Inclusion Criteria

Inclusion

- Patients with histologically proven DCIS or stage I-III invasive carcinoma of the
breast that is estrogen and/or progesterone receptor positive by immunohistochemical
staining who are considering aromatase inhibitor therapy; women may receive the AI on
this study as initial adjuvant hormonal treatment or following tamoxifen; patients
must have completed any adjuvant chemotherapy; patients may have received
preoperative chemotherapy

- Postmenopausal status, defined as: >= 60 years of age; or < 60 years of age and
amenorrheic for >= 12 months prior to day 1 if intact uterus/ovaries; or < 60 years
of age, and the last menstrual period 6-12 months prior to day 1, if intact
uterus/ovaries and meets biochemical criteria for menopause (FSH and estradiol within
institutional standards for postmenopausal status); or < 60 years of age, without a
uterus, and meets biochemical criteria for menopause (FSH and estradiol within
institutional standards for postmenopausal status); or < 60 years of age and history
of bilateral oophorectomy; or prior radiation castration with amenorrhea for at least
6 months; < 60 years of age and taking medication designed to suppress ovarian
function and meets biochemical criteria for menopause (estradiol levels within
institutional standards for postmenopausal status; women would have had to be taking
the drug for at least 30 days prior to day 1)

- ECOG performance status 0-2

- Patient is aware of the nature of her diagnosis, understands the study regimen, its
requirements, risks, and discomforts, and is able and willing to sign an informed
consent form

Exclusion

- Concurrent use of hormone replacement therapy

- Concurrent use of tamoxifen; patients taking tamoxifen must discontinue the drug
prior to first dose of zoledronic acid

- Concurrent use of other selective estrogen receptor modulator (SERM) such as
raloxifene

- Concurrent consumption of soy supplements; routine dietary consumption of soy
containing foods will be permitted

- Prior use of an aromatase inhibitor in any setting

- Current bisphosphonate use (oral or intravenous); prior bisphosphonate users would be
eligible as long as the use was > 1 month ago for oral bisphosphonates and/or > 12
months ago for intravenous bisphosphonates, prior to starting study treatment

- Moderate to severe renal impairment (serum creatinine greater than 2 mg/dL or
creatinine clearance less than 50 mL/min)

- Hypersensitivity to letrozole or zoledronic acid or any of its excipients

- Concomitant treatment with oral or intravenous corticosteroids

- Current active dental problems including infection or the teeth or jawbone (maxilla
or mandibular); dental or fixture trauma, or a current or prior diagnosis of
osteonecrosis of the jaw (ONJ), of exposed bone in the mouth, or of slow healing
after dental procedures

- Recent (within 6 weeks) or planned dental or jaw surgery (e.g. extraction, implants)