Can Zometa improve survival rate?

This study investigated the influence of zoledronic acid (Zometa) on disseminated tumor cell (DTC) and survival of early stage breast cancer patients.

DTC are tumor cells that can be found in the bone marrow (the fatty and bloody tissue that fills the bone cavities and is the source of red blood cells and many white blood cells) of early breast cancer patients and are likely to play an important role in the development of distant metastases (cancer spread in distant organs and tissues of the body). They serve as an early indicator of tumor spread and are usually associated with poorer outcomes.

Bisphosphonates such as zoledronic acid (ZOL) are usually used as treatment for osteoporosis (a condition in which the bones become fragile due to loss of bone tissue). These drugs can slow or stop the natural process that dissolves bone tissue. Previous studies have shown that ZOL can eliminate DTC from the bone marrow of breast cancer patients. This trial investigated whether ZOL combined with adjuvant therapy (a therapy given after surgery to help remove cancer cells that may have been missed during surgery) for breast cancer can improve the survival of patients by eliminating DTC. 

For this trial, 86 patients with breast cancer and DTC in their bone marrow were included. Patients were randomly assigned to receive either ZOL and adjuvant therapy (40 patients) or adjuvant therapy alone (46 patients – the control group). The main parameters evaluated were the presence of DTC in the bone marrow after a period of time after treatment and overall survival or OS (the percentage of patients who survived for a defined period of time). 

After approximately 88 months of follow-up, patients in the control group were likely to have poorer OS compared to patients in the ZOL group. Also, while 16% of patients in the control group were still DTC positive after 2 years of follow-up, all patients in the ZOL group became DTC negative. In addition, 15% of patients in the control group developed recurrences (return of the cancer) compared to 8% in the ZOL group.

In summary, therapy with zoledronic acid reduced DTC in the bone marrow of breast cancer patients, with potential benefits on their survival.  

The study included a very small number of participants, which is not enough to state the actual efficiency of the drug on survival of breast cancer patients. Further larger trials are needed in order to determine the real effects of zoledronic acid regarding the outcomes of early stage breast cancer patients.

This study was funded by Novartis Pharmaceuticals Corporation, the manufacturer of Zometa. 

Consult your physician whether zoledronic acid is appropriate in your situation.