OC12. Specific inhibition of the VEGF homolog placental growth factor is protective against osteolytic bone metastasis in mice

cer receiving anastrozole 1 mg/day versus placebo for 5 years. Out of 1940 women recruited to date in the prevention study, 753 women took part in the bone substudy. Lumbar spine and total hip BMD were assessed at baseline and 1 year by DXA scans for 350 women at the time of analysis. Out of 350 women, 227 with normal T-score joined stratum-I and received only monitoring with DXA scan, 80 osteopenic women joined stratum-II and were further randomised to receive either risedronate or placebo, 43 osteoporotic women joined stratum-III of the study and all received treatment with risedronate. Results: In stratum-I, a greater BMD loss was observed in the anastrozole versus placebo group at both the lumbar spine ( 2.3% versus 0.80%; P = .006), and total hip ( 0.91% versus 0.73%; P = 0.67). In stratum-II, women randomised to risedronate had higher BMD scores both in the anastrozole and in the placebo arm. The BMD changes were (risedronate versus non-risedronate group; Spine 0.5% versus 1.0 %, P = 0.23, hip 0.30% versus 2.1%, P = 0.07) in the anastrozole arm, and (spine 0.65% versus 0.07%, P = 0.45; hip 1.3% versus 1.1%, P = 0.03) in the placebo arm. In stratum-III, the BMD changes observed were (spine 2.1% versus 3.5%, P = 0.24; hip 0.88% versus 1.2%, P = 0.64) in the anastrozole and placebo group, respectively. Discussion: Women with normal BMD at baseline had a significant BMD loss with anastrozole treatment. However, women on anastrozole, who had osteopenic or osteoporotic T-score, gained BMD after receiving risedronate treatment for a year. This data confirm the BMD losses observed with third generation AIs on breast cancer patients, but it is also reassuring that BMD loss can be controlled if women receive DXA scans at baseline and bisphosphonate treatment as needed along with AIs. This data will be further updated at the time of the meeting.