A significant number of breast cancer patients may never have to experience unnecessary chemo therapy again.
A new study conducted by the ECOG-ACRIN Cancer Research Group and sponsored by the National Cancer Institute has revealed that a gene test called Oncotype DX can determine whether a patient will receive any benefit from chemo therapy. With more than half a million women having taken the test since 2004, the test may have effectively changed the treatment course for roughly 175,000 patients.
The study was published by the New England Journal of Medicine and quickly became a major topic of discussion at the 2015 European Cancer Congress. The trial period of the study revealed that in 99% of patients where cancers had not spread to lymph nodes, treatments using hormone-blocking drugs were effective in treating cancers that were fueled by estrogen. These results meant that complicated and expensive chemo therapy treatments were unnecessary for those patients.
This gene test “lets us focus our chemotherapy more on the higher risk patients who do benefit,” Dr. Clifford Hudis of New York’s Memorial Sloan Kettering Cancer Center told ABC News. He noted that others can now be spared an often painful ordeal that can cause a number of other health complications.
The study involved early stage breast cancer, which is the most common type, affecting more than 100,000 women in the United States each year. In the past, doctors typically relied on chemo treatments to kill cancer cells that may have spread to other parts of the body despite the fact that many women didn’t need chemotherapy. At the time, there was no alternative way to treat it, because there was no way to detect whether women could skip the treatment.
Enter California-based Genomic Health Inc., creators of Oncotype DX. The test analyzes 21 genes present in the tumor and monitors their activity. Then it provides a score on a scale of 1-100 based on a tumor’s genetic signature. This number determines the level of risk that a cancer will return. Any patient whose number is below 11 is deemed to have a low risk of the cancer returning.
Of the 10,253 women involved in the study, 1,626 had a low recurrence score. Of those low risk patients, 98% were living after five years, approximately 94% did not have any further experience with an invasive cancer and the previously mentioned 99% had not relapsed.
Tumor Profiling
Like every other cell in the body, tumors have genes. They contain the genetic code that makes your body unique. By looking at the hormone receptor status and whether certain types of proteins are present in the tumor, doctors can determine whether the cancer is likely to recur or spread to other areas of the body.
From this information, doctors can now determine which women need to include chemotherapy in their treatment and which women can forego it knowing that the genetic makeup of their cancer cells indicate it is not likely to return.
