Cost-Effectiveness Study Compares Surgery and Radiation Therapy for Localized Prostate Cancer—Small Differences in Outcomes, Big Differences in Cost
January 24, 2013 -- While a plethora of treatment options exist for men diagnosed with localized prostate cancer—growths confined to the prostate gland—there is a dearth of studies comparing those treatments in terms of both cost and effectiveness. Now an ambitious, comprehensive comparative effectiveness modeling study of surgery vs. radiation therapy for men treated for localized prostate cancer reports minor differences in terms of how patients fare post treatment but large differences in cost. The study, led by PCF Young Investigator Dr. Matthew Cooperberg of the University of California at San Francisco, was published in the British Journal of Urology and conducted in a unique way that factored in lifetime costs and effects.
The study authors used outcomes collected from 232 separate clinical studies to build their complex decision model that ran algorithms that followed hypothetical men with low, intermediate and high risk prostate cancer post initial treatment with either surgery or radiation over the course of their lifetimes. The surgical options considered in the study were open, laparoscopic, or robot-assisted radical prostatectomy; the radiation therapy options considered were dose-escalated three-dimensional conformal (3DCRT), intensity-modulated (IMRT), brachytherapy (BT), and external beam + brachytherapy (EBRT + BT). In their various analyses, men could have a multitude of outcomes such as remission after initial treatment, recurrence, salvage treatments (such as hormone therapy or chemotherapy) for their recurrence, metastatic cancer spread, death from prostate cancer, or death from other causes.
Dr. Cooperberg explains that they ran and reran the men through their various treatment algorithms and that a certain number of men would wind up in each possible health state. Once they’d run their model enough times to get rid of any statistical noise, he said, “eventually what we got was a measure of the effectiveness of a treatment that is expressed as both life years—how long do you live—and the quality of that life.”
Among the radiation options, in terms of quality-of -life years (QALY) differences were small:
- Low risk men receiving 3DCRT had 10.3 QALYs, compared to a high of 10.8 QALYs for men with IMRT or BT.
- Men of intermediate risk group receiving radiation therapy ranged from 9.6 QALYs to a high of 10.1 for EBRT +BT.
- And men with high risk disease showed the most significant quality-of-life survival differences with a high of 9.1 QALYs in men treated with EBRT + BT compared to 7.9 for men receiving 3DCRT.
Among surgery options there was no statistical difference in terms of QALYs for men with low, intermediate, or high risk disease.
In comparisons of surgery to radiation therapy, the authors found that surgery tended to be more effective than radiation; however the differences were modest.
- For low-risk men, EBRT + BT and BT tied for the highest number of QALYs (10.8) compared to 11.3 for all surgical options.
- For intermediate -risk men, EBRT + BT gave 10.1 QALYs compared to RARP surgery with 10.5.
- For high-risk men, EBRT + BT gave the most QALYs (9.1) among the radiation therapy options and was comparable to surgical methods that ranged from 9.2 for ORP to 9.3 for RARP and LRP.
Of note: when survival was measured without quality-of-life adjustments (Life Years) surgery held a small advantage, except for EBRT + BT when given to high-risk men. (EBRT + BT yielded 14.1 life years and ORP yielded 13.1 life years.)
In terms of cost, radiation therapy was significantly and consistently higher than surgery. (The authors factored in both lifetime payer costs and patient costs.) For surgery cost was modeled at ~$20,000 compared to ~$50,000 for radiation therapy. Radiation therapy is typically reimbursed at a higher rate than surgery as the higher costs of delivery—medical oncologists, multimillion dollar radiotherapy machines, medical physicists, radiation therapists, and other highly trained technical staff—are factored into payment schedules.
As a validation test of their study model, Cooperberg and his study colleagues used a 2010 clinical study out of Memorial Sloan-Kettering Cancer Center in New York that compared surgery to radiation therapy in terms of eight year probability to cancer spread to distant sites. (That study found that surgery was associated with a reduced risk of metastasis as well as death from prostate cancer.) The modeling study results closely matched those of the clinical study of real-world patients.
“This is a really important first step for making broad comparisons between surgery and radiation, says Dr. Timothy Showalter, a radiation oncologist and PCF Young Investigator who is working on his Master of Public Health degree, who said he was particularly impressed with the study’s use of a lifetime horizon, because, traditionally, only 10-year time horizons are used.
“What’s challenging when you take such a comprehensive approach is that you encounter many problems because in a sense you are comparing apples to oranges,” he said, referring to the many variables involved in constructing a global model. Showalter points out, as did the study’s authors, that the average age of men undergoing radiation therapy for prostate cancer is significantly older than men who have surgery and that older patients are much more likely to have a number of other serious health issues.
“Although [they] took some steps to adjust for differences in age and life expectancy, there is some chance individualized detail is missing,” said Showalter. He says the study seems less directed at patients making personal treatment decisions and more applicable at the health policy level. And indeed the study authors write that their “findings may inform future policy discussions about strategies to improve efficiency of treatment selections for localized prostate cancer.”
Of particular interest to Showalter is the provocative finding that in high-risk patients, the combination of external beam radiation therapy with brachytherapy was slightly more effective in terms of life years than open surgery, because currently only 20% of patients with high-risk disease receive EBRT + BT.
Dr. Jonathan Simons, president and CEO of the Prostate Cancer Foundation, welcomes this study as an “excellent interim analysis of comparative effectiveness of surgery vs. radiation. “The field will have to wait years for evidence collection from randomized clinical studies,” he says. “In the meantime this study offers perspective at the 30,000 foot level.”
Cooperberg says that a British clinical trial, dubbed ProtecT, is underway and has accrued patients with localized prostate cancer for a randomized clinical study of surgery vs. radiation comparisons vs. active surveillance that will measure survival outcomes for up to 15 years after initial treatment. But as Simons points out, those results are futuristic and decision makers can use this information in the here and now.
The ultimate take home of their study says Dr. Cooperberg, is that “we found no massive survival differences between radiation therapy and surgery, but we did find massive differences in cost.”