Once breast tissue has been obtained through biopsy or surgical removal, a pathologist analyzes the sample to confirm a cancer diagnosis and determine tumor characteristics. The pathology report enables the physician care team to design an individualized treatment plan.
Extensive experience in breast pathology is a critical factor in the ability to identify rare breast cancers as well as cancers that mimic benign conditions. The Breast Cancer Program includes two pathologists who specialize in evaluating and diagnosing breast abnormalities.
Core Biopsy Analysis
A core biopsy is a small sample of abnormal breast tissue obtained by a radiologist during an image-guided needle procedure. A breast pathologist analyzes the core sample to determine whether the abnormality is benign or malignant and gain an initial understanding of tumor characteristics. The outcome of the core biopsy report often determines whether or not a tumor needs to be surgically removed.
Sentinel Lymph Node Biopsy
Breast cancer surgery may include the removal of the lymph nodes of the armpit (the axillary lymph nodes). This is often critical to controlling the cancer, but it can lead to other health problems. Sentinel lymph node (SLN) mapping is a technique that can allow breast cancer patients to undergo an appropriate axillary surgery without having a large portion of the lymphatic system removed.
A pathologist is on call during all breast surgeries that will include SLN mapping. Before the breast tumor is removed, the surgeon excises a small number of axillary lymph nodes that are most at risk for cancer spread. The node samples are sent immediately to pathology for frozen section analysis, and the pathologist provides a diagnosis while the patient is still under anesthesia. If the sentinel nodes do not contain cancer cells on frozen section (pathology), the patient may not require any further node dissection, depending on the results of the final pathology report.
Post-Surgery Tumor Pathology
Once a breast tumor has been surgically removed, it is sent to the lab for a complete pathological analysis. The pathologist determines the type and grade of the tumor (including how fast it is multiplying) and verifies that the margins of the excised tissue are clear of cancer cells (an important indication that no cancer has been left behind). The pathologist also assigns the stage of the cancer, which is based on tumor size and the extent of any spread to other parts of the body. Any additional lymph nodes taken out during the surgery are evaluated. In the case of a mastectomy, the pathologist also examines other tissues that have been removed.
Tumor Gene Profiling
Medical oncologists are increasingly able to tailor drug therapies to the genetic characteristics of the patient’s individual breast tumor. By identifying certain genes that are present at higher levels within the tumor cells, physicians can ascertain how the tumor might behave and what drugs might be beneficial in fighting the cancer.
Pathologists in the Breast Cancer Program regularly test biopsy and surgical samples for HER2 and hormone receptor genes. Multi-gene assays such as Oncotype DX are also used.