Osteoporosis and AI's

[Blondy28]

Quick background...I'm stage IIa, HER2+, ER+100%/PR+30%. I've been getting Herceptin since August (started weekly with Taxol, and since November 3, when done with chemo, have been getting it every 3 weeks). I've been getting monthly zoladex shots, and started taking Arimidex on December 8. I had to stop due to severe hip pain, which I attributed to the drug. Plan was to see Onc on January 19 to discuss options (switching to another AI?). Yesterday, I was diagnosed with full blown osteoporosis in my hips (I just turned 40 in November), and osteopenia in my spine and pelvis. I'm terribly concerned that my oncologist is not going to let me proceed with ovarian supression and an AI due to the risk of increased bone loss, but I know Tamoxifen isn't nearly as effective (some say not at all effective). Has anyone had experience with this?

Thank you for any information.

Pam

[heblaj01]

Pam,
Any AI can & usually does cause more or less bone loss so the onc or a bone specialist should protect the patient with medication generally a bisphosphonate.
The most effective of them appears to be Zometa as reported in several trials including the Z-FAST trial which combined Femara (one of the most powerful estrogen suppressor & thus danger for bones) with Zometa:

Two-Year Z-FAST Trial Shows Zoledronic Acid Prevents Bone Loss in Breast Cancer Patients Taking Letrozole: Presented at SABCS

By Charlene Laino

SAN ANTONIO, TX -- December 18, 2006 -- Concurrent administration of the third-generation bisphosphonate zoledronic acid (Zometa) appears to prevent the bone loss often seen among early stage breast cancer patients on aromatase inhibitor therapy, researchers reported here at the 29<SUP>th</SUP> Annual San Antonio Breast Cancer Symposium (SABCS).

Two-year interim results from the Zometa-Femara Adjuvant Synergy Trial (Z-FAST) indicate that patients who were assigned to intravenous treatment with zoledronic acid 4 mg every 6 months along with 2.5 mg letrozole daily had improvements in bone density measures at key sites.

"At 24 months, upfront zoledronic acid increased lumbar spin bone mineral density 5.9% and total hip bone mineral density by 4.7% compared with patients who were on a delayed start of bisphosphonate therapy," said presenter Adam Brufsky, MD, assistant professor of medicine, Magee-Women's Hospital, University of Pittsburgh Medical Center/University of Pittsburgh Cancer Institute Breast Cancer Program, Pittsburgh, Pennsylvania.

In the Z-FAST study, 301 patients with early stage breast cancer were randomly assigned to receive zoledronic acid at the same time as they initiated treatment with letrozole. A second group of 301 patients were assigned to initiate letrozole alone, and were given zoledronic acid only if they had a marked decreased in bone mineral density as detected in imaging studies, if they had a symptomatic fracture or if they had an asymptomatic fracture by 36 months.

During the first 2 years of therapy, 12.7% of patients in the delayed cohort initiated zoledronic acid, Dr. Brufsky reported in a poster presentation on December 16<SUP>th</SUP>.

At 24 months, the bone mineral density in the lumbar spine had increased by 3% among patients who initiated zoledronic acid at the same time as letrozole; those in the delayed treatment cohort experienced a 2.9% loss in bone mineral density at time point. That 5.9% overall difference reached statistical significance at the P< .0001, he said.

Bone mineral density in the total hip increased by 1.5% at 24 months among patients who initiated therapy with zoledronic acid at the same time as letrozole, while those in the delayed treatment cohort experienced a 3.2% loss at this time point. That 4.7% overall difference reached statistical significance at the P< .001, Dr. Brufsky said.

Clinical fractures occurred in 4.3% of the upfront bisphosphonate treatment group compared with 4% of the patients receiving delayed treatment, a nonsignificant difference, Dr. Brufsky said. "An analysis of fracture rates at 36 months is planned," he said.