• Takafumi Toita, Yasumasa Kakinohana, Kazuhiko Ogawa, Genki Adachi, Hidehiko Moromizato, Yutaka Nagai, Toshiyuki Maehama, Kaoru Sakumoto, Koji Kanazawa, and Sadayuki Murayama.
• Department of Radiology, University of the Ryukyus School of Medicine, Okinawa, Japan. b983255@med.u-ryukyu.ac.jp
• Int. J. Radiat. Oncol. Biol. Phys. 2003 Aug 1; 56 (5): 1344-53.

PurposeTo determine an appropriate dose and fractionation schedule for a combination of external beam radiotherapy (EBRT) and high-dose-rate intracavitary brachytherapy (HDR-ICBT) for uterine cervical cancer.MethodsEighty-eight patients with uterine cervical squamous cell carcinoma treated with EBRT and HDR-ICBT were analyzed. Twenty-five patients were classified as early disease (nonbulky Stage I/II, less than 4-cm diameter) and 63 patients as advanced disease (greater than 4 cm diameter or Stage IIIB) according to the American Brachytherapy Society definition. Tumor diameter was measured by MRI. Pelvic EBRT was delivered before applications of ICBT. HDR-ICBT was performed once a week, with a fraction point A dose of 6 Gy. Source loadings corresponded to the Manchester System for uterine cervical cancer. No planned optimization was done. A Henschke-type applicator was mostly used (86%). Median cumulative biologic effective dose (BED) at point A (EBRT + ICBT) was 64.8 Gy(10) (range: 48-76.8 Gy(10)) for early disease, and 76.8 Gy(10) (range: 38.4-86.4 Gy(10)) for advanced disease. Median cumulative BED at ICRU 38 reference points (EBRT + ICBT) was 97.7 Gy(3) (range: 59.1-134.4 Gy(3)) at the rectum, 97.8 Gy(3) (range: 54.6-130.4 Gy(3)) at the bladder, and 324 Gy(3) (range: 185.5-618 Gy(3)) at the vagina. Actuarial pelvic control rate and late complication rate were analyzed according to cumulative dose and calculated BED.ResultsThe 3-year actuarial pelvic control rate was 82% for all 88 patients: 96% for those with early disease, and 76% for advanced disease. For pelvic control, no significant dose-response relationship was observed by treatment schedules and cumulative BED at point A for both early and advanced disease. The 3-year actuarial late complication rates (Grade > or =1) were 12% for proctitis, 11% for cystitis, and 14% for enterocolitis. There were significant differences on the incidence of proctitis (p < 0.0001) and enterocolitis (p < 0.0001), but not for cystitis by the treatment schedules and cumulative point A BED. All 4 patients treated with 86.4 Gy(10) at point A suffered both proctitis and enterocolitis. Patients with cumulative BED at rectal point of > or =100 Gy(3) had significantly higher incidence of proctitis (31% vs. 4%, p = 0.013).ConclusionsIn view of the therapeutic ratio, cumulative BED 70-80 Gy(10) at point A is appropriate for uterine cervical cancer patients treated with a combination of EBRT and HDR-ICBT. Present results and data from other literatures suggested that cumulative BED at the rectal point should be kept below 100-120 Gy(3) to prevent late rectal complication.

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