Finding out whether you have cancer is scary in of itself. But the process of understanding the jargon around cancer can be challenging. Here is a little break-down of commonly used terms to describe a person’s cancer diagnosis, staging and prognosis.
Staging is the process of finding out how much cancer is in the body. That is, where the cancer is located and how far it has spread.
Staging is used to give doctors and patients an idea of how well they will survive, called a prognosis, from cancer, and what types of treatments should be used (eg. Type of chemotherapy, radiation therapy, etc.). Staging can help predict the course of the cancer and how successful certain treatments will be.
Not all cancers are staged. For example, leukemias, cancer of blood cells, are not staged, as they are technically found throughout the body.
Overall staging, or stage grouping, uses roman numerals I, II, III, IV (e.g. Stage IV Cancer). Arriving at this designation uses information from many factors, such as type of cancer, where it has spread, etc.
Different exams and tests are done to determine a person’s cancer stage. Such tests or exams are the initial physical exam done by the doctor, imaging, such as a CT scan, and finally a biopsy (e.g. FNA), to diagnose the type of cancer.
Timing of Staging:
Cancer is staged when it is first diagnosed, before any treatment is given, and sometimes again, after treatment.
There are different types of “staging” that help formulate the “overall” staging mentioned above: Clinical, Pathological, Post-treatment (post neo-adjuvant therapy), & Recurrence.
Clinical staging estimates the extent of cancer based on physical exam, imaging, blood tests, bone marrow biopsy, etc. It is used to determine the best treatment options and outcomes.
Pathological staging is also called “surgical” staging, as it is determined once the cancer is removed surgically (if no other treatments are used first). It is more precise. It helps predict treatment response and prognosis.
Post therapy staging helps measure response to a particular treatment done usually before the surgical removal of the tumor, such as chemotherapy, targeted drug therapy and radiation therapy. It is similar to clinical staging in that it helps determine what type of surgery (if needed) to be done. This staging system also helps measure the patient’s response to specific treatments.
Recurrence or Retreatment Staging helps guide further treatment after a cancer has come back or recurs.
Re-staging can occur. It is usually done after initial staging and is added to the original staging (not replacing it).
TNM nomenclature is a way to categorize the cancer in a more precise way, which helps with formulating an overall stage.
N= Lymph node metastasis
M= Metastasis to distant organs (away from the original site)
Each type of cancer has its own TNM category. Lung Cancer TNM is different from Breast Cancer TNM. So, the letters and numbers do not mean the same for each type of cancer.
Each letter has a subletter or number that tells us how much cancer there is.
T0 = No evidence of tumor (or it cannot be found)
Tis = “in situ”, which means that the tumor is within the confines of its own tissue and has not breached the barrier that keep cancer from spreading
T1,2,3… = Tumor size and spread to adjacent tissue. The larger the number, the larger the tumor and the more it has spread to adjacent structures. Sometimes there are subcategories like T3a .
X is used to mean that there is no information on it (Tx, Nx, Mx)
N0 = no lymph node metastasis has been found.
N1,2,3… = size, location or number of lymph nodes found regionally (near the cancer)
M0 = no distant metastasis has been found anywhere in the body.
And so forth.
The TNM system is used mostly in pathological staging seen as pTNM, as well as in clinical staging, cTNM.
Stage vs. Grade
Stage is different from grade.
Grading a tumor is based on how abnormal the cancer cells are from its origin. A low-grade cancer looks fairly like normal tissue and it tends to grow slowly and have a better outcome.
A high-grade cancer looks very abnormal, even bizarre, and sometimes one cannot tell on first look where the cancer originally came from. These types of cancers can grow rapidly, and prognosis is varied.
The importance of grading comes when considering treatment options as tumors with different grades often need separate therapies.
There are other staging systems that do not use this terminology. Lymphomas, gynecological tumors (use FIGO staging) and brain cancers (they don’t spread outside the central nervous system) do not use TNM staging system.
When all this information is brought together, doctors can predict a patient’s overall prognosis. This prediction is based on a “survival rate”, which is a statistical number based on how many people have survived from that particular cancer out of 100 people within a given time (i.e., 5-year survival rate). It is given a percentage.
So, for instance, if a specific cancer has a 5-year-survival rate of 80%, that means that 80 people out of 100 with this type of cancer will be alive after 5 years.
Survival rates are based on the stage at the time of initial diagnosis.
Other factors that affect prognosis
There are other factors that affect a person’s prognosis, such as age and overall health at the time of cancer diagnosis. Another thing to consider are whether the cancer cells have changes in them, such as genetic, chromosomal or protein abnormalities. In addition, how cancer responds to treatment is important in predicting survival.
When gathering information about cancer statistics online, be sure to look into the correct type of cancer and understand that each type of cancer stage is unique to that cancer and can represent different things.