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.
Rene
Nicholas
N
Department of Radiation Oncology, McGill University Health Centre, Montreal, Quebec, Canada.
Faria
Sergio
S
Cury
Fabio
F
David
Marc
M
Duclos
Marie
M
Shenouda
George
G
Souhami
Luis
L
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