Communicating the Risk to Patients
There are some key items to understand as you communicate the risk of prostate cancer to patients based on this tool.
- The risk estimated by the askMUSIC model is based only on patients who underwent prostate biopsies as part of usual care. We do not know what happened to individuals who did not undergo biopsies.
- Our recommendation: Use this tool to assess the risk of finding prostate cancer if you (as a urologist) have already decided that a biopsy is indicated for a patient. Do not use this tool to decide whether a biopsy is indicated.
- Contraindications: Do not use this tool in settings outside of a urology office (such as in primary care) or in settings where low-risk patients are routinely referred to urologists. In such settings, this tool may overestimate the risk of prostate cancer.
Why Does this Tool Predict High-Grade Cancer More Often than Low-Grade Cancer?
Patients undergoing a prostate biopsy in MUSIC have a greater overall probability of having high-grade as compared to low-grade cancer. As a result, the model developed using MUSIC data will generally predict high-grade cancer with greater probability than low-grade cancer. This finding is consistent with the recently published Prostate Biopsy Collaborative Group (PBCG) risk calculator (available here: http://riskcalc.org/PBCG/)
One key item to note is that the MUSIC model, in its current form, does not differentiate 3+4 from 4+3 disease. Both are considered high-risk.
Comparing Risk with the PCPT Model
We have included a button to view the risk estimate from the Prostate Cancer Prevention Trial (PCPT) risk calculator at the bottom of the output of our tool after you press the Calculate button. This model was developed within the context of a randomized control trial of low-risk men. Many of the patients included in the PCPT trial would not necessary receive a prostate biopsy in contemporary practice. As a result, though the PCPT trial avoids the bias introduced by only including men undergoing biopsy (as in the askMUSIC model), it may significantly underestimate the risk of prostate cancer among patients referred to a urology practice because patients seeing a urologist comprise a higher risk group than men who participated in the PCPT trial.
Learn More about the Model
More details about the development of the askMUSIC Model are available here:
Citation: Auffenberg GB, Merdan S, Miller DC, Singh K, Stockton BR, Ghani KR, Denton BT. Evaluation of prostate cancer risk calculators for shared-decision making across diverse urology practices in Michigan. Urology. 2017. In Press