Too often, men and women hear the words “prostate cancer,” “breast cancer,” and “colorectal cancer” from their doctor and they immediately think the worst. However, many times the aggressive therapies that they are offered or demand are unnecessary—and 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 cancer tumor and predict both the biology and aggressiveness of the cancer. What each of these novel genomic tests offers is the potential to reduce unnecessary cancer treatment and save lives.
For prostate cancer, the new tests can also predict whether a patient truly has a low-risk form of the disease. And if the test confirms that a patient is low-risk, then treatment decision can be made with confidence based on the biology of the tumor.
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 regime, 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 of cancer recurrence within three years.
In 2013, the Food and Drug Administration approved an innovative prostate cancer test consisting of a 17-gene panel that determines how aggressive a prostate cancer is based on the biology of a man’s individual tumor. Used along with other standard lab results, this additional information provided from this test can help a man determine just how favorable his tumor biology is, enabling him to then personalize his treatment plan. In addition, these test results will give both doctor and patient greater confidence in choosing the course of care, knowing that decisions are being made based on individual biological information.
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.
What this test did was triple the number of patients who could more confidently consider active surveillance—the treatment plan that entails monitoring cancer closely with blood tests, digital rectal exams, and biopsies at regular intervals to see if the cancer is growing—and avoid unnecessary treatment and its potential side effects, which can include erectile dysfunction and incontinence. The test also identified a smaller number of patients who, despite seemingly low-risk clinical factors, had more aggressive disease and, would suggest that they consider immediate treatment.
We are now in a new age of cancer diagnosis. Thanks to the new genomic tests for a variety of cancers, what we are now witnessing is the beginning of the era of true precision medicine that has its basis in biology.
Where Are They Now
With continuing research, genomic tests are now available for various types of cancer; including brain, lung, thyroid, pancreatic and melanoma. Multiple clinical trials are ongoing to evaluate the efficacy of integrating genomic-driven tumor testing, with databases compiling data to compare treatment options based on genomics rather than cancer type. In 2017, the FDA approved the first ever cancer treatment for any solid tumor with a specific genetic feature. This is the first time the agency has approved a treatment based on a common biomarker, rather than location in the body. Additionally, beginning in 2018, the cancer staging system will change nationwide to include analysis of molecular assays. Genome guided tumor diagnostics will continue to gain speed as the technology for these genomic tests continues to advance.