Estimation of the Number of Individuals Living With Metastatic Cancer in the United States

Abstract

Background: The purpose of this study was to estimate the number of individuals living with metastatic breast, prostate, lung, colorectal, or bladder cancer or metastatic melanoma in the United States using population-based data.

Methods: A back-calculation method was used to estimate the number of individuals living with metastatic cancer for each cancer type from US cancer mortality and survival statistics from the Surveillance, Epidemiology, and End Results registries. The percentages of those living with metastatic cancer who advanced to metastatic disease from early stage cancer vs who were diagnosed with metastatic cancer de novo were calculated. One- and 5-year relative survival rates for de novo metastatic cancer were compared by year of diagnosis to assess time trends in survival.

Results: It is estimated that, in 2018, 623 405 individuals were living with metastatic breast, prostate, lung, colorectal, or bladder cancer, or metastatic melanoma in the United States. This number is expected to increase to 693 452 in 2025. In 2018, the percentage of metastatic cancer survivors who were initially diagnosed with early stage cancer and advanced to metastatic cancer ranged from 30% for lung cancer to 72% for bladder cancer.

Conclusions: This study demonstrates increasing numbers of individuals living with metastatic cancer of the 6 most common cancer types in the United States. This information is critical for informing the allocation of research efforts and healthcare infrastructure needed to address the needs of these individuals.

Figure 1.

Illustration of MIAMOD back-calculation method. A) MIAMOD first back-calculates the incidence of metastatic cases (de novo or recurrent) diagnosed in a year from cancer deaths and cancer survival after metastasis. Cancer survival after metastasis is estimated from de novo metastatic survival and adjustments. B) The number of people living with metastatic cancer (ie, metastatic prevalence) is then estimated from the estimated metastatic cancer incidence and survival (overall) as $\mathrm{Prevalence}=\sum \mathrm{Incidence}\times \mathrm{Survival}$. MIAMOD = Mortality Incidence Approach Model.

Figure 2.

Percentages of estimated metastatic cancer cases (on January 1, 2018) who were initially diagnosed with metastasis (de novo) or who experienced recurrent metastatic disease after being initially diagnosed with early stage disease. Numbers above each bar represent total estimated metastatic prevalence for each cancer type.

Figure 3.

Percentage of estimated metastatic prevalence (on January 1, 2018) by years since diagnosis for each cancer type.

Figure 4.

Estimates and projections of metastatic cancer incidence and prevalence for both sexes combined in the United States from 1990 to 2025 (gray bars) by cancer type. Dashed black line is estimated number of new incidence cases with metastatic cancer, including de novo and recurrent metastatic cancer. Solid blue line is observed number of cancer deaths (all stages) from 1990 to 2018. Dotted blue line is projected number of cancer deaths (all stages) from 2019 to 2025. Dotted red line indicates projections from 2019 to 2025.

Figure 5.

One-year and 5-year de novo metastatic relative survival (%) for each cancer type by year of diagnosis. Solid points correspond to cumulative relative survival. Solid lines correspond to predicted joinpoint survival model fits.