Risk Stratification after Biochemical Failure following Curative Treatment of Locally Advanced Prostate Cancer : Data from the TROG 96.01 Trial

Abstract EN

Purpose.

Survival following biochemical failure is highly variable.

Using a randomized trial dataset, we sought to define a risk stratification scheme in men with locally advanced prostate cancer (LAPC).

Methods.

The TROG 96.01 trial randomized 802 men with LAPC to radiation ± neoadjuvant androgen suppression therapy (AST) between 1996 and 2000.

Ten-year follow-up data was used to develop three-tier post-biochemical failure risk stratification schemes based on cutpoints of time to biochemical failure (TTBF) and PSA doubling time (PSADT).

Schemes were evaluated in univariable, competing risk models for prostate cancer-specific mortality.

The performance was assessed by c-indices and internally validated by the simple bootstrap method.

Performance rankings were compared in sensitivity analyses using multivariable models and variations in PSADT calculation.

Results.

485 men developed biochemical failure.

c-indices ranged between 0.630 and 0.730.

The most discriminatory scheme had a high risk category defined by PSADT < 4 months or TTBF < 1 year and low risk category by PSADT > 9 months or TTBF > 3 years.

Conclusion.

TTBF and PSADT can be combined to define risk stratification schemes after biochemical failure in men with LAPC treated with short-term AST and radiotherapy.

External validation, particularly in long-term AST and radiotherapy datasets, is necessary.