The key difference in identifying early versus late-stage breast cancer involves the location of the tumor. In addition to the diagnosis, there are many other contrasts between early and late-stage disease.
In early breast cancer, the tumor is confined to the breast. In advanced, or late-stage cancer (also called metastatic breast cancer), the tumor has spread from the breast to other parts of the body. Metastatic breast cancer tumors most often spread to the bones, lungs, liver, or brain. The bones are the most common site for the cancer cells to spread, accounting for 70% of metastases.1
How cases are counted
The National Cancer Institute collects cancer statistics in a specialized database that tracks patients diagnosed with cancer in the US: who gets the disease, where they live, at which stage they are diagnosed, certain characteristics of their tumor, their first course of treatment, and whether or not they survive their disease. The database is called SEER—the Surveillance, Epidemiology, and End Results Program.
Although SEER contains a wealth of information, it only collects data on metastatic breast cancer for people who get it at first diagnosis. That includes only 5% of breast cancer cases.2 People who develop metastatic cancer as a recurrence do not get counted in SEER. That makes it very hard to know how many people have advanced breast cancer in the US. The NCI and national cancer advocacy groups consider these patients to be an “understudied population.”
People living with disease
A recent study conducted by epidemiologists at the National Cancer Institute and the Fred Hutchinson Cancer Research Center was able to use mathematical models to fill in the gaps in counting people with advanced breast cancer. They found that as of January 2017, 155,000 people in the US were living with metastatic disease. Twenty-five percent were diagnosed initially (also called “de novo”), and 75% had progressed from early-stage disease.3
Patients with early-stage breast cancer almost never die from the disease, as long as they receive treatment. The five-year survival rate for people diagnosed with early stage breast cancer, localized in the breast, is 99%.
Metastatic breast cancer is incurable, but there are a variety of treatments for the disease, both on their own and in various combinations. The median survival time for people diagnosed with metastatic breast cancer is three years, up from two years in the early 1990s.6 The five-year survival rate for women with metastatic breast cancer is 27% and for men, it is 20%. This number tells us the number of people still alive five years after their diagnosis.
The success rates of treating early-stage breast cancer are very high, with 99% of people with localized tumors living five years past diagnosis.5 Treatment for people diagnosed at this stage centers on a cure. There is no cure for metastatic breast cancer, though, so the focus of treatment for advanced disease is reducing the tumors around the body and improving quality of life.4
If caught and treated early, breast cancer is almost never fatal. However, more than 40,000 people die of metastatic cancer per year. This number has not changed in over two decades.4
Given this fact, people with metastatic breast cancer often face fear and worry that they have to manage, along with their diagnosis and treatment.
Understanding Breast Cancer Metastasis. Breast Cancer. Updated January 14, 2019. https://breast-cancer.ca/metsurv-stat/ Accessed January 15, 2019.
Breast Cancer - Metastatic: Statistics. American Society of Clinical Oncology. Updated May 2018. https://www.cancer.net/cancer-types/breast-cancer-metastatic/statistics Accessed January 17, 2019.
Filling in the gaps on an ‘understudied population.’ Diane Mapes, May 17, 2017. Accessed at
https://www.fredhutch.org/en/news/center-news/2017/05/new-nci-study-estimates-metastatic-breast-cancer-rates.html Accessed January 17, 2019.
Difference Between Early-Stage and Metastatic Breast Cancer. Metastatic Breast Cancer Network. Available at https://www.facebook.com/MetastaticBreastCancerNetwork/photos/a.437164806302555/1926593160693038/?type=3&theater Accessed January 16, 2019.
Breast Cancer: Statistics
Study estimates number of U.S. women living with metastatic breast cancer. National Cancer Institute. May 18, 2017. Available at
https://www.cancer.gov/news-events/press-releases/2017/metastatic-breast-cancer-survival-rates Accessed January 15, 2019.