There are different types of treatments for breast cancer, some of which are standard, i.e., currently used, and some of which are in clinical trials.
Clinical trials about treatments are designed to help and improve the current treatment of cancer, or to get information about new treatments.
When clinical trials show that a new therapy is better than the standard therapy, that new therapy may become the standard therapy, and there are currently 5 standard treatments for breast cancer as follows.
Surgery
Most people with breast cancer will have surgery to remove the tumor.
Lymph node management
An anterior lymph node biopsy is the removal of an anterior lymph node during surgery. The anterior lymph node is the lymph node that first receives lymphatic drainage from the tumor, the lymph node to which the cancer may first metastasize.
The doctor injects a radioactive substance, a blue dye, near the tumor and they flow down the lymphatic vessels to the lymph nodes. The lymph nodes that receive this radioactive substance or dye first will be removed and looked at by a pathologist under a microscope to look for the presence of cancer cells.
After an anterior lymph node biopsy, the doctor will remove the tumor using breast-conserving surgery or mastectomy, which may not require removal of more lymph nodes if no cancer is found, and if cancer is found, the doctor will remove more lymph nodes through a separate incision, which is called a lymph node dissection.
Breast cancer surgery includes the following types.
Breast-conserving surgery
Breast-conserving surgery, which is surgery to remove the tumor and some normal tissue around it but not the breast itself, or part of the chest wall if the tumor is located near the chest wall, may also be removed.
This type of surgery may also be called mastectomy, partial mastectomy, segmental mastectomy, quadrantectomy, or breast-conserving surgery.
Total mastectomy
A procedure to remove all of the breast on the side with cancer, also called a simple mastectomy, in which the surgeon may remove some axillary lymph nodes and check for cancer, is performed at the same time as or after breast surgery, through a separate incision.
Modified radical mastectomy for breast cancer
Modified radical surgery for breast cancer involves removing all of the breast on the side with cancer, multiple axillary lymph nodes, the musculofascia of the chest, and sometimes some of the chest wall muscles.
Breast reconstruction
Breast reconstruction (for reconstruction of the breast shape) may be considered if a mastectomy is about to be performed, and can be done at the same time as or sometime after the mastectomy.
Reconstructed breasts can come from the patient’s own (non-breast) tissue or with implants such as silicone gel-filled implants.
Postoperative treatment
Before surgery to remove the tumor, the surgeon may give chemotherapy, which can shrink the tumor and reduce the amount of tissue that needs to be removed during surgery, a treatment given before surgery called preoperative therapy or neoadjuvant therapy.
Even if the surgeon surgically removes all the lesions that can be seen, radiation, chemotherapy, endocrine therapy, etc. may be given to some patients after surgery to destroy any cancer cells that may be left behind.
Treatment given after surgery to reduce the risk of cancer recurrence is called postoperative therapy or adjuvant therapy.
Radiotherapy for breast cancer
Radiotherapy is a treatment that uses high-energy X-rays or other radiation to kill cancer cells or prevent their growth, and includes two types:
- External radiation therapy, which uses a machine located outside the body to send rays to the cancer site.
- Internal radiation therapy, in which radioactive material is sealed inside an implant such as a needle, pellet, thin metal wire, or capsule, and the implant is placed directly into or near the tumor.
The type of radiation therapy depends on the type and stage of cancer to be treated, and external radiation therapy is usually used to treat breast cancer.
Breast cancer chemotherapy
Chemotherapy is a way to stop the growth of cancer cells by using drugs to kill the cells or stop them from dividing.
When chemotherapy is given orally, intravenously, or intramuscularly, the drug goes into the bloodstream for systemic chemotherapy.
When chemotherapy drugs are injected directly into the cerebrospinal fluid, organs, or body cavities (such as the abdomen), they mainly affect cancer cells in these areas (local chemotherapy).
The type of chemotherapy depends on the type and stage of cancer to be treated; the main type of chemotherapy used to treat breast cancer is systemic chemotherapy.
Ovarian denervation therapy
Endocrine therapy is a way of removing hormones from the body or stopping them from working, and by doing so can stop the growth of cancer cells, and some hormones can cause specific cancer growth.
If tests find places on cancer cells where hormones can attach (receptors), drugs, surgery, or radiation therapy can be used to reduce the production of hormones or block their action.
The ovaries can produce estrogen, which promotes the growth of some breast cancers, and the treatment that stops the ovaries from producing estrogen is called ovarian debulking therapy.
Tamoxifen endocrine therapy
Tamoxifen, an endocrine therapy, is often used for early stage limited breast cancer that can be removed surgically or for metastatic breast cancer (where the cancer has metastasized to other parts of the body).
The drug can act on cells throughout the body and can increase the risk of endometrial cancer. Women who take tamoxifen should receive annual pelvic exams for cancer screening.
Any vaginal bleeding that occurs other than menstrual bleeding should be reported to your doctor as soon as possible.
Aromatase inhibitor endocrine therapy
Used in postmenopausal breast cancer patients who are hormone receptor positive, aromatase inhibitors reduce the amount of estrogen in the body by inhibiting the conversion of androgens to estrogen by an enzyme called aromatase, and anastrozole and letrozole are two aromatase inhibitors.
For surgically resectable early-stage limited breast cancer, some aromatase inhibitors can be used in place of tamoxifen in adjuvant therapy or after 2-3 years of tamoxifen application.
For metastatic breast cancer, there are studies comparing the effects of aromatase inhibitors with tamoxifen.
Targeted therapy
Targeted therapy is an approach that uses drugs and other methods to find and attack specific cancer cells without harming normal cells, and includes the following categories.
Monoclonal antibodies
Antibodies are a type of antibody prepared in the lab to treat tumors that recognize substances on cancer cells or contain normal substances that help cancer cells grow, and the antibody attaches to these substances, killing the cancer cells, blocking their growth, or preventing them from metastasizing.
Monoclonal antibodies are administered by infusion, either alone or to carry drugs, toxins, or radioactive substances to cancer cells, and can be used as adjuvant therapy with chemotherapy. The main drugs include the following:
Trastuzumab
A monoclonal antibody that blocks the action of HER-2, a protein that acts to send growth signals to breast cancer cells, about 1 in 4 breast cancer patients can receive trastuzumab in combination with chemotherapy.
Pattuzumab
A monoclonal antibody that can be used in combination with trastuzumab and chemotherapy, patuximab can be used to treat some HER-2-positive breast cancers that have metastasized (metastasized to other parts of the body).
It may also be used in neoadjuvant therapy for some early-stage HER-2-positive breast cancers.
Antibody-drug coupling
Trastuzumab-metanephrine couples are monoclonal antibodies linked to an anticancer drug, known as antibody-drug couples, that can be used to treat HER-2-positive breast cancer that has metastasized or recurred.
Tyrosine kinase inhibitors
Targeted therapeutics that can block some of the signals needed for tumor growth are used in combination with some other anticancer drugs in adjuvant therapy.
Lapatinib is one of these drugs that blocks the action of HER-2 protein and some other proteins in tumor cells.
For HER-2-positive breast cancer that has progressed after trastuzumab treatment, lapatinib in combination with other drugs may be considered.
Cyclin-dependent kinase inhibitors
These drugs block the action of proteins called cyclin-dependent kinases, which promote cancer cell growth.
Piperacillin is one of these drugs and can be used in combination with letrozole to treat estrogen receptor-positive, HER-2-negative metastatic breast cancer, or in postmenopausal women who have not received endocrine therapy.
Polyadenosine diphosphate ribose polymerase (PARP) inhibitor
This is a targeted therapy that can block DNA repair and thus potentially cause cancer cell death, and the role of PARP inhibitors in the treatment of triple-negative breast cancer and BRCA1/BRCA2 mutated tumors is being investigated.
A new exploration beyond standard therapy
High-dose chemotherapy combined with stem cell transplantation
A therapy that gives high-dose chemotherapy with replacement of treatment-damaged blood cells, doctors first take stem cells (immature blood cells) from the patient’s or donor’s blood or bone marrow and freeze them for preservation.
After chemotherapy is completed, the preserved stem cells are thawed and infused back into the patient, and these returned stem cells will grow into the patient’s blood cells.
Studies have shown that high-dose chemotherapy combined with stem cell transplantation is not better than standard chemotherapy for breast cancer, and the investigators believe that high-dose chemotherapy can only be used in clinical trials at this time.
Before participating in such a clinical trial, patients should discuss with their doctors the serious side effects, including death, that can result from high-dose chemotherapy.
Participation in a clinical trial
For some patients, participation in a clinical trial may be the best treatment option. Clinical trials are part of cancer research designed to explore whether new cancer therapies are safe and effective or better than standard therapies.
Many of the current standard therapies for cancer are based on previous clinical trials, and participation in a clinical trial may lead to acceptance of the standard therapy or to being the first to receive the new therapy.
Participation in clinical trials can also help improve how cancer is treated in the future, and even if clinical trials do not result in effective new treatments, they often answer important questions that help advance research.
Patients can join a clinical trial before, during, or after cancer treatment begins.
What is a breast cancer clinical trial? How should I participate?
Some clinical trials include only patients who have not yet received treatment, others will target people whose cancer is not in remission, and still others are designed to test new ways to prevent the cancer from coming back or to reduce the side effects of treatment.
Clinical trials are conducted in many regions, and participants in clinical trials may need to be followed up with repeat tests designed to diagnose cancer or clarify cancer staging, and some tests may need to be repeated to see the effects of treatment.
The results of these tests are used to decide whether to continue, change, or stop treatment, and tests may be done occasionally after treatment ends to determine whether there has been a change in the disease or whether the cancer has returned, sometimes called follow-up or physical exams.