Patel Payal, Deufel Christopher, Haddock Michael, Petersen Ivy
Mayo Clinic Alix School of Medicine, Rochester, MN, USA.
Department of Radiation Oncology, Mayo Clinic, Rochester, MN, USA.
J Contemp Brachytherapy. 2020 Dec;12(6):562-571. doi: 10.5114/jcb.2020.101689. Epub 2020 Dec 16.
Intracavitary vaginal brachytherapy (VBT) cylinders are limited in treating upper/apical vaginal disease due to the distance between the target and radiation source positions. Interstitial brachytherapy devices directly expose the vaginal mucosa to radiation sources, increasing morbidity. To target apical disease while limiting excessive treatment to the vaginal mucosa and organs at risk, we modified the commercially available multichannel MIAMI applicator, allowing the direct extension of needles into the apex with the protection of cylinder.
The device has one central plastic core with six peripheral channels. The modified device permits titanium needles to surpass the apical surface into vaginal tissue. A retrospective analysis on thirteen patients treated with this device was conducted. Patient demographics, gross tumor volume (GTV)/clinical target volume (CTV), initial diagnosis and management, toxicity data, and EQD data for the bladder and rectum were obtained.
There were ten patients with vaginal recurrences and three with primary vaginal/cervical cancers. Mean dosage of VBT treatment was 25.5 Gy in 3-5 fractions. Mean dosage of external beam radiation therapy (EBRT) treatment was 44 Gy. Common acute toxicities included diarrhea, fatigue, cystitis, and nausea. Common chronic toxicities were pelvic pain, vaginal stenosis, and skin telangiectasia. Mean EQD dose for bladder and rectum were 72.3 Gy and 62.3 Gy, respectively. Ten patients had no evidence of relapse, two suffered from distant metastases, and one patient with stage IIIA cervical adenocarcinoma had loco-regional recurrence seventeen months after radiation treatment.
Our data suggests that the custom applicator is associated with robust dosimetric coverage, good loco-regional control, acceptable toxicity, and reduced tissue trauma. This device allows treatment of apically located vaginal tumors without significant damage to the vaginal vault and organs at risk. Additionally, it provides the flexibility to treat multiple patients with variable vaginal diameters and sizes/depths of apical tumors using a single device.
腔内阴道近距离放射治疗（VBT）圆柱体在治疗阴道上段/顶端疾病方面存在局限性，因为靶区与放射源位置之间存在距离。组织间近距离放射治疗设备会使阴道黏膜直接暴露于放射源，从而增加发病率。为了在治疗顶端疾病的同时限制对阴道黏膜和危险器官的过度照射，我们对市售的多通道迈阿密施源器进行了改良，使其在圆柱体的保护下能将针直接延伸至顶端。
该设备有一个中央塑料芯和六个周边通道。改良后的设备允许钛针穿过顶端表面进入阴道组织。对使用该设备治疗的13例患者进行了回顾性分析。获取了患者的人口统计学数据、大体肿瘤体积（GTV）/临床靶体积（CTV）、初始诊断和治疗情况、毒性数据以及膀胱和直肠的等效剂量数据。
有10例阴道复发患者和3例原发性阴道/宫颈癌患者。VBT治疗的平均剂量为25.5 Gy，分3 - 5次给予。外照射放疗（EBRT）治疗的平均剂量为44 Gy。常见的急性毒性反应包括腹泻、疲劳、膀胱炎和恶心。常见的慢性毒性反应为盆腔疼痛、阴道狭窄和皮肤毛细血管扩张。膀胱和直肠的平均等效剂量分别为72.3 Gy和62.3 Gy。10例患者无复发迹象，2例发生远处转移，1例IIIA期宫颈腺癌患者在放疗后17个月出现局部区域复发。
我们的数据表明，定制施源器具有可靠的剂量覆盖、良好的局部区域控制、可接受的毒性以及减少的组织创伤。该设备能够治疗位于顶端的阴道肿瘤，而不会对阴道穹窿和危险器官造成显著损伤。此外，它提供了灵活性，使用单个设备就能治疗多名阴道直径以及顶端肿瘤大小/深度各异的患者。
