September 4, 2003
While a diagnosis of breast cancer is almost always shocking, not all breast cancers behave in the same way. In an effort to provide the best possible plan of attack, cancer specialists perform a series of tests to classify breast tumors into stages. This information determines the extent of the cancer and is used to guide treatment decisions. While early-stage disease refers to those cancers that are still contained within the breast or have not spread very far, later-stage breast cancers may have advanced to other parts of the body.
Below, Dr. D. Lawrence Wickerham, associate chairman of the National Surgical Adjuvant Breast and Bowel Project (NSABP) and an associate professor of human oncology at Drexel University College of Medicine in Pittsburgh, explains how staging is assessed and what it means in terms of long-term treatment planning.
What are the stages of breast cancer?
Breast cancer stage is a method that we can use to describe how advanced a particular cancer is. The earliest invasive breast cancers are stage I, where the cancer is limited to the breast itself. Stage II is a little bit more advanced. It involves not only the breast, but some of the lymph nodes, primarily in the armpit. Stage III disease refers to larger cancers that are more advanced, but it isn't until stage IV, the most advanced stage, that the tumor spreads into other organs in the body.
Isn't there a stage earlier than stage I?
Actually, the earliest stage is stage 0. Twenty years ago, these noninvasive breast cancers, which are cancers that haven't yet developed the biological ability to spread to other organs, were a rare event. It occurred in approximately 2 percent to 3 percent of the breast cancers detected every year.
Now, 20 percent to 25 percent of the women who develop breast cancer in the United States will have these noninvasive breast cancers. The most common type of noninvasive breast cancer is ductal carcinoma in situ, which we abbreviate as DCIS. Ductal carcinoma in situ means that under the microscope, the duct tissue within the breast itself has the appearance of a breast cancer, but it hasn't spread outside of the ducts, the tubes within the breast. So it is in place, or in situ.
The other noninvasive breast cancer is lobular carcinoma in situ, or LCIS. Sometimes it's called lobular neoplasia. Lobular carcinoma in situ affects an area of the breast within the lobules, but it's the same idea. It's a breast cancer under the microscope, but remains in place within the lobule.
Why are these non-invasive breast cancer diagnoses becoming more common?
The reason noninvasive breast cancers have become more common, particularly DCIS, is the increasing use of screening mammograms, which are given to women who do not have symptoms of breast cancer. With mammograms, we can find these little specks of calcium within the breast that we call microcalcifications. They are a frequent occurrence in women with DCIS.
How are breast cancers staged?
Staging of breast cancer depends on a variety of components of the breast cancer, particularly the size of the breast cancer and its spread within the body. We use three separate components in what we call the TNM category of staging. The T refers to the size of the tumor, the N is whether or not lymph nodes in the armpit are involved and how many lymph nodes are involved, and M is whether or not the cancer has metastasized, or spread to other organs in the body.
How are tumors actually evaluated?
At the time of diagnosis and following surgical treatment, we measure the size of the cancer under the microscope and evaluate lymph nodes in the armpit and other parts of the body to determine whether there are cancer cells present in these lymph nodes. They also often do other tests, such as X-rays and scans, to see if there is any evidence of breast cancer outside of the breast in regional lymph nodes.
Why is it important for doctors to use this system to classify cancers?
The classification by stage is an important factor in prognosis, or how the patient is going to do over the long-term, and can be a factor in choosing therapy. For example, if a patient has stage II disease, the idea of combination therapy with chemotherapy and hormonal therapy is considered more frequently than it is in people with stage I or stage 0 disease.
How does the stage of the cancer affect treatment options?
When a patient is initially diagnosed with breast cancer, part of the treatment decision-making process will be determining how advanced her cancer is. Cancers that are stage Iinvasive cancers limited to just the breasthave a better overall prognosis, and the treatment options may be easier. It may be limited simply to hormonal treatments in those individuals who have estrogen-receptor positive breast cancer, which is cancer that grows in response to estrogen.
Stage II breast cancer, which involves not only the breast but the regional lymph nodes, usually involves a combination of treatments. Frequently, that will be chemotherapy first followed by long-term hormonal treatments for those who have estrogen-receptor positive breast cancer.
Stage III disease is larger tumors that involve greater numbers of lymph nodes, and they are treated with more aggressive treatments over longer periods of time. Individuals with stage III disease who have estrogen-receptor positive breast cancer are going to be offered a combination of chemotherapy and hormonal treatments as well.
Stage IV disease is metastatic cancer, or cancer that has spread to other organs. This type of cancer has a poorer prognosis in the short-term, and requires very aggressive treatments. The specifics vary from individual to individual. It will vary depending on where the cancer has spread and which organs are involved. But increasingly, if the original breast cancer was hormone receptor positive, we will try other hormonal treatments where the quality of life is as good as it can be. It is an effective way to prolong survival.
How has our ability to treat breast cancer across all the stages of disease
Over the past 20 years, there has been a gradual but important decline in the number of deaths from breast cancer in this country, despite the fact that the number of cancers diagnosed in a given year has actually increased. This improvement in outcome is the result of two things. One is better screening for breast cancer. More and more women are not only having mammograms but are having them on a regular basis, so that when the cancers are diagnosed, they are the smallest size, the treatment options are largest, and the prognosis of treatment is best.
The second factor in improving the survival of women with breast cancer has been improvements in treatment. Hormonal treatments, which are used broadly around the world, have been a major component in that improvement.
© 2003 Healthology, Inc.