A new nomogram, unlike previous attempts, incorporates stronger predictors of survival.
CHICAGO—Researchers say they have developed a nomogram that could provide more accurate survival predictions of men with hormone-refractory prostate cancer (HRPC).
“Right now, we have two other nomograms for this disease state, and this [new] nomogram compares favorably with these in its predictive ability,” study investigator Andrew Armstrong, MD, assistant professor of medicine in the division of medical oncology at Duke University Health System in Durham, N.C.
“However, this nomogram contains several clinically applicable variables such as pain, type of progression, and PSA kinetics that are not captured in prior nomograms, and was validated in docetaxel-treated patients.” The nomogram could be useful in making bedside prognoses and allow for patient stratification in randomized phase III trials, he said.
Dr. Armstrong and his colleagues identified 10 factors that independently predicted overall survival: Pain, liver metastases, number of metastatic sites, performance status, type of progression, absolute PSA, and PSA doubling time (PSADT), hemoglobin, tumor grade, and alkaline phosphatase.
“Previous nomograms have not incorporated prostate cancer pain at all in their ability to predict outcomes,” Dr. Armstrong said. “We were able to collect that information, and that was actually one of the most strongly predictive factors,” Dr. Armstrong said. “We hope this nomogram will be beneficial to urologists and better guide them on when to begin chemotherapy in individual patients.”
The nomogram, which is designed to predict one-, two-, and five-year survival probability, was constructed using data derived from 1,006 patients and 800 mortality events who had participated in TAX 327, a randomized Phase III multicenter trial of 1,006 men with HRPC that established the superiority of three weekly docetaxel treatments over three weekly mitoxantrone treatments in terms of overall survival, PSA declines, quality of life, and pain control. The mean age of the men in the study was 68 years (range 36-92 years).
Among other findings, the study revealed that the risk of death decreased as PSADT increased. Using PSADT of less than a month as a reference, the researchers found that a PSADT of one to two, two to three, three to six, and more than six months was associated with a 21%, 31%, 47%, and 63% reduction in death risk.
Although a simple 2 x 2 table of PSA and PSADT at baseline provides a reasonable and easy-to-obtain estimate of overall survival, the most significant predictors of mortality in this patient population are liver metastasis, metastatic burden, and clinically significant pain, Dr. Armstrong said. Prospective trials are planned to externally validate the new nomogram in men with
Study findings were presented here at the American Society of Clinical Oncology annual meeting.