Variable definitions influence the reporting of biochemical failure rates

Area of Science:

• Urology
• Oncology
• Radiation Oncology

Background:

• Localized prostate cancer treatment efficacy is often measured by biochemical failure (BF) rates.
• Current BF definitions lack standardization, hindering comparative analysis of treatment outcomes.
• Prostate-specific antigen (PSA) monitoring is a key component in assessing treatment response.

Purpose of the Study:

• To evaluate the impact of three distinct BF definitions on reported failure rates.
• To compare BF rates across I-125 brachytherapy, 3D-conformal radiation therapy, and radical prostatectomy.

Main Methods:

• Retrospective analysis of 315 men with localized prostate cancer.
• Treatments included I-125 brachytherapy (n=109), 3D-conformal radiation therapy (n=99), and radical prostatectomy (n=107).
• BF assessed at 12, 24, and 36 months using three definitions: PSA nadir >0.5 ng/ml, PSA rise by 0.5 ng/ml, and three consecutive PSA rises.

Main Results:

• The choice of BF definition significantly altered failure rates in brachytherapy and radiation therapy groups.
• For I-125 brachytherapy at 24 months, BF rates varied from 4% to 46% depending on the definition.
• For 3D-conformal radiation therapy at 24 months, BF rates ranged from 3% to 39% based on the definition used.
• No biochemical failures were observed in the radical prostatectomy group across all definitions.

Conclusions:

• The definition of biochemical failure critically impacts the reported efficacy of localized prostate cancer treatments.
• A lack of a universal BF definition complicates the comparison of brachytherapy and external beam radiation therapy outcomes.
• Establishing a standardized definition for biochemical failure is essential for accurate treatment efficacy assessment and clinical decision-making.