Three dimensional conformal radiation therapy in prostate adenocarcinoma: survival and rectal toxicity.

Technological advances in radiation beam planning and linear accelerator based radiation delivery have led to the development of three dimensional conformal radiation therapy (3D-CRT). The 3D-CRT clinical treatment in our hospital was started in September 1998 and till December 2002, 51 patients with M(0) stage prostate carcinoma were treated. Treatment method consisted of pelvis and leg immobilization, planning CT scan, marking of planning target volume and organs at risk and 3D beam plan using multileaf collimated beam shaping through beam's eye view display. Network controlled 3D conformal radiation therapy was delivered with portal image verification. The median 3D-CRT dose was 72 Gy. Of the 51 patients, 35 were followed-up till December 2002 (minimum follow-up 2 years) in whom 32 were disease free and 3 had progressive disease. Eleven patients died, 8 of progressive disease, one due to second malignancy and two of intercurrent illness. Five patients were lost for follow up during 0 - 29 months period, after 3D-CRT. The acute rectal reaction (RTOG criteria) in 51 patients was grade 0 in 4, grade I in 31 and grade II in 16. None had greater than grade II rectal toxicity. The late rectal toxicity in 49 patients who had a minimum 6 months follow-up was grade 0 in 41, grade I in 3 and grade II in 5. Our experience suggests that a dose of 72 Gy by 3D-CRT can be safely delivered to the prostate and gastrointestinal tolerance during treatment and follow-up period was excellent.