Background and purpose: In our institution, rotational 3D-conformal radiation therapy (also called conformation therapy) has been applied since the late 1970s to conform the target volume of high-dose radiation to the cancerous tissue while minimizing radiation to the surrounding normal tissues. This technique has been used most commonly to treat prostate cancers in combination with hormonal therapy. The results of Stage B2/C prostate cancer treated with this method were analyzed.
Patients and methods: Between 1987 and 1997, 33 cases of prostate cancer were definitively treated with this method: 9 Stage B2 tumors and 24 Stage C tumors. Of these 33 tumors, 3 were well differentiated, 18 were moderately differentiated, and 12 were poorly differentiated. The average patient age was 75.6 years. The median pretreatment PSA value was 23.8 ng/ml. The total radiation dose ranged from 60 Gy to 70 Gy (average: 63.5 Gy) with conventional fractionation. Hormone therapy was administered permanently; the primary hormonal agent was diethylstilbestrol phosphate.
Results: The overall survival rate after 5 years was 58.2% and that after 10 years was 29.6%. The biochemical relapse-free rate after 5 years was 87.0% and that after 10 years was still 87.0%. There were 4 cases of biochemical failure, but no cases of death from prostate cancer. Stage, differentiation, and pretreatment PSA value were not prognostic factors. One of the 2 cases with delayed complications was a case of RTOG Grade 3 gastrointestinal complication.
Conclusions: Rotational 3D-conformal radiation therapy combined with hormone therapy might be promising for the treatment of prostate cancer.