Considering prophylactic use of Zometa

[dblwhammy]

I am age 60 and 10 months ago was diagnosed with IDC, tumor grade 2, size 1.2 cm in one breast only. With a family history of breast cancer, I opted for bilateral mastectomies with SN Biops. which were negative, and other breast was without disease. The tumor is ER pos, Pr neg. Her2/neu negative and was also evaluated by Oncotype DX. The recurrence score was 27 so I've completed 4 cycles of Taxotere and Cytoxan. I have been on Arimidex for 4 months. What might be my chances of a distant metastasis? I have pre-osteopenia per a bone density. My oncologist said I might consider Zometa infusions which would be given every 6 months. Does it only help prevent bone metastasis or other mets as well? I know the research is still out on this but an early study indicated a greater than 30% reduction in risk of bone mets. That seems substantial.

Thanks very much for your thoughts

[dblwhammy]

Thank you Dr. Roque, for your very helpful information and statistics. I will certainly consider Zometa treatments. I understand the drug is generally well tolerated and side effects seem no worse than those I experience on Arimidex ... achy knees and hands.

Your response is much appreciated.

[Fernando Roque, MD]

Hi.  I calculated your risk of cancer recurrence in ten years using a software program called Adjuvant Online.  I have factored in such data as your tumor size, grade, age, hormone receptor status and treatment history in the calculation.  The figure I'm presenting to you is your overall 10 year recurrence risk.  It does not specify whether the recurrence will come in the form of distant metastases or local recurrence (nobody can know that for certain). Here are the figures:

10 year recurrence risk without chemotherapy/ hormonal treatment: 23.6%
10 year recurrence risk with Taxotere-Cytoxan plus 5 years of Arimidex:  8.8%

Regarding the use of Zoledronic Acid:  the study you're referring to is the one done by the Austrian Breast and Colorectal Cancer Study [see J Clin Oncol 26: 2008 (May 20 suppl; abstr LBA4) ].  Early results from this study indicate that Zometa in combination with endocrine therapy (goserelin plus tamoxifen or goserelin plus arimidex) lowers the 5-year risk for breast cancer recurrence by 36% compared to those women who were being given endocrine therapy alone.  Zometa apparently not only prevented bone metastases, but metastases to other body parts as well.  It also decreased recurrence risk in the unaffected breast.

What you have to note is that this study was done in a population of women who may have some characteristics which are different from your condition, hence the study results may not be entirely applicable to you.  Like you, the women in the study had early stage breast cancer, and had hormone receptor positive tumors.  However, these are all premenopausal women (I'm assuming that you're already menopausal because of your age) and none of the women received chemotherapy after their surgery (which you did).  

I think there's nothing wrong with your doctor offering Zometa to you at this point.  But with the available evidence, we're not yet sure if it's going to work in your particular situation.