Dosimetric comparison of three-dimensional conformal radiotherapy versus volumetric-arc radiotherapy in cervical cancer treatment: applying the central-shielding principle to modern technology

Tamaki, Tomoaki; Hirai, Ryuta; Igari, Mitsunobu; Kumazaki, Yu; Noda, Shin‐ei; Suzuki, Yoshiyuki; Kato, Shingo

doi:10.1093/jrr/rry054

Cited by 10 publications

(10 citation statements)

References 26 publications

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“…However, none of these studies applied WPRT-CS, given that they enrolled patients in Western countries. Tamaki et al reported a dosimetric analysis of WPRT-CS using VMAT for UCC as a planning study (26). To the best of our knowledge, this is the first report of the combination of HDR-ICBT and IMRT, which consisted of WPRT and WPRT-CS using TomoTherapy or other IMRT modalities, for UCC patients in clinical practice.…”

Section: Discussionmentioning

confidence: 96%

Treatment Outcome of the Combination Therapy of High-dose rate Intracavitary Brachytherapy and Intensity-modulated Radiation Therapy With Central-shielding for Cervical Cancer

Mukai

Minagawa

Inoue

et al. 2020

In Vivo

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Background/Aim: This study aimed to evaluate the clinical outcome of intensity-modulated radiation therapy (IMRT) and high-dose-rate intracavitary brachytherapy (HDR-ICBT) in uterine cervical cancer (UCC). IMRT consisted of whole-pelvic radiation therapy (WPRT) and sequential WPRT with central-shielding (WPRT-CS).Patients and Methods: Thirty UCC patients treated with IMRT using TomoTherapy, were retrospectively analyzed. Results: The median dose of Gy and the median total dose of these was 50 Gy in 25 fractions (Fr). Median HDR-ICBT dose/Fr to Point A was 25 Gy/5 Fr. Median 2 Gy per fraction-equivalent dose (EQD2) of combined WPRT and HDR-ICBT to Point A (α/β=10) was 71.0 Gy. The 3-year local control, disease-free survival, and overall survival rates were 89.9%, 83.3%, and 86.3%. Conclusion: IMRT of WPRT and WPRT-CS given in combination with HDR-ICBT was a feasible therapy resulting in good disease control and tolerance in patients with UCC.With recent increases in the rate of uterine cervical cancer (UCC) in Japan, the role of radiation therapy (RT) in this disease has become more important. Standard RT for UCC includes the combination of external beam radiation therapy (EBRT) to whole pelvis (WP) using three-dimensional conformal radiation therapy (3D-CRT) and high-dose-rate intracavitary brachytherapy (HDR-ICBT) (1-3). Several recent reports have described the use of intensity-modulated radiation therapy (IMRT) for WPRT instead of 3D-CRT (4-7). This strategy appears to provide excellent dose distribution and fewer acute adverse effects compared with 3D-CRT (4, 8-11). In Western countries, 45-50 Gy of WPRT followed by HDR-ICBT is recommended as standard therapy for UCC. However, Asian women typically have a smaller physique than Caucasian women and may have a smaller uterus and vagina surrounded by a thinner layer of fatty tissue. It can be challenging to maintain sufficient space between the HDR-ICBT source and rectal wall during treatment for UCC, resulting in excess exposure to the rectum. Therefore, in Japan and in other Asian countries, standard EBRT includes the combination of WPRT and sequential WPRT with central shielding (WPRT-CS) to avoid overexposure of the rectum in advance of HDR-ICBT. In 3D-CRT, CS comprises a simple rectangular midline block of 4 cm in width, formed by multi-leaf collimators (MCL) (12,13).In the present study, we applied IMRT consisting of WPRT and WPRT-CS instead of 3D-CRT for the treatment of patients with UCC and evaluated the feasibility, treatment outcome, and tolerance of this strategy. To our knowledge, this is the first report of the combination of WPRT and WPRT-CS using IMRT.

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Section: Discussionmentioning

confidence: 96%

Treatment Outcome of the Combination Therapy of High-dose rate Intracavitary Brachytherapy and Intensity-modulated Radiation Therapy With Central-shielding for Cervical Cancer

Mukai

Minagawa

Inoue

et al. 2020

In Vivo

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“…All patients had stage I-IIB disease with a maximum tumor size <4 cm. Definitions of the CTVs for non-bulky cervical cancer cases were defined and described in a previous report on the application of WP-VMAT and CS-VMAT (10). Briefly, the CTVs for primary disease of the uterine cervix (CTV-PD) and pelvic lymph nodes (CTV-LN) were delineated according to published guidelines (17,18).…”

Section: Methodsmentioning

confidence: 99%

“…In order to improve standard radiotherapy for cervical cancer in Japan, we previously conducted a dose-planning study which applied IMRT/VMAT to radiotherapy for early-stage non-bulky cervical cancer cases. For CS-EBRT in that study, we re-examined the principle of CS and defined the specific clinical target volume (CTV) of CS-EBRT, a crucial step in the treatment planning of IMRT/VMAT (10). Nonetheless, the original purpose of CS-EBRT, which is to specifically shield the bladder and the rectum, must be maintained in CS-VMAT.…”

mentioning

confidence: 99%

Plan-Optimization Method for Central-shielding Pelvic Volumetric-modulated Arc Therapy for Cervical Cancer

Hirai

Tamaki

Igari

et al. 2020

In Vivo

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Aim: To establish a method of plan optimization in pelvic volumetric-modulated arc therapy (VMAT) for cervical cancer using the central-shielding (CS) principle. Patients and Methods: We created external beam VMAT plans for eight cases with non-bulky stage I-IIb using the CS principle based on the Japanese standard guideline. Clinical target volumes (CTVs) for whole-pelvis (WP) irradiation were created using published guidelines, and CTVs for CS irradiation were created by subtracting the uterus corpus and 4 cm-wide regions centered at the cervix and vagina from the CTVs for WP irradiation. For plan optimization of CS irradiation, a 4-cm diameter cylindrical volume centered in the cervix and vagina was created as the volume receiving a high dose in brachytherapy, and the volume overlapping with the rectum was defined as the Ant-Rectum. Dosevolume histogram (DVH) parameters of two CS VMAT plans with and without (VMAT OPT /VMAT NO ) dose optimization to the Ant-Rectum were compared. Results: VMAT OPT plans resulted in significantly lower DVH parameters of the Ant-Rectum and rectum compared to VMAT NO plans. These were comparable to the DVH parameters of three-dimensional conformal radiotherapy (3DCRT) plans. Both VMAT plans resulted in significantly better coverage of planning target volumes than did the 3DCRT plans. Conclusion: In the implementation of IMRT/VMAT as the standard treatment for cervical cancer in Japan, our optimization method may be an essential step toward fully benefitting from the CS principle.

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“…All 30 plans were created using PBS with PSAS. In the planning comparison study, 20 patients with NSCHN treated using PBS with PSAS were selected at random from the 30 patients (Table 1) because the majority of previous planning studies used <20 cases [13, 15–17], and the findings obtained did not appear to differ markedly between a study using >80 cases and studies using <20 cases [15]. The same contours created by MIM Maestro version 6.5® (MIM Software Inc., Cleveland, OH, USA) were transferred to VQA version 3.0.5® (Hitachi, Ltd, Tokyo, Japan) and iPlan version 4.1® (Brainlab AG, Feldkirchen, Germany).…”

Section: Methodsmentioning

confidence: 99%

Proton therapy for non-squamous cell carcinoma of the head and neck: planning comparison and toxicity

Iwata

Toshito

Hayashi

et al. 2019

Journal of Radiation Research

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To investigate optimal treatment planning using proton beams for non-squamous cell carcinoma of the head and neck (NSCHN), the dose distributions of plans involving pencil beam scanning (PBS) with or without a patient-specific aperture system (PSAS), passive-scattering proton therapy (PSPT) and X-ray intensity-modulated radiotherapy (IMRT) were compared. As clinical results, toxicities of PBS with PSAS, including changes in quality of life, were reported. Between April 2014 and August 2016, a total of 30 patients were treated using PBS with PSAS. In 20 patients selected at random, the dose distributions of PBS with or without the PSAS, PSPT and IMRT plans were compared. Neutron exposure by proton therapy was calculated using a Monte Carlo simulation. Toxicities were scored according to CTCAE ver. 4.0. Patients completed EORTC quality of life survey forms (QLQ-C30 and QLQ-HN35) before and 0–12 months after proton therapy. The 95% conformity number of PBS with the PSAS plan was the best, and significant differences were detected among the four plans (P < 0.05, Bonferroni tests). Neutron generation by PSAS was ~1.1-fold higher, but was within an acceptable level. No grade 3 or higher acute dermatitis was observed. Pain, appetite loss and increased weight loss were more likely at the end of treatment, but recovered by the 3 month follow-up and returned to the pretreatment level at the 12 month follow-up. PBS with PSAS reduced the penumbra and improved dose conformity in the planning target volume. PBS with PSAS was tolerated well for NSCHN.

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Dosimetric comparison of three-dimensional conformal radiotherapy versus volumetric-arc radiotherapy in cervical cancer treatment: applying the central-shielding principle to modern technology

Cited by 10 publications

References 26 publications

Treatment Outcome of the Combination Therapy of High-dose rate Intracavitary Brachytherapy and Intensity-modulated Radiation Therapy With Central-shielding for Cervical Cancer

Treatment Outcome of the Combination Therapy of High-dose rate Intracavitary Brachytherapy and Intensity-modulated Radiation Therapy With Central-shielding for Cervical Cancer

Plan-Optimization Method for Central-shielding Pelvic Volumetric-modulated Arc Therapy for Cervical Cancer

Proton therapy for non-squamous cell carcinoma of the head and neck: planning comparison and toxicity

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