Primary ADT Does Not Extend Low-Risk Prostate Cancer Survival

Androgen deprivation therapy for the treatment of men with low-risk prostate cancer is not supported by long-term study data

medwireNews: Androgen deprivation therapy (ADT) does not improve the survival of older men with localised prostate cancer, confirm 15-year study findings published in JAMA Internal Medicine.

“Health care providers and their older patients should carefully weigh our findings against the considerable adverse effects and costs associated with primary ADT before initiating this therapy in men with clinically localized prostate cancer”, recommend Grace Lu-Yao, from Rutgers Cancer Institute of New Jersey in New Brunswick, USA, and co-authors.

Their instrumental variable analysis included 66,717 men aged 66 years or older who were recorded in the US Surveillance, Epidemiology, and End Results Program as having been diagnosed with stage T1 or T2 prostate cancer between 1992 and 2009. None of the men had received definitive local treatment within 180 days of their diagnosis.

Following up the men for a median of 110 months, the researchers found no significant difference in the 15-year rate of overall survival for men living in health service areas in the top tertile for use of primary ADT and those in the bottom tertile, at 15.9% and 16.8%, respectively.

The 15-year rate of prostate cancer-specific survival was 85.4% in areas in both the top and bottom tertile, the team reports.

And 15-year rates of overall survival and prostate cancer-specific survival remained comparable in patients from the top and bottom area tertiles when the researchers separately analysed data for patients with moderately or poorly differentiated disease.

“These findings, the fact that primary ADT does not delay the use of secondary cancer therapies, and the fact that randomized clinical trials show no survival benefit, demonstrate that there is a limited role for ADT as primary therapy for men with localized prostate cancer”, Grace Lu-Yao et al emphasise.

Their research is reported alongside a second article in JAMA Internal Medicine examining the impact of physician influence on the management of 12,068 men aged at least 66 years old with stage T1 to T2a prostate cancer.

Overall, 80.1% of patients underwent surgery, radiotherapy, cryotherapy or ADT, while 19.9% underwent observation or active surveillance. But the case-adjusted rate for use of any treatment varied significantly from 4.5% to 64.2% for patients of diagnosing urologists and between 2.2% and 46.8% for patients of consulting radiation oncologists.

Moreover, Karen Hoffman, from the University of Texas MD Anderson Cancer Center in Houston, USA, and co-authors found that the diagnosing urologist’s influence accounted for 16.1% of variation in the decision to receive upfront treatment versus undergo observation compared with just 7.9% for patient and tumour characteristics.

Of concern, patients were more likely to be treated for low-risk disease if their diagnosing urologist also treated patients with later stage prostate cancer or billed patients for treatment directly.

“Public reporting of physicians’ cancer management profiles would enable primary care physicians and patients to make more informed decisions when selecting a physician to diagnose and manage prostate cancer”, Karen Hoffman et al suggest.

References

Lu-Yao G, Albertsen P, Moore D, et al. Fifteen-year survival outcomes following primary androgen-deprivation therapy for localized prostate cancer. JAMA Intern Med 2014; Online First 14 July. doi:10.1001/jamainternmed.2014.3028

Hoffman K, Niu J, Shen Y, et al. Physician variation in management of low-risk prostate cancer. A population-based cohort study. JAMA Intern Med 2014; Online First 14 July. doi:10.1001/jamainternmed.2014.3021

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