CT-based 3D Dose-Volume Parameter of the Rectum and Late Rectal Complication in Patients with Cervical Cancer Treated with High-Dose-Rate Intracavitary Brachytherapy

Abstract

This study evaluated the efficacy of computed tomography (CT)-based three-dimensional (3D) dose-volume parameters of the rectum as predictor for late rectal complication (LRC) in cervical cancer patients treated with radiotherapy alone. Eighty-four patients treated with a combination of external radiotherapy and high-dose-rate intracavitary brachytherapy between January 2000 and December 2004 were retrospectively analyzed. Brachytherapy was prescribed with standard 2D planning. Patients underwent pelvic CT at brachytherapy. The external rectal wall was contoured on the CT images, and the minimum doses delivered to 0.1cc, 1cc, and 2cc of the most irradiated rectal volumes were calculated with dose-volume histograms. The International Commission of Radiation Units and Measurements (ICRU) rectal point dose was also calculated by conventional method. Total dose (external radiotherapy plus brachytherapy) to the rectum was transformed to the biologically equivalent dose in 2-Gy fractions with alpha/beta of 3 Gy (D(0.1cc), D(1cc), D(2cc) and D(ICRU)). The relationships between these dosimetric parameters and the incidence of LRC were analyzed. The 5-year overall actuarial rate of LRC was 26.4%. The values of D(0.1cc), D(1cc), and D(2cc) were significantly higher in patients with LRC than in those without (p < 0.001), but the difference in the values of D(ICRU) was not statistically significant (p = 0.10). The rate of LRC increased significantly with increasing D(0.1cc), D(1cc), and D(2cc) (p = 0.001). However, no positive dose-response relationship was observed between D(ICRU) and the rate of LRC (p = 0.42). The present study has suggested that CT-based 3D dose-volume parameters of the rectum may be effective for predicting LRC.

The association of rectal equivalent dose in 2 Gy fractions (EQD2) to late rectal toxicity in locally advanced cervical cancer patients who were evaluated by rectosigmoidoscopy in Faculty of Medicine, Chiang Mai University

“…Volume-based planning brachytherapy could be more accurate on delineating organs-at-risk including rectum and assessing doses through dose volume histograms [29]. The study from Kato et al [30] reported the dose evaluation of 48 patients who were treated by combination of WPRT plus HDR-ICBT. Computed tomography-based three dimensional (3D) dose-volume parameters of the rectum may be effective for predicting late rectal complications while no correlation between rectal dose in ICRU point and toxicity was found [30].…”

“…The study from Kato et al [30] reported the dose evaluation of 48 patients who were treated by combination of WPRT plus HDR-ICBT. Computed tomography-based three dimensional (3D) dose-volume parameters of the rectum may be effective for predicting late rectal complications while no correlation between rectal dose in ICRU point and toxicity was found [30]. The using of 3D-based approach will be reported in the future.…”

Dose-volume histogram parameters of high-dose-rate brachytherapy for Stage I-II cervical cancer (<=4cm) arising from a small-sized uterus treated with a point A dose-reduced plan

“…However, dose constraints for rectal D2cc had not yet been standardized in the Japanese treatment schedule. Kato et al evaluated the efficacy of CT-based dose–volume parameters of the rectum as a predictor of late rectal complications in 84 cervical cancer patients treated with RT alone [4]. RT was carried out according to the accepted treatment schedule in Japan.…”

“…With radical hysterectomy and pelvic lymphadenectomy, the most common adverse effects are lymphedema and urinary complications [2], whereas with RT the major sites of complications are the rectum, bladder and small bowel [3]. In particular, late rectal complication is one of the most important dose-related toxicities, occurring earlier than other late complications [4]. …”

The use of trans-applicator intracavitary ultrasonography in brachytherapy for cervical cancer: phantom study of a novel approach to 3D image-guided brachytherapy

“…Technological advancements have led to the inclusion of three-dimensional (3D) imaging modalities such as computed tomography (CT) and magnetic resonance imaging (MRI) in brachytherapy treatment planning [1, 2]. Thus, 3D image-guided brachytherapy (IGBT) has yielded improvements in disease control [3, 4] and the avoidance of adverse effects [5, 6, 7]. On a global scale, high incidence rates of cervical cancer have been reported in countries with low and medium national income levels [8].…”