Background: In early breast cancer patients, bone marrow (BM)-disseminated tumor cells (DTCs) were associated with distant metastasis and locoregional recurrence. Our aim was to determine whether BM DTC detection could be related to specific locoregional dissemination of cancer cells, according to radiotherapy volumes.
Patients and methods: The relationship between locoregional recurrence-free survival (LRFS) and DTC detection was evaluated according to the various locoregional volumes irradiated after surgery.
Results: BM DTCs were detected in 94 of 621 stage I-III breast cancer patients (15%) and were not associated with axillary node status. Eighteen patients (2.9%) experienced locoregional recurrence (median follow-up 56 months), of whom eight (44%) were initially BM DTC positive. BM DTC detection was the only prognostic factor for LRFS [P = 0.0005, odds ratio = 5.2 (2.0-13.1), multivariate analysis]. In BM DTC-positive patients, a longer LRFS was observed in those who were given adjuvant hormone therapy (P = 0.03) and radiotherapy to supraclavicular nodes (SCNs)/internal mammary nodes (IMNs) (P = 0.055) (multivariate analysis; interaction test: P = 0.028).
Conclusions: The presence of DTC in BM may be associated with a different pattern of locoregional cancer cell dissemination and influences LRFS. The possible reseeding of the primary cancer area by DTC could be prevented by systemic hormone therapy but also by SCN/IMN irradiation.