Decoding Cancer Stage
When discussing cancer, the terms ‘cancer at stage 1’ or ‘stage 2’ or ‘stage 4’ are used and heard and they refer to the medical set standard or benchmark of the spread of cancer where and within the patient’s body.
Importance of Cancer Staging
The doctors must have a fair idea of the location of cancer and how much it has spread within the patient. It helps them in deciding the treatment options and path forward. This also helps in standardization of treatment as all involved parties will understand the condition better.
Other factors also help to determine the treatment along with the stage of cancer. It is also possible that cancer with different stages can be treated in the same way, or cancer at a similar stage can be treated differently. The treatment approach depend entirely upon the overall health condition of the patient.
Types of Cancer and Staging
All cancers do not have stages, for instance, leukemia is cancer that affects the blood cells, which gets detected by the time it spreads to a large extent within the body. The staging of leukemias is different from tumors developed due to cancer. There are some cancer like thyroid cancer and cancer of testis which do not have stage 4 at all. Staging of each cancer is different.
Determining stages of cancer
Various tests that help in knowing the stage of cancer and its spread, apart from a physical exam, are
- CT Scans, PET CT scans, Ultrasound, X-rays, and other imaging tests
- Endoscopic examination or endoscopy refers to inserting a thin tube whose mouth is fitted with a light enabling the doctor to get a fair view of cancer within the digestive system. Various endoscopy procedures are performed depending upon the type of cancer.
- The biopsy is yet another test that confirms the presence of cancer. It involves removing a part or whole of tumor or lump that is felt or viewed during an imaging procedure and testing it further. The doctor will perform a biopsy during an endoscopy or through surgery or using a hollow, thin needle as the case may be.
- After the biopsy, the tumor or cell samples undergo testing at a laboratory to know the stage of cancer. The staging of cancer can change during treatment too.
This staging can be referred to as a reading of all the different tests conducted to date, i.e., imaging, physical tests, biopsies, endoscopy, and other lab tests. This reading throws light on how to treat the patient, and the chances of total recovery or survival as the case may be.
People generally refer to this stage of cancer after a complete diagnosis, but treatment has yet to begin.
This stage refers to the stage of cancer after a surgery has been performed on the patient to treat cancer while keeping in mind the clinical stage of cancer before the surgery. It is a cumulative report that considers the stage of cancer before and during the surgery to treat cancer.
In a way, the pathological stage gives a better and clear picture of the extent of cancer within the patient. The surgery may highlight more cancer-related details and help the doctors to proceed with a more definitive action to tackle cancer. That is why this is also called final staging.
This staging is also known as post-neoadjuvant therapy staging. In some cancers, the tumors are treated to shrink in size through chemotherapy, radiation, or targeted drug therapy before surgery. This approach is called as neoadjuvant therapy. It helps to decide whether it is advisable to proceed with the surgery or not. The staging is done after therapy to measure the extent of cancer after treatment for clarity purposes. This is done using a PET CT or MRI or any such scan along with clinical assessment.
If the patient is diagnosed with cancer again or further spreads, staging is done once again to determine the further course of treatment. This restaging stage does not replace the initial stage of cancer, which is very crucial. The doctors will always refer to the initial stage of cancer followed by the restaging stage before suggesting the line of treatment. The restaging stage is referred to when discussing survival rates.
Methods of defining stages of cancer
The TNM system is the most preferred way of defining stages of cancer where
T – Refers to the main or original tumor.
N – Refers to the spread of cancer to lymph nodes in proximity.
M – Refers to metastasis, i.e., the spread of cancer across the body.
The doctors begin with the source or origin of the tumor, i.e., from where it started, its size, location, and spread. They also check for the presence of tumors, if any. The grading of the tumor, its size, and spread is as follows –
TX – The existing tumor is not measurable, or there is no information about it
T0 – The tumor cannot be located, or there is no evidence of it
It is the pre-cancerous stage or the in situ stage where the cancer cells grow in the initial layer of cells and have not spread within the inner layers.
T1, T2, T3, or T4 – The number mentioned after the letter ‘T’ refers to the size of the tumor and/or its spread in the tissues located nearby.
The higher the number placed against the letter ‘T’, the larger is the size of the tumor and the spread.
N – The lymph nodes
Lymph nodes are small glands that provide immunity. They work as filters in the body. The lymph nodes present near the primary tumor are checked for cancer. If yes, then this is the first indicator that the cancer is likely to spread further.
The grading of lymph nodes and presence of cancer is as follows
- NX – No information regarding the lymph nodes located nearby, or they cannot be checked.
- N0 – The lymph nodes are not cancerous.
- N1, N2, or N3 – The number placed after the letter ‘N’ refers to the number of lymph nodes affected, their number, and size too.
M - Metastasis or the spread of cancer
It is important to check the other parts of the body for cancer, especially locations far from the primary source of the tumor. This condition is referred to as metastasis. The number after the letter ‘M’ refers to the spread of cancer.
M0 – Cancer has not spread to distant areas
M1, M2 etc. – Cancer has spread to areas located quite far away from its primary source.
These are the primary abbreviations; other abbreviations include letters in lower case placed after the category. For instance – T3b
In case of letters in lower case placed before the category, they relate to either clinical staging or pathological staging –
cT1 – refers to the clinical stage
pT1 – refers to the pathological stage
ycT3 or ypT1 – the letter ‘y’ is placed before the stages ‘p’ and ‘c’ mean restaging of cancer after therapy
rcT3 or rpT1 – the letter ‘r’ is placed before the stages ‘p’ and ‘c’ mean recurrence or further spread of cancer.
Decoding Tumor Grade
General reader are often confused between stage and grade of cancer. These two are different entities. Apart from these are multiple factors that influence the staging of select cancers, which are –
Grade – A grade is a number referring to the abnormality or differentiation factor of cancer cells. The low-grade numbers mean low-grade cancers which grow slowly and are slightly better in abnormality
High-grade numbers mean high-grade cancer in which cells are very abnormal, and the cancer is likely to spread faster.
It is the grade factor that determines the line of treatment and patient’s recovery.
Cells and their types – There are various types of cells in the human body; the same goes for cancer. Different cancer cells need to be treated differently and staged accordingly. There is a difference between adenocarcinomas and squamous cell cancers, and their treatment depends on the location and their staging.
The values of the size of the tumor, nodes, and spread of cancer variables are determined; they are combined to arrive at a stage for determining the line of treatment.
Staging in cancer
Unlike the TNM stage that is explained above, this method of grouping in to 5 stages makes it simpler to understand for general public. However, the oncologists tend to use TNM more often as it contains more details about the disease parameters.
Stage 0 cancer – carcinoma in situ, refers to very initial stage.
Stage 1 and 2 cancer –earlylocalized cancer which are amenable to treatment.
Stage 3 cancer – locally advanced cancer which has spread to local lymph nodes (mostly).
Stage 4 cancer- when the cancer has spread to far away organs.
Cancers such as Hodgkin and non-Hodgkin lymphomas have a different staging system.
Cancers of the female reproductive organs are similar to that of TNM grading as determined by the International Federation of Gynecologists and Obstetricians (FIGO) for ease in conversion to and froth within these systems.
Cancer in the brain does have a staging system as it does not spread to other parts of the body and lymph nodes. However, cause problems locally.
The person’s outlook is synonymous with the survival rate. In most cases, it refers to the people who have a certain type of staged cancer but are still living after its diagnosis, say five years ago.
Survival rates are merely an estimate but other factors that determine life. In general, survival rates refer to the initial stage of cancer on its earliest diagnosis. The survival rate is likely to change in the case of a restaging of cancer.
Other factors can also affect outlook or survival rate