Arimidex vs Femara

Hi Debisongird,

Letrozole is a very powerful hormonal agent, and its choice in light of your node status might make a lot of sense. It is known to lower one's estrogen the deepest (estrogen being what ER+cells appear to thrive on), but just being lowest in estrogen in and of itself is not clearly associated with increased survival. Letrozole has been shown to be associated with a slightly higher (we're talking very small percentage point) distant disease free state. Because Letrozole cuts circulating estrogen so, our bones are more likely to break than with the other AI's, Arimidex and Aromasin. For this as well as the suggestion that IV Zometa may lower metastasis, infusion of this powerful bisphosphonate is also recommended. Your doctor and you would need to pick a schedule which seems appropriate, be it monthly, q 3 month or every 6 month (4 mg Zometa). There are fancy blood and urine bone metabolism tests which can be run to suggest the Zometa is helping, but outside of Universities or other clinical trial sites, I don't see many run.

I have been on both Arimidex (5 years) and Femara (1 year). I do note the muscle/bone/joint pain on both. I have noted Femara causes worse vaginal dryness, altering the ph and status there significantly. Just trying to keep the tissue moist and intact is more of a job than when on Arimidex.

It's such a personal choice. No matter which AI you choose, it may be good to have your blood tested (by a GOOD reference lab, able to look for small estrogen amounts in frozen blood) four weeks or so after you start. From what I've read, and in contradistinction to what I wrote about does the value matter, most oncologists like to see a persons serum estradiol below 10 micrograms/ml, and preferably about 7 or so. Maybe others will help out here. On Arimidex my values were 22 micrograms/ml, which in retrospect were somewhat high. No wonder then I feel the change from Letrozole dropping my estrogen even lower.

 Weight fluctuations, specifically gains, are ideally avoided in ER+ breast cancers. Fat is one place where estrogen can be metabolized from testosterone, and at some point of weight gain as well as via other mechanisms (insulin and fatty acids), pose a risk where AI's alone don't do the trick.

 Lastly, I did have post mastectomy radiation, including the collarbone area but not the internal mammary node area (by the chest bone). I do not have any SE's up in my collarbone area. You may wish to discuss with your radiation oncologist if they will be including the internal mammary nodal basin, which is often included with greater than 4 nodes and central breast tumor location.

Good luck to you and post as you think of more questions. My best to you and yours,

Tender 

Hi debisongbird,

Oh, I did do a run on of Femara/Arimidex into Zometa, didn't I? Sorry. I tend to think of using the drugs as a dynamic duo; the AI's to lower your body's estrogen (given an estrogen sensitive breast cancer) and the Zometa (an intravenous bisphosphonate) to integrate with our bones and effectively stop calcium loss. So I refer to them in tandem, or hand in hand. Most women and men on a bone calcium leaching hormonal, are made aware of bisphosphonates (there are both oral and intravenous ((Aredia)).

 As to which aromatase inhibitor (AI) may cause you the least distress, every person reacts differently to Arimidex and Femara. My personal feeling is my body reflects that extra drop in estrogen when switched from Armidex to Femara. I'm more sore (muscles/bones/joints), more cognitively slow, more fatigued, and more dry. Plus dizzy. But again, one person's report is typically different from another. I would say I was less distressed on Arimidex, but jmo.

Wishing you well, you're asking great questions!

Tender