Study confirms tamoxifen is superior to fulvestrant in blocking estrogen

[News]

For the first time, researchers at Seattle Cancer Care Alliance have demonstrated the feasibility of using serial positron emission tomography (PET) scans, using a special estrogen-containing isotope, to confirm the relative effectiveness of estrogen-blocking and estrogen-depleting therapy in patients with metastatic breast cancer.

More... (http://www.news-medical.net/news/20110819/Study-confirms-tamoxifen-is-superior-to-fulvestrant-in-blocking-estrogen.aspx)

[bejuce]

Did I read this right that they found Tamoxifen superior
to AIs as well???

[Rich66]

That's how I read it:

The PET scans, taken before, during and after hormonal therapy, confirmed the superior effectiveness of estrogen (http://www.news-medical.net/health/Estrogen-What-is-Estrogen.aspx)-receptor-blocking drugs such as tamoxifen (http://www.news-medical.net/health/What-is-Tamoxifen.aspx) and fulvestrant over estrogen (http://www.news-medical.net/health/Estrogen-What-is-Estrogen.aspx)-depleting therapies such as aromatase inhibitors in blocking the estrogen (http://www.news-medical.net/health/Estrogen-What-is-Estrogen.aspx) receptor in cancer (http://www.news-medical.net/health/What-is-Cancer.aspx) cells. The study also confirmed that tamoxifen (http://www.news-medical.net/health/What-is-Tamoxifen.aspx) is superior to fulvestrant in blocking estrogen (http://www.news-medical.net/health/Estrogen-What-is-Estrogen.aspx).

This begs the question regarding Fulvestrant's ability to often work after Tamoxifen doesn't. Must be more to situation than estrogen.

And it's also supportive of a few oncologist's use of AI along with SERMS like Tamoxifen or Fulvestrant.

[Becky]

Perhaps some of the studies of Tamoxifen versus Arimidex (where the Arimidex is deemed better) stems from the fact that a certain percentage of the population does not respond to Tamoxifen. So if they test responders versus Arimidex - I wonder if the results would be the same?

[Becky]

Okay - I read the full study elsewhere. In the study, they were studying estrogen blocking more than estrogen depleting. They gave patients radioactive estrogen and then scanned them. Of course an AI would do more poorly because an AI prevents the synthesis of estrogen in the body and the researchers were giving estrogen. However, it is a good study in relation to which drug blocks estrogen better.

It was difficult to comprehend that with all the studies on the 3 AIs, all concluding that an AI is better than Tamoxifen, that this study would say differently and the reason is the study gives estrogen so those taking an AI would of course have uptake since in theory, their bodies can't make estrogen.