Long-term survival and toxicity in patients treated with high-dose intensity modulated radiation therapy for localized prostate cancer.
OBJECTIVE
To report long-term survival and toxicity outcomes with the use of high-dose intensity modulated radiation therapy (IMRT) to 86.4 Gy for patients with localized prostate cancer.


METHODS
Between August 1997 and December 2008, 1002 patients were treated to a dose of 86.4 Gy using a 5-7 field IMRT technique. Patients were stratified by prognostic risk group based on National Comprehensive Cancer Network risk classification criteria. A total of 587 patients (59%) were treated with neoadjuvant and concurrent androgen deprivation therapy. The median follow-up for the entire cohort was 5.5 years (range, 1-14 years).


RESULTS
For low-, intermediate-, and high-risk groups, 7-year biochemical relapse-free survival outcomes were 98.8%, 85.6%, and 67.9%, respectively (P<.001), and distant metastasis-free survival rates were 99.4%, 94.1%, and 82.0% (P<.001), respectively. On multivariate analysis, T stage (P<.001), Gleason score (P<.001), and >50% of initial biopsy positive core (P=.001) were predictive for distant mestastases. No prostate cancer-related deaths were observed in the low-risk group. The 7-year prostate cancer-specific mortality (PCSM) rates, using competing risk analysis for intermediate- and high-risk groups, were 3.3% and 8.1%, respectively (P=.008). On multivariate analysis, Gleason score (P=.004), percentage of biopsy core positivity (P=.003), and T-stage (P=.033) were predictive for PCSM. Actuarial 7-year grade 2 or higher late gastrointestinal and genitourinary toxicities were 4.4% and 21.1%, respectively. Late grade 3 gastrointestinal and genitourinary toxicity was experienced by 7 patients (0.7%) and 22 patients (2.2%), respectively. Of the 427 men with full potency at baseline, 317 men (74%) retained sexual function at time of last follow-up.


CONCLUSIONS
This study represents the largest cohort of patients treated with high-dose radiation to 86.4 Gy, using IMRT for localized prostate cancer, with the longest follow-up to date. Our findings indicate that this treatment results in excellent clinical outcomes with acceptable toxicity.
Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York, USA.
Daniel E
DE
Spratt
Xin
X
Pei
Josh
J
Yamada
Marisa A
MA
Kollmeier
Brett
B
Cox
Michael J
MJ
Zelefsky
D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D018572:Disease-Free Survival; D041981:Gastrointestinal Tract / Q000528:radiation effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D010410:Penile Erection; D011467:Prostate / Q000473:pathology; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000097:blood / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D011879:Radiotherapy Dosage; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects / Q000379:methods*; D014566:Urogenital System / Q000528:radiation effects
D017430:Prostate-Specific Antigen