Inclusion Criteria

Inclusion Criteria

- Female

- Post-menopausal hormone status defined as:

- Patients with menostasis (amenorrhea) > 12 months or history of oophorectomy.

- Patients ≥ 55 years with history of hysterectomy or having continued/renewed
menstruation on cyclic hormone treatment.

- Patients of 50-54 years: Menopausal status was determined on the basis of
follicle-stimulating hormone (FSH)/luteinizing hormone (LH) values.

- Histologically confirmed resected breast cancer and eligible for adjuvant endocrine
therapy. As a minimum, patients had to have receptor-positive tumors, which were
defined either as estrogen receptor (ER) and/or progesterone receptor (PgR) ≥ 10
fmol/mg cytosol protein; or ≥ 10% of the tumor cells positive by immunocytochemical
evaluation.

- Adequate bone marrow function (white blood cell count [WBC] > 3.0 x 109 /L, platelets
≥ 100.0 x 109 /L, and hemoglobin > 10 g/dL).

- Documented evidence of adequate renal function (creatinine < 180 µmol/L) and hepatic
function (bilirubin < 30 µmol/L, alanine aminotransferase (ALT) < 1.5 x upper normal
limit of the laboratory).

- Life expectancy of at least 24 months at the time of enrollment.

- Written voluntary informed consent prior to initiation of any study procedure.

- Willingness to undergo all scheduled tests and examinations for evaluation of bone
density and bone metabolism, and lipid profiles in addition to the standard
assessments for monitoring their breast cancer status.

Exclusion Criteria

- Patients with distant metastases as defined by the criteria of the Danish Breast
Cancer Co-operative Group (DBCCOG).

- Pre-existing bone disease (e.g. osteomalacia, osteogenesis imperfecta, Paget's
disease).

- Patients receiving bisphosphonates for more than 3 months before randomization.

- Chronic treatment with drugs known to interfere with bone metabolism, e.g.

- Anti-convulsants within the past year.

- Corticosteroids at doses greater than the equivalent of 5 mg/day prednisone for more
than two weeks in the past 6 months (prior to randomization).

- Any previous treatment with sodium fluoride at daily doses ≥ 5 mg/day for a period
exceeding 1 month.

- Anabolic steroids in the past 12 months.

- Long term use of coumarin derivatives and heparin at the time of randomization.

- Metabolic diseases known to interfere with bone metabolism (e.g.,
Hyperparathyroidism, hypoparathyroidism, uncontrolled thyroid disease, Cushing's
disease, vitamin D deficiency, malabsorption syndrome, etc.).

- Treatment with lipid-lowering agents within the 3 months prior to randomization (this
exclusion criterion did not apply to patients randomized in the United Kingdom).

- Patients receiving other anti-cancer treatment.

- Previous neoadjuvant / adjuvant chemotherapy and /or previous adjuvant endocrine
therapy (e.g., anti-estrogens, AIs).

- History of previous or concomitant malignancy within the past 5 years other than
adequately treated basal or squamous cell carcinoma of the skin or in situ carcinoma
of the cervix. Patients who had a previous other malignancy must have been disease
free for five years. Patients with endometrial cancer and/or invasive breast cancer
at any time in their medical history were excluded. Patients with invasive bilateral
breast cancer were excluded. Patients with vaginal discharge/ vaginal bleeding with
evidence of malignancy were excluded.

- Any other non-malignant systemic diseases (cardiovascular, renal, hepatic, lung
embolism, etc.) which would prevent prolonged follow-up.