One of the challenges in treating men with intermediate or high-risk prostate cancer is identifying those who will benefit from androgen deprivation therapy (ADT), prostatectomy, or radiation therapy. As a prostate cancer surgeon, my goal is to make the best choice based on each individual man’s unique needs helping bring long-term remission while preserving the quality of life.
One of those decisions may involve whether a man will benefit or not from using ADT. Since most prostate cancers depend on testosterone to fuel tumor growth, the decision may be made to use ADT to suppress testosterone production. However, suppressing testosterone production by using ADT, can also result in side effects which may include the following:
- Loss of bone density
- Lowered lidibo
- Erectile dysfunction
- Loss of muscle mass and strength
- Changes in blood lipids
- Fatigue and mood swings
- Growth of breast tissue or gynecomastia
ADT for prostate cancer treatment
Making the decision to use ADT or not for some men with prostate cancer, has now become easier with the help of a genetic test predicting the aggressiveness of a man’s prostate cancer as found from a presentation at the 2021 Genitourinary Cancer Symposium.
The genetic test is called Prolaris, a genome test developed by Myriad Genetics that examines the expression of 31 genes involved in cell-cycle progression (CCP), an important regulatory step in the development of cancer. This type of testing also has benefits of preventing overtreating men with therapies such as ADT which could have a significant impact on their health and wellbeing.
The way the Prolaris tool works is it helps predict cancer aggressiveness by analyzing the activity of 46 genes involved in cancer cell proliferation, using tissue collected during a biopsy confirming a cancer diagnosis or during surgery to remove the prostate.
Once it has the information it needs, it will be combined with a man’s Gleason score. The Gleason score is the grading system used to determine the aggressiveness of prostate cancer and the levels of prostate cancer antigen, a biomarker of prostate cancer. This information can be used to choose appropriate treatment options. The Gleason score ranges from 1-5 and describes how much cancer from a biopsy looks like healthy tissue (lower score) or abnormal tissue (higher score) – most cancers score a grade of 3 or higher.
When the Gleason score is combined with the Prolaris tool, it determines a man’s cell-cycle risk (CCR) score, providing a more accurate look at the rate of prostate cancer progression over 10 years. This gives a man’s physician the information they need to make a more informed, individualized, and precise treatment plan avoiding unnecessary or excessive treatment raising the risk of side effects.
A 2021 study found in the Journal of Clinical Oncology, using clinical data of 718 men, wanted to see if Prolaris, using the CCR score, could predict the benefit of adding ADT to radiation therapy in participants who either had intermediate or high-risk prostate cancer. The men were followed for almost 6 years and each was given dose-escalated radiation therapy either by itself or in combination with ADT.
At the end of the study, results showed men with CCR scores below the high-risk threshold (high-risk threshold of 2.112), had a 10-year risk of metastasis of 4.2% while men with scores higher than the threshold, had a risk of 25.3%. In addition, results also revealed that around 50% of men with both intermediate or high-risk prostate cancer, and 20% of men with high-risk disease may have CCR scores below the risk threshold and therefore, safely consider the use of radiation therapy by itself. It also helped determine that men scoring below the threshold likely would not reduce their 10-year risk of metastasis if they also used ADT. This helped solidify that CCR can be a valuable tool for predicting metastasis in these men helping their doctors determine the best approach for treatment.
In a 2013 study of 413 men treated with surgery for prostate cancer conducted by the UCSF Department of Urology, the Prolaris CCP score was shown to have significant accuracy in predicting recurrence.
The technology of Prolaris looks to be a game-changer in the fight against prostate cancer. Anytime new medical innovations can assist physicians in making the right decision in treating prostate cancer but any cancer is a good day in the battle of winning the cancer war.