Breast cancer is caused by malignant tumors that arise from the uncontrolled growth of breast cells. It occurs primarily in the ducts that carry milk to the nipple during breastfeeding (lactation), and secondarily in the milk-producing glands within the lobules. Breast cancer is different from cancers that spread to the breast from other parts of the body. Men also experience breast cancer. However, this article focuses on breast cancer in women. While breast cancer occurs in women of all ages, the risk of developing it increases with age.

Between 5% and 10% of breast cancers are associated with any inherited defect in one of two breast cancer genes, BRCA1 or BRCA2, and in the majority of cases, breast cancer develops due to reasons that have not yet been proven.

Generally,

• People who have had breast cancer in their first or second-degree relatives,
• Those who have previously developed breast cancer in the other breast,
• In people who have not yet had children,
• Women who have their first child after the age of 30

the risk of developing breast cancer is higher.

Each type of breast cancer has unique characteristics. Some types are slow-growing, while others can be more aggressive. Some types are sensitive to hormones such as estrogen and progesterone, while others secrete excessive amounts of protein. 

The characteristics of the cancer are very important as they affect the treatment plan and the potential for cancer recurrence.

Breast Cancer Stages

Breast cancer is classified into three stages based on the extent of cancer spread within the body:

Early Stage Breast Cancer

It is a type of non-invasive breast cancer that is limited to its initial location. If the cancer is confined to the milk ducts, it is called ductal carcinoma in situ (DCIS); if confined to the lobules, it is called lobular carcinoma in situ (LCIS).

At this stage, the cancer cannot be felt as a lump in the breast, but digital mammography can detect DCIS.

Breast Cancer in the Advanced Stage

In the invasive stage, breast cancer has spread beyond the ducts or lobules into surrounding areas of breast tissue. At this stage, breast cancer can be detected through a breast self-exam, a clinical breast exam by a doctor, or a mammogram.

Metastatic Stage Breast Cancer

In the metastatic stage, breast cancer has spread to other parts of the body, including nearby lymph nodes. The treatment plan for this stage requires the collaboration of multiple specialists, such as a surgeon, oncologist, and radiologist.

Breast Cancer Symptoms

It is important to remember that most lumps in the breast are not cancerous but benign, and that signs and symptoms associated with breast cancer may be due to other causes.

Breast cancer symptoms usually appear in the following forms:

• A lump or swelling in the breast,
• Indentations, redness or thickening of the breast skin,
• Nipple retraction,
• Swelling or pain in the breast,
• Nipple pain or discharge,
• Swelling in the lymph node near the armpit.

Breast Cancer Diagnosis

The goals of breast cancer treatment are to identify genetic risk in high-risk patients, identify and diagnose breast cancer in its early stages, determine how far the cancer has spread, evaluate the characteristic features of the cancer to create a treatment plan, monitor the effectiveness of treatment, determine if there is any cancer recurrence in the woman, and follow the patient during the treatment period. 

In the following headings, the diagnostic methods used in breast cancer diagnosis are examined in detail.

Laboratory Tests

Laboratory tests for breast cancer are performed to diagnose, determine treatment options, monitor treatment, detect recurrence, and determine genetic risk.

Cytological methods may be used to make a diagnosis. Tumor cells obtained by fine-needle aspiration and tissues taken by surgical biopsy are examined microscopically.

To determine treatment options, the tumor's HER-2/neu gene amplification status and estrogen and progesterone receptor status are evaluated.

Repeated measurements of CA 15-3 or CA 27.29 in the blood are monitored to monitor treatment and detect relapse.

In order to determine the genetic risk in high-risk patients, mutations that may exist in the BRCA1 and BRCA2 genes are tried to be determined.

Some breast cancer tests are performed with a patient's blood sample; others are performed with cells or tumor tissue.

Cytology and Surgical Pathology Examinations

When the radiologist detects the presence of a suspicious area such as calcifications or a non-palpable mass on mammography, or when a lump is detected during clinical examination or self-examination, the breast surgeon often requests a needle biopsy, surgical biopsy, or fine needle aspiration biopsy. 

In each case, a small tissue sample is taken from the suspicious area of ​​the breast. A pathologist then examines the cells under a microscope to detect signs of cancer. This pathological examination determines whether the lesion is benign or malignant.

Malignant cells exhibit some changes and deviations from normal cells. Signs of disease will include changes in the size of cell nuclei and evidence of increased cell division. 

Pathologists can diagnose cancer based on the changes observed, determine how abnormal the cells appear, and determine whether there are single or mixed changes. These results will not only help diagnose breast cancer but also guide its treatment.

Needle aspirations are of limited benefit because of the limited number of samples obtained. A tissue sample is required to determine whether the cancer is early-stage or has spread. 

When the breast cancer mass is surgically removed, the tumor cells, adjacent tissues, and lymph node cells are examined by a pathologist to determine where the cancer has spread.

Tests Applied to Tumor Tissue

If the pathologist diagnoses breast cancer, several tests may be performed to examine the cancer cells. The results of these tests will inform prognosis and will also be used by the oncologist to guide the patient's treatment. 

The most useful tests for tumor tissue examination are HER-2/neu, estrogen and progesterone receptor tests.

Her-2/neu is an oncogene. It codes for a receptor for a specific growth factor that causes cells to proliferate. Normal epithelial cells contain two copies of the Her-2/neu gene and produce low levels of Her-2 protein on their cells. 

In approximately 20% to 30% of invasive breast cancers, the Her-2/neu gene is amplified, and the protein is overproduced. These tumors will be sensitive to treatments that specifically bind to the overproduced protein. 

The chemotherapy drug Herceptin (Trastuzumab) blocks protein receptors from replicating and multiplying, thus blocking tumor growth. Patients with an amplified Her-2/neu gene are more likely to respond favorably to the drug and have a good prognosis.

Estrogen and progesterone receptor status are important markers for the prognosis of breast cancer. The higher the overall positivity percentage and density of cells, the better the prognosis. Estrogen and/or progesterone receptor positivity in breast cancer cells indicates sensitivity to hormones. In such cases, the patient would be considered a good candidate for antihormone therapy.

Blood Tests

Blood tests may be done to determine whether the tumor is responding to treatment or has recurred. In women at high risk of developing breast cancer, certain blood tests may also be ordered to determine if there is a genetic component to their risk.

CA15-3 or CA 27.29

CA15-3 and CA 27.29 are tumor markers that are ordered at regular intervals after treatment to monitor patients for breast cancer recurrence. While not used for breast cancer screening, these tests can be used to monitor patients once diagnosed.

BRCA1 or BRCA2 Gene Mutation

 High-risk women with  a strong family history of early-onset breast cancer or  ovarian cancer may be checked for a BRCA gene mutation.

A woman with a mutation in one of the two genes is considered at high risk for developing breast cancer in her lifetime. However, it's important to understand that only 5% to 10% of women with a BRCA gene mutation develop breast cancer. Therefore, we recommend genetic counseling both before and after receiving positive test results.

Other Tests

In addition to tests applied to breast cancer  tumor tissue that help evaluate numerous genetic patterns, many other tests are under investigation. Tests that can indicate breast cancer recurrence and treatment outcomes are being investigated. While these tests are promising in most cases, the data supporting their routine clinical use is still insufficient. 

Oncotype DX 

The Oncotype DX test, which measures 21 genes,  is used to predict the risk of cancer recurrence in patients diagnosed with early-stage breast cancer  , those without cancer spread to the lymph nodes, those with estrogen receptor-positive tumors, and those taking the drug tamoxifen.

MammaPrint Test

The MammaPrint test is available in Europe and recently received FDA approval for use in the US. It assesses patterns of gene activity across 70 tumor genes. This test can be used to predict the likelihood of breast cancer recurrence and/or metastasis in women under 61 with early-stage breast cancer who have no cancer in their lymph nodes. 

In some breast cancer cases, additional testing such as DNA ploidy, Ki-67, or other cell proliferation markers may be performed. However, most authorities believe it is extremely important to first assess HER-2/neu and estrogen and progesterone receptor status. 

Other tests are not important for treatment, nor are they important in isolation, given the severity and stage of the disease and the appropriate course of the disease. Some hospitals use these tests to obtain additional information in patient evaluations. 

Other Examinations

In addition to laboratory tests, laboratory examinations of equivalent importance may be performed. 

Mammography is a frequently recommended screening test. Mammography uses X-ray technology to create an image of the breasts. This technology can detect a lump, a sign of breast cancer, approximately two years before it reaches a size that can be felt during a clinical examination or self-exam.

New technologies such as digital mammography and computer-aided diagnosis can provide clearer images than mammography in some cases. Tumors may be missed on standard mammography X-rays, especially in young women, due to the dense breast tissue. Therefore, ultrasound and magnetic resonance imaging (MRI) may be recommended.

In women at high risk of developing cancer, breast lavage may be used for screening. In this procedure, the doctor extracts a few cells through a tiny tube inserted into the patient's nipple. These cells are then evaluated for signs of cancer.

Ways to Prevent Breast Cancer

While research is ongoing to identify factors that increase or decrease the risk of developing the disease, there is no definitive set of processes that cause or prevent breast cancer. Women should collaborate with their obstetrician to identify their individual risk factors.

To minimize your risk of developing breast cancer;

• Exercise regularly,
• Maintain a healthy body weight, 
• Avoid alcohol and cigarette consumption.

Women at high risk of developing breast cancer  may be prescribed the medication tamoxifen to reduce their risk. However, because tamoxifen can increase the risk of blood clots, endometrial cancer, and cardiovascular disease, your doctor will weigh the risks and benefits of such treatment with you.

Prophylactic mastectomy, or surgical removal of the breast, is an option for women with gene mutations associated with breast cancer (BRCA1 and BRCA2). Women who choose this option are choosing to have both breasts removed rather than risk developing high-risk disease later in life. Studies have shown that this surgical procedure reduces the risk of developing breast cancer by approximately 90%. 

After developing cancer in one breast, women may choose to have a preventive mastectomy for their other, cancer-free breast. If you're considering a preventive mastectomy, your specialist will help you navigate the process.

Early Diagnosis Saves Lives! 

90% of breast cancer cases diagnosed and treated at an early stage are completely cured.

Primary early diagnosis methods include regular breast self-examination by women, clinical breast examination, and mammography.

To detect breast cancer in its early stages, the following recommendations are accepted in today's medical world: Women aged 20 and over should self-examine their breasts monthly. Women under 39 should undergo a clinical breast examination every three years. Women aged 40 and over should have a mammogram annually. All women over 20 should have a gynecological examination twice a year.

Women with certain risk factors may be advised to have screening tests earlier and more frequently.

After your doctor assesses your risk of developing breast cancer, he or she will tell you how often you should have screening tests.

Breast Cancer Treatment

Breast cancer treatment generally involves surgically removing all or as much of the cancer as possible and then killing or controlling the remaining cancer cells with one or more methods.

In a lumpectomy, the cancerous tissue is removed while the remaining breast tissue is left untouched. 

A mastectomy is a more extensive surgical procedure, and the amount of breast and surrounding tissue removed remains unchanged. While mastectomy was once the preferred treatment, even for early-stage breast cancer, more options are now available. 

Many early-stage breast cancers are treated with a lumpectomy followed by radiation therapy. The surgeon may remove some or all of the axillary lymph nodes along with the lumpectomy or mastectomy. The removed tissue may be sent for pathological examination to determine whether the cancer has spread.

The use of radiation therapy, chemotherapy  , and other drug treatments depends on the woman's immune system, the characteristics of the cancer, and the extent of the cancer. 

Drug treatments may include tamoxifen, aromatase inhibitors, and other antiestrogen drugs that target hormone-sensitive cancers. People who overexpress the Her-2/neu protein may benefit from Herceptin (Trastuzumab) treatment.

There's a lot of new research being conducted in the field of breast cancer treatment  . Your doctor will be your best source of information on these topics. 

In modern medicine, new drugs with minimal side effects are being developed. Gene-targeting drugs and vaccines are also available for limited or investigational use.