Cancer Resources > Cancer News > 2009 > June

Bisphosphonates may prolong survival in metastatic breast cancer patients

David Douglas

Last Updated: 2009-06-15 14:23:14 -0400 (Reuters Health)

NEW YORK (Reuters Health) - IV bisphosphonate in addition to chemotherapy or hormonal therapy has an anti-tumor effect on hormone receptor (HR)-negative breast cancer patients with bone metastases, who may gain a survival advantage, according to Korean researchers.

Because of the retrospective nature of the study, investigator Dr. Jungsil Ro told Reuters Health, "we cannot strongly claim prolonged survival. However, the data appear encouraging enough to design a prospective study to confirm the anti-tumor activity of IV bisphosphonate."

In a May 20th paper published in BMC Cancer, Dr. Ro and colleagues at the National Cancer Center, Goyang-si point out that bisphosphonates have become the standard therapy for breast cancer patients with bone metastasis. This treatment reduces the symptoms and complications of bone involvement. However, the clinical relevance of their anti-tumor effect has not been established.

To gain more information, the researchers studied data on 230 patients with HR-positive tumors and 87 with HR-negative tumors. All had bone metastasis at diagnosis and known breast cancer subtypes.

Most of the women (n=262; 82.6%) received therapy with bisphosphonates during follow-up. The median number of cycles of treatment was 17.7 and the median interval between cycles was 31 days.

No survival benefit was seen in HR-positive patients, but HR-negative patients receiving bisphosphonates showed significantly improved survival (hazard ratio, 0.56). Median overall survival was 1.7 years in HR-negative patients who received bisphosphonates compared with 1.3 years in HR-negative patients who did not receive bisphosphonates.

Multivariate analysis showed that in HR-negative patients, bisphosphonate was a significant overall survival factor. More bisphosphonate-treated HR-negative women also had disease-free intervals of more than 2 years and fewer than three metastatic sites.

The researchers conclude that bisphosphonate treatment "may give a survival benefit in metastatic breast cancer patients, particularly in patients with HR-negative tumors, which are known to have a poorer prognosis."

"We have designed a prospective study in metastatic breast cancer patients without bone metastasis to see whether IV bisphosphonate -- zoledronic acid -- in combination with chemo- or hormone therapy as a first-line therapy will show an anti-tumor effect... or decrease bone metastasis," Dr. Ro added.

BMC Cancer 2009;9.

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