Breast Cancer Facts & Figures 2019-2020 (part 3)

 Breast Cancer Facts & Figures 2019-2020

Breast Cancer Treatment

Treatment decisions are made jointly by the patient and the physician after consideration of the stage and biological characteristics of the cancer, the patient’s age, menopausal status, and preferences, and the risks and benefits associated with each option. 

Ductal carcinoma in situ

 Since there is currently no certain way to determine the progressive potential of a DCIS lesion, surgery and sometimes radiation and/or hormonal therapy are the usual course of action following a diagnosis of DCIS. However, there is likely a group of patients that could safely forgo surgical treatment for DCIS.192 Several clinical trials are currently underway that are comparing standard treatment to active monitoring (with optional hormonal therapy) in women with “low-risk” DCIS.6 Ongoing research also seeks to identify molecular markers of DCIS that could predict recurrence or progression to invasive cancer.

Invasive breast cancer

 Figure 12 shows treatment patterns among US women with invasive breast cancer in 2016 by stage at diagnosis. Most women with early-stage breast cancer will have some type of surgery, which is often combined with other treatments such as radiation therapy, chemotherapy, hormone therapy, and/or targeted therapy to reduce the risk of recurrence. Patients with metastatic disease are primarily treated with systemic therapies, which can include chemotherapy, targeted therapy, hormonal therapy, and more recently immunotherapy.

Surgery 

The primary goals of breast cancer surgery are to remove the cancer and determine its stage. Surgical treatment involves mastectomy (surgical removal of the entire breast) or breast-conserving surgery (BCS). With BCS (also known as partial mastectomy or lumpectomy), only cancerous tissue, plus a rim of normal tissue (tumor margin), is removed. BCS is generally not an option in those with high tumor-to-breast ratio, multiple tumors within the same breast, or inflammatory or locally advanced cancers. In most cases, BCS is followed by radiation to the breast. Mastectomy can also be followed by radiation.

Despite equivalent survival when combined with radiation, BCS-eligible patients are increasingly electing mastectomy for a variety of reasons, including reluctance to undergo radiation therapy, fear of recurrence, and desire for symmetry.193, 194 Some women who are diagnosed with breast cancer in one breast also choose to have the unaffected breast removed, which is known as bilateral mastectomy or contralateral prophylactic mastectomy (CPM). Younger patients (<40 years of age) and those with larger and/or more aggressive tumors are more likely to be treated with mastectomy or CPM.195-197 Although CPM nearly eliminates the risk of developing a new breast cancer, it does not improve long-term breast cancer survival for the majority of women and nearly doubles the risk of surgical complications.198-200 In the US, the percentage of surgically treated women with early-stage disease in one breast who undergo CPM has increased rapidly, from 10% in 2004 to 33% in 2012 among women ages 20-44 and from 4% to 10% among those 45 years of age and older.197

Women who undergo mastectomy may have breast reconstruction, either with a saline or silicone implant, tissue from another part of the body, or a combination of the two. A woman considering breast reconstruction should discuss this option with her breast surgeon prior to the mastectomy in order to coordinate the treatment plan with a plastic surgeon.

 

Both BCS and mastectomy are usually accompanied by removal of one or a few regional lymph nodes from the armpit (axilla) to determine if the disease has spread beyond the breast. This procedure identifies the lymph node(s) to which cancer is most likely to spread and is called sentinel lymph node biopsy (SLNB). The presence of cancer cells in the lymph nodes increases the risk of recurrence, and so results from the SLNB can help determine whether further treatment is needed. Some breast cancer patients need to undergo more extensive lymph node surgery, called an axillary lymph node dissection (ALND). Surgery involving the axillary lymph nodes can lead to lymphedema, a serious swelling of the arm caused by retention of lymph fluid. It affects about 20% of women who undergo ALND and 6% of patients who receive SLNB.201 Axillary radiation and excess body weight are also associated with increased risk of lymphedema. The onset of symptoms usually occurs within 3 years of surgery, but has been reported to occur even 20 or more years later.202 Early diagnosis and treatment are critical to reduce the risk of progression to more severe lymphedema.

For more information about breast cancer survivorship, see Cancer Treatment and Survivorship Facts & Figures, available online at cancer.org/statistics.

Radiation therapy 

Radiation therapy is often used after surgery to destroy cancer cells remaining in the breast, chest wall, or underarm area and reduce the risk of recurrence. BCS is almost always followed by radiation therapy to the breast because it has been shown to reduce the risk of cancer recurrence by about 50% at 10 years and the risk of breast cancer death by almost 20% at 15 years.203 However, studies have shown that radiation does not improve survival for breast cancer patients 70 years of age and older with small, lymph node-negative, HR+ cancers who take hormonal therapy, although it does reduce the risk of local recurrence.204 Older patients with HR+ tumors who opt to omit radiation must be aware of the heightened importance of adhering to their prescribed hormonal therapy regimen. Some mastectomy-treated patients also benefit from radiation if their tumor is larger than 5 centimeters, growing into nearby tissues, or if cancer is found in the lymph nodes. Radiation can also be used to treat the symptoms of advanced breast cancer, especially when it has spread to the central nervous system or bones.

Radiation therapy may be administered as external beam radiation, internal radiation therapy (brachytherapy), or a combination of both. The method depends on the type, stage, and location of the tumor, as well as patient characteristics and doctor and patient preferences. External beam radiation is the standard type of radiation, whereby radiation from a machine outside the body is focused on the area affected by cancer. Brachytherapy uses a radioactive source placed in catheters or other devices that are put into the cavity left after BCS and is sometimes an option for patients with early-stage breast cancers. Accumulating evidence suggests that radiation therapy given at higher doses over fewer days (known as accelerated partial breast irradiation) may be as effective as conventional therapy.205 Intra-operative radiation therapy, in which a single fraction of radiation is given into the cavity left by tumor removal during BCS, is also sometimes an option.

Systemic therapy 

Systemic therapies are drugs that travel through the bloodstream, potentially affecting all parts of the body, and work using different mechanisms. For example, chemotherapy drugs generally attack cells that grow quickly. Hormonal therapy works by either blocking or decreasing the level of the body’s natural hormones, which sometimes act to promote cancer growth. Targeted therapies work by attacking specific proteins on cancer cells (or nearby cells) that normally help them grow. Immunotherapy stimulates the patient’s immune system to attack the cancer.

When systemic therapy is given to patients before surgery, it is called neoadjuvant or preoperative therapy. For larger breast tumors, it is often used to shrink the tumor enough to make surgical removal easier and less extensive (such as BCS in women who would otherwise have required mastectomy). Systemic treatment given to patients after surgery is called adjuvant therapy and is used to kill any undetected tumor cells (micrometastases)

that may have migrated to other parts of the body. Systemic therapy is the main treatment option for women with metastatic breast cancer.

Systemic therapy can affect fertility in premenopausal women, so young breast cancer patients who are interested in future childbearing should consult with a reproductive endocrinologist to determine fertility prevention strategies. In addition, hormonal therapy is not recommended during pregnancy and chemotherapy can cause premature ovarian failure.

Chemotherapy 

The benefit of chemotherapy is dependent on multiple factors, including the size of the tumor and the number of lymph nodes involved, as well as HR and HER2 status. Triple negative and HER2+ breast cancers tend to be more sensitive to chemotherapy than HR+ tumors.206 There are also gene expression panels (such as Oncotype DX, PAM 50, and MammaPrint) that can help assess the risk of distant recurrence and potentially identify those who would more likely benefit from adjuvant chemotherapy. The Oncotype Dx 21-Gene Recurrence Score is used most widely in the United States, but it is only applicable for patients with early-stage HR+/HER2- breast cancer. A high recurrence score identifies women who will benefit from adjuvant chemotherapy (in addition to hormonal therapy), whereas a low score identifies women who could safely avoid it. Evidence is less clear for patients with intermediate risk scores, although recent clinical trial results based on 9 years of follow-up suggest that most patients over age 50 with intermediate scores are unlikely to benefit from the addition of chemotherapy.207 

Although most women who are treated with chemotherapy receive it after surgery, a recent study documents an increase in the use of neoadjuvant chemotherapy, particularly among patients with HER2+ and triple negative breast cancers.208 A summary analysis of clinical trials recently concluded that neoadjuvant chemotherapy is as effective as the same therapy given after surgery in terms of survival and distant recurrence.209 However, breast and axillary surgery remains necessary after neoadjuvant chemotherapy, even when the preoperative treatment appears to have completely

cleared all clinical evidence of the cancer. Recent clinical trials have focused on identifying therapies that can improve outcomes among neoadjuvantly treated breast cancer patients who have residual disease detected during surgery.210, 211

Hormonal (endocrine) therapy

 Estrogen, a hormone produced by the ovaries in addition to other tissues, promotes the growth of HR+ breast cancers. About 83% of breast cancers are HR+ (Figure 1) and can be treated with hormonal therapy to block the effects of estrogen on the growth of breast cancer cells. These drugs are different than menopausal hormone therapies, which actually increase hormone levels.

For premenopausal women, tamoxifen for up to 10 years is standard treatment; however, the combination of ovarian suppression and either tamoxifen or an aromatase inhibitor is recommended for those women with a high risk of recurrence.212 For postmenopausal women, aromatase inhibitors (i.e., letrozole, anastrozole, and exemestane) are the preferred hormonal treatment. The decision to treat with an aromatase inhibitor beyond 5 years is individualized based on patient factors and the expected benefit from the reduction in risk of subsequent breast cancers. Studies have found that adherence to hormonal therapies remains suboptimal, particularly among black women, and may be in part due to out-ofpocket costs.213, 214

Targeted therapy 

Multiple medications are available for the treatment of the HER2+ subtype, which accounts for about 15% of all female breast cancers in the US (Figure 1). Trastuzumab, the first approved drug, is a monoclonal antibody that directly targets the HER2 protein. Several newer drugs have been developed that target the HER2 protein and can be used in combination with trastuzumab or if trastuzumab is no longer working. All invasive breast cancers should be tested for HER2 to identify women who would benefit from this therapy. Additional targeted therapy drugs, such as CDK4/6, PARP, and PIK3 inhibitors, are available for treatment of select patients with advanced disease.

Immunotherapy

 Immunotherapy drugs are an emerging area of breast cancer treatment. These drugs stimulate a person’s own immune system to recognize and destroy cancer cells more effectively. Checkpoint inhibitors are one type of immunotherapy drug that has been identified to treat some breast cancers, particularly the triple negative subtype. Drugs that target these checkpoints help to restore the immune response against breast cancer cells. Atezolizumab targets the PD-L1 “checkpoint” and can be used along with the chemotherapy drug nab-paclitaxel in patients with advanced triple negative breast cancer whose tumor makes the PD-L1 protein.215 Research on other immunotherapy drugs for metastatic breast cancer treatment is ongoing.

What Is the American Cancer Society Doing about Breast Cancer?

With a dedicated team of volunteers and staff, the American Cancer Society is leading the fight for a world without breast cancer – and all cancers.

Patient and caregiver services 

The American Cancer Society provides patients and caregivers with resources that can help improve – and even save – lives. From free rides to treatment and other cancer-related appointments, places to stay when treatment is far from home and our 24/7 helpline, we’re here for everyone with cancer questions and concerns, when and where they need us.  

Cancer information 

 Caring, trained American Cancer Society staff connect people to answers about a breast cancer diagnosis, health insurance assistance, American Cancer Society programs and services, and referrals to other services at our 24/7 helpline at 1-800-227-2345. Our website, cancer.org, offers reliable and accurate breast cancer information and news, including current information on treatments and side effects, and programs and services nearby. We also help people who speak languages other than English or Spanish find the assistance they need at cancer.org/easyreading or cancer.org/cancer-information-in-other-languages.

People can visit cancer.org/breast cancer to find information on every aspect of the breast cancer experience, from prevention to survivorship. We also publish a wide variety of pamphlets and books that cover a multitude of topics, from patient education, quality-of-life and caregiving issues to healthy living. Visit cancer.org/bookstore for a complete list of books that are available for order. All of our books are also available from all major book retailers such as Amazon and Barnes & Noble. Call 1-800-227-2345 or visit cancer.org for brochures.

Programs and services

 Survivorship: American Cancer Society survivorship work aims to help people living with and beyond cancer from diagnosis through long-term survivorship to the end of life. Efforts focus on helping survivors understand and access treatment; manage their ongoing physical, psychosocial, and functional problems; and engage in healthy behaviors to optimize their wellness. Our posttreatment survivorship care guidelines are designed to promote survivor healthiness and quality of life by facilitating the delivery of high-quality, comprehensive, coordinated clinical follow-up care. Our survivorship research efforts focus on understanding the impact of cancer on multiple facets of survivors’ lives and on developing and testing interventions to help survivors actively engage in their health care and improve their health and well-being through and beyond treatment. Through the National Cancer Survivorship Resource Center, a collaboration between the American Cancer Society and the George Washington University Cancer funded by the Centers for Disease Control and Prevention, we created the Cancer Survivorship E-Learning Series for Primary Care Providers. The free e-learning program is designed to teach clinicians how to care for survivors of adult-onset cancers.

Support for caregivers: Approximately 7% of the US population is made up of family caregivers of a loved one with cancer, and we are committed to meeting their information, education, and support needs. Approximately 4% of the US population is surviving cancer, meaning the ratio of family caregivers to cancer survivors is nearly double, supporting the notion that cancer is not isolated only to the individual diagnosed but rather impacts an entire family unit and network of close friends. One of the informational tools we offer caregivers is our Caregiver Resource Guide, which can help them: learn to care for themselves as a caregiver, better understand what their loved one is going through, develop skills for coping and caring, and take steps to help protect their own health and well-being.

Help navigating the health care system 

Learning how to navigate the cancer journey and the health care system can be overwhelming for anyone, but it is particularly difficult for those who are medically underserved, those who experience language or health literacy barriers, and those with limited resources. The American Cancer Society Patient Navigator Program reaches those most in need. It has specially trained patient navigators across the country who can help: find transportation to treatment and other cancer-related appointments; assist with medical financial issues, including insurance navigation; identify community resources; and provide information on a patient’s cancer diagnosis and treatment process.

Breast cancer support

 The American Cancer Society Reach To Recovery® program connects trained volunteers with breast cancer patients to provide peer-to-peer support on everything from practical and emotional issues to helping them cope with their disease, treatment, and long-term survivorship issues. 

Finding hope and inspiration 

Women with breast cancer and their loved ones do not have to face their experience alone. The American Cancer Society Cancer Survivors Network® provides a safe online connection where cancer patients and caregivers can find others with similar experiences and interests. At csn.cancer.org, members can participate on discussion boards, join the chat room, and build their own support network from among other members. Other online resources, including Springboard Beyond Cancer and Belong, provide additional support for patients, survivors, and caregivers and allow them to better communicate to receive the help they need during and after cancer.

Transportation to treatment 

Lack of transportation can be one of the biggest roadblocks to treatment. That is why the American Cancer Society started the Road To Recovery® program. It is at the very heart of our work of removing barriers to quality health care by providing patients transportation to treatment through volunteer drivers, partners, or community organizations. Other transportation programs are also available in certain areas.

Lodging during treatment 

The American Cancer Society Hope Lodge® program provides a free home away from home for cancer patients and their caregivers. More than just a roof over their heads, it is a nurturing community that helps patients access the care they need. Through our Hotel Partners Program, we also partner with local hotels across the country to provide free or discounted lodging for patients and their caregivers who are not able to make frequent trips for treatment appointments.

Hair-loss and mastectomy products 

The American Cancer Society “tlc” Tender Loving Care® publication offers affordable hair loss and mastectomy products for women coping with cancer, as well as advice on how to use those products. Products include wigs, hairpieces, hats, turbans and breast forms, as well as mastectomy bras, camisoles, and swimwear. Call 1-800- 850-9445, or visit the “tlc”TM website at tlcdirect.org to order products or catalogs.

Support after treatment 

The end of breast cancer treatment does not mean the end of a cancer journey. Cancer survivors may experience long-term or late effects resulting from the disease or its treatment. The Life After Treatment: The Next Chapter in Your Survivorship Journey guide may help cancer survivors as they begin the next phase of their journey. Visit cancer.org/survivorshipguide to download a free copy of the guide.

The American Cancer Society also has a follow-up care guideline for breast cancer survivors that builds upon available evidence, surveillance guidelines, and standard clinical practice and is designed to facilitate the provision of high-quality, standardized, clinical care by primary care providers.216 The breast cancer guideline addresses the assessment and management of potential long-term and late effects, as well as recommendations for health promotion, surveillance for recurrence, screening for second primary cancers, and the coordination of care between specialists and primary care clinicians.

Research 

Research is at the heart of the American Cancer Society’s mission. We invest more in breast cancer research than any other cancer type. Our funded research has led to the development of potentially lifesaving breast cancer drugs such as tamoxifen and Herceptin, as well as improved understanding of genes linked to breast cancer. Ongoing research studies span the cancer continuum from prevention and early detection to treatment and beyond. As of August 1, 2019, the American Cancer Society is funding more than $67 million in breast cancer research through 162 research and training grants. 

Examples of projects in which researchers in the American Cancer Society Extramural Research program are engaged include:

 • Identifying new targets for treating triple negative breast cancers 

• Understanding the role of the immune system in the spread of breast cancer to other parts of the body 

• Evaluating the effects of a high-protein, low-calorie diet on breast tissue and the risk of breast cancer recurrence

 • Examining the impact of breast density legislation on women’s breast cancer knowledge and screening decisions

Internally, the American Cancer Society also conducts epidemiologic studies of breast cancer and performs surveillance and health services research to understand the factors that underlie racial and socioeconomic disparities in breast cancer screening, incidence, treatment, survival, and mortality. Using information collected from more than 600,000 women in Cancer Prevention Study-II, American Cancer Society epidemiologists study the influence of many risk factors, including alcohol consumption, physical activity, menopausal hormones, family history of cancer, obesity, smoking, and spontaneous abortion on the risk of death from breast cancer. In order to continue to explore the effects of changing exposures and to provide greater opportunity to integrate biological and genetic factors into studies of other risk factors, more than 304,000 men and women were enrolled in the American Cancer Society Cancer Prevention Study-3 (CPS-3), and nearly all provided a blood sample at the time of enrollment. When female participants are diagnosed with breast cancer, consent is requested to bank tumor tissue specimens to better understand differences in risk and prognostic factors by molecular subtypes of breast cancer. The blood and tissue specimens together with the questionnaire data collected from CPS-3 participants will provide unique opportunities for research in the US.

Advocacy 

The American Cancer Society’s nonprofit, nonpartisan advocacy affiliate, the American Cancer Society Cancer Action NetworkSM (ACS CAN), advocates at the federal, state, and local levels to increase access to quality breast cancer screenings, diagnostic and treatment services, and care for all women; to increase government funding for breast cancer research; and to provide a voice for the concerns of breast cancer patients and survivors. 

Following are some of the efforts that ACS CAN has been involved with in the past few years to fight breast cancer – and all cancers:

Improving Access to Affordable Care through Health Care Reform: The Affordable Care Act (ACA) was signed into law on March 23, 2010, giving cancer patients access to quality, affordable health care. All new health insurance plans, including those offered through state health insurance exchanges, are required to cover preventive services rated “A” or “B” by the US Preventive Services Task Force, including mammography screening, at no cost to patients. Additionally, the ACA removed cost sharing for any preventive services covered by Medicare. ACS CAN advocates for clear, comprehensive coverage of these preventive services, including breast cancer screening, and encourages states to broaden access to health care coverage for all low-income Americans through state Medicaid programs.

The National Breast and Cervical Cancer Early Detection Program (NBCCEDP): Protecting and increasing funding for the NBCCEDP is a high priority for ACS CAN at both the state and federal levels. Administered by the Centers for Disease Control and Prevention, this successful program provides community-based breast and cervical cancer screenings to low-income, uninsured, and underinsured women. Women who are uninsured are much less likely to be screened for cervical and breast cancer than those who are insured. The NBCCEDP program helps to decrease this disparity in screening. Unfortunately, only one in 10 eligible women can be served by the program due to lack of federal and state funding. ACS CAN is asking Congress and states to increase funding to ensure that more women have access to cancer screening.

Protecting the Breast and Cervical Cancer Prevention and Treatment Act (BCCPTA): In 2000, Congress passed the BCCPTA, ensuring that low-income women diagnosed with cancer through the NBCCEDP were provided a pathway to treatment services through their state Medicaid program. 

In recent years, a number of states have considered proposals to eliminate the treatment program due to misconceptions around coverage needs following implementation of the ACA. Additionally, states have considered proposals that could jeopardize access to this program through the 1115 demonstration waiver process.

Breast Density and Mammography Reporting: Mammography sensitivity is lower for women with mammographically dense breasts because dense breast tissue makes it harder for doctors to see cancer on mammograms. The Food and Drug Administration proposed a rule to incorporate breast density reporting on mammograph reports for the first time. ACS CAN has advocated for several years for a national standard developed through an evidence-based process to inform women about breast density and risk.

Patient Navigation: Patient navigation can improve quality of cancer care, particularly in vulnerable populations. ACS CAN supports the federal Patient Navigation Assistance Act, which would create a coverage solution that incentivizes providers to use patient navigators in order to improve care coordination for patients. The organization also is working with Congress and federal agencies to help increase funding for patient navigation programs.

Funding for Cancer Research: ACS CAN continues to work to increase government funding for cancer research at the National Institutes of Health, including the National Cancer Institute and the National Center on Minority Health and Health Disparities.

It is important to note that the preceding references to ACA provisions and other federal laws and guidance reflect current law as of June 1, 2019, and do not take into account potential changes to the ACA or other federal laws and guidance subsequently considered by Congress and the administration.

Sources of Statistics

 General information. Unless otherwise stated, the statistics and statements in this publication refer to invasive (not in situ) female breast cancer.

 Estimated new breast cancer cases. The overall estimated number of new invasive breast cancer cases diagnosed in the US in 2019 was projected using a spatiotemporal model based on incidence data from 48 states and the District of Columbia for the years 2001- 2015 that met the North American Association of Central Cancer Registries’ (NAACCR) data inclusion standards.8 This method considers geographic variations in sociodemographic and lifestyle factors, medical settings, and cancer screening behaviors as predictors of incidence, and also accounts for expected delays in case reporting. The number of DCIS cases diagnosed in 2019 were estimated by 1) approximating the actual number of cases in the 10 most recent data years (2007-2016) by applying annual age-specific incidence rates (based on 48 states) to corresponding population estimates for the  overall US; 2) calculating the average annual percent change (AAPC) in cases over this time period; and 3) using the AAPC to project the number of cases three years ahead. These estimates were also partially adjusted for expected reporting delays using invasive factors. The estimated number of DCIS invasive cases by age and overall were calculated as the proportions of cases in each age group in the NAACCR data during 2012-2016 applied to the overall 2019 DCIS and invasive estimates. 

 Incidence rates. Incidence rates are defined as the number of people who are diagnosed with cancer divided by the number of people who are at risk for the disease in the population during a given time period. Incidence rates in this publication are presented per 100,000 people per year and are age adjusted to the 2000 US standard population. Breast cancer incidence rates for the US in the most recent time period (2012-2016) were calculated using data on cancer cases collected by NAACCR.8 When referenced as such, NAACCR incidence data were made available on the NAACCR website (naaccr.org) and within the Cancer in North America publications.217, 218 Longterm (1975-2016) incidence trends are based on the National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER) 9 registries, which account for about 8% of the US population. Analyses of trends (2001- 2016) by race/ethnicity are based on NAACCR incidence data and were adjusted for reporting delay using delay factors for the SEER 21 registries.

Breast cancer subtype distribtuion. Using the approach of Anderson et al,219 we imputed missing estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) status assuming that status was missing at random, conditional on year of diagnosis, age, race/ethnicity, and ER/PR/ HER2 status. Specifically, two-step imputation was performed to obtain imputed HR status based on the joint distribution of ER (positive, negative, and missing) and PR (positive, negative, and missing) status. Please see DeSantis et al37 for more information on this method.

Estimated breast cancer deaths. The overall estimated number of breast cancer deaths in the US is calculated by fitting the number of breast cancer deaths for 2002-2016 to a statistical model that forecasts the number of deaths expected to occur in 2019. Data on the number of deaths are obtained from the National Center for Health Statistics (NCHS) at the Centers for Disease Control and Prevention (CDC). Age-specific estimates were calculated using the proportions of deaths that occurred in each age group during 2013-2017 applied to the overall 2019 estimate.

Mortality rates. Similar to incidence rates, mortality rates (or death rates) are defined as the number of people who die from cancer divided by the number of people at risk in the population during a given time period. Death rates were calculated using data on cancer deaths compiled by NCHS and population data collected by the US Census Bureau. All death rates in this publication were age adjusted to the 2000 US standard population. 

Survival. Five-year survival statistics are based on cancer patients diagnosed during 2009-2015; 10-year survival rates are based on diagnoses during 2001-2015; and 15-year survival rates are based on diagnoses during 1998-2015. All patients were followed through 2016. When referenced as such, 5-year survival statistics were originally published in SEER Cancer Statistics Review, 1975-2016.20

Probability of breast cancer diagnosis or death. Probabilities of developing or dying from breast cancer were calculated using DevCan 6.7.7 (Probability of Developing Cancer Software), developed by the National Cancer Institute.220 These probabilities reflect the average experience of women in the US who were not previously diagnosed with breast cancer and do not take into account individual behaviors and risk factors (e.g., utilization of mammography screening and family history of breast cancer).

Screening. State-level prevalence estimates of mammography are based on Behavioral Risk Factor Surveillance System (BRFSS) data.187 The BRFSS is an ongoing system of surveys conducted by the state health departments in cooperation with the CDC. Data from the CDC’s National Health Interview Survey were used to generate national prevalence estimates of mammography.185 

Important note about estimated cases and deaths. While these estimates provide a reasonably accurate portrayal of the current cancer burden in the absence of actual data, they should be interpreted with caution because they are model-based projections that may vary from year to year for reasons other than changes in cancer occurrence. In addition, they are not informative for tracking cancer trends. Instead, trends in cancer occurrence should be analyzed using age-adjusted incidence rates reported by population-based cancer registries and mortality rates reported by the NCHS.