Breast Cancer Basics: Circulating Tumor Cell Testing

After cancer treatments are over, many breast cancer survivors question why we don’t routinely order imaging studies (aside from breast imaging) and tumor markers to keep a closer eye on their disease free status. The preponderance of data shows no significant improvement in survival when these studies are conducted in asymptomatic patients, which has led to this recommendation by the expert consensus panels. Liquid biopsies may become standard in the future to assess one’s prognosis of recurrence.

In a study of 206 patients (SUCCESS-A) with follow-up information and known circulating tumor cell (“CTC”) status at 5 years, 8% were CTC positive at 5 years, which was associated with a 6-fold increase in recurrence. Knowing that you have a higher risk of recurrence certainly increases stress and anxiety, and doesn’t mean you’ll have a recurrence.

Oncologists do not yet know what to do with this information, so it’s not typically ordered. Many proposals are being developed on when and how to use CTC assays. One is to recommend longer course endocrine therapy in this higher risk group.

As an integrative oncologist, I would like to see studies designed to investigate whether this information could also potentially identify a group of individuals for whom more rigorous attention to directed anticancer lifestyle changes might improve outcomes.

This video shows the CTC liquid biopsy result of one of my breast cancer survivors who asked me to run this test (Biocept) for her. It found no circulating tumor cells. Yay!!

These same assays can also identify targetable mutations in CTCs and circulating tumor DNA fragments, when present. When cancer is metastatic, biological targeted drugs may be a recommended treatment option. Liquid biopsies (instead of a getting a new tissue biopsy) can be used to run a “next generation sequencing” (NGS) assay, allowing the oncologist to select drugs that are designed to kill cancer cells with these mutations:


Here’s a good review on this topic:

  • “CTC Surveillance in Early-Stage Breast Cancer: What’s Next?”

Dr. Lawenda offers this lab test here.