Adherence to guidelines for the use of combination radiation therapy and androgen deprivation therapy in the United States for the treatment of high-risk or locally advanced prostate cancer has decreased over time, according to data presented by Paolo Dell’Oglio, MD.
San Diego-Adherence to guidelines for the use of combination radiation therapy and androgen deprivation therapy (ADT) in the United States for the treatment of high-risk or locally advanced prostate cancer has decreased over time, according to data presented by Paolo Dell’Oglio, MD.
Moreover, examination of individual patient characteristics indicates random variability in adherence to guidelines, he said at the 2016 AUA annual meeting in San Diego, where the study was first reported. It was subsequently published in European Urology (2016; 70:429-35).
The combination of radiation therapy and androgen deprivation therapy (ADT) has been proven definitively to be superior to radiation therapy alone followed by deferred ADT on relapse in the treatment of patients with high-risk and locally advanced prostate cancer, as demonstrated by several phase III randomized trials.
For this reason, the National Comprehensive Cancer Network and the European Association of Urology guidelines recommend using radiation therapy with ADT for the treatment of these patient groups.
Dr. Dell’Oglio and colleagues sought to examine the rate of adherence to these guidelines within a large-scale population-based data repository.
“We hypothesized near-perfect guideline adherence,” he said.
The study population consisted of 14,180 patients from the Surveillance, Epidemiology, and End Results (SEER)-Medicare database who were diagnosed with high-risk (clinical T1-T2 with WHO histological grade 3) or locally advanced (clinical T3-T4) prostate cancer between 2003 and 2009.
To qualify for inclusion, patients needed to receive treatment with either first-line radiation therapy alone or first-line radiation therapy with concomitant adjuvant ADT within 6 months from prostate cancer diagnosis.
Study authors assessed the annual rates of adherence to guidelines with respect to use of radiation therapy-ADT in the overall population and after stratification according to stage-grade groupings, Charlson comorbidity index, and pre-existing cardiovascular disease. Multivariate logistic regression analyses were performed to assess predictors of radiation therapy-ADT use.
“There was a trend toward lower adherence to guidelines with respect to radiation therapy and ADT use from 2003 to 2009,” said Dr. Dell’Oglio, from the Urological Research Institute at IRCCS Ospedale San Raffaele Turro, Universitá Vita-Salute San Raffaele in Milan. “The highest rate of adherence was observed in 2003 at 75%, and conversely, the lowest rate of adherence was observed in 2009 at 58%.”
With the number of randomized controlled trials to support radiation therapy-ADT in this group of patients continuing into the mid-2000s, culminating in the 2008 trial by investigators at Brigham and Women’s Hospital in Boston (JAMA 2008; 299:289-95), “we would expect the opposite,” he said.
When stratified according to stage-grade groupings, a higher rate of adherence to guidelines was found in patients with T3-T4 and any grade cancer compared with T1-T2 and grade 3 (p<.0001). However, even in this higher stage group, there was a trend toward lower guideline adherence over time, he said.
Similar findings were obtained when stratifying patients according to age, Charlson comorbidity index, and pre-existing baseline cardiovascular risk, with less guideline adherence over time.
In multivariate analyses, more recent year of diagnosis (OR 0.90, p<.001), younger patient age (OR 1.30, p<.001), stages T1-T2 G3 disease (OR 0.35, p<.001), Charlson comorbidity index of 0 (OR 0.87, p=.036), African-American race (OR 0.85, p<.001), high socioeconomic status (OR 0.90, p=.067), unknown marital status (OR 0.77, p<.001), urban residence (OR 0.64, p<.001), and residence in the Midwest, South, and West (OR 0.51, OR 0.63, OR 0.60, respectively; all p<.001) were associated with lower radiation therapy-ADT use.
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