Long-term outcome of high dose intensity modulated radiation therapy for patients with clinically localized prostate cancer.
OBJECTIVE
We report on the long-term results and late toxicity outcomes of high dose intensity modulated radiation therapy for patients with clinically localized prostate cancer.


METHODS
Between 1996 and 2000 a total of 561 patients with clinically localized prostate cancer were treated with intensity modulated radiation therapy. All patients were treated to a dose of 81 Gy prescribed to the planning target volume. Prostate specific antigen relapse was defined according to the American Society for Therapeutic Radiology and Oncology consensus and Houston definitions (absolute nadir plus 2 ng/ml dated at the call). Median followup was 7 years (range 5 to 9).


RESULTS
The 8-year actuarial PSA relapse-free survival rates for patients in favorable, intermediate and unfavorable risk groups according to the American Society for Therapeutic Radiology and Oncology definition were 85%, 76% and 72%, respectively (p <0.025). The 8-year actuarial prostate specific antigen relapse-free survival rates for patients in favorable, intermediate and unfavorable risk groups according to the Houston definition were 89%, 78% and 67%, respectively (p = 0.0004). The 8-year actuarial likelihood of grade 2 rectal bleeding was 1.6%. Three patients (0.1%) experienced grade 3 rectal toxicity requiring either 1 or more transfusions or a laser cauterization procedure. No grade 4 rectal complications have been observed. The 8-year likelihood of late grade 2 and 3 (urethral strictures) urinary toxicities were 9% and 3%, respectively. Among patients who were potent before intensity modulated radiation therapy, erectile dysfunction developed in 49%. The cause specific survival outcomes for favorable, intermediate and unfavorable risk cases were 100%, 96% and 84%, respectively.


CONCLUSIONS
These long-term results confirm our previous observations regarding the safety of high dose intensity modulated radiation therapy for clinically localized prostate cancer. Despite the application of high radiation doses, the incidence of rectal bleeding at 8 years was less than 2%. Despite the increased conformality of the dose distribution associated with intensity modulated radiation therapy, excellent long-term tumor control outcomes were achieved.
Zelefsky
Michael J
MJ
Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA. zelefskm@mskcc.org
Chan
Heather
H
Hunt
Margie
M
Yamada
Yoshiya
Y
Shippy
Alison M
AM
Amols
Howard
H
D000368:Aged; D000369:Aged, 80 and over; D018572:Disease-Free Survival; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000097:blood / Q000473:pathology / Q000532:radiotherapy*; D011836:Radiation Tolerance; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects; D012007:Rectum / Q000528:radiation effects; D016896:Treatment Outcome; D014551:Urinary Tract / Q000528:radiation effects
D017430:Prostate-Specific Antigen