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 radical prostatectomy. In the case of lymph node invasion, its presence or absence was only known if lymph node dissection was performed.
Our recommendation: Use this tool to assess the risk of finding prostate cancer that extends beyond the prostate at the time of surgery. Because lymph node invasion was only identified when lymph node dissection was performed, the tool should not be used to decide which patients warrant a lymph node biopsy but rather to communicate the risk of lymph node invasion if you (the urologist) have already decided that a lymph node dissection is warranted.
Comparing Risk with the MSK Model
We have included a button to view the risk estimate from the Memorial Sloan Kettering Cancer Center (MSK) risk calculator at the bottom of the output of our tool after you press the Calculate button. This model was developed at MSK, a tertiary care referral center that cares for a disproportionate amount of high-risk patients. Seminal vesicle invasion is more frequently observed in the MUSIC cohort than in the MSK cohort, but the MSK cohort has a greater risk of non-organ-confined disease, including extraprostatic extension and lymph node invasion. These differences in patient populations are reflected in the differences in predicted percentages between the MUSIC and MSK models.
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.