Breast Cancer – causes, symptoms, diagnosis, treatment, pathology

learning medicine is hard work osmosis makes it easy it takes our lectures and notes to create a personalized study plan with exclusive videos practice questions and flashcards and so much more try it free today breast cancer or breast carcinoma is an uncontrolled growth of epithelial cells within the breast it’s the second most common cancer in women but can also on rare occasion affect men as well breast cancer is also the second leading cause of cancer deaths in women after lung cancer this is largely due to the fact that oftentimes breast cancers don’t cause any pain or discomfort until they spread to nearby tissues the breasts are milk-producing glands that sit on the chest wall on either side of the breastbone they lie on top of the ribs and the pectoral muscles and are divided into three main parts the glandular tissue that makes the milk is made up of 15 to 20 lobules inside each of these lie a bunch of grape like structures called the AVO lie which are modified sweat glands surrounded by a basement membrane made largely of collagen zooming in on the AVO eye there’s a layer of avalor cells that secrete breast milk into the lumen which is the space in the center of the gland wrapping around the alveolus our special myoepithelial cells that squeeze down and push the milk out of the lumen of the alveolus down the lactiferous ducts and out one of the pores of the nipple now surrounding the glandular tissue is the stroma which contains adipose or fat tissue and this makes up the majority of the breast suspense Ettore ligaments called Cooper’s ligaments run through the stroma and help keep it in place these ligaments attach to the inner surface of the breast on one end in the pectoralis muscle on the other just beneath the skin covering the breast there’s a network of tiny lymphatic vessels that drain the lymph which is a fluid containing cellular waste products and white blood cells these lymphatic vessels mainly drain into a group of lymph nodes in the axilla or the armpit now the cells of glandular tissue have receptors for certain hormones like estrogen and progesterone which are released by the ovaries in prolactin which is released by the pituitary gland these hormones stimulate the ABI alure cells to divide and increase in number which makes the lobule enlarged without these hormones the glandular cells particularly the alveolar cells can survive and undergo apoptosis which is programmed cell death for example after menopause estrogen production stops which leads to death of the Abiola cells and over time that breast tissue gets replaced by fat during the menstrual cycle there’s increased secretion of estrogen and progesterone from the ovaries and right after menstruation that secretion decreases as a result during every menstrual cycle the alveolar cells undergo division and apoptosis men have some breast tissue as well but they lack milk secreting a voi each time cells divide there’s a chance that a genetic mutation will occur and a mutation can lead to tumor formation so with more menstrual cycles there’s an increased risk of tumor formation that’s why there’s an increased risk of breast cancer with things that increase the number of menstrual cycles like early age of menarche which is the first menstrual bleeding and late age of menopause similarly medications containing estrogen also increase the risk of breast cancer there are also other environmental risk factors such as ionizing radiation like from chest x-rays and CT scans on the flip side some things that are associated with a decreased risk of breast cancer include early pregnancy and a longer time breastfeeding breast cancer has also been linked to specific mutations in tumor suppressor genes such as breast cancer gene or brca1 and brca2 and T p53 which normally slowed down cell division or make cells die if they divide uncontrollably mutations in brca1 or brca2 are both autosomal dominant mutations which can be inherited and cause familial breast cancer in addition to breast cancer they also cause an increased risk of ovarian cancer some breast cancers also have mutations in the erbb2 gene that increased human epidermal growth factor receptor 2 or her2 which when activated promotes the growth of cells in males breast cancer is usually caused by inherited mutations in the brca1 and 2 genes once a cancer-causing mutation does occur the affected cell which is most commonly an epithelial cell that lines the ducts or the lobules begins to grow and replicate out of control forming a tumor this tumor also called an in situ carcinoma is initially localized within the basement membrane of the apo eye and can be of two types the first type is called ductal carcinoma in situ or DCIS and that’s where tumor cells grow from the wall of the ducts into the women if left untreated over time DCIS can cross the basement membrane to become invasive ductal carcinoma also cancer cells from DCIS can migrate along the Ekta forest duct and through the pore onto the skin over the nipple this is called Paget disease of the nipple these cancer cells release a substance called mobility factor which helps them break into and settle in between the squamous epithelial cells as the cancer cells move into the epithelium there’s inflammation which brings extracellular fluid out through the breaks in the skin this fluid then dries and formed crusts over the skin surface the second type is called lobular carcinoma in situ or LC is and that’s where clusters of tumor cells grow within the lobules without invading the ducts causing the affected evii Li to enlarge unlike DCIS over time LC is doesn’t cross the basement membrane to form invasive lobular carcinoma LC is got its name many years ago before it was realized that it’s actually not a breast cancer in the sense that it doesn’t invade surrounding tissues just like healthy avio ourselves some breast cancer cells have hormone receptors that allow them to grow in the presence of the hormones based on the type of hormone receptors breast cancers can be divided into three major types estrogen receptor or ER positive and her2 negative carcinoma which is most common her2 positive and ER positive negative carcinoma and ER negative in her to negative carcinoma breast cancer can cause a few complications first the tumor causes local inflammation which causes damage to the suspence Ettore ligaments and lactiferous ducts resulting in their fibrosis next the cancer can invade nearby tissues like the pectoral muscles below and the skin above cancer cells can also enter and block the thin lymphatic vessels which causes lymph to build up in the interstitial space normally this fluid buildup what causes swelling but the attachment of suspense Ettore ligaments doesn’t allow the skin to stretch so the skin becomes thickened and dimpled like an orange peel called po d’orange appearance finally tumor cells can spread via the blood to the spine brain and bone or the lymph to other sites like axillary lymph nodes and the other breast in males breast tissue is very thin which makes it easier for the cancer to spread to underlying tissues the first symptom of breast cancer is a hard painless lump or swelling which is most commonly in the upper and outer part of the breast additionally there may be a swelling under the armpit if cancer is spread to the axillary lymph nodes the breast can become a mobile and fixed or stuck onto the chest wall due to infiltration if cancer cells spread into the pectoral muscles another symptom is dimpling of the skin over the breast due to involvement of the skin fibrosis of lactiferous ducts and suspense story ligaments causes retraction or pulling in of the nipples when pageant disease is present it can cause itching redness crusting and discharge from the nipple diagnosis of breast cancer usually begins by feeling a breast lump breast cancer can be treated effectively when it is detected early in the course of a disease that’s why regular screaming with mammography which is an x-ray of the breasts is done in high-risk individuals in addition imaging using ultrasound and MRI may be done to detect the tumor finally a biopsy of the swelling or a fine needle aspiration and cytology where fluid from the swelling is taken may be done to confirm the diagnosis to determine the risk of breast cancer each one is staged by the TNM system t indicates the size of the tumor and whether or not it is grown in nearby areas for example the chest wall muscles and describes the degree to which cancer has spread to nearby lymph nodes particularly the axillary lymph nodes and finally M indicates the degree to which the cancer is spread to other sites or metastasized each of these categories is ranked from zero to four with four being the most severe finally the combinations of these sub stages determine the stage group which are assigned zero to four treatment for breast cancer is based on the type and stage of the cancer but commonly involves surgery radiation therapy chemotherapy and hormonal therapy localized tumors are removed surgically by partial mastectomy where the affected part is removed in larger tumors which have spread to nearby tissue are removed by total mastectomy where the entire breast is removed in addition nearby structures like lymph nodes may also be removed if the cancer has metastasized to them hormone therapy is used when tumor cells have hormone receptors like estrogen and her2 in may include medications which block the formation or effects of estrogen all right as a quick recap breast cancer or breast carcinoma is the uncontrolled growth of epithelial cells lining the ducks and lobules of the breast breast cancer usually begins as an in situ carcinoma which can either be ductal carcinoma in situ or DCIS which is localized to the ducts or lobular carcinoma in situ or LCIS which is localized within the lobules over time in situ carcinoma can invade the basement membrane to become invasive carcinoma involving the ducks and lobules breast cancer screening by mammography is done for early detection of cancer which can be treated by a variety of treatment options including surgery radiation therapy chemotherapy in hormonal therapy thanks for watching if you’re interested in a deeper dive on this topic take a look at as Moses org where we have flashcards questions and other awesome tools to help you learn medicine otherwise you can always support us by donating on patreon subscribing to our channel or following us on social media you