Mj. Zelefsky et al., LOCALLY ADVANCED PROSTATIC-CANCER - LONG-TERM TOXICITY OUTCOME AFTER 3-DIMENSIONAL CONFORMAL RADIATION-THERAPY - A DOSE-ESCALATION STUDY, Radiology, 209(1), 1998, pp. 169-174
PURPOSE: To determine the long-term effects of 75.6- and 81.0-Gy doses
of three-dimensional conformal radiation therapy in a dose-escalation
study in patients with stage T2c-T3 prostatic cancer. MATERIALS AND M
ETHODS: Fifty patients received an initial 75.6-Gy dose, and the dose
in 46 patients was subsequently escalated to 81.0-Gy. Median follow-up
was 60 and 40 months, respectively. RESULTS: The rates of effects of
acute toxicity during the course of treatment were similar for both do
se levels. Among the 96 patients, the rate of grade 2 morbidities nece
ssitating medication to relieve acute symptoms was 17% (16 patients) f
or rectal and 36% (35 patients) for urinary morbidities. All other pat
ients had either no or grade 1 morbidities. Fourteen patients (15%) de
veloped late grade 2 rectal morbidities. There were no differences in
5-year actuarial rates of late grade 2 rectal or urinary morbidities a
mong patients who received 75.6 Gy versus those who received 81.0 Gy.
One patient treated with 81.0 Gy developed a grade 3 urethral strictur
e, which was resolved with dilatation. CONCLUSION: Tumor dose escalati
on beyond conventional radiation doses for localized prostatic cancer
is feasible when delivered with three-dimensional conformal radiation
therapy, with no increase in morbidity in normal tissue.