Impact of two different dose rates on frequency and severity of complications and survival of patients with advanced cervix carcinoma

Background: To estimate the impact of two different dose rates on treatment efficacy and toxicity of pts with advanced cervix cancer, the survival and morbidity of 36 women with squamous cell carcinoma of uterine cervix stage III-B, treated with radical radiotherapy, was evaluated. Patients and methods: The median age was 58 years (range: 34 to 76 years). Teletherapy (AP/PA fields, 8 MeV linear accelerator) - 40 Gy in 4 weeks to whole pelvis and 20 Gy in 2 weeks to parametria. Brachytherapy - 25 to 40 Gy (median 40 Gy) to point A; 137Cs radioactive sources afterloaded in Henschke applicator set. In 13 pts (Group A) 137Cs sources were afterloaded manually- dose rate to point A was 57.9 to 69.8 cGy/h (median 64 cGy/h); in 23 pts (Group B) remote afterloading system (Curietron) was used- dose rate to point A was 77.7 to 83.9 cGy/h (median 83.2 cGy/h). Toxicity was assessed using Franco-Italian glossary (Radiother. Oncol. 26:195-202, 1993). Results: The median dose rates at point A differed significantly between the treatment groups (p<0.0001). The distribution of complications was as follows (Group A vs. Group B): (1) by total number: 33 complications in(11(13)) pts vs. 57 complications in (20(23)) pts; (2) by degree of severity: G1 (mild)- 13/33 (40%) vs. 26/57 (46%), G2 (moderate)- 10/33 (30%)vs. 22/57 (39%), G3 (severe)- 9/33 (27%) vs. 7/57 (12%) and G4 (fatal)- 1/33 (3%) vs. 2/57 (3%); (3) by organ systems: urinary- 3/33 (9%) vs. 7/57 (12%), gastro-intestinal- 5/33 (15%) vs. 3/57 (5%), vascular- 3/33 (9%)vs. 3/57 (5%), cutaneous- 4/33 (12%) vs. 10/57 (18%), uterus-vagina-vulva-9/33 (27.5%) vs. 16/57 (28%), pelvic soft tissue- 9/33 (27.5%) vs. 18/57 (32%). The distribution of complications by grade and organ sites and 5-year survival rates (38 vs. 52%) did not differ significantly between groups. Conclusion: There were no differences in treatment efficacy and toxicity between two different dose rates we used. Since a higher dose rate was associated with shorter treatment times, it was better tolerated and more comfortable for the patients