The majority of breast cancers are now found during routine screenings. The decrease in deaths from breast cancer is at least partially related to this. It is therefore critical to understand the recommended screening tests for breast cancer.
Screening for breast cancer is a triad of tests, which includes breast self-exam, exam by a healthcare provider (e.g., physician, nurse practitioner, physician assistant), and mammography. The American Cancer Society recommends the following:
- Breast self-exam: Monthly starting at age 20
- Physical exam by a healthcare provider: Annually starting at age 20
- Mammography: Annually starting at age 40 (with a baseline between age 35 and 40)
ANY suspicious mass found on physical exam or mammography should be biopsied using a fine needle aspiration (FNA). This is an outpatient procedure that requires only a local anesthetic. It should be stressed that suspicious masses should be biopsied in ALL AGES of women. Although the risk of breast cancer increases with age, clinicians and patients should not think that a woman is too young to have breast cancer. This may delay the diagnosis of a potentially curable cancer.
Abnormalities found on screening are generally one of four things:
- Atypical hyperplasia
- In situ (non-invasive) carcinoma
- Invasive carcinoma
The tests and staging described here are applicable to a diagnosis of invasive carcinoma.
Once the diagnosis of invasive breast cancer is confirmed by biopsy, the patient undergoes a wide variety of tests to evaluate the extent of disease, the prognosis for survival, and to establish baseline organ function prior to treatment. It is very important that experienced pathologists and laboratory personnel interpret the biopsy and subsequent surgical specimen and run the appropriate tests (particularly estrogen and progesterone receptor status and presence of HER2 over-expression). This allows clinicians to make an accurate assessment of recurrence risk and the potential effectiveness of available therapies.
The extent of breast cancer is determined by:
- Bilateral diagnostic mammograms
- Breast ultrasound, if mammography is inconclusive
- Breast MRI, if mammography and ultrasound are inconclusive
- CT scans of the chest, abdomen and pelvis, as well as bone scans, are only performed if the patient has symptoms of metastatic spread
- Surgical excision of the primary tumor (see Treatment Options)
- Sentinal lymph node biopsy, with or without axillary lymph node removal
Sentinel lymph node assessment involves taking a biopsy only from the first draining lymph node of the tumor bed, rather than performing an extensive axillary lymph node dissection. Sentinel node assessment is done using blue dye and a radioactive substance. The idea is that the status of the sentinel node reflects the status of all the axillary lymph nodes. Patients with a negative sentinel lymph node are spared some complications, especially lymphedema and sensory loss. Patients with a sentinel node positive for breast cancer undergo a more extensive axillary lymph node evaluation, to quantitate the number of positive lymph nodes.
Note that the use of PET scans in the work-up of breast cancer patients is not generally recommended. PET stands for positron emission tomography, with the imaging provided by cellular uptake of fluorine-18-fluorodeoxyglucose. Viable cancer cells are able to take up this sugar, while dead or fibrotic cells will not. Unfortunately in breast cancer, PET scans have high rates of false negatives and false positives. At this time, PET scans are only recommended if the results of CT scans are inconclusive.
Patient prognosis is determined by:
- Evaluation of performance status
- Histologic subtype of breast cancer (Infiltrating ductal is by far the most common, at 85 to 90%; Tubular and lobular have the best prognosis; Inflammatory breast cancer has the worst prognosis)
- Tumor grade of I, II, or III (I is a well differentiated tumor and the best prognosis)
- HER2 status (20 to 25% of patients have breast cancer that over-expresses HER2; This portends a much poorer prognosis)
- Estrogen (ER) and progesterone (PR) receptor status (ER/PR positive tumors have a better prognosis and are more common in post-menopausal women)
- Genetic counseling, if high risk for hereditary breast cancer
Baselines are established for the following:
- Complete blood count (Almost all chemotherapy causes bone marrow suppression)
- Serum electrolytes, including serum calcium
- Renal and liver function tests
- ECHO or MUGA to evaluate heart function (Many of the treatments for breast cancer can cause heart failure)