Your cancer’s stage describes how much cancer there is in your body and how far it has metastasized (spread from its original location). Doctors use staging information to estimate your outlook and better understand which treatment plans to recommend.
How cancer is staged
Different types of cancer are staged in different ways. In general, the higher the cancer stage, the more cancer there is and the further it may have spread.
Doctors determine your cancer stage using staging systems. There are many different systems, but they all generally take into account things like how big a tumor is, which type of cells make up the tumor, and whether cancer cells have spread to nearby or more distant locations.
The TNM system
The most common staging system is tumor node metastasis (TNM) classification. Using this system, doctors assign your tumor a number in three different categories:
Tumor — This category grades how big your tumor is and whether it has started growing into nearby tissues on a scale of one to four. T1 tumors are small and located in one area, while T4 tumors may be very large and invade nearby organs.
Nodes — This category refers to lymph nodes, the small structures that filter out damaged or cancerous cells from your tissues. Doctors classify your cancer as N0 if they don’t find any cancer in your lymph nodes. N1 means that cancer cells are found in lymph nodes very close to the original tumor, N2 occurs when cancer has spread to lymph nodes a little further away, and N3 means that cancer cells have spread to far-away lymph nodes.
Metastasis — This category describes whether cancer cells have spread to distant parts of the body. Your cancer is classified as M0 if you don’t have any metastases (distant tumors) or M1 if your cancer has metastasized.
Usually, each of these TNM categories is combined into one overall stage using Roman numerals. For example, a small prostate tumor (T1) that hasn’t spread to the lymph nodes (N0) or to distant locations (M0) might simply be referred to as “stage I.”
Letters may also be added to the stage’s Roman numeral. For example, stage IIA lung cancer involves tumors that are medium-sized or have grown into nearby tissues (T2), but haven’t spread to the lymph nodes (N0) or other parts of the body (M0). However, stage IIB tumors have slightly different criteria. These lung cancers might involve slightly larger tumors, or they may be smaller tumors that have spread to nearby lymph nodes.
Other factors may also be combined with TNM staging. For example, breast cancers are often staged with TNM plus two other factors. One is the tumor grade — how abnormal the cells look and how aggressively they grow. The other factor is cancer’s biomarker status, which refers to the presence or absence of proteins on the cell’s surface called estrogen receptor (ER), progesterone receptor (PR), or HER2. If your cancer cells have a higher tumor grade or contain certain biomarkers, you might be diagnosed with higher-stage breast cancer.
Other staging systems
For certain cancer types, doctors don’t use TNM staging and instead use specialized staging systems. For example, gynecological cancers such as cervical cancer, ovarian cancer, and endometrial cancer use the Federation of Gynecology and Obstetrics (FIGO) staging system. FIGO staging takes into account similar factors as TNM staging.
Additionally, most types of leukemia are not staged. Leukemia does not generally cause solid tumors — instead, it leads to cancerous blood cells that travel all around the body. Therefore, it doesn’t make sense to talk about tumor size or analyze whether cancer cells have spread from one part of the body to another.
When does staging occur?
There are several types of staging that can occur at different points along your cancer journey. They include:
- Clinical staging — Estimates of tumor sizes and locations based on physical exams and imaging tests like CT scans or MRIs
- Pathologic staging — Staging that occurs after surgery and incorporates information from the surgeon related to how much cancer they found
- Post-therapy staging — Staging that happens after you’ve been treated to determine how much cancer remains and see how effective the treatment was
- Restaging — Figuring out how much cancer is in the body if it returns
Cancer staging and survival
Several factors affect how effectively your cancer can be treated. One of the main factors is the cancer stage — being diagnosed at a higher stage means that you may have a worse outlook. Your cancer may be less likely to go away after being treated or more likely to come back. You may also have a shorter life expectancy.
Having a high cancer stage doesn’t necessarily mean that you will have a poor outcome. Several other factors also influence your outlook, such as what type of cancer you have, your cancer biomarkers, and your age and overall health.
Treating different cancer stages
Because higher-stage cancers tend to be harder to treat, your doctor will take into account staging information when recommending a treatment plan. You may need more aggressive treatments for advanced cancer.
If your cancer is found in the very early stages, you may only need surgery as a treatment. This is true for common tumors like breast cancer, lung cancer, and colon cancer. More advanced cancers may need additional treatments such as chemotherapy or radiation therapy. For some cancers, these additional therapies may be recommended even in the early stages. Stage I prostate cancer, for example, is often treated with radiation therapy.
It is often difficult to surgically remove stage IV cancer. Metastatic cancer often requires treatments that travel around your body, like chemotherapy or targeted therapy drugs.
Knowing what to expect with cancer staging
Talk to your doctor if you’d like to learn more about which cancer stage you have and why your tumor was staged that way. Your doctor can also help you understand why certain treatments may be a better fit based on your cancer stage.
Your cancer stage is a number that describes how much cancer is in your body.
Doctors determine cancer stage based on tumor size, whether cancer cells can be found in nearby lymph nodes, and whether cancer has spread to other areas.
Higher cancer stages may be a sign of a worse outlook and require more intense treatments.
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