Understanding The Staging Of Breast Cancer
Breast cancer is a disease which occurs when some breast cells begin to grow abnormally and spread to other parts of the body. When you get a breast cancer diagnosis, you would be told the ‘stage’ of the cancer, which is mostly a combination of alphabets and numbers. Do not get startled by the stage; this article will help you understand the different stages of breast cancer.
The universal staging system for breast cancer is called “TNM staging”. Let us understand more about this system.
What Is TNM Staging? What Does Each Word Stand For?
TNM staging is globally recognised and standardised system used to describe and classify the extent of the cancer. Having a standardised staging system is essential for creating a treatment plan, for estimating the prognosis, evaluating treatment results and for information exchange between different practitioners or clinics.
TNM stands for Tumour-Node-Metastasis, each of these is a category, which encodes a bit of detailed information on the nature of the cancer.
“T” describes the primary tumour site and size of the tumour. An imaging technique or scan is used to measure the size of the tumour and its relative position.
“N” describes the spread of cancerous cells to nearby or regional lymph nodes.
Your lymphatic system is a system of vessels and nodes similar to the circulatory system that transports a fluid called “lymph”. Lymph contains many immune cells that help fight invaders. Sometimes cancer cells can aggregate in the lymph nodes.
“M” describes the presence or absence of metastasis of tumour in near or distant sites. Metastasis is the spread of cancerous cells from an initial or primary site to a different or secondary site in the body.
What Are The Different Stages And What Do They Mean?
The stages of breast cancer are determined using the TNM staging criteria along with grade of the cancerous cells (how abnormal the cancer cells look under the microscope).
Breast cancer is usually categorised as 5 primary stages from stage 0 to stage 4 depending on extent and severity.
Stage 0:
Stage 0 is often referred to as carcinoma in situ. This is considered the earliest stage of breast cancer. It is non-invasive with no indication of the tumour cells spread to other parts of breast tissues. It is sometimes also considered a “pre-cancerous” condition.
Stage I:
Earliest stage of invasive cancers are categorised as stage I. The size of the tumour is usually 2cm or less in diameter and there may or may not be cancerous cells in the lymph nodes in the underarm.
Generally the prognosis for this stage of breast cancer is good.
Stage II:
This category encompasses tumours that are between 2-5cms in diameter. There may be involvement of lymph nodes on the same side as the primary site of the tumours growth. It is a slightly more advanced form of the disease than stage I. There is more area involved in cancer spread but there is no distant spread of the cancer cells. A self-examination done at this stage would reveal a hard lump in the breast.
Stage III:
More invasive with larger tumour 5cms or more in diameter or larger spread to lymph nodes around or above the collar bone without metastasis. Sometimes even the skin of the breast or chest-wall may be involved, making it appear inflamed. Cancers in stage III may or may not be operable.
Stage IV:
At this stage, the cancer has spread beyond the breast tissue and lymph nodes in the underarm. Secondary cancerous growths may be seen in distant sites like bones, brain, liver, lungs or other sites. This cancer is likely to result in recurrence even after treatment.
How Are Treatments Based On Different Stages?
As expected, the greater the extent of the cancer the more treatment you would require.
Treatment For Stage 0:
Stage 0 cancers are localised with no evidence of invasion into surrounding structures. The preferred treatment would be surgical, either a breast conserving surgery (BCS) or a mastectomy.
A breast conserving surgery (BCS) is sometimes called lumpectomy or partial mastectomy. It is when the doctor removes the cancer while leaving as much normal breast as possible. Some surrounding healthy tissue and lymph nodes may be removed as well.
A mastectomy is a surgery to remove all breast tissue from a breast. Usually, removal of lymph nodes of the underarms may also be done at the time of a mastectomy. Most women don’t require radiation after a mastectomy if they have stage 0 breast cancer.
Hormonal therapy may be done if the cancer is found to be hormone receptor positive.
Treatment For Stage I:
Treatment starts with local therapy such as surgery and radiation. After localised treatment, doctor may move you on to systemic therapy, such as chemotherapy. If the cancer is found to be hormone receptor positive, you may be given hormone therapy either before or after surgery.
Treatment For Stage II:
Treatment for stage II breast cancer starts with local therapy like surgery or radiation therapy. If breast conserving surgery is done, it is followed by radiation therapy. If a mastectomy is done, radiation therapy may be required only if the lymph nodes show the presence of cancer cells. If you require chemotherapy, radiation is delayed until chemotherapy is completed.
Some women may require hormone therapy, depending on the type of cancer. If so, it may be started either before or after surgery and continued for a period of 5 years.
Treatment For Stage III:
At this stage, the tumours are 5cms or larger in diameter, and have usually invaded the surrounding tissue. To tackle a cancer at this stage there are two common approaches. The first, involves starting chemotherapy and hormone therapy (if necessary) before surgery. This is done so that the tumour shrinks in size and make operating on it easier. The second approach involves starting a surgery (typically a mastectomy) followed by chemotherapy and hormone therapy. Radiation may also be given after surgery in both these approaches.
Treatment For Stage IV:
When the cancer has progressed in to stage IV, it is considered incurable and all treatments that are done to either slow the growth and spread of the cancer or to alleviate the symptoms.
Drug therapy is the main mode of treatment in stage IV cancers, this includes- hormone therapy, chemotherapy, targeted drugs, immune therapy or combination of the above.
References:
TNM staging. Cancer Research UK. https://www.cancerresearchuk.org/about-cancer/breast-cancer/stages-types-grades/tnm-staging. Accessed on 05-08-2021.
Breast Cancer Stages and Staging. Susan G. Komen website. https://www.komen.org/breast-cancer/diagnosis/stages-staging/. Accessed on 05-08-2021.
Breast Cancer Stages. Breastcancer.org. https://www.breastcancer.org/symptoms/diagnosis/staging. Accessed on 05-08-2021.
Breast Cancer: Stages. American Society of Clinical Oncology (ASCO). https://www.cancer.net/cancer-types/breast-cancer/stages. Accessed on 05-08-2021.
Breast Cancer Stages. American cancer Society. https://www.cancer.org/cancer/breast-cancer/understanding-a-breast-cancer-diagnosis/stages-of-breast-cancer.html. Accessed on 05-08-2021.
Breast cancer stages. Cancer Treatment Centers Of America. https://www.cancercenter.com/cancer-types/breast-cancer/stages. Accessed on 05-08-2021.
What is the TNM cancer staging system? Union for International Cancer Control. https://www.uicc.org/resources/tnm?gclid=CjwKCAjwjJmIBhA4EiwAQdCbxoUhtGWACebfYvp1uavUufYJnaVTzKeAExPt0W6Tqlx2D_WqfmSjBxoC9cYQAvD_BwE. Accessed on 05-08-2021.
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