Living with breast cancer is challenging for millions of women today. Some new ways of evaluating the likelihood that breast cancer will recur may allow doctors to determine who might benefit most from chemotherapy and other treatments.
With any cancer, the tumor cells divide uncontrollably. Cancer cells can then invade nearby tissues and spread through the bloodstream and lymphatic system to other parts of the body (called metastasizing). To kill cancer cells, doctors have routinely given patients with breast cancer the standard prescription: tumor removal via mastectomy or sometimes lumpectomy, usually followed by radiation and chemotherapy.
Until now, doctors have not been able to tell which women are at higher risk for breast cancer recurrence. Rather than take chances, every patient received the standard course of chemotherapy, which often has toxic side effects for many patients.
As we've learned more about cancer, researchers now realize that not all women with early breast cancer, including stage I and II, lymph node-negative breast cancer, actually benefit from adjuvant systemic therapy, which refers to chemotherapy, hormone therapy, and/or the drug trastuzumab (Herceptin).
Not All Breast Cancer Is the Same
More researchers are now thinking that not all breast cancers should be treated the same. Through findings from breast cancer clinical trials, scientists are discovering they can do a risk analysis of each woman's particular cancer and then base the outcome of breast cancer therapy (and specific type of therapy) upon the estimated risk of breast cancer recurrence.
Using a tool called the Recurrence Score, scientists are learning to quantify the likelihood of breast cancer recurrence in women with node-negative, estrogen receptor-positive (ER+) breast cancer and also predict the extent of chemotherapy benefit. While chemotherapy is necessary for some types of breast cancer, it may not be necessary for other types. And that's where the Oncotype DX test comes into play.
Breast Cancer and Oncotype DX
Oncotype DX is a diagnostic test that assesses the tumor tissue and estimates the likelihood that invasive breast cancer will return, or recur after treatment. By analyzing the expression pattern of certain genes in breast tumors, the Oncotype DX test can more precisely estimate a woman's risk of cancer recurrence when compared with the standard assessments doctors normally use to evaluate the risk of cancer returning.
The Oncotype DX screening test is performed on each tumor sample to get the Recurrence Score. The Oncotype DX test scores the breast tumor on 21 different genes involved in breast cancer and gives a Recurrence Score, or a number between 0 and 100 that shows a the chance of the breast cancer returning within 10 years of the original diagnosis.
The Recurrence Score is then categorized into one of three groups: low, intermediate, or high risk. For example, if a tumor has a Recurrence Score over 31, a high-risk score, this means there's a greater chance that the breast cancer will return. If a tumor gets a Recurrence Score of 18 or less, a low-risk score, this signals a lower chance that the breast cancer will return.
Using the Recurrence Score as a measure of risk, researchers now acknowledge a correlation between the score and the type of cancer treatment that is required. For example, with a low Recurrence Score, hormone therapy alone may successfully treat the woman's cancer. Alternately, a high Recurrence Score indicates a greater chance of the breast cancer returning, so the patient may benefit from adjuvant systemic therapy, including chemotherapy.
Who Might Benefit From the Oncotype DX Test?
The Oncotype DX test is recommended for breast cancer patients who are newly diagnosed, node-negative, estrogen receptor-positive, stage I or II, and who will be treated with tamoxifen, a selective estrogen-receptor modulator (SERM). Early findings from prospective trials indicate that a low Recurrence Score may determine which patients with ER+, node-negative breast cancer do not need chemotherapy.
The TAILORx TRIAL for Breast Cancer
More clinical trials are ongoing testing the Oncotype DX test. A groundbreaking clinical trial known as TAILORx is using the Oncotype DX test to see if some of the genes involved in breast cancer recurrence can also determine the need for chemotherapy -- and, more importantly, who will do better without it.The eventual results will help doctors recommend therapy that's based on the unique characteristics of each breast cancer tumor so they can maximize both effectiveness and safety in breast cancer treatment.
Use of the Oncotype DX test is limited to women with estrogen receptor-positive, node-negative breast cancer to help doctors determine if they can avoid the toxicity of chemotherapy if they have a low Recurrence Score. If women still want to undergo chemotherapy, that's a choice they can make with their oncologists.
Future Trends in Breast Cancer Treatment
In the near future, scientists predict the Recurrence Score may be used on other types of cancer, thus aiding doctors in prescribing individualized treatment that is safe and effective for cancer patients. A web-based tool called Adjuvant! Online allows doctors to incorporate the Recurrence Score from an Oncotype DX test to determine the benefit of chemotherapy in women with node-negative, ER-positive breast cancer. Using data from the Surveillance, Epidemiology and End Results (SEER) program of the National Cancer Institute, and from the year 2000 analysis of the Early Breast Cancer Trialists Collaborative Group (EBCTCG) findings, along with a proprietary formula, Adjuvant! Online can assist doctors in estimating each patient's prognosis and the benefit of adjuvant systemic treatment.
Reprinted from Web