Patient education: Breast cancer guide to diagnosis and treatment (Beyond the Basics)

INTRODUCTION — Breast cancer is the most common female cancer in the United States, the second most common cause of cancer death in women (after lung cancer). When found and treated early, breast cancer is most often curable.

Breast cancer deaths have decreased by one-third or more over the past three decades. This is due in part to increased screening, as well as earlier and improved treatment for breast cancer. Screening usually detects the disease at an earlier stage, when the chances of successful treatment are higher. Early detection and treatment of breast cancer improve survival because the breast tumor can be removed before it has a chance to spread (metastasize). In addition, there are treatments that can be used to prevent cancer cells that have escaped the breast from growing in other organs (see 'Systemic therapy' below). Screening recommendations are discussed in more detail elsewhere. (See "Patient education: Breast cancer screening (Beyond the Basics)".)

UpToDate contains a number of patient education articles that discuss breast cancer. The purpose of this overview is to provide a guide to the issues and questions that arise in women with newly diagnosed breast cancer. This topic can serve as a "road map" to the patient education articles that are relevant to your particular situation.

This guide will focus only on the diagnosis and treatment of breast cancer. Other articles within UpToDate discuss the risk factors for breast cancer and methods to prevent breast cancer in women who are at high risk. (See "Patient education: Factors that affect breast cancer risk in women (Beyond the Basics)" and "Patient education: Medications for the prevention of breast cancer (Beyond the Basics)".)

More detailed information about breast cancer, written for health care providers, is available by subscription. (See 'Professional level information' below.)

DIAGNOSING BREAST CANCER — Breast cancer is sometimes found when a person (or their health care provider) notices a lump or other change in the breast or armpit. Other times, cancer is found during a routine screening test, before a lump can be felt.

Abnormal lump — In addition to a lump, other abnormal changes may include dimpling of the skin, a change in the size or shape of one breast, retraction (pulling in) of the nipple when it previously pointed outward, bloody nipple discharge, or a discoloration of the skin of the breast not related to infection or skin conditions such as psoriasis or eczema.

To evaluate a breast lump, a mammogram and a breast ultrasound are usually recommended. If suspicious, a breast biopsy may also be recommended (see 'Breast biopsy' below). A suspicious lump should never be ignored, even if a mammogram is negative. Between 5 and 15 percent of new breast cancers are not visible on a mammogram [1-3].

Mammogram — Breast cancer is most often diagnosed with a routine "screening" mammogram, before a lump or other change in the breast develops.

A mammogram is a very low-dose X-ray of the breast. The breast tissue is compressed for the X-ray, which decreases the thickness of the tissue and holds the breast in position so the radiologist can find abnormalities more accurately. Each breast is compressed between two panels and X-rayed from two directions (top-down and side-to-side) to make sure all the tissue is examined. Mammograms are currently the best screening method to detect breast cancer. Some mammograms capture images digitally, offering better clarity, the ability to adjust the image, and a decreased likelihood of needing to return on a different day for repeat pictures.

3D tomosynthesis is a type of improved digital mammogram that captures multiple pictures of the breast while the breast is compressed in the two directions (top-down and side-to-side) instead of just one picture. This technology allows the radiologist to examine multiple pictures of each breast. This can help the radiologist see abnormalities that may be concealed by overlapping tissue. Additionally, finer detail is seen, which is helpful in determining which lumps are benign (not cancer) and which need further investigation with additional pictures [4-6].

Breast ultrasound — An ultrasound uses sound waves to look at breast tissue and can tell if a lump is a fluid-filled cyst or a solid lump. An ultrasound is only used to examine a limited area of the breast and is not routinely used as a screening test in place of a mammogram.

Breast MRI — Magnetic resonance imaging (MRI) uses a strong magnet to create a detailed image of a part of the body. It does not use X-rays or radiation but does require injection of a contrast agent (a material that shows up on imaging) into a vein.

Breast MRI is not usually used to screen for breast cancer but can aid in the diagnosis of breast cancer in select situations. As examples:

●Breast cancer screening for people who have an increased risk of breast cancer (eg, mutations in the BRCA1 or BRCA2 genes). (See "Patient education: Genetic testing for hereditary breast, ovarian, prostate, and pancreatic cancer (Beyond the Basics)".)

●Evaluation for breast cancer in a woman who is diagnosed with cancer of the lymph nodes (glands) under the arm but who has no sign of breast cancer on physical examination or mammogram of the breast on that side. Sometimes the breast MRI can be used to determine if the cancer first developed in the breast, and its location.

●Evaluation of a woman with newly diagnosed breast cancer with dense breasts on mammograms, because the density of the breast tissue makes the mammograms difficult to interpret.

Breast biopsy — If breast cancer is suspected, the next step is to sample the abnormal area to confirm the diagnosis. Regardless of whether the lump can be felt or not, the sample should be obtained using a needle biopsy with the help of an imaging study (such as mammography, ultrasound, or MRI).

A fine needle aspiration may be sufficient to establish a diagnosis of breast cancer, though a core needle biopsy, which utilizes a larger needle, is often preferable as it provides a larger sample to better characterize certain features of the cancer. (See 'Hormone receptors' below and 'HER2' below.)

Core needle biopsies are performed with local anesthesia and do not require sedation. The area biopsied is preferably marked with a clip or another method to mark the location. This can help facilitate surgical removal if the biopsy shows cancer or allow follow-up if the results are benign (not cancer).

Types of breast cancer — Although there are several different types of breast cancer, they are treated similarly, with some exceptions (figure 1).

In situ breast cancer — The earliest breast cancers are called "in situ" cancers.

Ductal carcinoma in situ — If cancers arise in the ducts of the breast (the tubes that carry milk to the nipple when a woman is breastfeeding) and do not grow outside of the ducts, the tumor is called "ductal carcinoma in situ" (DCIS). DCIS cancers do not spread beyond the breast tissue. However, DCIS can progress into invasive cancer if not treated.

The best treatment for DCIS will depend on the size of the area of disease relative to the size of the breast, the grade of the disease, hormone receptor status, and the woman's overall health:

●Most women can be treated with removal of the cancerous area (breast-conserving therapy, also known as lumpectomy) followed by radiation therapy. Surgical removal of the cancerous area without radiation may be an option, particularly for older women with a very small area of hormone receptor positive, low-grade disease that is completely removed. Women with DCIS who are being treated with lumpectomy do not need their lymph nodes checked for spread of tumor.

●Women with extensive DCIS may need a mastectomy, which may be done with or without reconstruction. A sentinel lymph node biopsy, a special technique to identify and remove only the most important lymph nodes in the armpit, is usually performed at the time of mastectomy for DCIS. Large areas of DCIS have an increased chance of being associated with hidden invasive cancer. If the lymph nodes are involved by this hidden invasive cancer, this will affect treatment decisions. It is not possible to reliably perform sentinel node biopsy after a mastectomy. (See "Patient education: Surgical procedures for breast cancer — Mastectomy and breast-conserving therapy (Beyond the Basics)".)

●Chemotherapy is not necessary for women with DCIS. Endocrine treatment (also called hormonal therapy) may be recommended for prevention of recurrence, particularly if the DCIS tests positive for responsiveness to estrogen (called "estrogen receptor positive" or "hormone receptor positive" cancer) and the woman did not have a mastectomy. The drug most often used for endocrine treatment is tamoxifen. Other drugs, anastrozole or exemestane, may also be effective in postmenopausal women treated for DCIS. Endocrine treatment reduces the chances that the cancer will come back in the treated breast; it also decreases the chances of developing a new breast cancer in the other breast.

Invasive breast cancer — The majority of breast cancers are referred to as invasive breast cancers because they have grown or "invaded" beyond the ducts or lobules of the breast into the surrounding breast tissue (figure 1). Several varieties of invasive breast cancers are possible.

Features of a breast cancer that influence the choice of treatment — At the time breast cancer is diagnosed and/or treated, the cancer should be studied for the presence of two types of proteins:

●Hormone receptors (estrogen and progesterone receptors)

●HER2 (for invasive cancers)

These proteins are important for selecting the appropriate medical treatment. These tests are performed by a pathologist, the doctor responsible for examining the breast cancer tissue under the microscope and making the diagnosis. The pathologist will also "grade" the cancer.

Grade — A tumor's grade describes how aggressively it grows, although this cannot be translated into a specific timeframe such as a month, a year, etc. Tumors are graded on a scale of 1 to 3, where 1 is the slowest and 3 is the fastest growing type of tumor. Tumors with higher grades are more likely to need chemotherapy.

Hormone receptors — More than one-half of breast cancers require the female hormone estrogen to grow, while other breast cancers are able to grow without estrogen. Estrogen-dependent breast cancer cells produce proteins called hormone receptors, which can be estrogen receptors (ER), progesterone receptors (PR), or both.

If hormone receptors are present within a woman's breast cancer, she is likely to benefit from treatments that lower estrogen levels or block the actions of estrogen. These treatments are referred to as endocrine or hormone therapies, and such tumors are referred to as hormone-responsive or hormone receptor positive.

In contrast, women whose tumors do not contain any ER or PR do not benefit from endocrine therapy, and it is not recommended. (See "Patient education: Treatment of early-stage, hormone-responsive breast cancer in premenopausal women (Beyond the Basics)".)

HER2 — HER2 is a protein that is present in about 15 to 20 percent of invasive breast cancers [7]. The presence of HER2 in the breast cancer identifies women who might benefit from treatments directed against the HER2 protein. Drugs that target the HER2 protein include trastuzumab (brand name: Herceptin), pertuzumab (brand name: Perjeta), ado-trastuzumab emtansine (brand name: Kadcyla), and fam-trastuzumab deruxtecan (brand name: Enhertu). (See "Patient education: Treatment of early HER2-positive breast cancer (Beyond the Basics)".)

If the cancer is HER2 negative as well as hormone receptor negative, this is called "triple negative" disease.

HAS THE BREAST CANCER SPREAD? — Once a diagnosis of breast cancer is established, the next important questions are the following:

●How extensive is the cancer involvement within the breast?

●Is there evidence that the tumor has moved to areas outside of the breast (metastasized)?

The extent of cancer involvement within the breast is usually determined by the findings on the biopsy, the results of the mammogram, ultrasound, and, in some cases, the results of the breast MRI scan.

Although by definition breast cancer starts within the breast, tiny cells or pieces of the cancer may break off from the breast tumor at any point and travel to other places through the bloodstream or the lymph channels. This process is called metastasis (figure 1).

When these stray tumor cells lodge themselves in a lymph node (gland) or an organ such as the liver or the bones, they grow, eventually producing a mass or lump that can sometimes be felt (eg, if it involves the skin or the lymph nodes in the armpit). In other cases, metastases may only be evident because they cause symptoms such as bone pain and can be seen on an imaging test such as a computed tomography (CT) scan, a bone scan, or a positron emission tomography (PET) scan. The use of these studies is discussed below. (See 'Staging and the staging workup' below.)

The importance of the axillary lymph nodes — One of the first sites of breast cancer spread is to the lymph nodes located in the armpit (axilla). These nodes (referred to as "axillary lymph nodes") can become enlarged and can sometimes be felt during a breast examination. Other times, they are found on the mammogram or MRI, leading to an ultrasound of the armpit. However, even if the lymph nodes are enlarged, the only way to determine if they truly contain cancer is to examine a sample of the tissue under the microscope.

The presence or absence of lymph node involvement is one of the most important factors in determining the long-term outcome of the cancer (prognosis), and it often guides decisions about treatment.

●If the axillary lymph nodes contain cancer (positive nodes), there is a higher chance that cancer cells have spread elsewhere, and most of these women are advised to have adjuvant systemic therapy.

●Systemic therapy, especially chemotherapy, is recommended less often for women who have no cancer cells detected in the axillary lymph nodes (node-negative breast cancer), particularly if the tumor is small or other prognostic factors (such as estrogen receptor [ER] positivity) are all favorable. Adjuvant endocrine therapy is usually recommended to all people with ER-positive breast cancer, even if the lymph nodes are negative, because it generally has less toxicity than chemotherapy and lowers the chances of recurrences and developing a second breast cancer in the future.

Examination of the axillary lymph nodes — The axillary lymph nodes should be examined for tumor spread. This is done first by physical examination and sometimes with ultrasound. If a suspicious lymph node is found, then a needle biopsy to obtain a tissue sample is performed. If there is cancerous involvement of the axillary lymph nodes, a surgical procedure called axillary lymph node dissection is performed at the time of the breast surgery to remove all the nodes from the axilla.

In people with early-stage breast cancer who do not have obvious involvement of the axillary lymph nodes, a surgical procedure called a "sentinel lymph node biopsy" is often performed. In this procedure, two tracers are used to mark the lymph nodes that the cancer would go to first (these are called "sentinel" nodes). These lymph nodes, which are usually under the armpit, are then removed for analysis. Older women with small hormone receptor positive invasive cancer may not need a sentinel lymph node biopsy.

The major benefit of the sentinel lymph node procedure is that it provides important staging information while causing fewer problems such as arm swelling (also called lymphedema) than a more extensive axillary lymph node dissection. (See "Patient education: Lymphedema after cancer surgery (Beyond the Basics)".)

Most people do not have cancer in their sentinel lymph nodes and will not need additional surgery. Some studies have shown that there are select people for whom an axillary lymph node dissection is not necessary even if one or two of the sentinel lymph node(s) are positive. People who have three or more positive sentinel nodes, however, will require dissection of the remaining axillary lymph nodes, in case there are additional cancer-containing nodes. (See "Patient education: Surgical procedures for breast cancer — Mastectomy and breast-conserving therapy (Beyond the Basics)", section on 'Management of axillary lymph nodes'.)

Staging and the staging workup — Oncologists (doctors who care for people with cancer) use a standard set of abbreviations, called the TNM staging system, to describe the stage of individual cancers. The "T" stands for the primary tumor, the "N" stands for the status of the regional lymph nodes, and the "M" stands for the presence or absence of metastases to other organs. The T, N, and M designations are then grouped together to form the stage grouping of a breast cancer, which ranges from stage I (least advanced) to IV (most advanced). Stage 0 cancer is the categorization for people with DCIS alone. The "stage" of the cancer is an indication of whether and how far it has spread.

People sometimes confuse stage and grade, but they are not the same thing. (See 'Grade' above.)

Tumor size (T) and nodes (N) — To establish the stage of a breast cancer, the first step is to evaluate the size of the tumor (T) and establish whether the lymph nodes have cancer in them or not (N). This is accomplished with:

●A complete physical, including careful examination of the breast and lymph nodes

●Mammogram (and sometimes other types of breast imaging such as ultrasound or breast MRI)

●Pathologic examination of the cancer and lymph nodes

Metastases (M) — If any cancer is detectable outside of the breast, these deposits are called metastases (M).

Several "staging" imaging studies may be done to help determine if the cancer has spread beyond the breast and axillary lymph nodes. These may include:

●Bone scan

●CT scan of the chest

●CT scan of the abdomen and pelvis

●PET scan

Not all of these studies will be recommended during the staging process. Indeed, for most women (including those who have no suspicious symptoms and who have small tumors with negative or only a few positive lymph nodes) nothing is needed for staging beyond the physical examination and breast imaging. The components of the staging evaluation are covered in more detail elsewhere. (See "Patient education: Surgical procedures for breast cancer — Mastectomy and breast-conserving therapy (Beyond the Basics)".)

Stage I and II breast cancer — Women with stage I or II breast cancers are said to have "early-stage" localized breast cancer. In general, stage I breast cancer refers to a tumor less than 2 cm (0.8 inches) in size that is node negative.

In general, stage II tumors are those with spread to the axillary lymph nodes and/or a tumor size larger than 2 cm but smaller than 5 cm (about 2 inches).

Stage III breast cancers — Women with stage III tumors are referred to as having locally advanced breast cancer. These consist of large breast tumors (greater than 5 cm, or about 2 inches, across), those with extensive axillary nodal involvement (more than 10 lymph nodes with cancer), nodal involvement of both axillary and internal mammary nodes (behind the ribs of the breast with cancer) at diagnosis, or nodal involvement of the soft tissues above or below the collarbone (called the supraclavicular and infraclavicular lymph nodes, respectively).

A tumor is also designated as stage III if it extends to underlying muscles of the chest wall or the overlying skin. Inflammatory breast cancer, a rapidly growing form of cancer that makes the breast appear red and swollen, is at least stage III, even if it is small and does not involve lymph nodes.

Stage IV breast cancer — Stage IV breast cancer refers to tumors that have metastasized to areas outside the breast and lymph nodes to the bones, lungs, liver, or other organs. The primary tumor may be any size, and there may be any number of affected lymph nodes. This is referred to as "metastatic" breast cancer.

OVERVIEW OF TREATMENT — The treatment of breast cancer must be individualized and is based upon several factors. Optimal management in most cases requires collaboration between surgeons (breast cancer surgeons and reconstructive surgeons, who are typically plastic surgeons) and doctors who specialize in radiation and medical oncology. Each woman should discuss the available treatment options with her doctors to determine what treatment is best for her.

Early-stage localized breast cancer

Local therapy — Two surgical options are available for treating localized breast cancer:

●Mastectomy (removal of the breast)

●Breast-conserving therapy (BCT), also called lumpectomy

BCT consists of breast-conserving surgery (lumpectomy), which may also be referred to as wide excision, quadrantectomy, or partial mastectomy. BCT also requires radiation therapy to reduce the chances of cancer coming back in the same breast. However, there are some people for whom radiation therapy to the remaining breast may not be necessary, particularly older women who have small, node-negative cancers that are hormone receptor positive. The combination of surgery and radiation usually results in cosmetically acceptable preservation of the breast without compromising breast cancer outcomes.

In centers that specialize in breast cancer treatment, approximately 60 percent of women with early-stage breast cancer are candidates for BCT. In 25 to 50 percent of women, there are medical, cosmetic, and/or social and emotional reasons for having a mastectomy rather than BCT. However, assuming that the patient is considered a good candidate for BCT, survival outcomes are the same whether BCT or mastectomy is performed. (See "Patient education: Surgical procedures for breast cancer — Mastectomy and breast-conserving therapy (Beyond the Basics)".)

Radiation therapy to the chest wall and surrounding lymph node areas may also be recommended for people who have had a mastectomy. Factors such as positive lymph nodes, large tumors, and positive margins play into the decision.

Breast reconstruction (surgery to rebuild the breast) is an important option for women who undergo mastectomy and may be considered at the time of the mastectomy or at a later date. Consultation with a plastic surgeon prior to the mastectomy is essential if immediate reconstruction is desired. Knowledge of the need for postmastectomy radiation may influence the plastic surgeon's decision as to the timing of the reconstruction (immediate or delayed). Also, not all women are eligible for reconstruction, so consultation with a plastic surgeon prior to surgery is important to determine eligibility. Some women choose not to have reconstruction.

Systemic therapy — Systemic (body-wide) anticancer treatment that is given before or after surgery is called "adjuvant systemic therapy." The term "neoadjuvant" is used when the treatment is given before surgery. Many women with early disease that is triple negative or HER2 positive will get neoadjuvant therapy; then, depending on the results of the surgery (and whether all the cancer was able to be removed), they may get additional treatment as well.

The goal of systemic therapy is to eliminate or prevent the growth of any cancer cells that may have escaped the breast and that might grow in other organs (metastases). The first place that breast cancer spreads is the lymph nodes under the armpit (axilla). When breast cancer metastasizes to lymph nodes in the axilla (the axillary lymph nodes), the chance for cure is lower than when it is only in the breast. People with metastases or cancer cells in other organs such as the liver, lung, or bone are rarely cured. However, systemic therapy may prevent metastases in many cases, and thus cure many women who would not be cured otherwise. Systemic therapy, therefore, has become an important component of breast cancer treatment because it significantly decreases the chance that a cancer will return, especially in situations where the cancer had already spread to the axillary lymph nodes. This, in turn, improves the chances of surviving breast cancer.

Systemic therapy is recommended for the vast majority of women with stage II breast cancer, and for many women with stage I disease. (See "Patient education: Treatment of early-stage, hormone-responsive breast cancer in premenopausal women (Beyond the Basics)" and "Patient education: Treatment of early-stage, hormone-responsive breast cancer in postmenopausal women (Beyond the Basics)".)

There are three types of systemic therapy. Some women may receive multiple types of these treatments depending on their tumor characteristics:

●Endocrine therapy (also called hormone or antiestrogen treatment) – Endocrine therapy is only recommended for women with estrogen receptor (ER)-positive breast cancer. Because it has very few life-threatening side effects and is so effective, it is recommended for almost all women with ER-positive disease, regardless of stage. Endocrine therapy reduces the odds of a breast cancer recurrence by nearly 50 percent. There are two types of endocrine therapies that are used in the adjuvant setting: selective estrogen receptor modulators (SERMs) such as tamoxifen or raloxifene and aromatase inhibitors (AIs) such as anastrazole. This is a treatment taken daily for a minimum of five years.

Women with high-risk hormone receptor-positive, HER2-negative disease may also be offered a medication called abemaciclib.

●Anti-HER2 therapy – Anti-HER2 therapy is usually recommended for people whose tumors make a lot of HER2 (see 'HER2' above). Trastuzumab (brand name: Herceptin) and pertuzumab (brand name: Perjeta) are approved for adjuvant and neoadjuvant (before surgery) treatment. The main risk of trastuzumab is a small risk of heart damage. Doctors usually do echocardiograms (imaging tests of the heart) to monitor for this. Some people who received systemic treatment before surgery may get a different drug after surgery called trastuzumab emtansine (T-DM1) if there is remaining cancer at the time of surgery.

●Chemotherapy – The decision to treat early-stage breast cancer with chemotherapy is based on many factors, such as the stage and grade of a tumor and whether it lacks hormone receptors or makes a lot of the HER2 protein. There are several types of chemotherapies used in the adjuvant setting, and they are usually given in combination or sequentially. Your oncologist will decide the regimen that is best for you. Additionally, they may want to give the chemotherapy before surgery, especially if the cancer is stage II with certain receptor patterns or if it is stage III.

A genetic test called Oncotype DX Recurrence Score (RS) can be performed on the tumor tissue to help with decision making about chemotherapy for women with ER-positive, HER2-negative, and node-negative breast cancer (and in select cases, people with node-positive breast cancer). The test looks at 21 different genes in order to evaluate the genetic makeup of the tumor and provides a number score to help predict the chance of recurrence. The score is called the "recurrence score," and the results range from 0 to 100. Cancer doctors will often use this information, in combination with other information about the individual and their tumor, to guide decision making about the need for chemotherapy.

In general, people with a low recurrence score whose cancers also have other low-risk features may not need chemotherapy, whereas those with a high score benefit more from chemotherapy. Antiestrogen therapy is recommended for all people with hormone receptor-positive disease, regardless of the recurrence score.

Other genetic tests are available that look at different genes than the RS and may be used on your tumor instead of Oncotype.

●Immunotherapy – Some women with "triple negative" cancers will benefit from immunotherapy, which uses the body’s own immune system to fight cancer.

●Other systemic treatments – For women with BRCA1 or BRCA2 genetic mutations whose cancer is HER2 negative but has high-risk features, use of a medication called a poly(ADP-ribose) polymerase inhibitor following adjuvant therapy can be beneficial. For women with hormone receptor-positive, HER2-negative, node-positive breast cancer at high risk of recurrence, the addition of a medication that inhibits cyclin dependent kinase 4/6 can improve outcomes.

Locally advanced and inflammatory breast cancer — Although not precisely defined, the term "locally advanced" implies one or more of the following: a tumor larger than 5 cm (about 2 inches), many palpable positive surrounding lymph nodes, cancer nodules or ulceration in the skin overlying the breast, or fixation of the cancer to the chest wall behind the breast. Another form of locally advanced breast cancer is "inflammatory breast cancer," which causes swelling, redness, or thickening of the skin due to its invasion by cancer cells. The likelihood of curing locally advanced and inflammatory breast cancer is lower than for smaller cancers and cancers that do not have any of these physical findings but is still possible with appropriate treatment.

Treatment generally includes a combination of systemic therapy, surgery, and radiation therapy. Additional therapies, depending on the cancer receptors, may include endocrine therapy (if the tumor is hormone receptor positive), anti-HER2 therapy (if the tumor is HER2 positive), immunotherapy (if the tumor is triple negative), and targeted therapy (eg, a cyclin dependent kinase 4/6 inhibitor, for select node-positive, hormone receptor-positive, HER2-negative cancers). In most cases, systemic therapy is given before surgery (neoadjuvant therapy). In fact, the treatment for locally advanced breast cancer is very similar to that for nonlocally advanced disease, except that more people receive neoadjuvant treatment, and more are treated with mastectomy than BCT (although BCT may be an option in some cases in which there has been a good response to neoadjuvant therapy), and almost everyone receives radiation therapy after surgery. (See "Patient education: Locally advanced and inflammatory breast cancer (Beyond the Basics)".)

Metastatic breast cancer — "Metastatic" means the cancer has spread beyond the breast. Few, if any, people with metastatic breast cancer are cured (meaning the disease goes completely away and never comes back); however, substantial progress has been made in improving the length of time people live with metastatic breast cancer and their quality of life during that time.

Doctors usually treat metastatic breast cancer with the approach that is most likely to reduce the symptoms related to the cancer with as few side effects as possible. This strategy is usually accomplished with a judicious use of "systemic therapy" that treats the whole body, such as chemotherapy, endocrine therapy, trastuzumab, immunotherapy, targeted therapy (which targets certain proteins that drive the growth of some cancers), or some combination of these options. Surgery and radiation therapy are used to control disease in certain areas, such as bone metastases that are particularly symptomatic or about to cause a fracture, brain or spinal cord metastases, and skin metastases on the chest that are causing symptoms. (See "Patient education: Treatment of metastatic breast cancer (Beyond the Basics)".)

The choice of treatment for metastatic breast cancer depends upon many individual factors, including features of the cancer (especially whether it produces hormone receptors and HER2), the expected response to various therapies, treatment-related side effects, the extent and location of metastases, and a woman's personal preferences.

Each woman should discuss the available treatment options with her physician to determine which choice is best for her. (See "Patient education: Treatment of metastatic breast cancer (Beyond the Basics)".)

CLINICAL TRIALS — There are many unanswered questions about the evaluation and treatment of breast cancer. Many advances have been made that have led to more effective and less toxic treatments over the last several decades. Ask your doctor if you are eligible for a clinical trial and then decide if participation is right for you.

Videos addressing common questions about clinical trials are available from the American Society of Clinical Oncology (https://www.cancer.net/research-and-advocacy/clinical-trials/welcome-pre-act).

WHERE TO GET MORE INFORMATION — Your health care provider is the best source of information for questions and concerns related to your medical problem.

This article will be updated as needed on our web site (www.uptodate.com/patients). Related topics for patients, as well as selected articles written for health care professionals, are also available. Some of the most relevant are listed below.

Patient level information — UpToDate offers two types of patient education materials.

The Basics — The Basics patient education pieces answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials.

Patient education: Breast cancer (The Basics)
Patient education: Breast cancer screening (The Basics)
Patient education: Common breast problems (The Basics)
Patient education: Genetic testing for breast, ovarian, prostate, and pancreatic cancer (The Basics)
Patient education: Breast reconstruction after mastectomy for cancer (The Basics)
Patient education: Choosing surgical treatment for early-stage breast cancer (The Basics)
Patient education: Ductal carcinoma in situ (DCIS) (The Basics)
Patient education: Inflammatory breast cancer (The Basics)
Patient education: Breast biopsy (The Basics)
Patient education: Sentinel lymph node biopsy for breast cancer (The Basics)

Beyond the Basics — Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are best for patients who want in-depth information and are comfortable with some medical jargon.

Patient education: Factors that affect breast cancer risk in women (Beyond the Basics)
Patient education: Medications for the prevention of breast cancer (Beyond the Basics)
Patient education: Breast cancer screening (Beyond the Basics)
Patient education: Genetic testing for hereditary breast, ovarian, prostate, and pancreatic cancer (Beyond the Basics)
Patient education: Surgical procedures for breast cancer — Mastectomy and breast-conserving therapy (Beyond the Basics)
Patient education: Treatment of early-stage, hormone-responsive breast cancer in premenopausal women (Beyond the Basics)
Patient education: Treatment of early HER2-positive breast cancer (Beyond the Basics)
Patient education: Lymphedema after cancer surgery (Beyond the Basics)
Patient education: Treatment of early-stage, hormone-responsive breast cancer in postmenopausal women (Beyond the Basics)
Patient education: Locally advanced and inflammatory breast cancer (Beyond the Basics)
Patient education: Treatment of metastatic breast cancer (Beyond the Basics)

Professional level information — Professional level articles are designed to keep doctors and other health professionals up-to-date on the latest medical findings. These articles are thorough, long, and complex, and they contain multiple references to the research on which they are based. Professional level articles are best for people who are comfortable with a lot of medical terminology and who want to read the same materials their doctors are reading.

Adjuvant systemic therapy for HER2-positive breast cancer
Adjuvant endocrine and targeted therapy for postmenopausal women with hormone receptor-positive breast cancer
Overview of the treatment of newly diagnosed, invasive, non-metastatic breast cancer
Breast-conserving therapy
Breast imaging for cancer screening: Mammography and ultrasonography
Clinical manifestations, differential diagnosis, and clinical evaluation of a palpable breast mass
Diagnostic evaluation of suspected breast cancer
Overview of the approach to early breast cancer in older women
Genetic testing and management of individuals at risk of hereditary breast and ovarian cancer syndromes
Cancer risks and management of BRCA1/2 carriers without cancer
Mastectomy
Tumor, node, metastasis (TNM) staging classification for breast cancer

The following organizations also provide reliable health information.

●National Cancer Institute

1-800-4-CANCER

(www.cancer.gov/)

●American Society of Clinical Oncology

(www.cancer.net/cancer-types/breast-cancer)

●American Cancer Society

1-800-ACS-2345

(www.cancer.org)

●Susan G. Komen Breast Cancer Foundation

(www.komen.org)