Standard vs conformal radiation therapy for adenocarcinoma of the prostate: no difference.

Objective: To compare results of treatment of adenocardinoma of the prostate using Standard (2D) vs Conformal (3D) treatment planning. Methods: The records of all patients with adenocarcinoma of the prostate treated curatively with radiation therapy alone from July 1991 to June 1994 were reviewed. Acute and late complications were scored by the RTOG criteria. Biochemical failure was defined as a rising PSA of at least 10% on two measurements separated >/=1 month or either a PSA nadir >4 ng/ml or >1 ng/ml. Disease free survival (DFS) was defined as no evidence of local, distant, or biochemical failure. 2D planning included standard simulation with target volume drawn from the treatment planning or diagnostic CT. 3D planning included a CT in the treatment position with computer simulation using beam's-eye-view for field design. Results: Two-hundred and seventeen 2D and 45 3D patients had similar median age and pre-treatment PSA, T-stage, and dose to the prostate. The median follow-up periods for the 2D and 3D groups were 32.0 and 21.5 months, respectively. The two-year actuarial survival, local or biochemical control, and DFS were not different. The 3D group had a significantly higher incidence of acute bladder side effects of all grades and acute grade 1/2 rectal complications. There were no differences in the incidence of late bladder or rectal complications. Conclusions: Careful 2D planning for the treatment of localized adenocarcinoma of the prostate is an acceptable means of treatment. Within the dose range of 64-70 Gy, this preliminary analysis demonstrated no reduction in complications nor improvement in local or biochemical control, or DFS was seen with the the use of 3D treatment planning.