Abstract
The "Roach formula" for the risk of pelvic lymph node metastases [(2/3) ( *) PSA + (Gleason score - 6) ( *) 10] was developed in the early prostate-specific antigen (PSA) era. We examined the accuracy of this formula in contemporary patients. We included men in the Surveillance, Epidemiology, and End Results Registry with a diagnosis of clinical T1c-T4 prostate cancer in 2004 who had a surgical lymph node evaluation, Gleason score (typically from prostatectomy), and baseline PSA level (n = 9,387). Expected and observed rates of node positivity were compared. Ninety-eight percent were clinical T1c/T2, and 97% underwent prostatectomy. Overall, 309 patients (3.29%) had positive lymph nodes. Roach scores overestimated the actual rate of positive lymph nodes in the derivation set by 16-fold for patients with Roach score less than or equal to 10%, by 7-fold for scores greater than 10-20%, and by approximately 2.5-fold for scores greater than 20%. Applying these adjustment factors to Roach scores in the validation data set yielded accurate predictions of risk. For those with Roach score less than or equal to 10%, adjusted expected risk was 0.2% and observed risk was 0.2%. For Roach score greater than 10-20%, adjusted expected risk was 2.0% and observed risk was 2.1%. For Roach score greater than 20-30%, adjusted expected risk was 9.7% and observed risk was 6.5%. For Roach score greater than 30-40%, adjusted expected risk was 13.9% and observed risk was 13.9%. Applied to contemporary patients with mainly T1c/T2 disease, the Roach formula appears to overestimate pelvic lymph node risk. The adjustment factors presented here should be validated by using biopsy Gleason scores and extended lymphadenectomies.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have