The breast consists of milk-producing glands surrounded by fat and connective tissue. The glands connect to the ducts, which carry milk out to the nipple. Breast cancer is generally an adenocarcinoma. It develops in the glands themselves and grows out. It is the most common cancer in US women. Approximately 230,000 people are diagnosed per year in the US. Is the second leading cause or cancer death in women approximately 40,000 deaths per year. Again notice the big difference between the number of cases diagnosed and the number of deaths, that's because most of the cancers are diagnosed early enough to be treated with surgery or radiation, which we'll talk about in our last lecture. Which leads to fewer deaths per diagnosed case per year. Again, 80% of primary breast cancers are called infiltrating ductal cancers. They are adenocarcinoma's. There are subtypes like lobular and nipple cancers. But again, the vast majority are adenocarcinomas.
What are the risk factors for breast cancer? Again, age. One in eight cancers in women occur under the age of 45, two-thirds over the age of 55. It is clear that family history is important as a risk factor. Having one first-degree relative mother, sister, or daughter with breast cancer doubles a woman's risk. There are genes that are associated with increased risk, known mutations in a woman's genome including breast cancer or BRCA1, which increases risk 55 to 65%. And breast cancer two, or BRCA2, which increases risk approximately 45%. These are genes in the DNA repair pathway and can now be screened for in appropriate populations. Dense breast tissue is also a risk factor, because it makes mammograms, which are screening tests, less accurate. Lifestyle is an important contributor to breast cancer. Obesity, lack of physical activity, alcohol abuse, not having children, oral contraceptive use, and post menopausal hormone therapy all contribute to increasing risk of breast cancer to some extent. The exact number or percent of increased risk is often unclear, but we know that these all contribute. Are there any ways to prevent breast cancer? Well no, there are no known proven strategies except for prophylactic mastectomy in high-risk women. This can be performed in women who for example, have family members who have had breast cancer and who are carriers of those genes BRCA 1 or 2 where it's thought that they have such a high risk of developing breast cancer in the future that the women chooses to have her breast removed. This is not done commonly. Other possibilities for breast cancer prevention include high-fiber, low-fat diets, staying physically active, and maintaining normal weight. You're probably starting to see a theme here, high fiber, low-fat diets, staying physically active, keeping a normal weight not becoming obese, and not smoking are all prevention strategies that cross many cancers.
Breast cancers screening consist of monthly self exams by women. Usually at the same time each month of their menstrual cycle. Yearly exams by a health practitioner. And mammograms, which are special x-rays that you'll hear about in a future lecture. There are other radiology techniques, magnetic resonance imaging or ultrasound, that are potentially useful for breast cancer screening, but self-exams, yearly exams, and mammograms remain the gold standard.
Comments
Post a Comment