Introduction
This study investigated the suitability of brachytherapy technique selection based on pre-brachytherapy magnetic resonance imaging (MRI) findings in cervical cancer by evaluating dose-volume histogram parameters.

Material and methods
We retrospectively evaluated data from 61 patients with cervical cancer who underwent pre-brachytherapy MRI within 7 days before their first high-dose-rate brachytherapy treatment, selected according to pre-brachytherapy MRI findings. Combined intracavitary brachytherapy with interstitial techniques (IC/ISBT) or interstitial brachytherapy (ISBT) were favored treatments for poor-responding tumors after concurrent chemoradiotherapy, asymmetrical tumors, bulky parametrial extensions, bulky primary disease, and extensive paravaginal or distal vaginal involvement. Intracavitary brachytherapy (ICBT) was the preferred treatment for small tumors without extensive involvement of the vagina and parametrium.

Results
The median tumor size was 58 mm on pre-treatment MRI and 38 mm on pre-brachytherapy MRI. On pre-brachytherapy MRI, 13 patients had a tumor with severe vaginal invasion, 15 patients presented with an asymmetrical bulky tumor, and 4 patients had bulky residual tumors. IC/ISBT or ISBT were administered to 26 patients (43%). Median equivalent dose in 2 Gy fractions of clinical target volume D90 was 70.8 Gy for all patients. Median clinical target volume D90 in each brachytherapy session exceeded the prescribed dose in both patients treated with ICBT and IC/ISBT or ISBT. Median equivalent dose in 2 Gy fractions of D2cc to the bladder, sigmoid colon, and rectum was 69.5, 52.0, and 58.4 Gy, respectively. All cases remained within the doses recommended for organs at risk.

Conclusions
Pre-brachytherapy MRI may be helpful in selecting suitable candidates for each type of brachytherapy and deliver the recommended doses to the tumor and organs at risk, particularly in cases with large tumors, poor response to concurrent chemoradiotherapy, asymmetrical tumors, severe vaginal invasion, extensive parametrial invasion, and/or corpus invasion.



中文翻译：

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近距离放射治疗前磁共振成像对接受放疗（包括高剂量率近距离放射治疗）的局部晚期宫颈癌患者的剂量-体积直方图的影响

简介
本研究通过评估剂量-体积直方图参数，研究了基于近距离放射治疗前磁共振成像（MRI）发现的近距离放射治疗技术选择在宫颈癌中的适用性。

材料与方法
我们回顾性评估了61位子宫颈癌患者的数据，这些患者在根据首次近距离放射治疗MRI发现进行首次高剂量率近距离放射治疗之前7天内接受了近距离放射治疗MRI。腔内近距离放射治疗与间质技术（IC / ISBT）或间质近距离放射治疗（ISBT）的结合是同时放化疗，不对称肿瘤，大块子宫旁膜延长，大块原发性疾病以及广泛的阴道旁或阴道远端受累后反应较差的肿瘤的首选治疗方法。腔内近距离放射治疗（ICBT）是不伴有阴道和子宫旁膜广泛侵犯的小肿瘤的首选治疗方法。

结果
治疗前MRI的平均肿瘤大小为58毫米，近距离放射治疗MRI的平均肿瘤大小为38毫米。在近距离放射治疗前MRI中，有13例患有严重阴道侵犯的肿瘤，有15例出现不对称的大块肿瘤，还有4例有大块的残留肿瘤。IC / ISBT或ISBT应用于26例患者（43％）。所有患者的临床目标体积D90的2 Gy分数中位数等效剂量为70.8 Gy。在接受ICBT和IC / ISBT或ISBT治疗的两名患者中，每个近距离放射治疗疗程的中位临床目标体积D90均超过规定剂量。在膀胱，乙状结肠和直肠中，D2cc的2 Gy馏分的中值当量剂量分别为69.5、52.0和58.4 Gy。所有病例均保持在有风险器官推荐剂量之内。

结论
近距离放射治疗前MRI可能有助于为每种近距离放射治疗选择合适的候选物，并向处于危险中的肿瘤和器官提供推荐剂量，特别是在肿瘤大，同时放化疗反应差，不对称肿瘤，严重阴道侵犯，广泛性肿瘤的情况下子宫旁膜浸润和/或invasion体浸润。