Breast cancer begins when healthy cells in the breast change and multiply without control, forming a mass called a tumor. A tumor can be cancerous or benign. A cancerous tumor is malignant, which means it can grow and spread to other parts of the body. A benign tumor means that the tumor can grow but will not spread.

Breast cancer spreads when the cancer grows to other parts of the body or when the breast cancer cells move to other parts of the body through the blood vessels and / or lymph vessels. This is called metastasis.

Whatever the stage of the cancer is, it describes the place where the cancer is located, how much the cancer has developed and whether or where it has been spread (metastasis) to.

Although breast cancer often spreads to nearby lymph nodes, it can also spread further through the body to areas such as bones, lungs, liver and brain. This is called metastatic or stage IV of the breast cancer.
If breast cancer reappears after the initial treatment (relapse), it can occur locally, such as, the breast and / or regional lymph nodes. The regional lymph nodes are the ones that are close to the chest, such as the lymph nodes under the arm, in the armpit. It can also reappear in other parts of the body which is called distant recurrence or metastatic recurrence.

Breast cancer can be invasive or non-invasive (in situ cancer). Invasive breast cancer is cancer that spreads to the surrounding tissues. Non-invasive breast cancer does not spread to the surrounding tissues. Most breast cancers start from lactating ducts or breast lobules and are called respectively breast carcinoma or lobular carcinoma of the breast:

Ductal Carcinoma.

These cancers start from the cells that cover the milk pores and happened to be the majority of breast cancers.

Ductal Carcinoma In Situ (DCIS). This is cancer that is found only in the breast pores and has not spread to the surrounding tissues.

Invasive Ductal Carcinoma. This is the type of cancer that has been spread outside the pore, filtering the invasiving breast tissue.

Lobular carcinoma of the breast.

This is the cancer that begins in the lobes.

Lobular carcinoma in situ (LCIS). The LCIS is only located in the pods. The LCIS is not invasive cancer. However, LCIS is a risk factor for the development of invasive breast cancer in both breasts.

Invasive lobular breast carcinoma. This is the type of cancer that has spread outside the lobes, that is, it has been invasived to the surrounding breast tissue.

The least common types of breast cancer include:

Myeloid breast carcinoma

Mucosal breast carcinoma

Tubular carcinoma of the breast

Metastatic breast carcinoma

Myeloid breast carcinoma

Inflammatory breast carcinoma is a fastest growing type of cancer that represents about 1% to 5% of all breast cancers.

Paget’s disease is a type of cancer that starts from the nipple pores. Although it is usually non-invasive, it can also be an invasive cancer.

There are 3 specific breast cancer subtypes identified by specific types of tests (Immunohistochemistry, IHC) in a tumor sample. These tests will help your doctor learn more about your cancer and decide the most effective treatment.

These tests on the tumor sample can find out if the cancer is:

Hormone-dependent cancer (positive at the hormone-indexes).

Breast cancers that express estrogen receptors (ER) and / or progesterone receptors (PR) are called positive at the hormone receptor. These receptors are proteins found in cells. The tumors which have estrogen receptors called ” ER- positive“. The tumors which have progesterone receptors called “PR- keys positive“. It is enough for only one of these receptors to be positive so that the cancer is named positive for hormonal receptors. The development of hormone receptor-positive cancers depends on estrogen and / or progesterone hormones.

Hormone receptor-positive cancers can occur at any age, but are more common in women who have gone through menopause. About 60% to 75% of breast cancers are positive for estrogen and / or progesterone receptors. Cancers that are not positive for hormone receptors are called “negative at the hormone receptor cancers“.

HER2- breast cancer positive.

About 15% to 20% of breast cancers depend on the gene called Human Epidermal Growth Factor Receptor 2 (HER2) in order to grow. These cancers are called “HER2-positive” and have many copies of the HER2 gene or high levels of the HER2 protein. The HER2 gene forms the HER2 protein, which is found in cancer cells and is important for the growth of cancer cells.

The HER2-positive breast cancers grow faster. They may also be positive for hormonal receptors or negative for hormonal receptors.

Cancers that do not have or have low levels of HER2 protein and / or few copies of the HER2 gene are called “HER2-negative” breast cancers.

Triple Negative Breast Cancer (TNBC).

If a tumor does not express estrogens ER, progesterone PR or HER2 protein, the tumor is named ‘triple negative‘. Triple negative breast cancer forms about 15% of invasive breast cancers. Triple negative breast cancer seems to be more common in younger women, especially younger women of color. Triple negative cancer is also more common in women with a mutation in the BRCA1 or BRCA2 genes.

Experts recommend that all people with triple negative breast cancer younger than 60 should be tested for BRCA1 & BRCA2 gene mutations. Click on Breast Signature for additional information.

For most types of cancer, biopsy is the only sure way for the doctor to know if an area of ​​the body has cancer. In a biopsy, the doctor takes a small sample of tissue for histological examination in a pathological laboratory.

This list describes diagnostic options for this type of cancer. Not all of the tests listed below are used for each person. Your doctor will consider the following factors when choosing a diagnostic test:

The type of cancer that is suspected

Your symptoms

The age and general state of your health

Results of previous medical examinations

The series of tests required to evaluate a potential breast cancer usually begins when your doctor discovers an abnormal lesion or calcification in the mammogram, or if he detects a nodule in the chest during a clinical examination or self-examination. Less often, redness or swollen breasts or a mass or nodule under the arm may be observed in the armpit.

The following tests can be used to diagnose breast cancer or to perform a screening after a diagnosis of breast cancer:

1. Mammography
2. Ultrasound
3. Magnetic resonance imaging (MRI)
4. Biopsy

Biopsy is the removal of a small amount of tissue for histological examination in the microscope. Only a biopsy can make a clear definitive diagnosis. The pathologist is a physician who specializes in interpreting a histological examination to evaluate cells, tissues, and organs for a definitive diagnosis.

There are several types of biopsies, which are classified according to the technique and / or the size of the needle which is used to collect the tissue sample.

Thin needle aspiration biopsy.

This type of biopsy uses a fine needle to remove a small sample of cells.

Core biopsy needle.

A needle of a larger diameter is used for this type to remove a larger tissue sample.

Surgical biopsy.

By surgical biopsy a larger amount of tissue is removed. Most often, core biopsies are the ones that are recommended for the diagnosis of breast cancer. This means that only 1 surgery is needed to remove the tumor and to take samples from the axillary lymph nodes.

Imaging-guided biopsy.

During this procedure, the needle is directed to the appropriate position (where the lesion appears to be) by means of a visualization technique, such as mammography, ultrasound or magnetic resonance imaging.

Sentinel Lymph node biopsy.

This procedure is one way to find out if there is cancer in the lymph nodes near the breast area.

Histological examination of the specimen removed during the biopsy may help your doctor learn about specific cancer features that help determine treatment options.

Tumor’s Characteristics.

Histological examination of the tumor under the microscope is used to determine if the cancer is invasive, if it originates from the pores of the breast or the lobes, and whether the cancer has spread to the lymph nodes (metastasis).

Surgical margins of the tumor are checked and the distances from the tumor are measured.

Hormones ER (estrogen) and PR (progesterone).

The control for ER and PR (see Special types), made in Immunohistochemistry –IHC, helps to determine the recurrence risk of the patient and the type of treatment that is more likely to reduce the risk of recurrence (relapse). ER and PR are often also measured in in situ carcinoma-DCIS (see Cancer Types).

In general, hormone therapy works good for ER-positive and / or PR-positive cancers.

HER2 positive cancer.

The HER2 status (see Specialties) helps to determine whether drugs targeting the HER2 receptor, for example trastuzumab treatment (Herceptin, Ogivri), can help in the treatment of cancer. The ASCO and the College of American Pathologists (CAP) recommend HER2 checking be done when first diagnosed the patient with an invasive breast cancer.

If the cancer has spread to another part of your body (metastasis) or recurs after treatment (relapse), there should be a new checking in the new tumor that has appeared or in the areas where the cancer has spread, especially if the results will affect the your treatment options.

Consult your Oncologist to get the best combination of exams for you.

If the test results are not clearly positive or negative, then the test may need to be re-tested, either on a different tumor sample or on a different test. Sometimes, even with repeated tests, the results may not be decisive, so you and your doctor should discuss the best treatment option.

If the cancer is HER2 positive, then an anti-HER2 treatment may be the recommended treatment for you. If the cancer is HER2 negative, an anti-HER2 treatment is not a treatment option for you and your doctor will give you other breast cancer treating options.

The Grade of the tumor.

The Grade of the tumor is also determined in histology, after a biopsy, and refers on how different the cancer cells look from healthy cells and if they grow slowly or quickly. If cancer resembles the healthy tissue it is called “good differentiation” or “low grade malignancy“. If the cancerous tissue looks very different from the healthy tissue, it is called “low -grade cancer” or “high-grade malignancy“.

There are 3 Grading Points: Grade 1 (well diversified), Grade 2 (moderately diversified), and Grade 3 (low diversified).

Molecular examination of cancer.

Your doctor may recommend performing other laboratory tests on the tumor sample to identify specific genes, proteins, and other factors unique to the tumor.

If you have locally advanced or metastatic breast cancer, your doctor may recommend testing for the following molecular features:

PD-L1 test, a protein that is found on the surface of cancer cells and on certain cells of the immune system. This protein prevents the body’s immune cells from destroying the cancer.

Testing for high microsatellite instability (MSI-H) or deficiency mismatched proteins (dMMR).

Tumors that have MSI-H or dMMR seem to have difficulty in repairing the damage in their DNA. This means that they develop many mutations or transformations. These transformations render abnormal proteins in cancer cells that facilitate immune cells to find and attack the tumor.

NTRK gene fusions.

is a specific genetic change found in a number of cancers, including breast cancer.