Abstract
In an effort to improve upon the historically poor local control and survival rates for locally advanced prostate cancer, a clinical trial was performed using intraoperative radiation therapy (IORT). Between April 1983 and May 1996, 54 patients with locally advanced prostate cancer (18 Stage B2, 26 Stage C, 10 Stage D1) were treated with a combination of (a) local external irradiation of 30 Gy in 2 Gy daily fractions, (b) IORT of 25 or 30 Gy, (c) pelvic lymphadenectomy, and (d) neoadjuvant and/or adjuvant hormonal therapy. A retropubic approach was employed as an operative procedure, and the electron energies selected ranged from 9 to 20 MeV. Since July 1987, a spacer had been inserted into the rectum at IORT to minimize the posterior rectal dose.
When 30 Gy was delivered at IORT without using a spacer, the incidence of grade 3 or 4 rectal morbidity was 20%, while, with the use of a spacer and delivering 30 Gy, the incidence of grade 3 morbidity decreased to 7 % and no grade 4 morbidity was observed. And when delivering 25 Gy using a spacer, no major morbidity was observed. The 5-year disease specific survival, relapse-free survival, and clinical local control rates for all patients were 89%, 74%, and 83%, respectively. The 2 and 5-year biochemical no evidence of disease (b-NED) survival rates for patients treated since 1992 were 90% and 75%, respectively. These results suggest that locally advanced prostate cancer can be well controlled by this unique and aggressive approach. Because of the small sample size and the relatively short follow-up period of time, however, further investigation is required for complete assessment.
