Doctors use various tests to locate or diagnosis breast cancer. They may also do tests to check if cancer has spread beyond the breast and the lymph nodes below the arm. If this happens, it is known as metastasis. They may also do tests to see which treatments could be most effective.
For most types of cancer, a biopsy is the only ensuring way for the doctor to know if a region of the body has cancer. In a biopsy, the doctor uses a small sample of tissue for testing in a laboratory.
Your doctor may analyze these factors when deciding a particular diagnostic test:-
- Type of cancer
- Signs and symptoms
- Age and overall health
- The results of previous medical tests
A woman or her doctor may detect a tumor or abnormal calcifications on screening mammography, or a lump or nodule in the breast during a clinical or self-examination, which triggers a sequence of tests to determine whether she has breast cancer. A red or puffy breast, as well as a lump or nodule beneath the arm, are less common symptoms.
The following tests may be practiced to diagnose breast cancer or for follow-up testing after a breast cancer diagnosis:-
Images of the interior of the body are produced through imaging tests. The following breast imaging tests may be used to learn more about a suspicious region discovered during screening. In addition to these, different new types of tests are being investigated which are given below:-
- Diagnostic mammogram- A mammogram is a type of X-ray that is used to examine the breast. It’s comparable to mammography screening except that it takes more images of the breast. It is frequently used when a woman has symptoms like a new lump or nipple discharge. If a screening mammogram reveals something abnormal, diagnostic mammography may be used.
- Ultrasound- Ultrasound imaging creates pictures of structures deep within the body using sound waves. An ultrasound can tell the difference between a solid tumor that might be cancer and a fluid-filled cyst that isn’t generally malignant. Ultrasound can also be used to guide a biopsy needle into a specific location, allowing cells to be extracted and screened for cancer. Swollen lymph nodes under the arm can also be treated this way. Ultrasound is readily available, simple to use, and does not expose the user to harmful radiation. It’s also less expensive than several other alternatives.
- MRI- An MRI utilizes magnetic fields, not x-rays, to generate detailed images of the body. Before the scan, a specific dye called a contrast medium is administered to aid in the creation of a clear image of the suspected cancer. The dye is injected into the vein of the patient. After a woman has been diagnosed with cancer, a breast MRI may be performed to determine how much the cancer has spread throughout the breast or to screen the other breast for cancer. Breast MRI, in addition to mammography, is a screening option for those women who are at a very high risk of developing breast cancer or who have a history of breast cancer. MRI may also be practiced if locally advanced breast cancer is diagnosed or if chemotherapy or endocrine therapy is being administered first, followed by a second MRI for surgical planning. Finally, after a breast cancer diagnosis and therapy, MRI may be utilized as a surveillance technique.
A biopsy is a procedure in which a tiny quantity of tissue is removed and examined under a microscope. Other tests may indicate the presence of disease, but a biopsy is the only method to confirm a diagnosis of breast cancer. A biopsy is a procedure in which your doctor extracts a core of tissue from a suspicious region using a specialized needle instrument guided by an X-ray or another imaging test. A tiny metal marker is frequently left at the location within your breast so that subsequent imaging tests may easily identify the region.
Biopsy samples are submitted to a laboratory for testing where specialists assess if the cells are malignant. A biopsy sample is also examined to establish the type of cells involved in breast cancer, the disease’s aggressiveness (grade), and whether the cancer cells have hormone receptors or other receptors that might affect your treatment options.
Analyzing the biopsy sample
(a) Tumor features:- The tumor is examined under a microscope to identify whether it is invasive or non-invasive (in situ), whether it is lobular or ductal, or another kind of breast cancer, and whether it has spread to the lymph nodes. The tumor’s margins or edges are also inspected, and the distance between the tumor and the excised tissue’s edge is quantified, which is known as margin width.
(b) ER and PR:- Breast cancers displaying ER i.e. estrogen receptors and/or PR i.e. progesterone receptors are termed as “hormone receptor positive.” These receptors are proteins that are found in cells.
Testing for ER and PR can assist in identifying a patient’s risk of recurrence of cancer as well as the sort of treatment that is most likely to reduce that risk. Hormonal treatment, commonly known as endocrine therapy, lowers the risk of recurrence of ER-positive and/or PR-positive malignancies in general. According to guidelines everyone newly diagnosed with invasive breast cancer or a breast cancer recurrence should have their ER and PR status evaluated on the region of spread of cancer and/or breast tumor.
(c) HER2- About 20% of breast cancers rely on the gene called human epidermal growth factor receptor 2 (HER2) to grow. These cancers are known as “HER2 positive” and have several copies of the HER2 gene or raised levels of the HER2 protein. These proteins are also known as “receptors.” The HER2 gene produces the HER2 protein, which is located on the cancer cells and is essential for tumor cell growth. The cancer’s HER2 status is used to assess if medicines that target the HER2 receptor, such as trastuzumab (Herceptin) and pertuzumab (Perjeta), can help to treat the cancer. Only aggressive tumours are subjected to this test. It is recommended that HER2 testing be done when you are first diagnosis with an invasive breast cancer. Furthermore, if the cancer has migrated to another region of your body or returns after treatment, testing on the new tumour or places where the cancer has spread should be done again.
(d) Grade- A biopsy is also used to identify the tumour grade. The grade describes how cancer cells vary from healthy cells, as well as whether they appear to develop slower or quicker. The cancer is considered “well differentiated” or a “low-grade tumour” if it resembles healthy tissue and has distinct cell groupings. A “poorly differentiated” or “high-grade tumour” is defined as malignant tissue that looks substantially different from healthy tissue. There are three levels of differentiation: grade 1 (highly differentiated), grade 2 (moderately differentiated), and grade 3 (poorly differentiated).
The results of these tests might assist you in deciding on your treatment options.
(C) GENOMIC TEST:-
Doctors employ genomic testing to check for certain genes or proteins, which are the molecules produced by genes, present in or on cancer cells. These tests aid clinicians in gaining a better understanding of the characteristics of each patient’s breast cancer. Genomic testing can also be used to predict the likelihood of the cancer returning following therapy. Knowing this information can assist doctors and patients in making treatment decisions, as well as help some people avoid undesirable side effects from therapies that aren’t required.
The genetic assays described below can be performed on a tumour sample that has already been removed via a biopsy or surgery:-
Oncotype Dx™- This test is available to patients who have ER-positive and/or PR-positive, HER2-negative breast cancer that hasn’t progressed to the lymph nodes, as well as certain situations where the cancer has spread to the lymph nodes. Patients and their doctors can use this test to determine if chemotherapy should be added to hormonal treatment.
MammaPrint™- This test is an alternative for people with ER-positive and/or PR-positive, HER2-negative or HER2-positive breast cancer that has not reached the lymph nodes or has only spread to 1 to 3 lymph nodes. This test estimates the probability of recurrence for early-stage breast cancer using information from 70 genes. This test can assist patients and their doctors to decide if chemotherapy should be added to hormonal treatment if they have a high chance of the disease recurrence. This test is not advised for those who have a low risk of cancer recurrence.
Additional tests- For patients with ER-positive and/or PR-positive, HER2-negative breast cancer that has not progressed to the lymph nodes, some additional tests may be available. PAM50 (Prosigna TM), EndoPredict, Breast Cancer Index, and uPA/PAI are some of the tests available. They can also be used to predict the likelihood of cancer spreading to other regions of the body.
Your doctor will go through all of the results with you when the diagnostic tests are done. These data can assist the doctor in describing the cancer if the diagnosis is cancer. This is referred to as staging. If a suspicious region is detected outside of the breast and adjacent lymph nodes, a biopsy of other parts of the body may be required to determine whether it is cancer.