Although advances in diagnostic testing for prostate cancer have improved the ability to detect the disease at an early stage, deciding which treatment approach will yield the most beneficial results for which patient can be challenging in the earliest stages of the disease. A new prognostic tool, developed at Memorial Sloan-Kettering Cancer Center, could aid physicians and patients in decision making regarding treatment options for early stage prostate cancer, and in identifying those patients who are at high risk of recurrence following radiation therapy. A combination of disease factors including stage of the cancer, prostate specific antigen (PSA) level, biopsy pathology, use of hormone therapy, and radiation dosage have been incorporated into a nomogram - a statistical device that predicts outcomes based on a combination of individual factors.
A study published in the September 28 issue of the Journal of Clinical Oncology concluded that the nomogram is more accurate than other models in predicting the probability of recurrent prostate cancer within a five-year period, following treatment with radiation therapy.
"We found that the nomogram provides the most accurate prognosis for prostate cancer patients considering radiation therapy when compared to existing prediction tools," said Michael Kattan, PhD, a researcher at Memorial Sloan-Kettering Cancer Center and lead author of the study.
Data from more than 1,000 patients treated with 3-D conformal radiation therapy at Memorial Sloan-Kettering over a 10-year period were retrospectively analyzed using the nomogram, which demonstrated more accurate estimates of treatment efficacy than those of eight other existing prognostic tools.
"Patients who need to make difficult treatment decisions when faced with early stage prostate cancer will be able to make better choices using tools like this nomogram in the management of their disease," said Peter Scardino, MD, chairman of the Department of Urology at Memorial Sloan-Kettering and co-author of the study.
Researchers determined the improved accuracy of the nomogram by calculating predicted outcomes using it and other prognostic tools and comparing them with observed patient outcomes. Three successive rises in PSA values following completion of treatment were considered evidence of recurrent disease. The nomogram predicted the overall five-year relapse-free survival probability to within 10 percent of the observed outcomes.
"No other prognostic tool considered radiation dose as a predictor variable in determining whether disease would return or not. This tool takes that into account," said Steven Leibel, MD, chairman of the Department of Radiation Oncology at Memorial Sloan-Kettering and senior author of the study.
