Had lumpectomy & SNB for classic ILC w/associated LCIS in left axillary tail; nodes negative, >.2cm clear margins, mBR grade 1 (well-differentiated), stage T1b, ER+, PR+, HER 2 -, Oncotype DX RS = 9; having radiation next week (APBI). Weight 106 lbs., 5'4" tall. Medical oncologist recommending Arimidex after radiation treatment. Should dosage of Arimidex be titrated for weight and current level of circulating hormones? Age 57, postmenopausal; BMI very low, virtually no adipose tissue. Logic would seem to dictate that a 106 lb. woman should not get same dosage as 200+ lb. woman.