Posted on October 19 2018
So far, in our month long series to Breast Cancer Awareness, we have covered topics regarding, what breast cancer is, the symptoms of it, unknown facts about the disease, and how genetics play a role in the development of breast cancer. Today, we will be sharing with you the different types of breast cancer, as well as their survival rates.
Types Of Breast Cancer
Breast cancer occurs in two broad categories: invasive and noninvasive.
Invasive Breast Cancer: Also called infiltrating breast cancer, invasive breast cancer is when cancerous cells break through normal breast tissue barriers and spread to other parts of the body through the bloodstream and lymph nodes.
Noninvasive Breast Cancer: Also called in situ breast cancer, is when cancerous cells remain in a particular location of the breast without spreading to surrounding tissue, lobules or ducts.
Breast Cancer is also classified based on where in the breast the disease started, how the disease grows, and other factors. Below, we'll explore common breast cancer types, common subtypes, and rare types. Other types of breast cancer include sarcoma of the breast, metaplastic carcinoma, adenocystic carcinoma, phyllodes tumor, and angiosarcoma. Genetic research has also led to a more specific classification of breast cancers that are based on their genes and proteins. For example, 60% of breast cancers are estrogen positive, while 20% are HER2 positive, and another 20% are triple negative.
Common Breast Cancer Types
Breast cancer is classified into different types based on how the cells look under a microscope. Most breast cancers are carcinomas, a type of cancer that begins in the linings of most organs.
Ductal Carcinoma In Situ: or, DCIS is characterized by cancerous cells that are confined to the lining of the milk ducts and have not spread through the duct walls into the surrounding breast tissue. If DCIS lesions are left untreated, over time the cancer cells may break through the duct and spread to nearby tissue, becoming an invasive breast cancer.
DCIS is the most common type of noninvasive breast cancer, with approximately 60,000 new cases diagnosed in the U.S. each year. About one in every five new breast cancer cases is DCIS.
DCIS is divided into several subtypes, mainly according to the appearance of the tumor. These subtypes include: micropapillary, papillary, solid, cribriform, and comedo. Women with DCIS are typically at a higher risk for seeing their cancer return after treatment, although the chance of recurrence is less than 30%. Most recurrences occur within 5 to 10 years after the initial diagnosis, and may be invasive or noninvasive. DCIS also carries a heightened risk for developing new breast cancer in the other breast.
A recurrence of DCIS will require additional treatment. The type of therapy for DCIS may affect the likelihood of recurrence. Treating DCIS with a lumpectomy - breast conserving surgery - without radiation therapy, carries a 25 to 35% chance of recurrence. Adding radiation to the treatment plan decreases this risk to approximately 15%. Thankfully, the long-term survival rate for women with DCIS is nearly 100%.
Invasive Ductal Carcinoma
Invasive Ductal Carcinoma, or IDC, begins in the milk ducts and spreads to the fatty tissue of the breast outside of the duct. IDC accounts for approximately 80% of invasive breast cancers.
Surgery is typically the first treatment for IDC. The goal of this treatment is to remove the cancer from the breast with a lumpectomy or mastectomy. The type of surgery recommended will depend on factors, such as: the location of the tumor, the size of the cancer, and whether more than one area in the breast has been affected. For patients with IDC, long term systemic treatment is recommended to prevent recurrence.
There are 4 types of IDC that are less common:
Medullary Ductal Carcinoma: This type of cancer is rare and accounts for only 3 to 5% of breast cancers. Medullary carcinoma can occur at any age, but it typically affects women in their late 40s and early 50s, and is more common in women who have a BRAC1 gene mutation. Medullary tumors are often "triple negative", which means they test negative for estrogen and progesterone receptors, and for the HER2 protein. Medullary tumors are less likely to involve the lymph nodes, are more responsive to treatment, and may have a better prognosis than more common types of invasive cancer.
Surgery is typically the first line treatment for Medullary Ductal Carcinoma. A lumpectomy or mastectomy may be performed, depending on the location of the tumor. In addition, chemotherapy and radiation therapy may also be used.
Mucinous Ductal Carcinoma: This type of breast cancer accounts for less than 2% of breast cancers. Microscopic evaluations reveal that these cancer cells are surrounded by mucus. Like other types of IDC's, mucinous ductal carcinoma begins in the milk duct before spreading to the tissues around the duct. Also called colloid carcinoma, this cancer tends to affect women after they have gone through menopause. Mucinous cells are typically positive for estrogen and/or progesterone receptors and negative for the HER2 receptor.
Surgery is also recommended to treat this type of cancer. Depending on the size and location of the tumor, a lumpectomy or mastectomy may be performed. Adjuvant therapy, such as: radiation, hormonal therapy, and chemotherapy, may also be required.
Papillary Ductal Carcinoma: This type of cancer is rare, accounting for less than 1% of invasive breast cancers, but typically has a better prognosis than other, more common breast cancers. In most cases, these types of tumors are diagnosed in older, postmenopausal women. Papillary breast cancers are typically small, and test positive for the estrogen and/or progesterone receptors, and negative for the HER2 receptor. Most papillary carcinomas are invasive, and treated like an invasive ductal carcinoma with treatment being: a lumpectomy or mastectomy, radiation, chemotherapy, and/or hormone therapy.
Tubular Ductal Carcinoma: Another rare type of IDC, this cancer makes up less than 2% of breast cancer diagnoses. As other types of IDC's, tubular breast cancer originates in the milk duct, then spreads to tissues around the duct. Tubular ductal carcinoma cells form tube shaped structures, and is more common in women over 50. Tubular breast cancers test positive for the estrogen and/or progesterone receptors, and negative for the HER2 receptor.
Treatment options for tubular breast cancer depend on the aggressiveness of the cancer and its stage. Most likely, treatment will consist of surgery, chemotherapy, radiation, and/or hormone therapy.
Lobular Carcinoma begins in the lobes or lobules, which are the glands that make breast milk. The lobules are connected to the ducts, which carry breast milk to the nipple.
Lobular Carcinoma In Situ: or, LCIS. LCIS begins in the lobules and doesn't typically spread through the wall of the lobules to the surrounding breast tissue or other parts of the body. While these abnormal cells seldom become invasive cancer, their presence indicates an increased risk of developing breast cancer later. About 25% of women with LCIS will develop breast cancer at some point in their lifetime. The breast cancer may occur in either breast, and may appear in the lobules or ducts.
Because LCIS is not actually cancer, treatment may not be recommended. If you are diagnosed with LCIS, you may want to discuss more frequent breast cancer screening with your doctor. Early detection is the key to most treatable stages.
Invasive Lobular Carcinoma: or ILC. ILC starts in the lobules, invades nearby tissue, and can spread to distant parts of the body. This breast cancer accounts for approximately 1 out of 10 invasive breast cancers. The treatment options for ILC include localized approaches, such as surgery and radiation therapy to treat the tumor and surrounding areas, as well as systemic treatments, such as chemotherapy, and hormonal or targeted therapies that travel throughout the body to destroy cancer cells that may have spread from the original tumor.
Rare Types of Breast Cancer
Inflammatory Breast Cancer: or, IBC. IBC is a rare type of breast cancer that often begins in the soft tissues of the breast, and causes the lymph vessels in the skin of the breast to become blocked. As a result, the breast may become firm, tender, itchy, red, and warm due to increased blood flow, and a build up of white blood cells. This type of cancer is distinct from other types, with major differences in symptoms, prognosis, and treatment.
The term inflammatory only refers to the appearance of the breasts. When breasts become inflamed due to an infection or injury, they often become tender, swollen, red and itchy. However, the underlying cause of IBC is unrelated to inflammation.
Because of the similarities in symptoms, IBC may at first be diagnosed as a breast infection, such as mastitis. Although antibiotics will resolve a breast infection, they cannot treat IBC. If your doctor prescribes antibiotics and your symptoms do not resolve in seven to 10 days, this may be a crucial sign that you have IBC.
IBC tends to grow quickly and aggressively, and is typically diagnosed when it is already in an advanced stage, most often stage IIIB or stage IV. Treatment of inflammatory breast cancer includes chemotherapy, followed by breast conserving surgery, or a total mastectomy, and radiation therapy. Additional therapy, such as hormone therapy and additional chemotherapy may also be given.
Male Breast Cancer
Many men may be surprised to learn that they too, can develop breast cancer. Men have breast tissue that develops in the same way as breast tissue does in women, and is susceptible to cancer cells in the same way. Breast cancer in men is uncommon because male breasts have ducts that are less developed, and aren't exposed to growth promoting, female hormones.
Male breast cancer occurs when malignant cells form in the tissues of the breast. Any man can develop breast cancer, but it is most common among men who are 60 to 70 years of age. About 1% of all breast cancers occur in men, and approximately 2,000 men are diagnosed with breast cancer each year.
As in women, breast cancer in men can begin in the ducts and spread to surrounding cells. Male breast cancer treatment consists of a mastectomy, followed by radiation therapy, chemo, hormone therapy, and targeted therapy. For men whose cancer has not spread to the lymph nodes, therapy given after surgery is generally the same as for a woman.
Metastatic Breast Cancer
Or, MBC, is also known as stage IV or advanced breast cancer. MBC is breast cancer that has spread to other organs in the body. Metastases from breast cancer may be found in lymph nodes in the armpit, or they can travel anywhere in the body. Common sites include: distant organs, such as the lungs, liver, bone, and brain. Even after an original tumor is removed, microscopic tumor cells may remain in the body, which allows the cancer to return and spread.
Patients may initially be diagnosed with MBC, or they may develop metastases months or years after their initial treatment. The risk of breast cancer returning and metastasizing varies from person to person, and depends greatly on the biology of the tumor and the stage at the time of the original diagnosis.
Treatment for MBC includes many of the same treatments as the other stages of breast cancer: chemo, hormone therapy, radiation therapy, targeted therapy, and surgery.
Paget's Disease of the Breast
Paget's disease is a form of breast cancer that causes distinct skin changes on the nipple. It accounts for fewer than 3% of all breast cancers. Under a microscope, Paget's cells look very different from normal cells, and they divide rapidly. About half of the cells test positive for estrogen and progesterone receptors, and most test positive for the HER2 protein.
Although women with Paget's disease sometimes have tumors inside of the breast tissue, it is most noticeable around the areola or the nipple itself, creating oozing or appearance of eczema. This cancer is typically diagnosed with a biopsy of the tissue, followed by a mammogram, sonogram, or MRI to confirm the diagnosis.
The main symptoms of Paget's disease of the breast include:
- A skin rash on the nipple or areola, resembling eczema, with the skin developing flakiness, redness, or itchiness
- Discharge from the nipple
- A burning, painful, or tingling sensation, especially in advanced stages of the disease
- Nipple changes, such as inverted nipples
- Changes to the breast, such as a lump, redness, oozing, crustiness, or a sore that doesn't heal
The primary treatment for this disease is the surgical remover of the tumor. Cancers that are diagnosed in the early stages may be treated with breast conserving lumpectomy, while more advanced stages may require a mastectomy. As with other breast cancers, your care team may recommend chemo and radiation.
Breast Cancer Molecular Subtypes
HER2 Positive: 1 in 5 invasive breast cancers is HER2-positive, making this one of the more common breast cancer subtypes in the U.S. HER2 positive breast cancer cells carry too many copies of the HER2 gene, which makes HER2 protein receptors that are found on breast cells. When they work normally, HER2 receptors control how a healthy breast cell grows, divides, and repairs itself. When they act abnormally, the receptors tell the cells to divide and grow rapidly and without control.
Luminal A: is the most common subtype for every race and age. These tumors tend to be estrogen receptor positive and progesterone receptor positive, and are typically slow growing.
Luminal B: includes tumors that are estrogen receptor positive, progesterone receptor negative, and HER2 positive. These tumors tend to grow more quickly than Luminal A tumors. Luminal B breast cancers are likely to benefit from chemo and may benefit from hormone therapy and treatments targeting the HER2 receptor.
Triple Negative Breast Cancer: or, TNBC, the cancer cells do not contain receptors for estrogen, progesterone, or HER2. This type of breast cancer is usually invasive and usually begins in the breast ducts. Approximately 10 to 20% of all breast cancers are triple negative and can be treated with chemo, radiation, and non-HER2 targeted therapy.
Understanding Breast Cancer Survival Rates
Like many cancers, chances for survival vary by stage of breast cancer. Non-invasive - stage 0, and early stage invasive breast cancers - stages I and II have a better prognosis than later stage cancers - stages III and IV.
Cancer that has not spread beyond the breast has a better prognosis than cancer that has spread to the lymph nodes. The poorest prognosis is for metastatic breast cancer - stage IV, when the cancer has spread beyond the lymph nodes to other parts of the body.
Localized breast cancer is where cancer cells haven't spread beyond the organ where they begin to grow, thus the 5 year relative survival rate is approximately 99%. Regionalized breast cancer is when the cancer cells have spread beyond the organ where they began, but the spread is limited. Therefore, the 5 year relative survival rate is about 85%
Distant breast cancer is when the cancer cells have spread to other parts of the body, and other organs. The 5 year relative breast cancer survival rate drops down to 27%. However, there are several factors that come into play for survival rates, including the general health of the individual, as well as how they respond to their diagnosis and the treatment.