Too often, men and women hear the words "prostate cancer," "breast cancer," and "colorectal cancer" from their doctors and they immediately think the worst. Many times the aggressive therapies are unnecessary that are offered or demanded. However, there are now genomic-based tests that can make these treatment decisions much easier and more reliable.
Genomics is the study of groups of genes and how they interact in cells and the role that they play in health and disease. A variety of genomic-based cancer tests are currently available that, without surgery, can analyze the genes in a person’s tumor and predict both the biology and the aggressiveness of the cancer. What each of these novel genomic tests offers is the potential to reduce unnecessary cancer treatments and avoid their attendant side effects. For prostate cancer, the new tests can predict whether a patient truly has a low-risk form of the disease and—based on the biology of the tumor—help a man decide if he is a good candidate for active surveillance rather than initial therapy.
For breast cancer, women with estrogen receptor-positive breast cancer can find out if they need chemotherapy in addition to hormonal therapy in their treatment regimen, or whether they can benefit from hormonal therapy alone. If a person has early-stage colorectal cancer, there is also a multi-gene expression test that looks at the gene activity with a person’s lymph node-negative tumor sample and can assess the risk and provide valuable information to the patient and doctor that traditional technologies do not capture.
To create their novel prostate test, scientists evaluated more than 700 patients and 288 candidate genes that predict for clinical recurrence expressed in common by both the primary and highest Gleason patterns, which are indicators of prostate cancer aggressiveness. They then honed the genes down to 17 and asked whether the expression of these 17 genes could predict the presence of high-grade cancer or cancer outside the prostate in men who underwent prostate surgery.
In these studies there was a substantial increase in the number of patients who could more confidently consider active surveillance. This treatment plan entails monitoring cancer closely with blood tests, digital rectal exams, and biopsies at regular intervals to see if the cancer is growing. The protocol avoids unnecessary treatment and its potential side effects, which can include erectile dysfunction and incontinence.
The genomic test also identified a smaller number of patients who, despite seemingly low-risk clinical factors, had more aggressive disease that might require more immediate treatment.
We are now in a new age of cancer diagnosis. Thanks to the development of a variety of genomic tests for various cancers, what we are now witnessing is the beginning of the era of true precision medicine that has its basis in biology.