Comparison between high dose-rate and low dose-rate brachytherapy for cervical cancer. Japanese experience with treatment and complications (1975-1985)

To compare the dose rate factor in the brachytherapy for cervical cancer, a questionnaire was sent to 13 facilities in Japan. Data were collected on 551 patients. There were 99 cases in stage I, 232 in stage II and 220 in stage III. Of these 300 cases were treated by the high dose-rate (HDR) technique (stage I: 63, stage II: 123, stage III: 114) and 251 cases by the low dose-rate (LDR) technique (stage I: 36, II: 109, III: 106). The fractionation schedule for intracavitary irradiation was: (a) the HDR group: 6.0±1.1 Gy/fr, and 27.9±4.2 Gy of total dose with 4.8 insertions (3-10 times) in 28.2±10 days; (b) the LDR group: 16.9±6.6 Gy/fr, 48.0±6.8 Gy of total dose with 2.9 insertions (1-5 times) in 21.4±11 days. The tumor CR rate was 81% for all, 83% for the HDR group (stage I: 98%, stage II: 90%, stage III: 68%) and 79% for the LDR group (stage I: 86%, stage II: 85%, stage III: 69%). The 5-year survival rate was 70% for all, 72% for the HDR group (stage I: 87%, stage II: 76%, stage III: 58%) and 68% for the LDR group (stage I: 80%, stage II: 73%, stage III: 59%). There were no statistically significant differences. The incidence of complications according to Kottmeier's grading system were 25.3% for the HDR group and 27.9% for the LDR group (NS). However, there were 20 patients with grade III complications in the HDR group and 12 in the LDR group. Deaths due to complications after irradiation occurred in 7 HDR cases and 1 LDR case. Our data shows that the effect on response and survival rates was equivalent and the dose rate factor was 0.58 over all, 0.57 with midline shield and 0.59 without midline shield. (author)