Ken Yoshida1, Hideya Yamazaki2, Tadayuki Kotsuma3, Tadashi Takenaka4, Mari Mikami Ueda5, Shunsuke Miyake5, Yutaka Tsujimoto5, Koji Masui2, Yasuo Yoshioka6, Iori Sumida6, Yasuo Uesugi7, Taiju Shimbo7, Nobuhiko Yoshikawa7, Hiroto Yoshioka7, Eiichi Tanaka3, Yoshifumi Narumi8. 1. Department of Radiation Oncology, Osaka Medical College, Takatsuki, Osaka, Japan. Electronic address: rad113@poh.osaka-med.ac.jp. 2. Department of Radiology, Kyoto Prefectural University of Medicine, Kyoto, Kyoto, Japan. 3. Department of Radiation Oncology, National Hospital Organization Osaka National Hospital, Osaka, Osaka, Japan. 4. Department of Radiology, National Hospital Organization Himeji Medical Center, Himeji, Hyogo, Japan. 5. Department of Radiology, National Hospital Organization Osaka National Hospital, Osaka, Osaka, Japan. 6. Department of Radiation Oncology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan. 7. Department of Radiation Oncology, Osaka Medical College, Takatsuki, Osaka, Japan. 8. Department of Radiology, Osaka Medical College, Takatsuki, Osaka, Japan.
Abstract
PURPOSE: To choose the optimal brachytherapeutic modality for uterine cervical cancer, we performed simulation analysis. METHODS AND MATERIALS: For each high-risk clinical target volume (HR CTV), we compared four modalities [classical conventional intracavitary brachytherapy (ConvICBT), Image-guided ICBT (IGICBT), intracavitary/interstitial brachytherapy (ICISBT), and interstitial brachytherapy (ISBT) with perineal approach] using dose-volume histograms using eight sizes of HR CTV (2 × 2 × 2 cm to 7 × 4 × 4 cm) and organs at risk model. RESULTS: In ConvICBT, the doses covered 90% of the HR CTV [D90(HR CTV)] decreased from 197% prescribed dose (PD) for the HR CTV size (2 × 2 × 2 cm) to 73% PD for 5 × 4 × 4 cm, whereas the other three modalities could achieve 100% PD for all HR CTV sizes. The minimum doses received by the maximally irradiated 2-cm(3) volumes for organs at risks of IGICBT demonstrated lower values than those of ConvICBT for the HR CTV size of 4 × 3 × 3 cm or smaller. ICISBT demonstrated lower values than those of IGICBT for 4 × 3 × 3 cm or larger. ISBT demonstrated lowest values for 5 × 4 × 4 cm or larger. CONCLUSIONS: HR CTV size of 4 × 3 × 3 cm seems to be a threshold volume in this simulation analysis, and IGICBT is a better choice for smaller HR CTV than the threshold volume. On larger HR CTV, ICISBT or ISBT is the better choice.
PURPOSE: To choose the optimal brachytherapeutic modality for uterine cervical cancer, we performed simulation analysis. METHODS AND MATERIALS: For each high-risk clinical target volume (HR CTV), we compared four modalities [classical conventional intracavitary brachytherapy (ConvICBT), Image-guided ICBT (IGICBT), intracavitary/interstitial brachytherapy (ICISBT), and interstitial brachytherapy (ISBT) with perineal approach] using dose-volume histograms using eight sizes of HR CTV (2 × 2 × 2 cm to 7 × 4 × 4 cm) and organs at risk model. RESULTS: In ConvICBT, the doses covered 90% of the HR CTV [D90(HR CTV)] decreased from 197% prescribed dose (PD) for the HR CTV size (2 × 2 × 2 cm) to 73% PD for 5 × 4 × 4 cm, whereas the other three modalities could achieve 100% PD for all HR CTV sizes. The minimum doses received by the maximally irradiated 2-cm(3) volumes for organs at risks of IGICBT demonstrated lower values than those of ConvICBT for the HR CTV size of 4 × 3 × 3 cm or smaller. ICISBT demonstrated lower values than those of IGICBT for 4 × 3 × 3 cm or larger. ISBT demonstrated lowest values for 5 × 4 × 4 cm or larger. CONCLUSIONS: HR CTV size of 4 × 3 × 3 cm seems to be a threshold volume in this simulation analysis, and IGICBT is a better choice for smaller HR CTV than the threshold volume. On larger HR CTV, ICISBT or ISBT is the better choice.