Hypofractionated radiotherapy for favorable risk prostate cancer.
OBJECTIVE
Since the recognition that prostate cancer probably has a low alpha/beta ratio, hypofractionated radiotherapy has become an attractive treatment option for localized prostate cancer. However, there is little experience with the use of hypofractionation delivering a high biologically equivalent dose. We report our experience with high-dose hypofractionated radiotherapy.


METHODS
A total of 129 patients with favorable risk prostate cancer were treated with three-dimensional conformal radiotherapy treatment plans to the dose of 66 Gy in 22 fractions, prescribed at the isocenter. Planning target volume consisted of the prostate plus a uniform 7-mm margin, including the rectal margin. No patient received hormonal therapy. Toxicity was prospectively graded by the Common Toxicity Criteria version 3. Biochemical relapse was defined as postradiotherapy nadir prostate-specific antigen + 2 ng/mL.


RESULTS
With a median follow-up of 51 months, the 5-year actuarial biochemical control rate is 98%. The only 3 cases with biochemical failure did not have a clinical local relapse. More than 50% of patients did not develop acute toxicity. For late toxicity, the worst crude rate of Grade >or=2 genitourinary (GU) and gastrointestinal (GI) toxicity seen at any time during follow-up were 32% and 25%, respectively. There was no Grade 4 or 5 toxicity. At the last follow-up, persistent Grade >or=2 late GU and GI toxicity were 2% and 1.5%, respectively.


CONCLUSIONS
This hypofractionated regimen provides excellent biochemical control in favorable risk prostate cancer with an acceptable rate of late toxicity. Further studies exploring this hypofractionation regimen are warranted.
Department of Radiation Oncology, McGill University Health Centre, Montreal, Quebec, Canada.
Nicholas
N
Rene
Sergio
S
Faria
Fabio
F
Cury
Marc
M
David
Marie
M
Duclos
George
G
Shenouda
Luis
L
Souhami
D000368:Aged; D003967:Diarrhea / Q000209:etiology; D019583:Dose Fractionation, Radiation; D006471:Gastrointestinal Hemorrhage / Q000209:etiology; D006801:Humans; D007413:Intestinal Mucosa / Q000528:radiation effects; D008297:Male; D008875:Middle Aged; D052016:Mucositis / Q000209:etiology; D009364:Neoplasm Recurrence, Local / Q000097:blood; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000097:blood / Q000473:pathology / Q000532:radiotherapy*; D011880:Radiotherapy Planning, Computer-Assisted; D020266:Radiotherapy, Conformal / Q000009:adverse effects / Q000379:methods*; D012062:Relative Biological Effectiveness
D017430:Prostate-Specific Antigen