Predicting the Risk of Pelvic Node Involvement Among Men With Prostate Cancer in the Contemporary Era
- Department of Statistics, University of Connecticut, Storrs, CT (United States)
- Harvard Radiation Oncology Program, Boston, MA (United States)
- Division of Radiation Oncology, Saints Medical Center, Lowell, MA (United States)
- Department of Radiation Oncology, Brigham and Women's Hospital and Dana Farber Cancer Institute, Boston, MA (United States)
Purpose: 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. Methods: 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. Results: 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%. Conclusion: 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.
- OSTI ID:
- 21276778
- Journal Information:
- International Journal of Radiation Oncology, Biology and Physics, Vol. 74, Issue 1; Other Information: DOI: 10.1016/j.ijrobp.2008.07.053; PII: S0360-3016(08)03298-7; Copyright (c) 2009 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0360-3016
- Country of Publication:
- United States
- Language:
- English
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