Breast cancer is the most common cancer in women throughout the world. The common signs and symptoms of breast cancer are breast lumps, bloody nipple discharge, skin changes over the breast, itchy rash involving the nipple and breast pain.
However, not all breast lumps are cancerous. Indeed, eight out of 10 lumps felt by a woman are not cancerous. Common benign (not cancerous) breast lumps include fibroadenoma (especially in women in their twenties) and fibrocystic disease (affecting women in the thirties and forties).
But regardless of a woman’s age, a lump that is hard and irregular, often painless, with changes to the overlying skin or nipple, should not be ignored.
There are various risk factors associated with breast cancer although the exact cause of the disease remains unknown. By modifying some of these risks, one can help reduce the chance of getting breast cancer.
The risk factors include older age, being female, a positive family history of breast cancer, prolonged exposure to estrogen, diet (too much red meat and animal fat) and weight gain, especially in post-menopausal women.
Breastfeeding can alter prolonged exposure to estrogen and hence reduce a woman’s risk of developing breast cancer. Based on studies, the relative risk of breast cancer is decreased 4.3 percent for every 12 months of breastfeeding, in addition to 7 percent for each birth.
Breast cancer occurs when normal cell growth is no longer regulated and starts to divide in an uncontrolled manner. The disease usually originates from the cells lining the milk ducts and glands.
Ductal cancers (i.e. arising from the ducts) are more common that lobular cancers (i.e. arising from the breast lobules).
At the early stage of breast cancer growth, the malignant cells are confined within the milk ducts and glands and do not invade into the surrounding breast tissue. When breast cancer is detected at this early stage, it is known as in-situ or non-invasive cancer. Treatment of in-situ breast cancer gives very good results and patients live longer.
However, when the cancer cells have broken out of the milk ducts and lobules invade the surrounding breast tissue, the cancer is now classified as invasive. Invasive breast cancer can penetrate the surrounding lymphatic and blood vessels to spread to lymph nodes and the bloodstream. The organs most commonly affected by cancer cells circulating in the bloodstream are the lungs, liver and bones.
Diagnosis of breast cancer is usually made after a clinical examination by doctor, followed by imaging. A mammogram is the most important way to image a woman’s breast. Occasionally, a breast ultrasound and/or a MRI scan of the breasts may be required too. Histological confirmation of cancer will ultimately require some form of breast biopsy, either as fine needle aspiration cytology, core biopsy or open surgery.
The treatment of breast cancer is basically divided into two aspects: Loco-regional treatment, consisting of surgery to the breast and axillary lymph nodes (in the armpit) — with or without radiotherapy to the breast tumor bed — and systemic treatment consisting of chemotherapy to target clumps of cancer cells that may be circulating in a breast cancer patient’s blood stream.
The mainstay of treatment of breast cancer is surgery.
Traditional surgical techniques include mastectomy, which is the removal of the whole breast and nipple, and wide excision or breast-conserving surgery, the removal of the cancerous lump, protected within a rim of normal tissue, while saving the rest of the unaffected breast.
There are newer surgical techniques like skin-sparing mastectomy, which involves removing the whole breast while maintaining an adequate skin envelope — and nipple-sparing mastectomy, which preserves even the nipple, in selected cases where the tumor is situated far away from the nipple. Both these techniques require immediate breast reconstruction by a plastic surgeon during the same operation.
During the operation, the surgeon may also check the lymph nodes in the axilla (i.e. armpit) for the presence of cancer through a procedure known as sentinel lymph node biopsy.
It is absolutely necessary for patients who have undergone breast-conserving surgery to reduce the risk of recurrence in the breast tumor bed. It is also indicated in some patients following mastectomy when the risk of recurrence is high (large number of lymph nodes involved with tumor spread or tumor size larger than 5 centimeters).
The need for systemic treatment after breast cancer surgery is based on the information obtained from microscopic analysis of the tumor and the axillary lymph nodes. There are three main forms of systemic treatment: Cytotoxic chemotherapy, which involves giving toxic drugs intravenously to target the cancer cells which are potentially circulating within the bloodstream; hormonal manipulation; and ovarian ablation, which applies to pre-menopausal women with hormone-positive breast cancers to induce early menopause in order to reduce the estrogen drive.
An ovarian ablation is achieved by surgical removal or radiation to the ovaries or by drugs like Goserelin to stop estrogen secretion at the level of the brain.