Femara (letrozole) is an aromatase inhibitor that works by suppressing the production of estrogen. In postmenopausal women estrogen is still produced in the body by the adrenal gland. Decreasing this production is a way of decreasing the risk of recurrence.

Tamoxifen on the other hand works by blocking the estrogen receptors on the cancer cell itself resulting in slower growth of the cell or cell death. Tamoxifen can be given to post or premenopausal women but Femara would only be prescribed to women that are postmenopausal. The reason being, is that a premenopausal women will still have estrogen produced by the ovaries. Femara would not be effective in this instance.

A Phase III clinical trial that is ongoing shows preliminary results that Femara is superior than Tamoxifen in women with early stage disease that are postmenopausal. The results of the study were published in the Annals of Oncology.

It's an unsettling journey -- the pursuit of the five-year cancer survival mark. Some say each year of cancer survival makes the future more of a sure thing. And so surviving five years -- the traditional landmark of real remission -- is a big accomplishment. But then there's the perspective of numbers that for me say I have a 93 percent chance of surviving breast cancer for five years. After that, though, there's no telling what will happen. So I am eagerly awaiting the moment when I cross the five-year finish line as I anxiously realize this very same moment may also signal a more dismal outlook.

The paradox hit me straight in the face yesterday as I was waiting for my radiation oncologist to give me another six-month all clear announcement. I was reading the January/February 2007 issue of Coping magazine while I waited. And as I flipped through the pages, I landed right at these words:

Studies show that half of all breast cancer recurrences occur after completion of five years of standard tamoxifen therapy. Additionally, a third of women with estrogen receptor-positive early breast cancer experience a recurrence, and more of half of these recurrences occur more than five years after surgery.

Now this doesn't apply directly to me. My breast cancer was estrogen receptor-negative which makes me a non-candidate for tamoxifen. And this is what scares me. My tumor was aggressive and while my treatment was also aggressive, I don't get the extra five-year protection from hormone therapy. If women taking this drug can have recurrences after completing the therapy, I wonder what's in store for me having not had it.

Maybe I'm making comparisons that don't amount to any real conclusions. Perhaps my type of disease allows for a more secure future. Or perhaps it places me on shaky ground. I don't know for sure. And I don't think I'll dive any deeper into research than I already have. Instead, I will live for today -- while enjoying the announcement my oncologist shared with me yesterday. All clear!