Clinicians versus nomogram: predicting future technetium-99m bone scan positivity in patients with rising prostate-specific antigen after radical prostatectomy for prostate cancer

Abstract

Objective: To compare the ability of clinicians vs a nomogram at predicting future bone scan positivity in patients with prostate cancer.

Materials and methods: This investigation was conducted during an advisory board meeting in June 2011. Details of 25 androgen deprivation therapy-naive prostate cancer patients were given to 24 prostate cancer experts, including urologists and oncologists. The clinicians were asked to predict the probability that the patients would have a positive bone scan if left untreated for 1 year. These predictions and those of the Slovin nomogram were compared with the actual occurrence of metastatic disease, and the discrimination ability was quantified using the concordance index (C index).

Results: A higher C index value was obtained with the Slovin nomogram (0.812) than with the clinicians (0.628). The nomogram outperformed all of the clinicians; individual clinician C index values varied between 0.47 and 0.75. The urologists provided superior predictions compared with the oncologists.

Conclusion: Future bone scan positivity can be predicted more accurately using a nomogram than by expert clinicians. Nomograms should, therefore, become an integral part of the clinical decision-making process in the prostate cancer setting for patients with a rising prostate-specific antigen level after radical prostatectomy.