Nomogram helps predict biochemical failure risk post RP

The Kattan biochemical recurrence-free progression nomogram helps predict biochemical failure risk at 5 and 10 years in men who have had radical prostatectomy, according to a recent study.

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Use of the nomogram, along with other factors, such as PSA level and family history, is a reliable, useful tool for helping urologists and their patients make better treatment decisions, the study’s lead author tells Urology Times.

Rochelle Payne Ondracek, PhD, of Roswell Park Cancer Institute, New York, led a study, published in the Journal of the National Comprehensive Cancer Network (2016; 14:1395-401), to validate the Kattan nomogram for prostate cancer recurrence after radical prostatectomy. Among the study’s authors are the nomogram’s developer, Michael W. Kattan, MBA, PhD, of Cleveland Clinic.

“Dr. Kattan has been developing nomograms for a variety of diseases and treatments. We were particularly interested in the post radical prostatectomy because we had a large group of patients with very detailed outcomes. We compared the predicted Kattan nomogram outcomes with the actual outcomes,” Dr. Ondracek said.

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The nomogram predicts probability for disease-free survival on a scale from 0% to 100%. To study it, the authors looked at data from 1,931 men who had radical prostatectomy performed at Roswell Park Cancer Institute between 1993 and 2014. The patients had been assessed for National Comprehensive Cancer Network-defined biochemical failure and Roswell Park Cancer Institute-defined treatment failure.

Next: “We found that the nomogram was very good at predicting actual recurrence-free progression"

When they compared the actual outcomes data with Kattan nomogram predictions, they found that at 5 and 10 years, the nomogram was an accurate predictor of biochemical failure-free survival and treatment failure-free survival, but tended to underestimate both compared to actual outcomes. In an effort to test the nomogram’s predictions among only high-risk patients, the authors found that the nomogram significantly overestimated biochemical-free progression. This suggests that the nomogram’s prediction should be used cautiously for higher risk patients, according to Dr. Ondracek.

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“We found that the nomogram was very good at predicting actual recurrence-free progression. That is particularly true at the high end of probability values; so, if a patient is predicted to have a 95% probability of being free of disease at 5 years, we know that patient has a really good shot of not ever having any recurrence of disease,” she said.

The Kattan nomogram’s predictions for patients at 10 years post radical prostatectomy were within the 95% confidence interval of actual biochemical-free recurrence at 10 years, according to a press release on the study.

Urologists can confidently add the nomogram’s results to other risk indicators, including PSA level, family history, age, and overall health to determine how aggressively to continue to treat these patients, according to Dr. Ondracek.

“This nomogram has been proven worthy multiple times,” she said.

One of the things that makes this study different is that the authors used modern, standardized failure definitions.

“The definitions of recurrence have shifted pretty significantly over the past 25 years. That has been in response to the creation of the PSA test and then the evolution of that PSA test to detect smaller and smaller concentrations (of PSA) in the blood,” she said.

The PSA test’s increasing sensitivity allows clinicians to detect problems earlier in the progression of the disease, but has also led to treating men who will not experience clinically significant disease, according to Dr. Ondracek.

“This nomogram helps urologists separate the patients who have more aggressive forms of prostate cancer from the ones who are probably not ever going to have any trouble with it. Ideally, we want a genetic or molecular marker for prostate cancer, but that hasn’t happened yet. The next-best tool right now is a nomogram,” Dr. Ondracek said.

More on Prostate Cancer:

Prostate Ca surveillance study has global implications

There’s something about PSA: Ben Stiller fights the good fight

Delay from biopsy to RP: Who is at risk of recurrence?

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