A new study integrates traditional National Comprehensive Cancer Network prostate cancer guidelines with genetic information found in biopsied tissue to more accurately predict which men have more aggressive forms of prostate cancer.
A challenge that remains in prostate cancer is distinguishing men who have aggressive and potentially lethal disease from men whose cancer is slow growing and unlikely to metastasize.
In the past, physicians have used guidelines established by the National Comprehensive Cancer Network (NCCN) to sort patients with prostate cancer into risk groups by identifying their prostate-specific antigen level, cancer grade, and tumor stage. These groups are then used to help establish a treatment course; however, the practice has shown some deficiencies.
“These risk groups were developed decades ago and were optimized for what is called biochemical recurrence, which simply means that a man’s PSA level rises again sometime after treatment. It was not optimized for more meaningful outcomes like identifying which men will ultimately develop metastases or die of prostate cancer,” said Daniel Spratt, MD, associate chair of research and assistant professor in the department of radiation oncology at Michigan Medicine, in a statement.
However, according to a press release, technology has advanced to the point where genetic information found in the tissue biopsied at diagnosis can more accurately predict which men have aggressive prostate cancer. A genomic classifier score is assigned based on the results of tests run on 22 genes known to increase the risk of developing metastatic disease.
A new study was published in the Journal of Clinical Oncology that sought to integrate the newly found biomarkers with the previous NCCN risk groups to create a new integrated system.
The study investigated 4 multicenter retrospective cohorts of nearly 7000 men, all of whom had gene expression biomarker scores. These participants were used to design, test, and validate a new model for assigning risk groups. Under this practice, 2 new clinical-genomic systems were created: a simple 3-tiered system and a more specific 6-tiered system.
Researchers compared the new risk group models against the traditional ones created by the NCCN and found that the new groups were more accurate predictors of the development of metastatic disease and death than the previous ones.
“What our new system does is not only more accurately identify men who either have indolent disease or aggressive disease, but it reclassifies almost 67% of men, potentially changing recommendations for their treatment,” said Spratt.
Results of the study then led to new implications for patient care. For men with a lower-risk slow-growing disease, defer of treatment and active surveillance is typically recommended.
“It’s great because you spare the cost and side effects of treatment. However, in the community setting, only about 50% or less of men who we would normally say should go on active surveillance actually go on it. That’s because clinicians don’t have great confidence in the old NCCN risk grouping system,” said Spratt.
Conversely, men found to be in the higher-risk patient group with more aggressive forms of prostate cancer would receive more intensive treatment, possibly radiation, hormone therapy, or clinical trials.
According to Spratt, this new clinical-genomic risk grouping system is ready to be used today.
“This could radically change the way we perceive and treat localized prostate cancer,” he said.
Spratt DE, Yousefi K, Deheshi S, et al. Individual patient-level meta-analysis of the performance of the Decipher genomic classifier in high-risk men after prostatectomy to predict development of metastatic disease. J Clin Oncol. 2017;35(18):1991-1998. doi: 10.1200/JCO.2016.70.2811.