External beam radiotherapy with or without androgen deprivation therapy in elderly patients with high metastatic risk prostate cancer

Highlights

• No survival benefit from the combination of ADT at RT relative to RT alone in patients aged 80 years or more with high metastatic risk PCa.

• Same findings in elderly patients with no comorbidity and in most contemporary patients.

• The combination of ADT at RT is associated with a significant cost increase.

Abstract

Objective

Several randomized controlled trials have documented significant overall survival benefit in high metastatic risk prostate cancer (PCa) patients treated with combination of androgen deprivation therapy (ADT) at radiotherapy (RT) relative to RT alone. Unfortunately, elderly patients are either not included or are underrepresented in these trials. In consequence, the survival benefit of combination of ADT at RT in the elderly warrants detailed reassessment, including its cost.

Methods

Between 1991 and 2009 within the Surveillance Epidemiology and End Results (SEER)-Medicare-linked database, we identified 3,692 patients aged 80 years or more with clinical T1–T2 PCa and WHO histological grade 3, or clinical T3–T4 PCa and any histological grade, treated with or without combination of ADT at RT. Competing risks analyses focused on cancer-specific mortality (CSM) and other-cause mortality, after accounting for confounders. All analyses were repeated in patients with no comorbidity and in most contemporary patients, treated between 2001 and 2009. Finally, we assessed median annual cost according to use of combination of ADT at RT, after adjusting for patient and tumor characteristics.

Results

In competing-risks multivariable analyses, no statistically significant difference was observed in CSM and other-cause mortality between patients treated with or without combination of ADT at RT. Same results were recorded in subgroup analyses of patients with no comorbidity and in most contemporary patients. The median annual costs of $36,140 and of $47,510 were recorded, respectively in patients treated without and with ADT at RT.

Conclusion

Our findings failed to confirm that combination of ADT at RT reduces CSM rates in high metastatic risk PCa patients aged 80 years or more. Moreover, combination of ADT at RT resulted in a significant cost increase, relative to RT alone.

Introduction

Contemporary guidelines recommend the use of combined external beam radiation therapy (RT) with androgen deprivation therapy (ADT) in men with high metastatic risk prostate cancer (PCa) [1], [2], [3]. However, most randomized controlled trials [4], [5], [6], [7] substantiating these guidelines included few, if any, elderly patients within their testing cohorts. Based on the paucity of elderly patients in such trials [4], [5], [6], [7], it is debatable whether their findings, as well as the guidelines [1], [2], [3] that are based on such trials, are applicable to the elderly. Based on this consideration, we decided to examine RT rates, delivered with or without ADT in elderly patients, within the Surveillance, Epidemiology, and End Results (SEER)-Medicare database. Our study had 3 specific objectives. First, we examined cancer-specific mortality (CSM). Here, we postulated that the combination of ADT at RT will exert a protective effect on CSM. Moreover, we hypothesized that other-cause mortality (OCM) will be unaffected by the addition of ADT. Finally, we examined the cost increase related to the treatment of high metastatic risk PCa patients with combination of ADT at RT vs. RT alone.