Radiation oncology consult linked to active therapy

San Francisco-Patients who receive a radiation oncology consultation after being diagnosed with localized prostate cancer are much more likely to receive active therapy than men managed only by a urologist, and the men seen by a radiation oncologist are particularly likely to be treated with radiation therapy, according to a Canadian population-based, retrospective cohort study.

The research raises several questions that deserve further investigation, said Robert K. Nam, MD, who presented the findings at the 2018 AUA annual meeting in San Francisco and is senior author of the published paper (Br J Cancer 2018; 118:1399-05).

“Chamie et al reported that seeing a radiation oncologist increased the likelihood that patients with indolent prostate cancer would receive radiation treatment, but that study was limited to men >65 years of age who were diagnosed at a time when active surveillance was less accepted than currently. To our knowledge, ours is the first study evaluating the impact of a radiation oncology consultation on treatment patterns for a population including all men diagnosed with localized prostate cancer in the contemporary era,” said Dr. Nam, Ajmera Family Chair in Urologic Oncology and professor of surgery, Edmond Odette Cancer Centre Sunnybrook Health Sciences Centre, University of Toronto.

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“As multidisciplinary assessment is being advocated for men with prostate cancer, it is important to consider potential referral biases. It is possible that patients referred to a radiation oncologist may be more likely to receive radiation therapy because they perceive that their urologist believes they need radiation. Perhaps our findings also reflect the intent of multidisciplinary assessments where patients desiring treatment provided with informed choices are more likely to choose patient-centered care. However, the findings also raise concerns about whether patients are being overtreated by radiation oncologists or not educated appropriately.”

The study conducted by Dr. Nam and colleagues identified 16,666 men diagnosed with non-metastatic prostate cancer in Ontario between 2010 and 2013. A total of 11,416 men were included in a matched pair analysis that compared treatment patterns for men who saw a radiation oncologist within 90 days of diagnosis and those without a radiation oncology consultation.

Results showed that men who received a radiation oncology consult were 5.7 times more likely to undergo active therapy in the year following diagnosis compared with those who saw a urologist alone. Among men who saw a radiation oncologist, 25% underwent radical prostatectomy (RP), 60% had radiation therapy (RT), and 15% had active surveillance/watchful waiting (AS/WW). In contrast, among the men who saw only a urologist, 45% underwent RP, only 7% received RT, and 48% were managed with AS/WW.

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Further analyses explored issues that might affect treatment decisions and found that receipt of active treatment remained higher among men seen by a radiation oncologist regardless of risk category and patient age/comorbidity. Among men with intermediate-/high-risk disease (Gleason score ≥7, stage 2, or PSA >10.0 ng/mL), 34% of patients seeing a urologist did not receive active treatment compared with just 11% who had a radiation oncology consultation. In the group referred to a radiation oncologist, more than twice as many men were managed with RT compared with RP (61% vs. 28%).

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“A lot of patients seen by the urologist only may have been undergoing monotherapy with androgen deprivation therapy, and we will be analyzing that in the future,” Dr. Nam said.

Among men with low-risk disease (Gleason stage 6, stage 1, and PSA <10.0 ng/mL), 87% of those seen by a urologist alone were managed with AS/WW compared with 44% of those who had a radiation oncology consult. When men with the “lowest of low risk” disease (Gleason stage 6, stage 1, PSA <10.0, and two or fewer positive cores) saw a radiation oncologist, they were more likely to be managed with AS/WW, but still 26% received RT and 11% underwent RP.

Interestingly, an analysis that stratified men into four subgroups based on age and comorbidity showed that increasing age and comorbidity increased the likelihood that men seen by a radiation oncologist would receive active treatment. Men in the oldest age/highest comorbidity subgroup were 20 times more likely to receive active treatment if they saw a radiation oncologist than men seen by a urologist alone, Dr. Nam reported.

Men diagnosed at an academic center where biopsies are reviewed by specialized genitourinary pathologists were 4.5 times more likely to receive active treatment than their counterparts whose cancer was diagnosed by a community practitioner.

Treatment patterns for men seen by a urologist alone were influenced by time as the rate of AS/WW rose from 85% for men diagnosed in 2010 to 93% for those diagnosed in the last 2 years of the study. However, the proportion of men undergoing AS/WW after seeing a radiation oncologist remained steady throughout the 4 years of the study