Fulvestrant With or Without Lapatinib and/or Aromatase Inhibitor Therapy in Treating Postmenopausal Women With Metastatic Breast Cancer That Progressed After Previous Aromatase Inhibitor Therapy

DISEASE CHARACTERISTICS: * Histologically or cytologically confirmed breast cancer * Metastatic disease * Confirmed disease progression after treatment with an aromatase inhibitor (AI) administered in the adjuvant or metastatic setting * Must have demonstrated a prior response to AI therapy (i.e., responded after \> 2 years of treatment in the adjuvant setting OR complete or partial response or stable disease after ≥ 24 weeks of treatment in the metastatic setting) AND have subsequent disease progression after completion of AI therapy * Meets 1 of the following criteria: * Measurable disease, defined as ≥ 1 lesion that can be accurately measured in ≥ 1 dimension (longest diameter to be recorded) as ≥ 20 mm with conventional techniques or ≥ 10 mm with spiral CT scan * Evaluable disease, defined as bone lesions, lytic or mixed (lytic and sclerotic), evaluable by plain x-ray, CT scan, or MRI * Lesions identified only by radionucleotide bone scan are not allowed * No HER2/neu-overexpressing tumor (IHC 3+ or FISH+) * Hormone receptor status: * Estrogen receptor- and/or progesterone receptor-positive primary or metastatic tumor PATIENT CHARACTERISTICS: * Female * Postmenopausal, as defined by any of the following criteria: * At least 60 years of age * 45 to 59 years of age and meets ≥ 1 of the following criteria: * Amenorrhea for ≥ 12 months and intact uterus * Amenorrhea for \< 12 months and follicle-stimulating hormone within the postmenopausal range (including patients with hysterectomy, prior hormone replacement therapy, or chemotherapy-induced amenorrhea) * Patients who received prior luteinizing hormone-releasing hormone (LHRH) analogues must not have restarted their menses after cessation of therapy * Over 18 years of age and bilateral oophorectomy * WHO performance status 0-2 * Life expectancy ≥ 8 months * Leukocytes ≥ 3,000/μL * Absolute neutrophil count ≥ 1,500/μL * Platelet count ≥ 100,000/μL * Total bilirubin normal * AST/ALT ≤ 2.5 times upper limit of normal * Creatinine normal OR creatinine clearance ≥ 60 mL/min * LVEF normal as measured by ECHO or MUGA * Able to swallow and retain oral medication * No ulcerative colitis * No malabsorption syndrome or disease significantly affecting gastrointestinal function * No known history of uncontrolled or symptomatic angina, arrhythmias, or congestive heart failure * No known immediate or delayed hypersensitivity reaction or idiosyncrasy to drugs chemically related to fulvestrant, aromatase inhibitors, lapatinib tosylate, or excipients * No unresolved or unstable serious toxicity from prior therapy * No active or uncontrolled infection * No dementia, altered mental status, or any psychiatric condition that would prohibit the understanding or rendering of informed consent * No other malignancy within the past 5 years except for adequately treated cervical carcinoma in situ, melanoma in situ, or basal cell or squamous cell carcinoma of the skin * No other concurrent disease or condition that would make the patient inappropriate for study participation * No serious medical disorder that would interfere with patient safety PRIOR CONCURRENT THERAPY: * See Disease Characteristics * Prior radiotherapy for the primary or metastatic tumor allowed * More than 4 months since prior LHRH analogues * More than 30 days (or 5 half-lives, whichever is longer) since prior investigational agents * More than 14 days since prior and no concurrent CYP3A4 inducers\*, including any of the following: * Rifampin, rifapentine, rifabutin, or other rifamycin class agents * Phenytoin, carbamazepine, or barbiturates (e.g., phenobarbital) * Efavirenz or nevirapine * Oral glucocorticoids (e.g., cortisone \[\> 50 mg\], hydrocortisone \[\> 40 mg\], prednisone \[\> 10 mg\], methylprednisolone \[\> 8 mg\], or dexamethasone \[\> 1.5 mg\]) * Modafinil * More than 14 days since prior and no concurrent herbal or dietary supplements\*, including any of the following: * St. John's wort * Ginkgo biloba * Kava * Grape seed * Valerian * Ginseng * Echinacea * Evening primrose oil * More than 7 days since prior and no concurrent CYP3A4 inhibitors\*, including any of the following: * Clarithromycin, erythromycin, or troleandomycin * Itraconazole, ketoconazole, fluconazole (\> 150 mg daily), or voriconazole * Delaviridine, nelfinavir, amprenavir, ritonavir, indinavir, saquinavir, or lopinavir * Verapamil or diltiazem * Nefazodone or fluvoxamine * Cimetidine or aprepitant * Grapefruit or grapefruit juice * More than 6 months since prior and no concurrent amiodarone\* * No prior fulvestrant and/or lapatinib tosylate * No prior resection of the stomach or small bowel * No other concurrent anticancer therapy, including chemotherapy, immunotherapy, and biologic therapy * Concurrent bisphosphonates allowed * No other concurrent investigational therapy * No concurrent participation in another clinical trial NOTE: \*For patients randomized to receive lapatinib