Mammographic signs of malignancy include stellate or dominant masses, architectural distortion, and skin or nipple thickening or retraction. Some types of microcalcifications are also associated with malignancy. The size, shape, number, density, and extent of microcalcifications help to determine the risk of a malignancy being present. Comparison to previous mammograms is essential. Additional coned or compression mammograms may be needed to define the calcifications.

It also is very important to discuss the findings with the radiologist. The American College of Radiology has proposed a classification system to help management decisions. Not all radiologists use this system, but consulting with the radiologist should help to classify the risk. If there is any doubt, obtain the opinion of a second radiologist (1).

One option is a needle localized breast biopsy (NLB). The radiologist places a long wire through the skin to the microcalcifications, using stereotactic guidance. During surgery, the wire is followed to the lesion; then a wide excision is done around the tip of the wire. To ensure that the microcalcifications are in the specimen, a radiograph of the specimen is taken. The procedure is complete only after the calcifications in the specimen are seen to be the same as those in the mammogram (2).

Sterotactic core biopsy (SCB) is quickly replacing NLB as the initial diagnostic modality for nonpalpable breast lesions. Stereotactic guidance is used to take tissue samples with large-gauge needles. Long-term follow-up of SCB shows that sensitivity and specificity is greater than 90% (3).

SCB has several advantages over NLB. It is less costly, allows for better cosmesis, is associated with a shorter recovery time, and, if the biopsy is positive, allows for optimal preparation of the patient and surgeon and a lower incidence of positive margins (4). Results from SCB must be concordant. In addition, some lesions such as atypical ductal hyperplasia and radial scar warrant NLB because there is an incidence of carcinoma in these patients that is not found due to the small sample size taken in SCB.

Almost 30% of breast neoplasms diagnosed by mammography are DCIS, a precancerous lesion characterized by malignant cells in the ducts but showing no evidence of invasion through the basement membrane. However, these lesions may progress to invade the basement membrane. It is thought that if untreated, 20% to 30% of these patients develop invasive ductal carcinoma. This is a demanding diagnosis for the pathologist. As high as 10% of these lesions may be reclassified as benign or malignant on review by a second pathologist (5).

The patient has two options: total mastectomy (removal of the breast with preservation of underlying musculature) or lumpectomy with radiation. Total mastectomy is associated with a cure rate of approximately 98% to 99%. Lumpectomy with clear margins and adjuvant radiotherapy has shown to have approximately 5% to 8% recurrence rate. The National Surgical Adjuvant Breast and Bowel Project (NSABP) B-17 randomized women to radiation or observation only after lumpectomy (6). There was no difference in survival between the two groups. Addition of radiation resulted in a statistically significant difference in local recurrence. Generally, adjuvant radiotherapy is recommended for all patients after lumpectomy.

Without further treatment, 2.6% of cases of DCIS recur per year; 50% of these recurrences are invasive. Death among patients with recurrent DCIS is very unusual. As for the role of axillary node dissection, less than 1% of axillary node dissections performed for DCIS show metastatic disease. Obviously, in these cases, an area of invasion was not seen by the pathologist. Axillary node dissection is not recommended for the treatment of patients with DCIS. Counsel the patient about the use of tamoxifen. NSABP B-24 showed that the addition of tamoxifen to women treated with lumpectomy and radiation reduced breast cancer events at 5 years (8.2% vs. 13.4%) (7).

Breast cancer is a disease of aging. The risk of developing breast cancer between the ages of 20 and 30 years is 0.04%. The risk of developing breast cancer between the ages of 65 and 75 years is 3.2%. A woman who lives 110 years has a 10% risk of developing breast cancer. Therefore, as a woman ages, the likelihood of a new breast mass being cancer increases. This means that the differential diagnosis varies among age groups. For women older than 50 years, this mass should be considered a malignancy until proven otherwise. It also may be fibrocystic change (especially if she is taking hormone replacement therapy) or fat necrosis (8).

A diagnostic mammogram would be useful. This provides more information about the characteristics of the mass and any other suspicious lesions, and it allows evaluation of the contralateral breast.

“A suspicious lump is a suspicious lump” until there is a histologic diagnosis. Mammograms miss 10% to 15% of cancers. Options for obtaining tissue for diagnosis are a fine-needle aspiration biopsy (FNAB), a core biopsy, and an open biopsy. FNAB is an excellent first test. Interpreting the result requires a pathologist skilled in cytology. The final pathology should provide a reasonable explanation for the mass and be concordant with the mammogram and clinical examination.

At this point there still is no diagnosis. It is now time to perform a core or open biopsy. I prefer a core biopsy in this clinical scenario because the level of suspicion is high. Core biopsy can be done in the office, and it allows for further decision making to be done when the pathology is available. This reduces cost, reduces time, and most importantly allows the patient to adequately prepare. In addition, potentially there may be one operation instead of two or more.

Axillary staging is performed to provide the clinician with prognostic information and for local control. The role of formal axillary dissection has come into question since the late 1990s. The reasons are multifactorial. Chemotherapy is offered to many patients, regardless of nodal status. Unless high-dose chemotherapy is better for high-risk patients, the number of positive nodes is not important. Increased use of mammography has resulted in finding more lymph node-negative cancers and in sentinel node mapping and biopsy. In addition, there is a small but real morbidity associated with axillary dissection including lymphedema, loss of range of motion, seroma, and nerve damage.

The sentinel lymph node (SLN) concept initially was used widely for melanoma (10). The technology has been subsequently applied to breast cancer (11). The SLN is the first node to receive lymphatic drainage from a primary tumor. Thus, it is the first node to which a tumor will metastasize. If the SLN is negative for metastatic disease, the remaining nodes in the lymphatic basin are also likely to be negative. The ability to detect a SLN is greater than 90% (12) in experienced hands. The false-negative rate is variable but has been reported to be from 5% to 15%. A study by Guiliano (11) showed no axillary recurrences in patients with early breast cancer. There are two large multicenter trials led by the American College of Surgeons Oncology Group and NSABP that will help substantiate other single institution studies in the literature and provide long-term follow-up.