Circulating Tumor Cells in Patients with Breast Cancer Dormancy

TLDR

The study aimed to determine whether circulating tumor cells (CTCs) persist many years after mastectomy in patients with breast cancer dormancy. Researchers screened 36 dormancy candidates and 26 age‑matched controls for CTCs using stringent cytomorphology, immunophenotype, and aneusomy criteria. Thirteen of 36 dormancy candidates had CTCs versus one of 26 controls (P = 0.0043), and the 1–2.4 h half‑life of these cells indicates continuous tumor replication that balances cell death, sustaining dormancy for up to 22 years.

Abstract

Abstract Purpose: The purpose of this study was to test the hypothesis that circulating tumor cells (CTCs) are present in patients many years after mastectomy without evidence of disease and that these CTCs are shed from persisting tumor in patients with breast cancer dormancy. Experimental Design: We searched for CTCs in 36 dormancy candidate patients and 26 age-matched controls using stringent criteria for cytomorphology, immunophenotype, and aneusomy. Results: Thirteen of 36 dormancy candidates, 7 to 22 years after mastectomy and without evidence of clinical disease, had CTCs, usually on more than one occasion. Only 1 of 26 controls had a possible CTC (no aneusomy). The statistical difference of these two distributions was significant (exact P = 0.0043). The CTCs in patients whose primary breast cancer was just removed had a half-life measured in 1 to 2.4 hours. Conclusions: The CTCs that are dying must be replenished every few hours by replicating tumor cells somewhere in the tissues. Hence, there appears to be a balance between tumor replication and cell death for as long as 22 years in dormancy candidates. We conclude that this is one mechanism underlying tumor dormancy.