We don’t know how many people who are initially diagnosed with early stage breast cancer will develop metastatic disease, because the national database that tracks cancer, SEER, does not track when someone’s cancer metastasizes. Estimates range from 20-36% of women and men with early stage breast cancer will later develop metastatic breast cancer.

That means SEER doesn’t track up to one-third of breast cancer recurrence. We do not know how many men and women in America today are living with metastatic breast cancer.

From Beth Caldwell’s Blog:

The database that tracks everyone in America who has cancer is called the SEER database. For breast cancer, it tracks your stage at diagnosis, and it tracks when you die, but it doesn’t track when you progress from early stage to metastatic disease….

So, say, for example, you’re a 45 year old woman and you’re diagnosed with stage 1 breast cancer. You get a lumpectomy, you have some chemo, you have some radiation…And then 3 years later, you have a terrible headache that turns out to be a metastatic breast cancer tumor in your brain. Now you’re stage 4. But in the database, you’d still be listed as stage 1.

How can we begin to solve the problem of metastatic recurrence when our current systems barely acknowledge the problem exists?


  • How many women are living with mets today? Beth Caldwell
  • White Privilege and Metastatic Breast Cancer. Beth Caldwell
  • As I lay dying. Laurie Beckland
  • Effect of HER2 Status on Distant Recurrence in Early-Stage Breast Cancer. Page 8 references SEER data.