Primary radiotherapy vs conservative management for localized prostate cancer-a population-based study.

Radiotherapy is the most common curative cancer therapy used for elderly patients with localized prostate cancer. However, the effectiveness of this approach has not been established. The purpose of this study is to evaluate the long-term outcomes of primary radiotherapy compared with conservative management in order to facilitate treatment decisions.

This population-based study consisted of 57 749 patients with T1-T2 prostate cancers diagnosed during 1992-2007. We utilized an instrumental variable (IV) analytical approach with competing risk models to evaluate the outcomes of primary radiotherapy vs conservative management. The IV was comprised of combined health service areas with high- and low-use areas corresponding to the top and bottom tertile in radiotherapy usage rates.

In patients with low-/intermediate-risk prostate cancer, 10-year prostate cancer-specific and overall survival was similar in high- and low-radiotherapy use areas (96. 1 vs 95. 4% and 56. 6 vs 56. 3%, respectively). In patients with high-risk disease, however, areas with high-radiotherapy use had a higher 10-year cancer-specific survival (90. 2 vs 88. 1%, difference 2. 1%; 95% CI 0. 3-4. 0%) and 10-year overall survival (53. 3 vs 50. 2%, difference 3. 1%; 95% CI 1. 3-6. 3%). Results were similar irrespective of the type of radiotherapy used. To assess the robustness of our choice of IV, we repeated the IV analytical approach using different IVs (using the median utilization rate as the cutoff) and found the results to be similar.

Among men >65 years of age, the benefit of primary radiotherapy for localized disease is largely confined to patients with high-risk prostate cancer (Gleason scores 7-10). Prostate Cancer and Prostatic Disease advance online publication, 23 June 2015; doi:10. 1038/pcan. 2015. 30.

Prostate cancer and prostatic diseases. 2015 Jun 23 [Epub ahead of print]

G L Lu-Yao, S Kim, D F Moore, W Shih, Y Lin, R S DiPaola, S Shen, A Zietman, S-L Yao

1] Department of Medicine, Rutgers, Robert Wood Johnson Medical School, Piscataway, NJ, USA [2] Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, USA. , 1] Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, USA [2] Department of Radiation Oncology, Rutgers, Robert Wood Johnson Medical School, New Brunswick, NJ, USA. , 1] Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, USA [2] Department of Biostatistics, Rutgers, School of Public Health, Piscataway, NJ, USA. , 1] Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, USA [2] Department of Biostatistics, Rutgers, School of Public Health, Piscataway, NJ, USA. , 1] Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, USA [2] Department of Biostatistics, Rutgers, School of Public Health, Piscataway, NJ, USA. , 1] Department of Medicine, Rutgers, Robert Wood Johnson Medical School, Piscataway, NJ, USA [2] Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, USA. , Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, USA. , Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA, USA. , 1] Department of Medicine, Rutgers, Robert Wood Johnson Medical School, Piscataway, NJ, USA [2] Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, USA.

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