An Overview of Breast Cancer

Rishi Agarwal, M.D., MSc, Oncology & Hematology

Rishi Agarwal, M.D.
Oncology & Hematology

Introduction
Breast cancer is the most common cancer in U.S. women except for skin cancer. It is second only to lung cancer as a cause of cancer death in women. Advances in research have led to several new effective changes in diagnosing and treating breast cancer, which have led to a gradual decline in the death rate from breast cancer in the last few decades.

Anatomy of the Breast
The breast is made up of lobes and ducts. Each breast has 15 to 20 sections called lobes, which have many smaller sections called lobules. Lobules end in dozens of tiny bulbs that can produce milk. Thin tubes called ducts link the lobes, lobules, and bulbs.

Epidemiology
Breast cancer remains the most common malignancy diagnosed among women in the world, with about 1.7 million women worldwide diagnosed in 2012. The incidence rates are higher in developed countries. In the United States, about 252,710 new cases of invasive breast cancer will be diagnosed in women and about 40,600 women will die of breast cancer in 2017. Also in the U.S., 1 in 8 women will develop breast cancer in their lifetime. Besides invasive cancer, about 63,400 women will likely be diagnosed with Carcinoma in Situ (precancerous or earliest form of breast cancer).

Breast Cancer in Kentucky
Approximately 3,500 new cases of breast cancer will be diagnosed in Kentucky in 2017 and an estimated 600 deaths due to breast cancer will occur. More patients are diagnosed at a later stage in Kentucky than the national averages.

Risk Factors
Risk factors include: older age; female gender; a family history of breast and/or ovarian cancer, particularly if onset occurred at age younger than age 50; extended estrogen exposure due to early onset of menarche; late age of menopause, and having never been pregnant (nulliparity); external estrogen exposure such as with hormone replacement therapy; radiation exposure; obesity; and alcohol consumption. Dense breasts and previous non-cancerous breast lesions are commonly known to adversely affect the risks of getting breast cancer. Lactation, pregnancy, and physical activity may decrease the risk.

Prevention
It is important to identify one’s risk of getting breast cancer because risk-reducing methods are available for high-risk populations. Bilateral risk-reducing removal of the breasts (mastectomy) or risk-reducing bilateral salpingo-oophorectomy (removal of ovaries) are the surgical options available for high-risk patients. Risk-reducing bilateral salpingo-oophorectomy if performed before age 50, may reduce the risk of developing ovarian cancer by 85% and breast cancer by 40% to 60% for women who have certain high-risk gene mutations such as BRCA. Bilateral risk-reducing mastectomy reduces the risk of developing breast cancer by more than 90% among women with BRCA mutations. High-risk patients may also benefit from using certain medications such as Tamoxifen and Raloxifene in reducing the risk for breast cancer. Lifestyle modification such as increasing physical activity and decreasing alcohol consumption may also reduce the risk for getting breast cancer.

Screening
Benefits of breast cancer screening is well established, but the optimal age of starting and optimal interval is not very clear. Benefits, method and guidelines differ for average and high-risk populations. For average risk, the U.S. Preventive Services Task Force (USPSTF) recommends initiating biennial screening at age 50 and continuing until age 74. The American Cancer Society (ACS) recommends annual imaging beginning at age 45. The American College of Radiology (ACR) and Society of Breast Imaging (SBI) recommend that women receive an annual mammogram starting at age 40. As per ACS recommendations screening may be continued after age 70 as long as there are no other significant comorbid conditions, appreciable life expectancy, and the woman is a candidate for treatment. Mammography is the most common method recommended for screening in average risk population.

In high-risk groups, supplementing mammography with MRI has been shown to improve the effectiveness of mammography. High-risk patients include women with genetic predisposition or women who received chest radiation treatment for lymphoma. In patients with history of radiation treatment, screening should begin approximately 10 years after completing radiation. For women at high risk due to familial (nonhereditary) causes, screening should begin approximately 10 years earlier than the age of the youngest woman in the family diagnosed with breast cancer, but not later than age 40.

Signs and Symptoms of breast cancer
Screening may help find breast cancer in early stages even in the absence of any signs or symptoms. It is also very important to know the symptoms of breast cancer because cancer may develop before routine screening is started or in between screenings. The most common symptom of breast cancer is a new lump or mass. It is important to have any new breast mass or lump or breast change checked by your healthcare provider. Other possible symptoms can include swelling of all or part of a breast (even if there is no discrete lump), irritation of the skin or dimpling, breast or nipple pain, inward turning of the nipple, nipple discharge other than milk, lump or pain in the underarm area or around the collar bone due to lymph node spread, and redness, scaling, or thickening of the breast skin.

Treatment
Breast cancer is treated by a multidisciplinary team involving a breast surgeon, radiation oncologist, medical oncologist, plastic surgeon and support services. The treatment depends on several factors such as the stage at presentation, lymph node involvement, pathology, and hormone status, as well as patient factors such as age and functional status. For local or early disease, options for surgery may include partial or complete removal of the breasts. Some patients may need chemotherapy or hormonal therapy before surgery to shrink the tumor. Most patients also need radiation therapy post-surgery. Most patients will also need hormonal therapy or chemotherapy, or both, after surgery. Patients who present in advanced or metastatic stage are often treated with hormonal therapy, targeted therapy or chemotherapy. Immunotherapy is also being studied in breast cancer. Several patients may benefit from enrolling in clinical trials. Recent studies have also shown benefit of using bisphosphonates in breast cancer treatment.

Conclusion
Breast cancer can be prevented, detected early and treated effectively with good response rates. All patients should be aware of their risks and discuss screening with their physicians to determine the best method and timing for screening. Several resources are available to help patients at The Medical Center at Bowling Green and online.

Resources/References
The Susan G. Komen Breast Cancer Foundation
American Cancer Society
Centers for Disease Control and Prevention
NIH National Cancer Institute Seer Database
National Comprehensive Cancer Network
Breastcancer.org
Kentucky Cancer Consortium
Kentucky Cabinet for Health and Family Services