Effect of adjuvant zoledronic acid (ZOL) on disseminated tumor cells (DTC) in the bone marrow (BM) of women with early-stage breast cancer (ESBC): Updated results.

1002 Background: DTC are associated with increased risk of distant recurrence and death in patients (pts) with ESBC, especially if present after adjuvant chemotherapy (AT). Bisphosphonates (BP) including clodronate and ZOL have demonstrated anti-tumor activity in several clinical trials. We designed a pilot study to evaluate the effect of ZOL on DTC in pts with ESBC and DTC following AT. We hypothesized that ZOL would reduce DTC which could serve as a surrogate marker of anti-tumor effect. Methods: Pts with stage I-III BC were evaluated for DTC with a unilateral BM aspiration after neoadjuvant or AT. Eligibility was defined as > 4 DTC/mL w/in 12 wks of study entry, defined as > 2.5 standard deviations above that found in 50 normal BMs (Park, Proc ASCO 2002). Pts received 4 mg of ZOL IV monthly for 24 months (mos). Concomitant hormonal therapy was allowed. Serum creatinine (Cr) and toxicity were evaluated monthly, urinary n-telopeptide (nTX) was measured at 0, 2, 4, 6, 12, and 24 mos, peripheral blood circ...