How do doctors determine what stage cancer is in and how long a patient has to live?
In: 99
Stage one- cancer is small and localized.
Two- has grown but still localized
Three- grown more and possibly spread to lymph nodes
Four- has spread to other organs and areas of the body
The time is always an estimate. Likely an average just based on other people at that stage, and how healthy they are otherwise.
The stage of the cancer depends on the size of the tumors and whether or not it has spread. Stage 4 cancer means it has already spread to other organs.
As for the survival rate, that’s where it gets a little complicated. It’s not just a percent chance of survival, but it’s a percent chance of survival for X years. For example, you might have a 75% chance to survive for 5 years. This is going to be based off of data comparing other people who have had a similar cancer and their outcomes.
Now what does the survival rate actually mean? Well, even when an early stage cancer is treated, there is a possibility that cancer cells were missed, or had already spread in your body. Even when treated, there is a decently high chance that the cancer was never fully defeated, and it will take a certain amount of time to grow back from individual cells into something that actually kills you. That’s why an individuals cancer is never really “cured”.
**STAGING**
Cancer stages are determined by specific criteria, including the size of the primary tumor, whether or not the cancer has spread or *metastasized*, and if there is metastasis, how far the cancer has spread. These things are determined using blood tests, MRIs, biopsies, exploratory surgery, etc…
Here are the stages for many of the most common cancers. Note, however, that each type of cancer is staged differently. A doctor takes the whole picture into account, so *please take these with a grain of salt.*
> Stage 0 — A small tumor that has not affected any nearby tissues. Cancer at this stage can typically be fully cured by surgically removing the tumor.
> Stage 1 — The cancer hasn’t spread to other body parts, but nearby tissues are impacted. (For example, there might be cancerous cells in the tissue immediately surrounding the tumor or primary cancer site.)
> Stage 2 — As soon as the cancer spreads to another body part, it becomes Stage 2. In this stage, the spread is still local, usually limited to the organs right next the the primary tumor. Occasionally, cancer that has spread to the lymph nodes is staged here.
> Stage 3 — Like Stage 2, this is usually limited to fairly localized cancer spread. In this stage, however, the regional spread is more advanced. This stage also includes significant spread to the lymph nodes. (Lymph nodes matter because cancer cells could *potentially* travel through your lymphatic system to other body parts).
> Stage 4 — Sometimes called metastatic cancer, this stage is usually reserved for advanced cancer that has traveled to distant body parts.
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**LIFE EXPECTANCY**
This is pretty straight forward: life expectancy is just a game of statistics. The doctor determines your type of cancer, stages it, then looks at data for other people who had the same diagnosis. They basically take the average of the lengths of time these other people lived and bam, there’s the life expectancy.
Sometimes it’s a little more complicated than that, but the most important takeaway is that **life expectancy is *not* a prediction…it’s a guess.** Some people die sooner, some die shortly after, and other people outlive their life expectancy by several years. [In fact, here’s an important rule of thumb to remember when you read any stats about anything: *statistics tell you nothing about the individual.*]
Staging varies between different cancers but they are all roughly the same.
Stage 1 will always be small and no spread from original site
Stage 4 will that it doesn’t matter what size the original tumour is. There is spread to distant sites, such as lung, liver, brain, bone, etc
The stages that vary more between the types of cancers is definition of stage 2 and 3
Stage two will either be just a larger version of stage 1. Or will be that the closest lymph nodes are involved (lymph nodes drain fluid from tissues)
Stage 3 will be that the lymph nodes are involved, possibly involving some that are a bit more distant to the original tumour than are included in stage 2. It’s likely to include rumours that have invaded other tissues next to the original tissues (e.g in a breast cancer, if the tumour has invaded into the skin or chest wall will be a stage 3 regardless of if lymph nodes have cancer in them)
As for predicting how long a patient has left, it is partly to do with this number as well as other factors. It is only a prediction, so you’ll get those who live longer or shorter than the prediction
Again like the staging system, it varies between cancers but the other things that impact the prediction will be things like how the individual cells under the microscope look (rather than where the cells are, it’s how they look. And it’s called the grade of the tumour), some genetic markers, some receptors that can be found on the cells. There will also be factors about the patient too. If they are otherwise fit and well, they will likely live longer without treatment than someone with other health problems. Likewise the health of a patient will also impact on what treatment they can get. An example is that there are some chemotherapies that can adversely affect the heart, so if someone already has heart problems, these won’t be an option for treatment, even if the tumour would respond very well to it, because it would injury/kill the patient.
All these things are put together and compared those with similar rumours to give predictions. It might be the chance of the person surviving a certain length of time with treatment (5 years is often the time used). Or for cancers that don’t have a chance of cure, then the prediction would be related to how long the person has to live. This will likely be without any treatment aimed at prolonging life, and with palliative treatment such as chemotherapy to give more time. In these situations in adults, they may choose to undergo treatment knowing that it will come with side effects but probably give more time, or decide that those effects aren’t worth the extra time for them
I hope this has made sense. Happy to clarify if any of it is unclear
Just want to add that anyone who is a patient or loved one of a patient can find clear, reliable, lay-friendly information about prevention, detection, and treatment of cancer from the National Comprehensive Cancer Network (NCCN). They have downloadable guides about specific cancer types, with helpful illustrations. https://www.nccn.org/patientresources/patient-resources/guidelines-for-patients
The guidelines are established by NCCN member institutions — the top cancer centers in the U.S. –and are based on scientific evidence about the best ways to prevent, detect, and treat cancer.
The National Cancer Institute is another place to find reliable information, but I find their website less user-friendly.
Lots of good explanation here but let me attempt a eli5 version:
Cancer starts as something very small and grows to something bigger. Imagine it starting as a pea size and becoming fist size. When it becomes fist sized, it can go to nearby places due to it just touching other things.
Once it travels to 1 nearby organs, that is when it can start traveling to everywhere. At this point, there’a data on how long a person can live based on what has happened.
To circle back:
Early stage: Still small and hasn’t traveled anywhere. Depending on where it is located, you can possibly remove it and be okay.
Late stage: It has traveled away from where it started. Survival is very low. Doctors look at similar situations on past to predict how long a patient can live.
Doc here.
This varies based on the particular type of cancer.
Melanoma, for instance, is staged based on its depth of invasion. Breast cancer, on the other hand, has a number of factors that we take into consideration.
Generally though it’s based on the “TNM classification” system
* **T** for tumor (how big it is)
* **N** for nodes (whether it’s spread to nodes and, if so, how many nodes or which ones)
* **M** for metastasis (whether it’s spread to other organs). M1 = yes; M0 = no.
A cancer may be written as T1N0M0. For breast cancer, that would mean a cancerous tumor that’s less than 2 cm, which hasn’t spread to any nodes or any other part of the body. This would be considered stage 1. If it has spread to other parts of the body, a cancer is virtually always considered stage 4. But every cancer is staged a little differently. We have charts that we can use to convert TNM definitions to stage.
Stage is mostly important for giving a prognosis (e.g., survival likelihood) and it only loosely relates to treatment. How we treat the patient is based on the size of the tumor, whether it’s spread to nodes, and whether there’s metastasis. One breast cancer could be really small (< 1 cm), but if it’s in the lymph nodes, we always use chemo as part of treatment. But another breast cancer could be large (3 cm+) but if it hasn’t spread to nodes or organs, we can typically just do surgery and radiation.
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