27 september 2011: Bron The New England Journal of Medicin

Hoewel Zometa - Zoledronic Acid voor alle vrouwen met borstkanker geen significant positief effect geeft blijkt uit een deelanalyse dat voor vrouwen in de leeftijd na de overgang Zometa wel degeljik een effectief middel kan zijn als aanvulling op chemo. Het verschil in ziektevrije tijd en overall overleving was maar liefst 25% bij die groep vrouwen in vergelijking met alleen chemo. Er is al zoveel gepubliceerd over Zometa, zie linkerkolom dat ik me beperk tot een link naar het volledige studieverslag: klik hier voor het volledige studieverslag in The New England Journal of Medicin. In Medscape worden de resultaten van de deelanalyse vermeld. Zie hier de belangrijkste resultaten daarvan of klik hier voor het volledige artikel.

When zoledronic acid (Zometa) was added to chemotherapy in postmenopausal women with breast cancer, it significantly reduced the risk for relapse and significantly improved overall survival

Source: Medscape

Further analysis of a subgroup from the large AZURE trial shows that when zoledronic acid (Zometa) was added to chemotherapy in postmenopausal women with breast cancer, it significantly reduced the risk for relapse and significantly improved overall survival.

This subgroup comprised about a third of the study participants (1101 of 3360 patients), who had well-established menopause, defined as 5 years or more after menstruation.

In this subgroup, after a follow-up of 5 years, there was a significant increase in the rates of invasive disease-free survival rate with zoledronic acid, compared with placebo (78.2% vs 71.0%; hazard ratio , 0.75; P = .02), as well as in rates of overall survival (84.6% vs 78.7%; HR, 0.74; P = .004).

These results were independent of tumor stage, lymph node involvement, and estrogen-receptor status, Dr. Coleman explained. They were also "highly significant — this is not a fluke," he emphasized at a press briefing.

In addition, there was a "profound" treatment effect on the rates of extraskeletal recurrence in this postmenopausal group," Dr. Coleman reported. "This was an unexpected result," he noted.

But how is a bone drug affecting the spread of cancer to other organs in the body? Dr. Coleman said this was an important question, but at the moment any answers are theoretical and speculative.

"We know that breast cancer cells can lie dormant for years," he said. "They live in the bone marrow and are supported by nutrients, and probably also by stem cells within the bone marrow," he explained. A drug such as zoledronic acid disrupts bone turnover, and "we think that this changes the fuel supplies to these breast cancer cells, so that they are less able to mature and spread to other parts of the body."

However, it appears that this effect of zoledronic acid on the bone marrow microenvironment, hampering the breast cancer cells from leaving and spreading around the rest of the body, is "only clinically relevant in the context of low levels of female reproductive hormones that we see after the menopause," Dr. Coleman explained.

This theory, that the effects on bone are overridden by estrogen when there are high levels of hormones in the body, was previously put forward as the explanation for the divergent effects of zoledronic acid on breast cancer between pre- and postmenopausal women. At the San Antonio meeting last year, when the AZURE results were first presented, Rowan Chlebowski, MD, PhD, medical oncologist at the Harbor-University of California in Los Angeles, and Michael Gnant, MD, professor of surgery at the Medical University of Vienna, Austria, both supported this explanation. Read more>>>>>>

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