VIRTUAL SIMULATION AND THREE-DIMENSIONAL CONFORMAL RADIATION THERAPY IN LOCALIZED PROSTATIC CANCER

From April 1997 through December 1997, the feasibility, efficacy and safety of virtual simulation and three-dimensional radiation therapy was analyzed in eight patients with localized prostatic cancer. Prior to treatment, prostate-specific antigen levels ranged from 16.2 to 66.8 ng/ml (median, 25.2 ng/ml). Initial tumor volume (prostate and seminal vesicles), boost tumor volume (prostate) and surrounding normal structures (bladder and rectum) were contoured in a virtual environment on computed tomography slices obtained following immobilization in treatment position. Parallel opposed anteroposterior and posteroanterior and parallel opposed right lateral and left lateral treatment fields were generated and initial and boost treatment plans were obtained in a virtual environment. Initial tumor volume was treated with 50 Gy in 25 fractions and boost tumor volume with 20 Gy in 10 fractions, using 6 My photons. Three patients developed Grade 1 or 2 acute genitourinary toxicity and seven patients developed Grade 1 or 2 acute gastrointestinal toxicity. At seven months after treatment, prostate-specific antigen levels ranged from 0.1 to 1.1 ng/ml (median, 0.6 ng/ml). Virtual simulation and three-dimensional radiation therapy in localized prostatic cancer was presumed to be feasible, efficient and safe.