TY - JOUR
T1 - Increasing external beam dose for T1-T2 prostate cancer
T2 - Effect on risk groups
AU - Thames, Howard D.
AU - Kuban, Deborah A.
AU - DeSilvio, Michelle L.
AU - Levy, Larry B.
AU - Horwitz, Eric M.
AU - Kupelian, Patrick A.
AU - Martinez, Alvaro A.
AU - Michalski, Jeff M.
AU - Pisansky, Thomas M.
AU - Sandler, Howard M.
AU - Shipley, William U.
AU - Zelefsky, Michael J.
AU - Zietman, Anthony L.
N1 - Funding Information:
Supported by the Buchanan-Seeger Research Professorship and physician investigator funds from the MD Anderson Cancer Center.
PY - 2006/7/15
Y1 - 2006/7/15
N2 - Purpose: The aim of this study was to investigate effect of increasing dose on risk groups for clinical failure (CF: local failure or distant failure or hormone ablation or PSA ≥25 ng/ml) in patients with T1-T2 prostate cancer treated with external beam radiotherapy. Methods and Materials: Patients (n = 4,537) were partitioned into nonoverlapping dose ranges, each narrow enough that dose was not a predictor of CF, and risk groups for CF were determined using recursive partitioning analysis (RPA). The same technique was applied to the highest of these dose ranges (70-76 Gy, 1,136 patients) to compare risk groups for CF in this dose range with the conventional risk-group classification. Results: Cutpoints defining low-risk groups in each dose range shifted to higher initial PSA levels and Gleason scores with increasing dose. Risk groups for CF in the dose range 70-76 Gy were not consistent with conventional risk groups. Conclusions: The conventional classification of risk groups was derived in the early PSA era, when total doses <70 Gy were common, and it is inconsistent with risk groups for patients treated to doses >70 Gy. Risk-group classifications must be continuously re-examined whenever the trend is toward increasing total dose.
AB - Purpose: The aim of this study was to investigate effect of increasing dose on risk groups for clinical failure (CF: local failure or distant failure or hormone ablation or PSA ≥25 ng/ml) in patients with T1-T2 prostate cancer treated with external beam radiotherapy. Methods and Materials: Patients (n = 4,537) were partitioned into nonoverlapping dose ranges, each narrow enough that dose was not a predictor of CF, and risk groups for CF were determined using recursive partitioning analysis (RPA). The same technique was applied to the highest of these dose ranges (70-76 Gy, 1,136 patients) to compare risk groups for CF in this dose range with the conventional risk-group classification. Results: Cutpoints defining low-risk groups in each dose range shifted to higher initial PSA levels and Gleason scores with increasing dose. Risk groups for CF in the dose range 70-76 Gy were not consistent with conventional risk groups. Conclusions: The conventional classification of risk groups was derived in the early PSA era, when total doses <70 Gy were common, and it is inconsistent with risk groups for patients treated to doses >70 Gy. Risk-group classifications must be continuously re-examined whenever the trend is toward increasing total dose.
KW - Clinical disease-free survival
KW - Multi-institutional analysis
KW - Prostate cancer
KW - Radiotherapy
KW - Risk groups
UR - http://www.scopus.com/inward/record.url?scp=33745192826&partnerID=8YFLogxK
U2 - 10.1016/j.ijrobp.2006.02.043
DO - 10.1016/j.ijrobp.2006.02.043
M3 - Article
C2 - 16750319
AN - SCOPUS:33745192826
SN - 0360-3016
VL - 65
SP - 975
EP - 981
JO - International Journal of Radiation Oncology Biology Physics
JF - International Journal of Radiation Oncology Biology Physics
IS - 4
ER -