Breast Biopsy

Breast Biopsy The diagnosis of breast cancer depends ultimately on examination of tissue removed by biopsy. Treatment should never be undertaken without an unequivocal histologic diagnosis of cancer. The safest course is biopsy examination of all suspicious masses found on physical examination and, in the absence of a mass, of suspicious lesions demonstrated by mammography. Approximately 30% of lesions thought to be definitely cancer prove on biopsy to be benign, and approximately 15% of lesions believed to be benign are found to be malignant. These findings demonstrate the fallibility of clinical judgment and the necessity for biopsy. The simplest method is needle biopsy, either by fine-needle aspiration (FNA) of tumor cells or by obtaining a small core of tissue with a stereotactic core-needle biopsy. A negative FNA should be followed by open biopsy because false-negative needle biopsies may occur in 10% of cancers. The definitive diagnostic method is open biopsy under local anesthesia as a separate procedure prior to deciding on treatment. Palpable masses are readily evaluated by a general surgeon. With the aid of diagnostic radiology, a nonpalpable, radiographically detected mass may be biopsied with the use of needle localization. The patient need not be admitted to the hospital. Decisions on additional work-up for metastatic disease and on definitive therapy can be made and discussed with the patient after the histologic diagnosis of cancer is established. This approach has the advantage of avoiding unnecessary hospitalization and diagnostic procedures in many patients as cancer is found in the minority of patients who require biopsy for diagnosis of a breast lump. In general, outpatient biopsy followed by definitive surgery at a later date gives patients time to adjust to the diagnosis of cancer, meet with members of the multidisciplinary team involved with managing breast cancer, and consider a second opinion, as well as alternative forms of treatment. Studies show no adverse effects from the short (1–2 weeks) delay of the two-step procedure, and this is the current recommendation of the NCI. At the time of the initial biopsy of breast cancer, it is important for the physician to preserve a portion of the specimen for immunohistochemical staining for hormone and growth factor (eg, HER-2-Neu) receptors. Tumor analysis using reverse transcriptase polymerase chain reaction (RT-PCR) technology from pathologic specimens to assess the tumor recurrence risk is now available. Such tests can aid the patient and physician in the decision for further adjuvant therapy or not. At the time of pathologic confirmation of a breast cancer diagnosis, patients on hormone replacement therapy (HRT) should be instructed to stop hormone use until counseled by an oncologist.