Early-stage breast cancer treatment
In a modified radical mastectomy (shown here), the axillary lymph nodes are also removed
At a glance
- Early-stage breast cancer is defined as a tumor measuring <2 cm with negative axillary lymph nodes.
- Factors that indicate lumpectomy over mastectomy include tumor size, location, number, and patient preference.
- Adjuvant treatment includes radiation therapy, chemotherapy, and/or endocrine (hormone-blocking) therapy.
- Aromatase inhibitors block the production of estrogen in such ancillary sites as fat cells and the adrenal glands.
Breast cancer is the leading cancer among women in the United States, the second most common cause of cancer death in women, and the main cause of death in women aged 40 to 59 years.1 Treatment is not straightforward or based on simple decision-making. A number of factors influence a provider's treatment decision and which path the patient ultimately chooses. This article explores the complexity of diagnosing early-stage breast cancer and the importance of understanding how this condition is defined to help make sense of the available therapeutic options. The goal is to describe the process from diagnosis to treatment planning in a clear, concise, and understandable way.
After a woman is diagnosed with breast cancer, she is typically referred to an oncologist, and oftentimes the primary-care provider (PCP) will not see the patient again until treatment is completed. Ideally, the PCP will be kept apprised of the patient's condition, treatment, and outcome through courtesy letters sent by the oncologist. However, these updates do not always explain how the treatment decision was reached, what the expectations of the treatment are, or what potential side effects the treatment entails. In an effort to close this gap, a better understanding from the PCP and patient perspective is essential.
Most breast abnormalities are detected by mammogram.2 However, an abnormal mammogram alone is not diagnostic. After an abnormality is found, the patient is referred for additional views and/or ultrasound-guided core-needle biopsy (CNB). The CNB is the preferred method over fine-needle aspiration (FNA), as it has several advantages, including histologic diagnosis.2 Knowing the histologic characteristics (type: ductal, lobular; grade: high, intermediate, low) is essential to the planning of surgery and treatment. Stereotactic CNB with a 14-gauge needle was shown to be a widely accepted method for diagnosing breast cancer effectively, with a sensitivity of 90.5% and specificity of 98.3%, compared with 62.4% and 86.9%, respectively, for FNA.3 CNB also can be used to detect in situ as well as invasive malignancy. In addition, the status of estrogen receptors in samples obtained via CNB can easily be ascertained.3
Early-stage breast cancer is defined as a tumor measuring <2 cm with negative axillary lymph nodes.2 The diagnosis is further broken down based on its pathology: Is it invasive (spread from the duct or lobule into surrounding, healthy tissue) or in situ (the cancer cells have begun to multiply but are confined inside the breast)? Is the cancer ductal or lobular? Ductal carcinoma is the most common breast cancer, accounting for approximately 75% of all cases.4
Once the type of breast cancer has been identified, testing for hormone receptor status is conducted on either the CNB specimen or tissue from the surgical excision of the tumor. This immunohistochemical assay will reveal the hormone status of the tumor: estrogen receptor (ER), negative or positive; and progesterone receptor (PR), negative or positive. Women with early-stage ER-positive breast cancer who receive no systemic therapy (hormone-blocking therapy or chemotherapy) after surgery have a 5%-10% lower risk of recurrence at five years than those who are ER-negative.5
Another component to decipher in the pathology of the breast tumor is the human epidermal growth factor receptor 2 (HER2/neu) oncogene status. HER2/neu oncogene is part of the epidermal growth factor receptor family, which stimulates the subcellular pathways that control epithelial cell growth and differentiation, resulting in control of the number of copies of the gene produced.2 Overexpression of HER2/neu causes the tumor to be more aggressive and grow at a faster rate.2 The rating of the HER2/neu oncogene on a pathology report reads 1+, 2+, or 3+. A negative result is 1+; and positive, or overexpressed, is reflected at 3+. The intermediate is a 2+, which requires an additional test called a fluorescent in situ hybridization (FISH) assay.2 If the FISH is positive, HER2/neu is considered overexpressed.2