Breast cancer is the second most common cancer in women worldwide and the most common cancer among women in both developing and developed countries. It is estimated that one in eight women will develop breast cancer at some point in their lives.

Breast cancer occurs when cells in the breast tissue grow and divide uncontrollably, leading to the formation of a tumor. While breast cancer is often associated with a genetic predisposition or family history, lifestyle factors such as diet, exercise and alcohol consumption can also contribute to its development.

Types of Breast Cancer

There are several types of breast cancer, which are defined by the type of cell that is affected and the degree of aggressiveness of the tumor:.

Ductal Carcinoma In Situ (DCIS)

DCIS is a non-invasive breast cancer that is confined to the milk ducts. While it isn’t immediately life threatening, if left untreated it can develop into a more aggressive form of breast cancer.

Invasive Ductal Carcinoma (IDC)

IDC is the most common form of breast cancer, accounting for about 75% of all breast cancers. It occurs when cancer cells from the milk ducts spread into the surrounding breast tissue.

Invasive Lobular Carcinoma (ILC)

ILC accounts for about 10% of breast cancers and occurs when cancer cells from the lobules (milk producing glands) spread into the surrounding breast tissue.

Inflammatory Breast Cancer (IBC)

IBC is a rare and aggressive form of breast cancer that accounts for about 1% of all breast cancers. It is characterized by redness, swelling and warmth in the breast, as well as nipple retraction and discharge.

Triple Negative Breast Cancer (TNBC)

TNBC is a subtype of breast cancer that is defined as having no estrogen, progesterone or HER2 receptor expression. It accounts for about 15% of all breast cancers and is often associated with a poorer prognosis.

The Role of BRCA Genes in Breast Cancer

The BRCA1 and BRCA2 genes are tumor suppressor genes that help to prevent the formation of cancer by repairing DNA damage.

When these genes are mutated, however, they are no longer able to perform this function and can instead promote the development of cancer. Women who inherit a BRCA1 or BRCA2 mutation have a significantly increased risk of developing breast and ovarian cancer compared to the general population.

In fact, it is estimated that up to 10% of all breast cancers are caused by inherited BRCA1 or BRCA2 mutations.

Deficient Tumors

Recent research has found that approximately a third of all breast tumors are deficient in a particular DNA repair pathway known as homologous recombination (HR).

This pathway is responsible for repairing double-strand breaks in DNA, which can occur as a result of exposure to radiation or other environmental factors, and is also critical for the treatment of cancer using targeted therapies such as PARP inhibitors. Tumors that are deficient in HR are therefore more difficult to treat and are associated with a poorer prognosis.

Treatment Options for Breast Cancer

The treatment options for breast cancer depend on the type and stage of the cancer, as well as the patient’s individual characteristics and preferences. Common treatments include:.

Surgery

Surgery is often the first line of treatment for breast cancer and involves removing the cancerous tissue from the breast.

In some cases, a breast-conserving surgery (also known as a lumpectomy) can be performed, in which only the cancerous tissue is removed while preserving the rest of the breast. In more advanced cases, a mastectomy (removal of the entire breast) may be necessary.

Chemotherapy

Chemotherapy uses drugs to kill cancer cells throughout the body. It is often used in combination with surgery to eliminate any remaining cancer cells and reduce the risk of recurrence.

Radiotherapy

Radiotherapy uses high-energy radiation to destroy cancer cells. It is often used post-surgery to reduce the risk of local recurrence.

Hormonal Therapy

Hormonal therapy is used to block the production or activity of hormones that can promote the growth of breast cancer cells. It is often used in patients with hormone receptor-positive breast cancer.

Targeted Therapy

Targeted therapy uses drugs to target specific proteins or pathways that are critical for tumor growth. It is often used in patients with HER2-positive breast cancer or in patients with tumors that are deficient in HR.

Prevention of Breast Cancer

While it isn’t possible to completely eliminate the risk of developing breast cancer, there are several steps that women can take to reduce their risk:.

Healthy Diet and Exercise

A healthy diet and regular exercise can help to maintain a healthy body weight, which in turn can reduce the risk of breast cancer.

Limit Alcohol Consumption

Alcohol consumption has been linked to an increased risk of breast cancer, so women should limit their intake.

Regular Screening

Regular screening, including mammograms and breast self-exams, can help to detect breast cancer early when it is most treatable.

Genetic Counseling and Testing

Women with a family history of breast cancer or certain other risk factors should consider genetic counseling and testing to determine if they are at an increased risk for the disease.

Conclusion

Breast cancer is a highly prevalent disease that affects women globally. While lifestyle factors such as diet and exercise can contribute to its development, genetic mutations in the BRCA1 and BRCA2 genes contribute to approximately 10% of all cases.

Recent research has also found that approximately a third of all breast tumors are deficient in the HR DNA repair pathway, making them more difficult to treat. Fortunately, there are several effective treatments available, including surgery, chemotherapy, radiotherapy, hormonal therapy, and targeted therapy.

Women can also take steps to reduce their risk of developing breast cancer through healthy lifestyle choices and regular screening.