PhII Neo-Adjuvant Letrozole & Lapatinib in Pts w/HER2+ & Hormone Receptor+ Operable Breast CA SPORE

DISEASE CHARACTERISTICS:

Inclusion Criteria:

* Clinical stage I, II, or III operable invasive mammary carcinoma, confirmed by histological analysis

  * Measurable residual tumor at the primary site

    * Measurable disease is defined as any mass that can be reproducibly measured by physical examination, mammogram, and/or ultrasound and can be accurately measured in at least one dimension (longest diameter to be recorded) as 10 mm (1 cm)
* Available core biopsies from the time of diagnosis

  * May include sections of paraffin-embedded material
* Scheduled to undergo surgical treatment with either segmental resection or total mastectomy
* Prior history of contralateral breast cancer allowed if patient has no evidence of recurrence of their initial primary breast cancer within the last 5 years
* HER2-positive by Herceptest (3+) or FISH
* ER-positive and/or PR-positive by IHC

Exclusion Criteria:

* Locally recurrent breast cancer
* Evidence of distant metastatic disease (i.e., lung, liver, bone, or brain metastases)

PATIENT CHARACTERISTICS:

Inclusion Criteria:

* Female
* Postmenopausal, as defined by any of the following:

  * At least 55 years of age
  * Under 55 years of age and amenorrheic for at least 12 months OR follicle-stimulating hormone (FSH) values ≥ 40 IU/L and estradiol levels ≤ 20 IU/L
  * Prior bilateral oophorectomy or prior radiation castration with amenorrhea for at least 6 months
* ECOG performance status 0-1
* ANC ≥ 1,000/mm³
* Platelet count ≥ 100,000/mm³
* Creatinine ≤ 1.5 times upper limit of normal (ULN)
* Bilirubin ≤ 1.5 times ULN
* AST and ALT ≤ 1.5 times ULN
* Able to swallow and retain oral medication
* Cardiac ejection fraction normal by echocardiogram (or MUGA scan if an echocardiogram cannot be performed or is inconclusive)

Exclusion Criteria:

* Premenopausal breast cancer, pregnant, or lactating
* Serious medical illness, that in the judgment of the treating physician, places the patient at high risk of operative mortality
* Malabsorption syndrome, disease significantly affecting gastrointestinal function, or resection of the stomach or small bowel
* Ulcerative colitis
* History of other malignancy

  * Patients who have been disease-free for 5 years, or patients with a history of completely resected non-melanoma skin cancer or successfully treated in situ carcinomas are eligible
* Active or uncontrolled infection
* Dementia, altered mental status, or any psychiatric condition that would prohibit the understanding or rendering of informed consent
* Known history of uncontrolled or symptomatic angina, arrhythmias, or congestive heart failure

PRIOR CONCURRENT THERAPY:

Exclusion Criteria:

* Prior chemotherapy for primary breast cancer
* Tamoxifen or raloxifene as a preventive agent within the past 21 days
* Hormone replacement therapy (e.g., conjugated estrogens tablets \[Premarin\]) within the past month
* Prior therapy with anthracyclines
* Investigational drug within the past 30 days or 5 half-lives, whichever is longer
* Concurrent anti-cancer therapy (chemotherapy, radiation therapy, surgery, immunotherapy, hormonal therapy, or any other biologic therapy) other than letrozole
* Concurrent treatment with an investigational agent