breast cancer stages singapore

    Understanding Breast Cancer Stages

    Once you are diagnosed with breast cancer, it is crucial to know what stage it is in. In doing so, you will have an informed decision on the next steps you need to take. Your doctor will guide you throughout the diagnosis and provide you the information that you need, however, even before being diagnosed with the disease, or if you know someone who’s been diagnosed with breast cancer, it would be helpful to familiarize yourself with the breast cancer stages to have a better understanding of how it can progress from Stage 0 to IV.

    Doctors have several ways of determining what stage of cancer you have. Initial symptoms of the disease can be pointed out through medical tests like physical exams, biopsies, X-rays, bone scans, and blood tests. Furthermore, a pathologist gets a tissue sample from the breast tissue or lymph node and exam it for diagnosis through a microscope.

    Based on the results of the tests, the doctor will be able to name the stage of breast cancer. The stages are numbered 0 to, Roman numerals, I to IV, where a higher number means a more advanced cancer. The number is followed by a letter (A, B, or C) to further explain the state of the disease.

    Breast cancer stages

    breast cancer stages

    Stage 0

    Stage 0 is the earliest detection of breast cancer, where the cancer cells have stayed in the ducts or milk glands and not yet developed. It is also called carcinoma in situ (in situ, meaning “in the original place”). However, this stage is commonly harder to detect because there may not be a lump during self-examination or no other symptoms showing. It is most often found by accident during a breast biopsy for other reasons, such as to investigate an unrelated breast lump. Still, self-exams and routine screenings are important for early diagnosis.

    Stage 0 breast cancer can be classified into two types:

    Ductal carcinoma in situ (DCIS)

    This type occurs when the breast cancer cells develop in the breast ducts. It can become invasive and early diagnosis and treatment are needed.

    Lobular carcinoma in situ (LCIS)

    This type occurs when the abnormal cells develop in the lobules. It is not cancerous and rarely becomes invasive. However, if you are diagnosed with LCIS, there is a higher risk for you to develop breast cancer in the future.

    Stage I

    Stage I is the earliest stage of invasive breast cancer, where the cancer cells have spread to the surrounding breast tissues. This stage is still a little difficult to detect because of the small size of the tumor.

    It is further divided into two subcategories:

    Stage IA

    The tumor is around 2 cm and has not spread beyond the breast, where no lymph nodes are affected.

    Stage IB

    This stage can manifest in two ways:

    • No tumor is located in the breast, but there are small groups of cancer cells- larger than 0.2 mm but not larger than 2 mm- in the lymph nodes.
    • There is a tumor located in the breast, no larger than 2cm, and there are small groups of cancer cells- larger than 0.2 mm but not larger than 2 mm- in the lymph nodes.

    Stage II

    During Stage II, the tumor has grown in size or the cancer cells have spread to the surrounding breast tissues or lymph nodes, but not to distant parts of the body. At worse, it can be both. Here, a tumor is more prominent during a self-exam when you feel a hard lump within the breast.

    Just like Stage I, it is further divided into two subcategories:

    Stage IIA

    It is considered Stage IIA if either of these cases happens:

    • There is no tumor in the breast, but cancer cells (larger than 2mm) are located in 1 to 3 axillary lymph nodes under the arm or near the breast bone.
    • The tumor is2cm and cancer has spread to the axillary lymph nodes.
    • The tumor is larger than 2cm but smaller than 5cm, and cancer cells have not spread to the axillary lymph nodes.

    Stage IIB

    It is labeled as Stage IIB if either of the following happens:

    • The tumor is larger than 2cm but smaller than 5cm, and there are small groups of cancer cells- larger than 0.2 mm but not larger than 2 mm- in the lymph nodes.
    • The tumor is between 2cm to 5cm and cancer cells are located in 1 to 3 axillary lymph nodes under the arm or near the breast bone.
    • The tumor is larger than 5cm but cancer cells have not spread to the axillary lymph nodes.

    Stage III

    Stage III is known as locally advanced breast cancer, the cancer is extensive in the underarm lymph nodes or has spread to other lymph nodes or tissues near the breast. At this stage, the cancer cells have not spread to bones and organs, but they are present in several axillary (underarm) lymph nodes. The tumor may also be quite large at this stage, possibly extending to the chest wall or the skin of the breast, making it harder for treatment.

    Unlike the previous stages, it is further divided into three subcategories:

    Stage IIIA

    It is classified as Stage IIIA under either of the following conditions:

    • There is no tumor in the breast, or the tumor may be any size, and cancer cells are found in 4 to 9 axillary lymph nodes under the arm or near the breast bone.
    • The tumor is larger than 5 cm and small groups of breast cancer cells- larger than 0.2 mm but not larger than 2 mm- are in the lymph nodes.
    • The tumor is larger than 5cm and the breast cancer cells spread to 1 to 3 axillary lymph nodes under the arm or near the breast bone.

    Stage IIIB

    Stage IIIB manifests in either of the following conditions:

    • The tumor may be any size and the cancer cells have spread to the chest wall and/or skin of the breast, which leads to swelling or ulcer.
    • Cancer has spread to up to 9 axillary lymph nodes under the arm.
    • Cancer cells have spread to lymph nodes near the breastbone.

    Stage IIIC

    It is considered Stage IIIC if any of the following happens:

    • There are no signs of cancer in the breast or if a tumor is located, it may be any size. Cancer cells also have spread to the chest wall and/or the skin of the breast.
    • Cancer has affected 10 or more axillary lymph nodes.
    • Cancer cells have spread to lymph nodes above or below the collarbone.
    • Cancer has affected the axillary lymph nodes under the arm or near the breast bone.

    Stage IV

    Stage IV is the most complicated stage of breast cancer. It is known as metastatic breast cancer, meaning it has spread through the body from the area it was first found. Here, cancer cells have affected the breast, lymph nodes, and other organs in the body, such as the lungs, liver, bones, and brain.

    At this stage, and other stages of breast cancer, the doctor usually uses the TNM Staging System to elaborate on the extent of the condition.

    TNM Staging System

    The TNM Staging System is a common tool used by professionals to describe the stages of breast cancer. It has three categories: Tumor (T), Node (N), and Metastasis (M).

    Tumor (T)

    This refers to the size of the lump or tumor. It is followed by a numerical value suggesting the size of the tumor. A higher number means a bigger or wider lump. The stage of cancer can be classified as either of the following:

    • TX: The tumor cannot be evaluated.
    • T0: There are no signs of cancer in the breast.
    • Tis: The cancer is “in situ”, or the tumor has not started growing in healthy breast tissues.
    • T1: The tumor is 20mm or smaller.
    • T1mi: a tumor that is 1 mm or smaller.
    • T1a: a tumor that is larger than 1 mm but smaller than 5mm.
    • T1b: a tumor that is larger than 5 mm but smaller than 10mm.
    • T1c: a tumor that is larger than 10 mm but smaller than 20mm.
    • T2: The tumor is larger than 20mm but smaller than 50mm.
    • T3: The tumor is larger than 50mm.
    • T4: The tumor has grown into the chest wall and/or skin, or it has become inflammatory breast cancer.

    Node (N)

    This category looks if the cancer cells have reached the nearby lymph nodes and, if so, how many has it affected. It can be classified as any of these cases:

    • NX: The lymph nodes cannot be evaluated.
    • N0: There are no signs of cancer in the lymph nodes or cancer cells smaller than 02.mm are in the lymph nodes.
    • N1: Cancer cells have spread to 1 to 3 axillary lymph nodes and/or the internal mammary lymph nodes. If the cancer in the lymph node is larger than 0.2 mm but smaller than 2 mm, it is called “micrometastatic” (N1mi).
    • N2: Cancer cells have spread to 4 to 9 axillary lymph nodes, or it has spread to the internal mammary lymph nodes, but not in the axillary lymph nodes.
    • N3: Cancer cells have spread to more than 10 axillary lymph nodes, or it has spread to the internal mammary and supraclavicular lymph nodes.

    Metastasis (M)

    This category identifies if there are signs of cancer in other areas of the body, spreading beyond the breast and lymph nodes. It can be either of the following:

    • MX: Distant spreading cannot be evaluated.
    • M0: Cancer has not affected other parts of the body.
    • M0 (i+): There are no clinical or radiographic signs of distant spreading. However, Microscopic evidence of cancer cells, no larger than 0.2mm, is located in the blood, bone marrow, or lymph nodes.
    • M1: Cancer cells are forming in other organs of the body.

    Having an understanding of the breast cancer stages can help you in preventing the disease from progressing. Once you notice any changes in the appearance or feel of the breast area, make sure to consult your doctor immediately. Remember that early detection and prevention is key in dealing with the different stages of breast cancer.