sometimes there might be a couple of rebels still hiding in the department and can then restart the partying and babying cycle.
So with this analogy, the ship is your body, the rebels are the cancer cells. Rebels having babies is uncontrolled cell growth, them disrupting workers around them is loss of function due to cancer. Rebels wondering into other workstations is metastasis and causing other organs to lose their functions. Unable to separate rebels from workers is cancer invasion resulting in the inability to completely resect the cancer without disrupting the organ. The rebels in hiding that will come back is the cancer relapsing/regrowing.
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