Study on Appropriate Rectal Volume for External Irradiation in Patients With Cervical Cancer.

Yanjiao Wu,Han Guo,Yanqiang Wang,Lei Tian,Wenyan Wang,Chunmei Liu,Xiaoying Xue,Zhiqing Xiao

doi:10.3389/fonc.2022.814414

Yanjiao Wu, Han Guo + Show 6 more

Open Access

https://doi.org/10.3389/fonc.2022.814414

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Abstract

ObjectiveTo investigate the appropriate rectal volume for external irradiation of cervical cancer.MethodsA retrospective study of 143 patients with cervical cancer who underwent external radiotherapy from January 2017 to September 2020 was conducted. Average rectum volumes and the cumulative dose (V30, V40, V50, D2cc) to organs at risk (bladder, rectum, and small bowel) during radiotherapy were evaluated using the treatment planning system. Rates of radiation cystitis and radiation proctitis were assessed.ResultsThe median follow-up was 48 months, and the included patients had a median age of 53 years. Patients were divided into 3 groups based on their average rectum volume: Group A: <40 ml; Group B: 40–70 ml; and Group C: ≥70 ml. V30 and V40 in the rectum bladder and small bowel were highest in Group A (mean ± SD standard deviation), but V50 and D2cc in the rectum and bladder were highest in Group C (mean ± SD). Patients in Group B had the lower incidence of both radiation cystitis and radiation proctitis. (p<0.05).ConclusionsFor external irradiation in patients with cervical cancer, a rectum volume of 40–70 ml seems most appropriate, whereas >70 ml increases the risk of severe radiation cystitis and radiation proctitis, and <40 ml increases the risk of mild radiation cystitis and mild radiation proctitis.

Highlights

Cervical cancer is one of the most common gynecological malignancies, ranking the third most common cancer among women worldwide
Doses to organs at risk were compared using non-linear analysis and t-tests, and odds of developing radiation cystitis and radiation proctitis were compared using the X2 test
A total of 160 patients with cervical cancer met the criteria for inclusion

Summary

Introduction

Cervical cancer is one of the most common gynecological malignancies, ranking the third most common cancer among women worldwide. 85% of cervical cancer cases occur in developing countries, and its mortality rate ranks second among female tumors [1]. The standard treatment for patients with locally advanced cervical cancer is a combined modality approach (chemotherapy and radiation therapy); the radiation therapy consists of external beam irradiation, followed by brachytherapy to boost the gross tumor in the cervix [2]. A retrospective study has shown that high-risk clinical target volume (CTVHR) dose -85 Gy (EDQ2, D90) delivered in 7 weeks provides a 3-year local control rate >94% in limited-size (20 cm3), >93% in intermediate-size (30 cm3), and >86% in large-size CTVHR (70 cm3) tumors [8]. The incidence of radiation cystitis and radiation proctitis is related to the patient’s physical condition and to the dose received [12]

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