Zometa - Zoledronic Acid voorkomt significant recidief bij vrouwen met borstkanker na de overgang en geeft significant betere resultaten op overleving, maar niet bij jongere vrouwen. Oestrogeen niveau lijkt hierin een bepalende rol te spelen

10 december 2010: Bron: Azure studie en Medscape

Zoledronic Acid - Zometa geeft een significant positief effect op zowel recidief en overleving bij postmenopauzale vrouwen met borstkanker (meer dan 5 jaar na de menopauze), maar geen effect op premenopauzale vrouwen. Dat blijkt uit een subanalyse van de grote fase III studie (Azure studie). Algeheel genomen bleek uit de Azure studie dat er geen effect was op het voorkomen van een recidief en overleving van vrouwen met borstkanker en zo wordt deze studie ook naar buiten gebracht. Novartis trekt dan ook hun advies in om aan alle vrouwen met borstkanker Zometa voor te schrijven. Echter voor vrouwen na de menopauze blijkt Zometa - Zoledronic Acid wel een grote rol te kunnen spelen in het voorkomen van een recidief en ook op de algehele overleving. Voor effect op botafbraak blijft Zometa - Zoledronic Acid als bisfosfonaat wel een prima middel natuurlijk. Zie studies daarover in linkerkolom

Medscape schreef over deze studie een groot artikel. Voor volledige artikel klikt u hier maar hieronder enkele citaten uit het artikel:

"......In light of the new and contradictory findings from AZURE, she said, "the routine use of zolendronic acid to prevent breast cancer recurrence is not indicated." The drug has a use in osteoporosis and other bone disorders, which are approved indications.

The finding of a significant effect in postmenopausal women in a subgroup analysis is "intriguing but not definitive," she said.

However, several experts disagreed and said that they were already prescribing the drug and would continue to do so.

Michael Gnant, MD, professor of surgery at the Medical University of Vienna, who led the positive Austrian trial, said after those results came out that he would use zolendronic acid in patients who were similar to the participants of that trial (premenopausal women who were treated with goserelin to induce artificial menopause). Now, on the basis of the positive subgroup findings, he said he would also use zolendronic acid in postmenopausal women.

"Before I would say that I would treat my wife, who is 42. Now I would also treat my mother, who is 82," he said.

Rowan Chlebowski, MD, PhD, medical oncologist at the Harbor-University of California in Los Angeles, told Medscape Medical News that he would also use zolendronic acid in postmenopausal women with breast cancer to reduce their risk for recurrence. "Many states cover use of zolendronic acid to prevent bone loss in the patient population, so I prescribe it for that," he said.

Last year, Dr. Chlebowski reported a large observational study that showed that women who were taking oral bisphosphonates (which did not include zolendronic acid, which is administered intravenously) for osteoporosis had a significantly lower risk for breast cancer. Two other observational studies have reported similar findings. In all of these studies, the women were postmenopausal, Dr. Chlebowski noted.......

.....Dr. Gnant explained that zolendronic acid is administered by injection once every 6 months, and that a healthy individual would clear the drug from the system in about 24 hours. But the drug persists in bone and changes the bone marrow environment, Dr. Gnant told Medscape Medical News. There is good reason to believe that breast cancer cells collect within the bone marrow, forming a "stem cell sanctuary," particularly in early disease. They can be dormant there, sometimes for years, before they escape and cause breast cancer recurrence, he said. It now appears that zolendronic acid is altering the bone marrow environment in such a way that the breast cancer cells are less likely to escape and cause a recurrence, he said.

...

The AZURE study was designed after the positive results from the Austrian trial came out and zolendronic acid began to be used in the wider breast cancer population, Dr. Coleman explained. It was an academic study, he emphasized, conducted in 3360 women from 174 centers worldwide (but mostly in the United Kingdom).

These women had stage II or III breast cancer. Nearly all were treated with adjuvant chemotherapy (93% anthracyclines, 23% taxanes), and some also received endocrine therapy. Half of them were randomized to receive zolendronic acid 4 mg intravenously over 3 to 4 weeks for 6 doses, and then every 3 months for 8 doses and every 6 months for 5 doses.

All of these details are different from the Austrian trial, Dr. Gnant noted, where all of the women were stage I, none received chemotherapy, and zolendronic acid was used once every 6 months.

Dr. Coleman explained that the more intensive administration schedule in AZURE was used because at the time the trial was designed, it was thought that zolendronic acid had a direct anticancer effect.

The differences in dosing schedule might also be related to the fact that osteonecrosis of the jaw, a known adverse effect of bisphosphonates, was not seen in the Austrian study, but was reported in 17 patients (1.16%) in the AZURE trial.

The overall results from AZURE, after a median follow-up of 59 months, show no significant effect from zolendronic acid on either disease-free or overall survival, although there was a positive trend for overall survival.

Significant Effect in Subgroup

However, in a preplanned subset analysis based on menopausal status, zolendronic acid did show a significant effect on overall survival in a subgroup of women (n = 1101) with well-established menopause (more than 5 years postmenopausal), reducing the risk for death by 29%. There were 86 deaths in the zolendronic acid groups, compared with 120 in the other group (hazard ratio, 0.71; P = .017)......

postmenopausaal, borstkanker, Zoledronic Acid