Breast Cancer
The information provided below is meant to help you understand the role of your breast cancer biology in treatment decisions by your treating physicians, as well, the role of other tools used in determining your ability to receive chemotherapy or targeted therapy (precision medicine).
Breast Cancer Incidence and Trends
There is an estimate of 271,270 new cases (2,670 in men) of breast cancer in the United States in 2019 (CA Cancer J Clin 2019; 69(1):7-30). Breast cancer is the most common malignancy for women in the United States.
The chance of developing breast cancer increases with age as following:
- < 49 years old (1 in 53)
- 50-59 years old ( 1 in 44)
- 60-69 years old (1 in 29)
- > 70 years old (1 in 15)
Thus, from birth to death a woman in the United States has a 12% lifetime risk (1 in 8) of developing breast cancer.
The incidence rates have been increasing by nearly 0.4% per year in recent years. Despite the steady increase in the number of breast cancer cases diagnosed each year, breast cancer mortality is declining, mainly due to the combined benefit of early detection (mammography) and more effective treatments. The 5-year survival has increased from 75% in the 1970s (1975-1977) to 91% in the 2000s (2005-2011).
Where breast cancer starts
Breast cancer can occur in lobules or ducts of the breast or in the fatty tissue or connective tissue within the breast. The most common site for the breast cancer cells to develop is in the milk duct (75%), and this type of cancer is called ductal carcinoma. The other site for breast cancer cells to develop is in the lobules, and this type of cancer is called lobular carcinoma. The lobules and ducts are responsible for the production and transport of the milk.
Treatment
There are three different approaches to treating breast cancer. Depending on the type of cancer you have, you may be recommended one or a combination of all three approaches.
These include:
- Breast surgery
- Breast radiation
- Chemotherapy
Surgery
There are two types of surgeries recommended for patients with breast cancer: lumpectomy (partial removal of the breast) or mastectomy (removal of the whole breast).
The goal of breast surgery is to completely remove the tumor and part of the surrounding tissue to ensure there all tumor is removed. The surrounding tissue that is removed is called a margin. Successful removal of the tumor will include a clear margin (i.e. free of cancer cells) and this should measure 1- 2mm of clear tissue, depending on the type of breast cancer you have.
You and your breast surgeon should discuss which of these options is best for you, considering such factors as the size of your tumor, your breast size, and the best approach to achieve the best cosmetic outcome. Breast reconstruction may be an option after breast surgery.
Radiation
If you decide to undergo a lumpectomy (removal of the tumor only), you may or may not need breast radiation after surgery. This decision is made by your radiation physician and it depends on your age and overall health status. You and your radiation oncologist will determine whether you will need to receive adjuvant radiation after the lumpectomy.
Chemotherapy/Targeted Therapy (precision medicine)
OncoGambit is designed to address this part of your treatment and offer you personalized information about your treatment options that will yield in best survival and quality of life.
There are multiple factors to affect your treatment options, and they are as follows:
- Cancer is a recurrence (you have had breast cancer before) or your cancer is a first time diagnosis. The treatment for recurrence is determined by the type of treatment you received for the first breast cancer. Certain chemotherapies can only be given once in your lifetime, and therefore if you already received a certain chemotherapy with your first cancer then that chemotherapy will not be recommended for you.
- Cancer stage: This is determined by the tumor size, number of lymph nodes removed during surgery or visualized on mammogram or MRI (if necessary), and whether the cancer spread to other areas of your body (bone, liver, lungs, skin, etc).
There are two types of breast cancer: non-invasive (it is still in the ducts or lobules) and invasive (has moved outside the ducts or lobules).
Breast cancer is staged as follows:
Stage 0: non-invasive breast cancer or ductal carcinoma in situ (DCIS)
Stage I: tumor is <= 2cm and no lymph node has cancer cells
Stage II: tumor is 2-5cm in size and /or 0-3 lymph nodes involved with cancer
Stage III: tumor is > 5cm or >= 4 nodes involved with cancer
Stage IV: tumor spreads to other parts of the body*If your tumor was not surgically removed, the staging may be determined from different tests, including mammogram, ultrasound, MRI, CT scan, bone scan, and/ PET/CT.
Not all early stage breast cancer (stage I and II) will require treatment with chemotherapy. In order to determine the risk of recurrence and whether you will benefit from chemotherapy, your physician will order a test called Oncotype DX or Mammoprint, or PAM50. These tests are only recommended for patients whose tumor biology has positive estrogen or progesterone features.
Stage IV or metastatic breast cancer treatment depends on whether this is a new cancer or a recurrence. You will need some form of treatment that includes chemotherapy, targeted therapy (precision medicine), anti-hormonal therapy or a combination of these. You may also need radiation or surgery if you are experiencing symptoms that may be alleviated with these treatments. Our web application will give you not just one but other choices for treatment in metastatic disease
- The molecular characteristics of the tumor (biology) greatly affects the treatment decisions. Currently, treatment is determined by whether your tumor expresses any of the following biological features: estrogen, progesterone, and/or Her2/neu. If the tumor has estrogen or progesterone features, it is called estrogen- or progesterone- receptor positive breast cancer. Receptors are proteins present on the tumor cells to which estrogen or progesterone bind to and promote the tumor growth. The HER2/neu is a protein that plays a role in the growth of breast cancer. These tests should always be performed, as they determine what type of treatment you will receive.
If your tumor biology has estrogen or progesterone features, then it is called hormone positive breast cancer. These features indicate that your treatment will include anti-hormonal therapy after either surgery, radiation, or chemotherapy. The anti-hormonal therapy type and duration will depend on your menopausal status: premenopausal (still having active regular menstrual period) or postmenopausal (last menstrual period was at least one year ago). Examples of anti-hormonal therapy include tamoxifen, anastrazole, letrozole, exemestane or fulvestrant.
If your tumor biology has HER2/new features, then it is called HER2-positive breast cancer. This feature indicates that your treatment will include targeted therapy against HER2/neu, and will be given either before or after surgery or radiation, and most likely in combination with chemotherapy. Examples of anti-HER2neu targeted therapies include trastuzumab, lapatinib, pertuzumab or ado-trastuzumab emtansine. These therapies have a small chance of affecting your heart function, thus routine heart monitoring with heart echo test will be part of your treatment monitoring plan.
If your tumor biology does not have estrogen, progesterone, or Her2/neu features, then it is called triple-negative breast cancer. This type of cancer is generally more aggressive, therefore its treatment is more aggressive, and will most likely include surgery, radiation, chemotherapy, or some combination of these treatments.
BRCA1/2 gene mutation: BRCA1/2 genes are tumor suppressor genes and are responsible for DNA repair among other functions. If you have this mutation, a newer drug called PARP (poly ADP ribose polymerase) inhibitors have recently made available for breast cancer patients. PARP1 is a protein that works to repair single-strand DNA breaks (‘nicks’ in the DNA), this process is important for cell division.
Exceptions
A small percentage of cancer do not present with the typical features mentioned above. These include inflammatory breast cancer, neuroendocrine or metaplastic carcinoma. The treatment for these is more complex, as they do not have the typical tumor biology. The treatment will depend on the tumor size and features of the tumor.
Treatment side effects
Chemotherapy, targeted therapies, and anti-hormonal therapies can result in unpleasant side effects, such as, hair loss, numbness of fingers or toes, cardiac toxicity, nausea, vomiting, diarrhea, abnormal liver function or low white blood count that could cause infection, hot flashes, fatigue. However, advances in the oncology field have led to numerous supportive measures, such as white blood cells growth support (such as Neulasta) or anti-nausea medications (such as Zofran), that have controlled most of the side effects, when used as prescribed.