Different Expertise, Different Treatment Recommendation?

An interesting study published in the June 2008 issue of the Canadian Urological Association Journal investigated whether Canadian urologists and radiation oncologists were more likely to recommend the treatment that they themselves deliver for localized prostate cancer. Researchers also polled these experts about their beliefs regarding PSA screening, the survival benefits of various treatments, and the likelihood of various side effects with each prostate cancer therapy.

The study was inspired, in part, by previous research. A 1988 survey of British, Canadian, and American urologists and radiation oncologists found that, should the experts themselves be diagnosed with localized prostate cancer, 72 percent of urologists would choose to have a radical prostatectomy and 92 percent of radiation oncologists would choose external beam radiation therapy. (Read an abstract of the article "How expert physicians would wish to be treated if they had genitourinary cancer." )

Ten years later, in 1998, data collected by surveying a random sample of American urologists and radiation oncologists discovered that 93 percent of urologists chose radical prostatectomy as the preferred treatment for men with moderately differentiated, clinically localized cancer and a more than 10-year life expectancy. On the other hand, 72 percent of radiation oncologists thought that "surgery and external beam radiotherapy were equivalent treatments" for these patients. (Read the 2000 article in the Journal of the American Medical Association that reported these results: "Comparison of Recommendations by Urologists and Radiation Oncologists for Treatment of Clinically Localized Prostate Cancer.")

And what of the most recent study? Pearce, Newcomb, and Husain (2008) asked Canadian urologists and radiation oncologists which treatment they would recommend in two different scenarios. First, the experts were asked to consider the case of a man with "low-risk prostate cancer" (stage cT2A or below, Gleason 6 or less, PSA 10.0 ng/mL or less), who had "a life expectancy of more than 10 years and no contraindications to any therapy." (Click here for information on staging and grading prostate cancer.) The experts could choose from 6 different treatment options: "watchful waiting," androgen suppression alone, prostatectomy, cryotherapy, brachytherapy, or external beam radiation.

Close to the same percentage of urologists and radiation oncologists were comfortable recommending "watchful waiting," which CPCN prefers to call "active surveillance" --- 44 percent and 49 percent, respectively. Neither expert group recommended androgen suppression alone, and few in either group recommended cryotherapy. Radiation oncologists recommended brachytherapy more often than urologists did (89 percent to 67 percent), and, although both groups considered surgery a good option, more urologists than radiation oncologists recommended this treatment (92 percent to 88 percent). External beam radiation was recommended significantly more by radiation oncologists than by urologists (82 percent to 56 percent, respectively).

For a man with "intermediate-risk prostate cancer" (stage cT2B, Gleason 7, PSA 11 ng/mL), who had a life expectancy of more than 10 years, the recommendation pattern of the expert groups remained similar: a higher percentage of radiation oncologists than of urologists recommended external beam radiation, brachytherapy, androgen suppression, and watchful waiting. However, only a few respondents in either group thought that watchful waiting, androgen suppression alone, or cyotherapy were appropriate treatments in this case. Of note was the finding that significantly more urologists than radiation oncologists would recommend surgery to this patient (98 percent versus 70 percent).

The bottom line, then, is that the experts in each group did display a significant preference for treatments that they themselves deliver. As Pearce, Newcomb, and Husain (2008) put it,

Although both urologists and radiation oncologists recommend prostatectomy for the treatment of low-risk prostate cancer, urologists were significantly less likely to recommend EBRT [external beam radiation therapy]. Conversely, when patients present with intermediate-risk prostate cancer, radiation oncologists were significantly less likely, compared with urologists, to recommend a prostatectomy. (p. 202)

And why is this finding important? Well, for one thing, men with prostate cancer who are deciding about therapy are very likely to be guided by the experts they consult. So this study supports the current trend toward using multidisciplinary health care teams or expert conferences in prostate cancer treatment, especially in decision-making consultations. The study also points to the idea that men with prostate cancer who ask questions, consult widely, do some research, and generally take an active role in treatment decisions might feel more satisfied with the choices they eventually make. (Read a CPCN article about Dr. Larry Goldenberg's research on men's level of participation in prostate cancer treatment decisions.)

Other findings from the 2008 study support this last point. For example, urologists were more likely than radiation oncologists to think that cryotherapy and external beam radiation would cause erectile dysfunction in a higher percentage of patients. Conversely, radiation oncologists were more likely than urologists to think that surgery would cause urinary incontinence in more patients. Each specialist group, then, seemed to have a tendency to see a higher risk of treatment-related side effects for the procedure that its members did not practice.

Of course, there is nothing sinister in these findings. As Dr. Joseph Chin writes in the same issue of the CUAJ, "Urologists may not be as familiar with the latest technical developments and improvements in conformal or intensity-modulated radiotherapy. Conversely, radiation oncologists may be less informed about improvements in surgical outcomes of urinary continence and erectile function preservation" (p. 204). So, wanting the best for their patients and knowing best the latest advances in their particular fields, experts naturally might tend to value the treatment option with which they are most familiar, and to be up on the most recent findings regarding reducing the risk of side effects from that treatment.

As interesting as how expert recommendations differed is how they agreed. Both expert groups rejected the recommendation against PSA screening made by the Canadian Task Force on Preventative Health Care. A majority of both the Canadian urologists and radiation oncologists surveyed recommended PSA screening for men 50 to 70 years old. Also, both groups were similarly comfortable (or uncomfortable) with active surveillance or "watchful waiting." Perhaps the START (Surveillance Therapy Against Radical Treatment) clinical trial will affect this comfort level. START will enrol and follow over 2,000 men newly diagnosed with low-risk prostate cancer to compare standard treatments (surgery or radiation) to active surveillance. (Get more information on START.)

References:
Pearce, A., Newcomb, C., & Husain, S. (2008). Recommendations by Canadian urologists and radiation oncologists for the treatment of clinically localized prostate cancer. Canadian Urological Association Journal, 2(3), 197-203.

Chin, J. (2008). Urologists and radiation oncologists: Working together for patient care. Canadian Urological Association Journal, 2(3), 204.

(Articles are available as downloadable pdf files from http://www.cua.org/cuaj-jauc/vol2-no3/journal_v2_n3.htm )