New Nomograms May Help Guide ADT Use
BOSTON—Researchers have developed two nomograms that use patients' clinical information to estimate the benefit of adding androgen deprivation therapy (ADT) to radiation therapy.
The nomograms could enable unprecedented determination of the risks and benefits of various durations of ADT in a particular patient, according to investigators at Fox Chase Cancer Center in Philadelphia.
Randomized studies have shown clear benefits with either dose-escalated radiotherapy (DERT) or the combination of ADT with standard-dose radiotherapy in men with prostate cancer. The benefit of adding ADT to DERT has not been well established.
The nomograms were developed based on findings from a study of 1,879 patients with high-risk prostate cancer. All were treated with radiotherapy at Fox Chase from April 1989 to February 2005. Subjects were stratified into four groups based on their duration of ADT: 0 months (1,479 patients), less than six months (short duration; 144 patients), 6-24 months (intermediate duration; 121 patients), and 24 months or more (long duration; 135 patients).
The researchers entered the following covariates into their model: palpation T-stage, biopsy Gleason sum, pretreatment PSA levels, ADT duration, radiotherapy dose, percentage of Gleason pattern 4/5, and percentage of positive tissue.
“Studies have generally lumped patients into three levels of risk, and physicians have recommended hormone therapy based on these studies,” said Niraj Pahlajani, MD, a radiation oncology resident at Fox Chase.
“Fortunately, we've been able to generate a nuanced prediction tool that incorporates disease burden and individualizes treatment recommendations. We can enter each patient's clinical information and estimate the probability of the cancer coming back using different durations of hormone therapy to determine the best course.” He presented study findings at the American Society for Therapeutic Radiology and Oncology annual meeting.
Although similar tools exist to predict cancer treatment outcomes, none is as personalized as the two new nomograms and none has yet been used to estimate the gains from different durations of hormone therapy, Dr. Pahlajani said.
“You can get a better estimate of what to expect if giving a patient hormone therapy for one year, two years, or long-term hormone therapy versus no hormone therapy,” said Dr. Pahlajani, noting that the nomograms will have to be further validated in other studies.