The late toxicity of medium-dose-rate brachytherapy combined with external beam radiotherapy in the treatment of advanced cervical carcinoma

The late toxicity of medium-dose-rate brachytherapy combined with external beam radiotherapy in the treatment of advanced cervical carcinoma

Abstracts / Brachytherapy 7 (2008) 91e194 Methods and Materials: This study is an institutional retrospective review of 42 women with stage IB-IIIB ce...

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Abstracts / Brachytherapy 7 (2008) 91e194 Methods and Materials: This study is an institutional retrospective review of 42 women with stage IB-IIIB cervical cancer treated with primary radiation and chemotherapy sensitization from March 2005 to October 2007. Median age was 52 years (range 22e84 years). Thirty-eight patients received chemotherapy (Cisplatin); four patients did not. FIGO clinical stage of disease was I in 20 patients (48%), II in 11 (26%), and III in 11 (26%). Radiation treatments included external beam radiation (median dose 45 Gy, EQD2 5 44.30 Gy) and HDR brachytherapy. Four patients (10%) received two fractions (median dose 8.50 Gy/fx, EQD2 5 26.20 Gy), fourteen patients (33%) received three fractions (median dose 7.00 Gy/fx, EQD2 5 29.80 Gy), nine (21%) patients received four fractions (median dose 5.50/fx Gy, range 5.25e7.00 Gy/fx, EQD2 5 28.40 Gy), and fifteen patients (36%) received five fractions (median dose 5.50 Gy/fx, EQD2 5 35.50 Gy) The cumulative median maximum HDR EQD2 rectal dose was 14.60 Gy (10.90e27.20 Gy); bladder dose was 13.50 (7.00e36.40 Gy). Median followup was 4.5 months. Results: Patient toxicity was scored using Common Terminology Criteria for Adverse Events version 3.0. Patients experienced the following rates of acute side effects: diarrhea 64%, rectal bleeding 21%, urinary frequency 21%, and vaginal pain 5%. In total, three grade 3 toxicities (all diarrhea) were documented. By number of HDR fractions, (2, 3, 4, or 5 fractions), patients experienced the following rates of acute side effects, respectively: diarrhea 25, 71, 56, and 41%; rectal bleeding 0, 14, 33, and 20%; urinary frequency 0, 21, 33, and 20%; and vaginal pain 0, 7, 11, and 0. Multiple regression analysis did not reveal significant correlation between total HDR dose, HDR dose per fraction, or maximum cumulative rectal/bladder dose and development of acute genitourinary or gastrointestinal toxicity. Conclusions: Patients tolerated all fractionation schemes well. The majority of toxicity was grade 1 and 2; only three grade 3 toxicities occurred. No local recurrences were identified during the followup period. No statistically significant correlation was identified between acute toxicity and the fractionation schemes studied. Larger study size is needed for stronger statistical analysis. Chronic toxicity will be reported after a longer followup period.

PO49 The late toxicity of medium-dose-rate brachytherapy combined with external beam radiotherapy in the treatment of advanced cervical carcinoma Claudia Ordeanu, Ovidiu Coza, Sorin Gavris, Eniko Szilagy, M. Bako, Valentin Cernea, Nicolae Ghilezan, Viorica Nagy Brachytherapy, Institute of Oncology ‘‘I.Chiricuta’’, Cluj-Napoca, Romania. Purpose: The analysis of the iatrogeneous morbidity, except the randomized trials or the ones of phase two, is not systematically done in the common practice, especially for the gynecological tumors treated with medium-dose-rate brachytherapy (MDR-BT). The purpose was to evaluate late toxicity. Methods and Materials: From 1999 to 2001, 261 patients with advanced loco-regional cancer of the uterine cervix (FIGO stages IIB-IIIB) were treated with curative intent. The cases were allocated in two groups: group A- 107 patients treated with radiotherapy (RT) followed by surgery, and group B-154 patients treated with RT alone; 43 patients from group A respectively 30 from group B received cisplatin as radiosensitizer. MDRBT was performed with a LDR/MDR Cs-137 Selectron machine; 10e14 Gy/point A were delivered in the preoperative group and 14e16 Gy/point A in 1e2 fractions in group B. Results: The treatment toxicity in this study was estimate by using the French-Italian Glossary. After a medium followup period of 44 months, 75 (28.7%) of the patients presented late toxicity: the highest percentage was represented by vaginal toxicity, 66 (25%), followed by rectal late toxicity, 21 (8%), respectively 6 (2%) bladder toxicity. 17 (6.5%) of the patients presented multiple, associated toxicities. The late toxicity grade was of light and medium (G1e2), and it appeared at 71 (27.21%) patients; only 4 (1.53%) presented G3. Of the 66 patients that presented vaginal toxicity, 54 (20.69%) presented G1, 11 patients G2 (4.21%), respectively one G3. Of the group of patients that presented global rectal toxicity, 13 patients (5%) presented G1; 6 presented G2 (2%), respectively 2 patients (1%) presented G3 rectal toxicity. Of the total of

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patients with late bladder toxicity, 5 presented G1 (2%), respectively, 1 patient presented G3. Depending on the therapeutic group, the late toxicity was of 3 (2.8%)in group A vs. 72 (46.75%) in group B. Conclusions: For the 261 patients in this study, the brachytherapy was done according to the anatomy of the patients: for 199 patients the ring uterovaginal applicator was used, respectively for 39 the colpostates uterovaginal applicator. In this study, 28.7% of the patients presented late toxicity: 25% vaginal, 8% rectal respectively 2% bladder late toxicity. Most of the rectal, bladder complications, respectively, appeared at the same therapeutical group-B and from these, the highest toxicity was presented by patients for which the ring applicator was used.

PO50 Dose modeling of the Xoft electronic brachytherapy source for tandem and ovoid applications in patients with cervical cancer Kathryn Huber, M.D., Ph.D., Jessica Hiatt, M.S., M. Yakub Puthawala, M.D., David E. Wazer, M.D. Radiation Oncology, Rhode Island Hospital, Providence, RI. Purpose: The severity of late complications in patients with cervical cancer treated with external beam radiation and high-dose rate intracavitary brachytherapy correlates with the dose received by the adjacent organs at risk. Dosimetric comparison of Ir-192 high-dose-rate brachytherapy (IB) to the Xoft microminiature 50-kV electronic brachytherapy (EB) source in partial breast irradiation showed a significant decrease in the dose delivered to the ipsilateral breast, lung and heart. This effect is due to the rapid dose fall-off characteristics of the EB source. In this study, we compare the relative dose delivered to the bladder and rectum when these two brachytherapy methods are utilized for tandem and ovoid applications. Methods and Materials: The planning CT scans from 10 patients who were treated with Ir-192 high-dose-rate brachytherapy with tandem and ovoids were used to compare dose parameters between IB and EB. The doses to point A, the ICRU bladder and rectal points, and the minimum dose to 0.1 cm3, 1 cm3 and 2 cm3 of the bladder and rectum were measured for both IB and EB plans. Results: The mean %dose for the IB and EB plans, respectively were as follows: Point A, 99.4% vs. 99.1% on the left and 100.6% vs. 100.9% on the right (p 5 0.16, nonsignificant); ICRU bladder point, 45.2% vs. 20.4% (p 5 0.0001); ICRU rectal point, 39.9% vs. 30.7% (p 5 0.0003); 0.1 cm3 bladder volume, 54.4% vs. 40.6% (p 5 0.0001); 1 cm3 bladder volume, 44.3% vs. 29.1% (p 5 0.0001); 2 cm3 bladder volume, 40.0% vs. 24.0% (p 5 0.0001); 0.1 cm3 rectal volume, 54.7% vs. 46.1% (p 5 0.01); 1 cm3 rectal volume, 45.2% vs. 32.3% (p 5 0.0006); and 2 cm3 rectal volume, 40.3% vs. 27.4% (p 5 0.0002). Conclusions: This dose modeling comparison of IB to the Xoft 50-kV EB source shows that EB provides similar dose to prescription points while significantly decreasing the dose to the bladder and rectum.

PO51 3D image-guided brachytherapy using cone beam CT Brigitte Reniers, Ph.D., Frank Verhaegen, Ph.D. Medical Physics, McGill University, Montreal, QC, Canada. Purpose: This paper focuses on HDR gynecological treatments using Fletcher or ring applicators. For GYN treatments, our present standard is to use orthogonal images to reconstruct the 3D position of the applicator. The organs at risk are defined using the ICRU points. The purpose of this study is to introduce 3D planning using a novel cone beam CT scanner. Methods and Materials: A novel cone beam CT scanner, dedicated for brachytherapy (Simulix Evolution, Nucletron) was used in this study. This new tool allows us to obtain full 3D images of our brachytherapy patients in the treatment room itself prior to treatment. These 3D images have been used to recalculate the actual dose delivered during the treatment using the Plato Brachytherapy Planning System (Nucletron). The first step was to optimize the image quality by modifying the acquisition protocol and some