Understanding Prostate Cancer Risk Groups
What Is a Risk Group?
Evaluating the results of treatment can be done in multiple ways. Patient results can be evaluated by a single measure such as the stage, the grade or the PSA. For example, all Stage T1c patients could be evaluated. However, in those T1c patients, there may be a few or many with high grade cancers which we know can worsen the prognosis and make those T1c results worse for one treatment than the other. Multiple studies have indicated that patients with slightly different characteristics can be organized into groups that behave very similarly with any treatment. For example a patient with a T1c, Gleason Score 6 cancer and a PSA of 5 will behave very similarly to a patient with a T2a, Gleason Score 6 and PSA of 8. By grouping patients with similar results, large numbers of patients can be analyzed for the results of a treatment. By grouping these patients, we are able to compare the success of any treatment regimen.
Why Evaluate by Risk Groups Instead of Just Stage?
The standard cancer staging system (TNM) does not take into account the influence of PSA or Gleason Score on prognosis. Both the PSA blood test and Gleason Score are also strongly predictive of response to treatment. Risk group classifications take into account the three most important predictors; the digital rectal exam (clinical Tstage), the pre-treatment PSA and the biopsy Gleason Score.
What Is the Value of Separating Risk Groups?
Risk groups allow one to separate patients into similar groups with the same prognosis in order to compare results of one treatment to another.
Aren’t Nomograms More Predictive of Prognosis?
Nomograms are mathematical models used to attempt to individualize prognosis for individual patients. They use the PSA, stage and grade to predict results of various treatments. But nomograms are only as good as the data that is entered into them. For example, the current MSKCC (Memorial Sloan Kettering Cancer Center) nomogram for brachytherapy is VERY outdated. It includes patients Dr. Grimm treated from 1988-1990, but not his more recent patients with modern techniques. This data is incorrectly compared to updated (modern) surgical data. It is well recognized that within all treatment regimens the results have improved over the past 15 years primarily because the patients are diagnosed earlier and that the treatments are improved. Dr. Steven Frank at MD Anderson reported on the expected results of the MSKCC nomogram for brachytherapy compared to modern brachytherapy results and found the nomogram extremely inaccurate. Article
Thus, using the current MSKCC nomogram to compare surgical versus brachytherapy outcomes is extremely misleading. Therefore, rather than using a dated nomogram to decide on treatment, instead, look at modern results. Prostate Cancer Results Study Group
Are There More Current Nomograms Using Modern Results?
Currently MDAH (MD Anderson) (Dr. Frank) and Princess Margaret Hospital (Dr. Crook) are combining their “modern” patient data and outcomes to create a modern, more accurate, brachytherapy nomogram.
What is My Risk Group?
Low, Intermediate and High Risk groups have been identified by NCCN (National Comprehensive Cancer Network) and D’Amico classifications.
Low Risk
(NCCN and D’Amico) - PSA < 10.0
And Gleason Score < 7
cT1c-T2a
Intermediate Risk
NCCN - PSA > 10.0 < 20.0
And/Or Gleason = 7
And/Or cT2b-c
D’Amico - PSA > 10.0 < 20.0
And/Or Gleason = 7
And/Or cT2b
High Risk
NCCN - PSA > 20.0
And/Or Gleason 8-10
And/Or cT3
Or 2 or More Intermediate Risk Features
D’Amico - PSA > 20.0
And/Or Gleason 8-10
And/Or cT2c-T3
How Are the Risk Groups Used to Evaluate Treatment?
Risk group analysis allows treatments to be compared and avoids biased selection of patients and the exclusion of “bad” patients. You can view the results of a comparison of risk groups recently conducted by the Prostate Cancer Results Study Group
I Have Heard That Other Factors May Be Included When Evaluating Treatment.
Yes, other factors such as the number of biopsies and the presence of Gleason Score 7 (4+3) versus a Gleason Score (3+4) may influence the treatment decision. The number of + biopsies is also strongly predictive of outcomes but not typically part of the risk grouping systems. An example would be a person with a multiple + biopsies (>34%-50%) Gleason 7. His cancer would be considered a High Intermediate Risk and require a combination of External Beam and radiation while another patient with only a few + biopsies (< 34%-50%) could be a Low Intermediate Risk patient and be a good candidate for an implant alone. These factors should be discussed with you doctor.