Defining Breast Cancer

There are many types of cancer. But for women, breast cancer is one of the most terrifying diagnoses, and for good reason. Breast cancer is in the top five most common causes of death for women of all ages. It is the second leading cause of cancer-related death, behind lung cancer. It is the primary cause of death in women who are 40 to 55 years old.[1]

Educating yourself about breast cancer gives you the ability to prevent the disease or to make more informed decisions about treatment if you have already been diagnosed. It is a complex disease, like most cancers, and can take a variety of paths depending on stage and treatment options.  Women must be vigilant in performing breast self-examinations and reporting any suspicious lumps, skin changes or discharge to their doctor right away. Many women are so afraid of what they might find after going to their doctor that they try to ignore a new change or lump in their breast. Denial is never going to help. The doctor may even confirm that the new change or lump is nothing, and give peace of mind, which is priceless.

Benign or Malignant?

The breast is subject to a number of benign (no ability to become invasive cancer) conditions that have no chance of becoming malignant (ability to invade and metastasize). This can sometimes make the diagnosis of breast cancer difficult, since a lump in the breast may indicate cancer; it could also be something quite harmless, such as fibrocystic changes, infection, or a simple cyst. The anatomy of the breast is quite complex, as it varies in size and shape between each individual. They even change in composition throughout a woman’s lifetime, as she enters different stages of development. They are composed of intricate networks of milk-producing lobules, ducts, blood vessels, nerves and lymphatic channels held together by fat and connective tissue.

One of the benefits of performing regular self-examinations is to learn what your “normal” breast feels like and monitor changes over time. For example, fibrous connective tissue in the breast may feel like a lump, but can vary with your menstrual cycles, meaning it is nothing to be concerned about. You must become familiar with what is normal for you, so you can detect a lump or change in the breast should one occur


What causes breast cancer? The answer is: No one thing can be blamed for causing breast cancer, as it is caused by a complex interaction of several factors. That may not be the answer you were looking for, but it is the truth. Some of the known risk factors are estrogen exposure, early age of menarche (first menstrual period), late menopause (when menstrual periods have stopped for at least a year), obesity, age, smoking, and nulliparity (never having a pregnancy). The biggest risk factor, however, is simply being female. Some of these risk factors are modifiable, some are not.

Breast cancer is spontaneous in 90 percent of all cases, which means that it is caused by several factors together as opposed to one identifiable cause. Thus, only up to 10 percent of all breast cancers are hereditary, or are caused by a gene that is inherited from your family. An exciting area of medical research is genetics. Advanced technology has allowed researchers to study inherited and acquired genetic alterations that lead to cancer development. There are even blood tests that can determine whether or not you have a hereditary genetic defect that predisposes you to breast cancer and other cancers.

Getting Specific About Types of Breast Cancer

A series of tests may determine that breast cancer is present, but the type of cancer and its stage will determine treatment. The three most common types of breast cancer are Ductal Carcinoma In-Situ (DCIS), Invasive Ductal Carcinoma (IDC) and Invasive Lobular Carcinoma (ILC). Other less common types include Lobular Carcinoma In-Situ (LCIS) and Inflammatory Breast Cancer (IBC) and even conditions that indicate high risk for developing breast cancer, such as Atypical Ductal Hyperplasia (ADH).3

The first step in determining the type of breast cancer is clinical exam, where a doctor will examine both breasts and axillae (“armpit” areas) for skin changes, lumps, nipple inversion or discharge, and enlarged lymph nodes. The next step is imaging. The area of concern may have been found on a mammogram prior to seeing a doctor, which is certainly acceptable. Likely, if the mammogram findings were suspicious for cancer, an ultrasound will be recommended to look for calcium deposits, or to determine if a mass is solid or fluid-filled. Based on these findings, a core needle-biopsy may be recommended, where a needle will be used to collect a piece of tissue from the area of concern. This tissue is evaluated by a pathologist, who first determines whether or not cancer is present. If cancer is present, the specific type of cancer is determined, as well as a number of other tumor characteristics. The pathologist can then grade the cancer using a specific format.

This information is combined with all of the other data by a team of professionals to assign a clinical breast cancer stage. This multi-disciplinary team may include a surgeon, radiologist, pathologist, medical oncologist, radiation oncologist, and even a nutritionist, who meets to discuss your specific case as a unit, and determines how to provide the best medical care possible.

More Research Needed

As you can see, defining breast cancer is not a simple task and involves a number of steps. Genetic and medical research is promising and continues to reveal important findings that will improve our understanding of risk factors, detection strategies and treatment options.4

It is important to follow the guidelines that are currently in place concerning screening, which leads to early detection while continuing to stay up to date with the exciting new discoveries that research provides.



1  Hartmann, Lynn C and Charles L. Loprinzi (2005) Mayo Clinic Guide to Women’s Cancers. New York: Mayo Clinic Health Information.

2 Ibid

3 Kaelin, Carolyn M. (2005) Living Through Breast Cancer. New York: McGraw-Hill.

4 Sotiriou, Christos; Soek-Ying Neo; Lisa M. McShane; Edward L. Korn; Philip M. Long; Amir Jazaeri; Philippe Martiat; Steve B. Fox; Adrian L. Harris; and Edison T. Liu. (2 September 2003) Breast cancer classification and prognosis based on gene expression profiles from a population-based study. Proceedings of the National Academy of Sciences of the United States of America. v 100:18; 10393-10398

This article was originally published on July 27,2012 and last revision and update of it was 9/2/2015.