Fulvestrant With or Without AZD6244 in Treating Patients With Advanced Breast Cancer That Progressed After Aromatase Inhibitor Therapy

DISEASE CHARACTERISTICS: * Histologically or cytologically confirmed breast cancer * Not amenable to curative therapy * HER-2 positive disease allowed * Disease relapse or progression after aromatase inhibitor as adjuvant therapy or for advanced stage disease * Bilateral breast cancer allowed provided tumor endocrine sensitivity has been proven on both sides * Measurable disease according to RECIST criteria v1.1 or other lesions assessable by radiological exams (i.e., bone-only disease or small but unequivocal liver or lung metastases) * Received no more than 1 line of chemotherapy for advanced stage disease * Estrogen receptor- and/or progesterone receptor-positive (≥ 10% tumor cells positive by immunohistochemistry or ≥ 10 fmol/mg cytosol protein by ligand binding assay) * No known CNS metastases * Patients with brain metastases treated with radiotherapy and without any sign of brain progression after ≥ 3 months since the end of radiotherapy may be considered eligible after trial chair approval) PATIENT CHARACTERISTICS: * WHO performance status 0-2 * Postmenopausal * Hemoglobin ≥ 90 g/L * Platelet count ≥ 100 x 10\^9/L * Absolute neutrophil count ≥ 1.5 x 10\^9/L * Creatinine clearance ≥ 30 mL/min * ALT ≤ 2.5 times upper limit of normal (ULN) (≤ 5 times ULN in patients with liver metastases) * Bilirubin ≤ 1.5 times ULN * INR \< 1.6 * PTT normal * LVEF ≥ 50% * Able to swallow AZD6244/placebo capsules * Capable of understanding information given by the investigator on the trial * Must adhere to and be geographically proximal to allow for proper staging, treatment, and follow up * No contraindication for intramuscular injections * No bleeding diathesis * No current or prior malignancy other than breast cancer within the past 5 years, except carcinoma in situ of the cervix or basal cell carcinoma of the skin treated curatively * No serious underlying medical condition that, in the judgment of the investigator, would impair the ability of the patient to participate in the trial (e.g., active autoimmune disease or uncontrolled diabetes) * No refractory nausea and vomiting, chronic gastrointestinal disease (e.g., inflammatory bowel disease), or significant bowel resection that preclude adequate absorption * No psychiatric disorder precluding understanding of information on trial-related topics, giving informed consent, or interfering with adherence for oral drug intake * No uncontrolled hypertension (systolic BP \> 150 mm Hg and/or diastolic BP \> 100 mm Hg, measured repeatedly at more than two visits despite adequate treatment with at least two different antihypertensive drugs) * No clinically significant (i.e., active) cardiovascular disease, including any of the following: * Cerebrovascular accident/stroke or myocardial infarction within the past 6 months * Unstable angina * NYHA class III-IV congestive heart failure * Serious cardiac arrhythmia or AV-block \> 1, requiring medication during the trial and which might interfere with regularity of the trial treatment, or not controlled by medication * No known hypersensitivity to trial drugs or any other component of the trial drugs PRIOR CONCURRENT THERAPY: * See Disease Characteristics * At least 30 days since other prior experimental drugs or participation in another clinical trial * No prior fulvestrant, AZD6244, MEK inhibitors, RAF inhibitors, or endocrine therapies other than aromatase inhibitors (e.g., anastrazole, letrozole, or exemestane) or tamoxifen * No more than 1 line of aromatase inhibitors (steroidal and nonsteroidal aromatase inhibitors are considered two different lines) * No concurrent full-dose anticoagulation therapy (e.g., low molecular weight heparin, acenocoumarol, phenprocoumon, or analogues) * Prophylactic doses of anticoagulation or antiplatelet may be allowed * No concurrent radiotherapy * No other concurrent anticancer therapy or experimental drugs * Concurrent bisphosphonate allowed provided the investigator rules out tumor progression