DEFINITIONS OF BIOCHEMICAL FAILURE THAT BEST PREDICT CLINICAL FAILURE IN PATIENTS WITH PROSTATE CANCER TREATED WITH EXTERNAL BEAM RADIATION ALONE: A MULTI-INSTITUTIONAL POOLED ANALYSIS

Using what is to our knowledge the largest data set of patients with prostate cancer treated with RT alone we correlated multiple definitions of BF with the strict clinical end points of DF alone and CF (DF or local failure). Defining BF as PSA greater than absolute nadir plus 2 ng/ml, dated at the call, PSA greater than current nadir plus 3 ng/ml, dated at the call, or 2 consecutive increases of at least 0.5 ng/ml, back dated, had higher sensitivity and specificity for DF alone or CF compared with the ASTRO definition. This information should contribute to the discussion regarding suggested modifications to the ASTRO definition of biochemical failure.