Radiotherapy doses at special reference points correlate with the outcome of cervical cancer therapy

Yoshimura, Ryo-ichi; Hayashi, Keiji; Ayukawa, Fumio; Toda, Kazuma; Iwata, Masaru; Oota, Sayako; Hoshi, Akihiko; Wakatsuki, Masaru; Kurosaki, Hiromasa; Okazaki, Atsushi; Shibuya, Hitoshi

doi:10.1016/j.brachy.2008.03.002

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Volume 7, Issue 3 , Pages 260-266, July 2008

Radiotherapy doses at special reference points correlate with the outcome of cervical cancer therapy

Ryo-ichi Yoshimura
- Department of Radiology, Tokyo Medical and Dental University, Tokyo, Japan
- Corresponding author. Department of Radiology, Tokyo Medical and Dental University, 5-45, Yushima 1-chome, Bunkyo-ku, Tokyo, Japan 113-8519. Tel.: +81-3-58035311; fax: +81-3-58030147.
Keiji Hayashi
- Department of Radiology, Tokyo Medical and Dental University, Tokyo, Japan
Fumio Ayukawa
- Department of Radiology, Tokyo Medical and Dental University, Tokyo, Japan
Kazuma Toda
- Department of Radiology, Tokyo Medical and Dental University, Tokyo, Japan
Masaru Iwata
- Department of Radiology, Toride Kyodo General Hospital, Ibaraki, Japan
Sayako Oota
- Department of Radiology, Tokyo Medical and Dental University, Tokyo, Japan
Akihiko Hoshi
- Department of Radiology, Musashino Red Cross Hospital, Tokyo, Japan
Masaru Wakatsuki
- Department of Radiology, Toranomon Hospital, Tokyo, Japan
Hiromasa Kurosaki
- Department of Radiology, Funabashi Medical Center Hospital, Chiba, Japan
Atsushi Okazaki
- Department of Radiology, Toranomon Hospital, Tokyo, Japan
Hitoshi Shibuya
- Department of Radiology, Tokyo Medical and Dental University, Tokyo, Japan

Received 25 August 2007; received in revised form 24 March 2008; accepted 25 March 2008. published online 25 June 2008.

Abstract

Purpose

The authors analyzed the correlation between radiotherapy doses at reference points on the uterine edge and the rectal wall and both pelvic control and late rectal complications of cervical cancer therapy.

Methods and materials

Between 1997 and 2005, 57 patients with Stages IB–IVA cancer of uterine cervix were treated with a combination of external beam radiotherapy and high-dose-rate intracavitary brachytherapy. Their high-dose-rate intracavitary brachytherapy was planned by dose-point optimization at six dose points located on the edge of uterus by computed tomography. A rectal reference point located on the anterior wall of the rectum by computed tomography was also used. The pelvic control rate and the rate of late rectal complications were calculated according to the biologically effective dose (BED) at each point and several clinical parameters.

Results

The overall 3-year pelvic control rate was 69.4%. The patients with a BED >80Gy10 at the point on the edge of the uterine cervix had better pelvic control (78.4% at 3 years) than the patients with a BED ≤80Gy10 (54.4% at 3 years), and the difference was significant. The difference in the BED (Gy3) at the rectal reference point between the patients with Grade 0–1 late rectal complications (median, 114Gy) and the patients who developed Grade ≥2 late rectal complications (median, 178Gy) was significant. Chemotherapy was a borderline significant parameter in regard to correlation with pelvic control and late rectal complications, but there were no correlations with other dosimetric or clinical parameters.

Conclusions

The radiotherapy dose at the reference point on the edge of the cervix affected pelvic control more than the clinical parameters, and the dose at the rectal reference point was more strongly correlated with the occurrence of late rectal complications.

Keywords: Uterine cervical cancer, Dose–response relationship, Intracavitary brachytherapy, Pelvic control, Late rectal complication