The role of hormone therapy in locally advanced prostate cancer treated with definitive radiation therapy
The purpose of this study was to determine whether the effect of androgen deprivation therapy (ADT) on the risk of biochemical (PSA) failure and distant metastasis varies at different doses of radiation in intermediate and high risk prostate cancer and whether different lengths of ADT had an effect on biochemical failures or distant metastasis. We conducted a retrospective analysis of 1218 intermediate and 1290 high risk prostate cancer patients who were treated with definitive external beam radiation therapy from June 1987 to March 2010 at the University of Texas MD Anderson Cancer Center. Patient, treatment, and tumor information was collected, including age, race, Gleason score, radiation dose, PSA, T-stage, and months on ADT. We evaluated our patient outcomes and developed a model to assist patients and their physicians in understanding the value of adding ADT in the current era of high dose radiation by developing a nomogram to predict 5- and 10-year risk of biochemical failure based on our patient population. The predictions from this nomogram were compared with those from the one published by Memorial-Sloan Kettering Cancer Center (MSKCC). We found that ADT reduced the risk of biochemical failure and distant metastasis in both low- and high-dose radiation groups among men with intermediate and high risk PCa. The effect of ADT on reducing risk of biochemical failure was statistically significantly greater among men with high risk prostate cancer who received low-dose radiation. In terms of optimal length of ADT, there was no improvement in PSA recurrence-free survival with longer duration of ADT use for intermediate risk patients, but improved PSA recurrence-free survival was seen with longer duration of ADT use in high risk patients. A clinical trial is needed to thoroughly determine the benefit of ADT in the dose escalation setting. Our nomogram predicting the 5- and 10-year probability of biochemical failures in high risk populations showed higher accuracy for our population than the MSKCC nomogram. For intermediate risk patients, our nomogram and the MSKCC nomogram predicted essentially similar results. In the era of personalized medicine, this nomogram may help physicians and patients better counsel patients on their individual risk of biochemical failure as they are deciding between treatment modalities for locally advanced prostate cancer.
Ludwig, Michelle Suzanne, "The role of hormone therapy in locally advanced prostate cancer treated with definitive radiation therapy" (2013). Texas Medical Center Dissertations (via ProQuest). AAI3606899.