Estimation of the Number of Women Living with Metastatic Breast Cancer in the United States

Abstract

Background Distant metastatic breast cancer (MBC), including metastases found at diagnosis (de novo) and those occurring later (recurrence), represents the most severe form of the disease, when resource utilization is most intensive. Yet, the number of women living with MBC in the US is unknown. The objective of this paper is to use population-based data to estimate the prevalence of MBC. Methods We used a back-calculation method to estimate MBC prevalence from US BC mortality and survival from the Surveillance, Epidemiology and End Results (SEER) registries. Based on the illness-death process, this method assumes that each observed BC death is the result of MBC, either de novo or a recurrence with metastatic disease. Results We estimate that by January 1, 2017 there will be 154,794 women living with MBC in the United States, 3 in 4 initially diagnosed with stage I–III BC who later progressed to MBC. Median survival and 5-year relative survival for de novo MBC increased over the years, especially in younger women. We estimate a 2-fold increase in 5-year relative survival from 18% to 36%, for women diagnosed with de novo MBC at age 15–49 between 1992–1994 and 2005–2012, respectively. Conclusion This study demonstrates an increasing number of women in the US living with MBC, likely the result of improvements in treatment and aging of the US population. Impact The increasing burden of MBC highlights the importance of documenting recurrence in order to foster more research into the specific needs of this understudied population.

Breast cancer statistics, 2019

“…As of January 1, 2019, there were more than 3.8 million women with a history of breast cancer living in the United States. This estimate includes more than 150,000 women living with metastatic disease, three‐quarters of whom were originally diagnosed with stage I, II, or III breast cancer …”

Metastatic Breast Cancer Collateral Damage Project (MBCCD): Scale development and preliminary results of the Survey of Health, Impact, Needs, and Experiences (SHINE)

“…Survival rates for de novo MBC have increased substantially since the early 1990s [2], in part due to advances in medical treatment [3]. Therefore, the MBC population is growing, with 154,794 women estimated to be living with MBC [2]. Most research has focused on extending the lives of people with MBC, rather than maintaining or improving quality of life (QOL).…”

The Difference in Prognostic Outcomes Between De Novo Stage IV and Recurrent Metastatic Patients with Hormone Receptor-positive, HER2-negative Breast Cancer

“…In these cases a primary treatment goal is symptom palliation (6,7). Patients with distant metastasis at initial diagnosis are classified as de novo stage IV metastatic patients and can be viewed as a distinct subgroup (8,9), and these patients could be considered a poor prognostic group with incurable disease. However, a previous report suggested that de novo BC patients tend to have a better prognosis relative to recurrent BC patients (10).…”