In vivo animal studies suggest that exemestane may be more bone sparing than letrozole, owing to its androgenic structure [ 12,13 ]. However, there are no human trials showing a differential effect of the individual AIs on bone. The MA-27 trial compared exemestane and anastrozole as adjuvant therapy in postmenopausal women [ 14 ]. Clinical fracture data were collected as adverse events. Although self-reported new diagnoses of osteoporosis were significantly less frequent on exemestane than anastrozole, there was no difference in the number of new clinical fragility fractures between the two groups (4 percent in each group).
Aromatase inhibitors tend to cause fewer serious side effects than tamoxifen, such as blood clots, stroke, and endometrial cancer. But aromatase inhibitors can cause more heart problems , more bone loss ( osteoporosis ), and more broken bones than tamoxifen, at least for the first few years of treatment. If you and your doctor are considering an aromatase inhibitor as part of your treatment plan, you may want to ask your doctor about having a bone density test to see if a bone strengthening medicine might be necessary while you're taking the aromatase inhibitor.
In normal tissue, DIM (300nM) can activate the ATM genetic repair pathway in response to irradiation damage in a manner dependent on BRCA1 (one of its targets  ) without increasing survival of breast cancer cells (MDA-MB-231  ); there are known alterations in this pathway in some breast cancers where BRCA1 is reduced while ATM itself seems to be hyperactive, and oral supplementation of 300mg DIM has been noted to increase BRCA1 mRNA levels after 4-6 weeks supplementation (measured in white blood cells) in women who had a low activity mutation.