Breast Cancer Screening and Diagnosis

Screening tools commonly used include the patient’s history, self and physician exam, mammography and ultrasound.
Mammogram recommendations:
1. Baseline mammograms are recommended in the United States at age 35.
2. Every year beginning at age 40.
3. In high risk patients, mammograms are recommended 5 years prior to the first case of breast cancer in the close family.

Limitations in mammography are secondary to dense breast tissue overlying lesions frequently seen in women <30 years old and older women on hormone replacement. Mammogram is associated with a false negative rate of 10-15%. This false negative rate is increased to 25% in women less than 40 years old.

The benefit of mammogram is the detection of lesions that are not yet palpable. Screening by mammogram can detect groups of microcalcifications that indicate ductal carcinoma in situ (DCIS). If the microcalcifications are linear or ductal, this indicates comedo type which has a worse prognosis. If they are sand-like, then cribiform or papillary is more common. These latter two have a better prognosis. This allows mammogram to detect cancer prior to invasion.

Ultrasound is also used to determine if a palpable lesion is cystic or solid. Benign lesions are very circumscribed. Malignant lesions are asymmetric with a lesion that is taller than it is wide and with irregular borders. Malignant lesions are hypoechoic and have posterior shadows. This technology is very helpful in women with dense breasts. The limitation with ultrasound is that microcalcifications are not viewed. Another limitation is that the technique is operator dependent and time consuming. Some cancers are visualized on ultrasound that are not seen on mammogram.

MRI is not used as a screening tool, but is used to determine recurrence vs. scar in lumpectomy patients. Recurrences have increased vascularity as seen on MRI.

Diagnosis
Stereotactic Biopsy
New biopsy techniques involve what is termed as minimally invasive management. This either uses stereotactic or ultrasound guided biopsy.3 Stereotactic machines biopsy microcalcifications or a nonpalpable mass on a geometric X, Y, and Z axis.4 Core biopsies are obtained by at least a 14 gauge needle. At least five cores are needed to perform an adequate tissue sample.5 A clip is usually placed at the biopsy site for future imaging and possible therapy.

Limitations with this technique include a lesion close to the skin or nipple or a patient with small breasts or a patient that is uncooperative. A very important point with stereotactic biopsy is that a diagnosis of atypia or DCIS cannot be made.6 This lesion needs to be openly excised to check for invasion.

An older option of diagnosis of nonpalpable lesion is needle localization by mammogram or ultrasound. The tissue removed should be sent to radiology or pathology to confirm removal of the lesion. This, however, requires an operative procedure and is more disfiguring to the breast.

Metastasis
Metastatic spread is by different pathways. The main metastatic area is to the ipsilateral axillary nodes as it drains 75% of the breast. Parasternal nodes drain the medial 25% of the breast. Vascular spread sends metastasis to the lungs, brain, and spine.
Preoperative evaluation includes:
1. LFT to check liver involvement
2. CXR to check for lung mets
3. Abdominal CT is performed if the LFTs are elevated
4. Bone scan is performed if there is elevated calcium or the patient has bone pain

If patients have metastatic disease to the bone, they may present with hypercalcemia. The treatment of this involves hydration, a loop diuretic like Lasix, and a long term biphosphonate (pamidronate) IV. If the patient presents with metastatic disease, no surgery is preformed and comfort measures only are invoked. If spinal cord compression syndromes present then dexamethasone is given and the patient may require spinal stabilization.