Lovastatin in Reducing Side Effects After Radiation Therapy in Women With Breast Cancer

DISEASE CHARACTERISTICS: * Diagnosis of invasive or in situ epithelial cancer of the breast * Stage 0, I, or II (Tis, T1, or T2) disease * Unifocal disease (single focus that can be encompassed by breast-conserving surgery) * Has undergone prior surgical resection of the primary lesion (lumpectomy) and axillary nodal evaluation (if invasive disease is present) * Negative surgical margins (≥ 1 mm) * Planning to undergo radiotherapy with either standard external beam radiotherapy or accelerated partial breast irradiation (interstitial or balloon brachytherapy) * No Paget disease of the nipple * No evidence of distant metastases * Hormone receptor status not specified PATIENT CHARACTERISTICS: * Menopausal status not specified * Karnofsky performance status 70-100% * Transaminases \< 3 times upper limit of normal (ULN) * Creatine kinase \< 5 times ULN * Creatinine clearance ≥ 30 mL/min * Negative pregnancy test * No active liver or muscle disease * No history of collagen vascular disease (e.g., systemic lupus erythematosus, scleroderma, or dermatomyositis) * History of prior malignancy allowed provided life expectancy is ≥ 4 years * No major medical or psychiatric illness that, in the investigator's opinion, would prevent completion of study treatment or interfere with follow-up * No contraindication to an HMG-coA-reductase inhibitor PRIOR CONCURRENT THERAPY: * See Disease Characteristics * No prior radiotherapy to the breast, lung, or mediastinum * Prior radiotherapy to the contralateral breast allowed * No chemotherapy for ≥ 2 weeks prior to, during, and for ≥ 2 weeks after completion of radiotherapy * No concurrent cytochrome P450 3A4 inhibitors * Concurrent HMG-coA-reductase inhibitor allowed provided patient is able to switch to 20 mg of lovastatin per day * Concurrent tamoxifen or an aromatase inhibitor allowed