Specialist bias, in which specialists recommend the therapy that they are capable of delivering, is thought to influence the treatment of patients with localized prostate cancer and to contribute to overtreatment of men with limited life expectancy,” Ayal A. Aizer, MD, MPH, and colleagues, from the Harvard Radiation Oncology Program, Massachusetts General Hospital, Brigham and Women’s Hospital–Dana-Farber Cancer Institute, and Beth Israel Deaconess Medical Center, Boston, stated in explaining the purpose of a study reported online by the Journal of Oncology Practice.1 The purpose of the study, the authors wrote, was “to determine if consultation with a medical oncologist is associated with increased rates of active surveillance in men with low-risk prostate cancer.”
Significant Findings
After reviewing data for 188 men with low-risk prostate cancer who were patients at one of three referral centers affiliated with Harvard Medical School, the researchers concluded that consultation with a medical oncologist was associated with increased rates of active surveillance, as well as adherence to National Comprehensive Cancer Network (NCCN) guidelines, and “minimization of overtreatment in men with early prostate cancer and limited life expectancy.”
Demographic and clinical characteristics were similar for the 81 patients who consulted with a medical oncologist and the 107 who did not. All patients had histories taken and underwent physical examinations, as well as prostate-specific antigen (PSA) measurements and a transrectal, ultrasound-guided prostate biopsy.
Most of the patients in both groups chose to have a prostatectomy—37 patients (46%) in the group that consulted with a medical oncologist and 46 patients (43%) in the group that did not. External-beam radiation therapy was selected by 12 patients (15%) in the consultation group vs 28 patients (26%) in the nonconsultation group, and brachytherapy was selected by 2 patients (2%) in the consultation group vs 11 patients (10%) in the other group. Active surveillance was selected by 30 patients who consulted with a medical oncologist and 22 patients who did not.
“Consultation with a medical oncologist was associated with increased rates of active surveillance (37% vs 21%, P = .01), an association that remained significant on multivariable logistic regression” (odds ratio [OR] = 2.70, 95% confidence interval [CI] = 1.27–5.75, P = .01), the researchers reported. “When applied to patients with limited life expectancy, this finding remained significant” (OR = 4.74, 95% CI = 1.17–19.25, P = .03), they added.
The authors noted that previous studies have demonstrated physician bias, including “a survey-based study demonstrating that both urologists and radiation oncologists overwhelmingly recommend the therapy that they are capable of delivering.”2 They added, “Our results suggest that medical oncologists might be able to estimate the impact of definitive therapy in patients with limited life expectancy better than other physicians, allowing for minimization of overtreatment of patients with limited life expectancy.”
Hypothesis Not Proven
Although the hypothesis of the study—that medical oncologists might not be biased toward a particular treatment modality and more inclined to recommend active surveillance—“certainly has face validity, the results of this study do not prove this,” according to an accompanying editorial by Alicia K. Morgans, MD, and David F. Penson, MD, MPH, of Vanderbilt University Medical Center in Nashville.3 These authors noted that “the study’s restrictive inclusion criteria limit the generalizability of the findings to the larger prostate cancer community.” The criteria excluded men who saw just one prostate cancer specialist, unmarried men, and patients at multidisciplinary clinics.
More importantly, “it is impossible to determine causation in the setting of a cross-sectional study,” Dr. Morgans and Dr. Penson asserted. “In other words, it may be that men who were already strongly considering or had decided on active surveillance sought out consultation with a medical oncologist, as opposed to the consultation with the medical oncologist causing them to select active surveillance. Only a prospective study, and preferably a randomized clinical trial, could conclusively show whether consultation with a medical oncologist results in increased use of active surveillance.”
Consultation with a medical oncologist “likely has value to patients and should be encouraged,” the editorialists continued. “Although medical oncologists can provide a unique perspective that urologists and radiation oncologists cannot, it is important to note these other specialists also bring something to the table that should not be ignored. This observation supports the role of multidisciplinary clinics in aiding patients newly diagnosed with prostate cancer to make the most informed decisions possible regarding treatment.” ■
Disclosure: For full disclosures of the study and commentary authors, visit jop.ascopubs.org.
References
1. Aizer AA, Paly JJ, Michaelson MD, et al: Medical oncology consultation and minimization of overtreatment in men with low-risk prostate cancer. J Oncol Pract. January 7, 2014 (early release online)
2. Fowler FJ Jr, McNaughton Collins M, Albertsen PC, et al: Comparison of recommendations by urologists and radiation oncologists for treatment of clinically localized prostate cancer. JAMA 283:3217-3222, 2000.
3. Morgans AK, Penson DF: The more, the merrier: Including a medical oncologist in treatment planning for localized prostate cancer. J Oncol Pract. January 7, 2014 (early release online).
