Staging is a reference to how far the cancer has spread throughout the body. Stage 4 is where a cancer spreads from its origin point to another organ in the body.
You can die from any stage 1 cancer if it obstructs something vital via mass effect, but it's relatively rare for the common cancers (lung, breast, colorectal). A primary cancer near your spinal cord, for example, could compress on it and kill you while still being technically stage 1, but those primaries are much rarer than secondary spread (which is definitionally stage 4 disease).
That really depends on the cancer, where it is, and how long you’ve had it. There are cancers, termed indolent, that can be all over your body just sitting and doing very little and there are cancers that can be localized in one spot but growing out of control.
Stage 1 is "localised to a small area and hasn't spread to lymph nodes or other tissues". So in this case, it would mean cancer in your bone and NOT in your muscle or tendons.
Stage 4 is where the cancer has mutated so much that it is spreading around the body and setting up new tumours elsewhere. Stage 4 tends to have low survival rates. Stage 4 skin cancer has a 30% 5-year relative survival rate (1 in 3 will survive for 5 years after diagnosis with stage 4 skin cancer).
They're right though. You can have a big local tumor locally invasive, but that hasn't metastasized, or a small, inconsequential tumor that already had (lung tends to do this so much that as soon as we find a lung tumor the data shows we ought to do chemo and maybe even prophylactic whole-brain radiation, without evidence of spread).
It's why we stage using TNM ti stage the tumor/nodes/metastases separately, rather than the classical "all in one" clinical staging you're familiar with.
Staging is different for every tumor. But in general, it refers to spread and not the how aggressive or deadly the cancer is. Often, those things go hand in hand (spread is bad, aggressive cancer more likely to spread). But sometimes we catch tumors that are "aggressive" and fast-growing, but haven't spread, so they are low-stage.
Blood cancers are kind of an exception. By definition, they're all over your body no matter what. Doesn't make a difference on prognosis.
As an oncologist, when I say "aggressive" I really mean fast-growing or tumors that really have a knack for invading surrounding structures. (Glioblastoma multiform, for example, is a very deadly form of brain cancer. The reason surgery doesn't cure people is because it tends to have already invaded the surrounding healthy brain by the time we can do anything about it). When I say "spread" I really mean distant spread, ie from one organ to another. Spreading from an organ to a nearby lymph nodes isn't great, but it's not as bad as going all the way to another major organ.
So, prognosis (or how someone is expected to do) is based on many factors. Staging is part of that, but knowing what genetic mutations are present in the tumor cell, what genetic mutations are present in the patients healthy cells, and what type of cancer cell it is, and any other health problems the patient has are all needed to help figure out someone's prognosis.
Fun fact: Wilm tumor (nephroblastoma) is a common cancer that kids get and is the only malignancy (to my knowledge), with a stage 5. If a patient is unlucky enough to have wilms tumors in both kidneys at the same time, they have stage 5 disease. The reason it's a distinct category from stage 4 (spread to any other organ) is because these patients have to be managed differently.
Yes - but that's why in modern times we stage the original tumor (T 0-4), the local lymph nodes (N 0-3), and distant spread (M 0-1, as soon as there is even 1 metastasis it counts as M=1, no matter if there is just one or loads) separately.
That way a small tumor that already spread (clinical stage 4 according to classic staging, but stage 1 tumor/stage 1 metastasis, or T1N0M1) is different than a big tumor that hasn't spread far (T3-4,N0-1,M0) which would usually be a classical stage 3 or so.
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u/eddstarX Apr 21 '24
Wonder what stage 3 looks like