Journal of Clinical Oncology, 2004 ASCO Annual Meeting Proceedings (Post-Meeting Edition).
Vol 22, No 14S (July 15 Supplement), 2004: 527
© 2004 American Society of Clinical Oncology

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Abstract

Ten-year follow-up of a randomized controlled trial of adjuvant clodronate treatment in node-positive breast cancer patients

Helsinki University Hospital, Helsinki, Finland

527

Background: There are three studies available of the effect of adjuvant bisphosphonate treatment on survival in primary operable breast cancer with conflicting results. We here present the extended 10 year follow-up result of the Finnish adjuvant clodronate study. Methods: Between 1990 and 1993, 299 women with primary node positive breast cancer were randomized to oral clodronate 1600 mg daily (149) or control groups (150) for three years. All patients received adjuvant chemo- or endocrine therapy. The final population was 282 patients. Intent-to-treat analyses were also performed. Pretreatment characteristics were well balanced between the groups except PgR receptor status. In the clodronate group there were more PgR negative patients (p = 0.03). Results: Within ten years bone metastases were detected at the same frequency in the clodronate and control groups: 44 (32 %) vs. 42 (29 %), respectively, (p = 0.35). The frequency of nonskeletal recurrences (visceral and local) was significantly higher in the clodronate group 69 (50 %) as compared to the controls 51 (36 %) (p = 0.005). Ten-year disease-free survival (DFS) remained significantly lower in the clodronate group (45 % vs. 58%, p = 0.01, respectively). In ER positive patients ten-year DFS was 55 % in the clodronate group, and 59 % in the controls with no difference between the groups (p = 0.47); while in ER negative patients the DFS difference was highly significant in favor of the controls: 25 % vs. 58 %(p = 0.004), respectively. In multivariate analyses of DFS nodal status, tumor size, PgR status and study treatment group remained statistically significant. No significant overall survival difference was found between the groups.Conclusions: As previously reported three-year adjuvant clodronate treatment did not prevent the development of bone metastases in node-positive breast cancer patients. A negative effect of clodronate on DFS by increasing the development of visceral metastases was still seen at 10 years especially in ER negative patients, but this did not significantly compromise overall survival.

No significant financial relationships to disclose.

Abstract presentation from the 2004 ASCO Annual Meeting