Tests and Predictions and Choices
Today's entry is specifically related to breast cancer, but the larger issues are relevant more broadly. Increasingly, there are molecular tests to identify specific genetic markers within tumors. These markers may indicate the potential value of targeted therapies and/or may help with other decisions about chemotherapy. The direction of cancer research and treatment is towards more individualized decisions and away from the long-standing approach of blasting all similar cancers with the same drugs.
For years, there has been a computer model called Adjuvant Online that oncologists could use to help with decisions around the need for chemotherapy. By plugging in details about a woman's pathology report, statistics about recurrence risk could be established and considered. About ten years ago, the Oncotype DX genetic test became available. The Oncotype DX test is a genomic test that analyzes the activity of a group of genes that can affect how a cancer is likely to behave and respond to treatment. It is useful only in cases of ER positive breast cancers, and originally was only used in cases that were also node negative. After the genetic analysis, a score (low, intermediate, or high) is calculated, and that indicates the liklihood of recurrence with only hormonal therapies. Extrapolating from there, it is helpful in making a decision re the wisdom of including chemotherapy in a woman's adjuvant treatment. The Oncotype DX is also used in making similar treatment decisions for some men with prostate cancer.
There are several similar tests being developed, and this is a report from Medscape about one, the MetaSite Breast Test. Not yet commercially available, it has shown early promise in helping oncologists and their patients consider the risk of recurrence and, therefore, the need for chemotherapy. It is important to remember that no test is perfect, and there is never going to be a way to predict with 100% accuracy which cancers are going to come back and which are less likely to do so. Sadly, cancer outwits us time and again.
This does look like a very positive step, and I am certain that there are similar tests being developed for other kinds of cancer. Remember, too, that scientists are learning that cancers that begin in various sites (e.g. lung vs kidney vs breast) may have characteristics in common, and treatments often are valuable across different types.
Here is the beginning of the article and a link to read more:
New Test Predicts Which Early Breast Cancer Will Metastasize
Alexander M. Castellino, PhD
Current tests that are used for determining prognosis in breast cancer are based on gene signatures found within the tumors ―
but a new test under development is focusing instead on the tumor microenvironment.
The new test, MetaSite Breast test, could be available commercially late next year. It relies on determining the tumor microenvironment of metastasis (TMEM) score, and a group of researchers from the Albert Einstein College of Medicine in New York City have shown that it is possible to correlate this score with the potential for breast cancer metastasis. The findings were published in the August issue of the Journal of the National Cancer Institute.
In an accompanying editorial, senior author Rakesh K. Jain, PhD, professor of tumor biology at the Massachusetts General Hospital and the Harvard Medical School, in Boston, and colleagues explained, "Certain gene signatures (eg, MammaPrint, Oncotype DX) have shown statistically significant association with distant disease recurrence and are in clinical use as prognostic markers. These signatures appear to be driven predominately by genes reflecting the level of proliferation and
hormone receptors in those tumors. But in addition to intrinsic properties of the cancer cells, a key role has been proposed for the tumor microenvironment in cancer cell survival and progression to metastasis."