Sharma Daya Nand, Kumar Pavnesh, Subramani Vellaiyan, Giridhar Prashanth
Department of Radiation Oncology, All India Institute of Medical Sciences, New Delhi, India.
J Contemp Brachytherapy. 2024 Aug;16(4):273-278. doi: 10.5114/jcb.2024.142938. Epub 2024 Sep 12.
For cervical cancer patients, intra-cavitary brachytherapy (ICBT) is utilized with various dose-rate systems, such as low-dose-rate (LDR), high-dose-rate (HDR), and pulsed-dose-rate (PDR). This retrospective analysis aimed to compare the therapeutic outcomes of cervical cancer patients treated with either LDR-, HDR-, or PDR-ICBT.
A total of 613 patients were treated with pelvic external beam radiation therapy (EBRT), followed by either LDR- (271 patients), HDR- (259 patients), or PDR- (83 patients) ICBT. Point-based planning was performed according to orthogonal radiographs in LDR patients, and computed tomography (CT) imaging in HDR and PDR patients. ICBT prescribed dose was as follows: for LDR treatment, 30 Gy in a single-session; for HDR: 7 Gy × 3 fractions (once a week fraction); and for PDR: 27 Gy in an hourly pulse of 70 cGy, with all the doses prescribed at point A. Radioactive source used was cesium-137 for LDR, and iridium-192 for HDR and PDR treatments.
Loco-regional control (LRC) rate was 74%, 75%, and 77% in LDR, HDR, and PDR groups, respectively ( = 0.80). The 5-year overall survival (OS) in the three groups, i.e., LDR, HDR, and PDR was 63%, 64%, and 68%, respectively ( = 0.77). Severe late toxicity (RTOG grade ≥ 3) rate in the three groups was comparable (LDR, 12%; HDR, 8%; and PDR, 8.9%, = 0.36).
Our study revealed comparable LRC, 5-year OS, and late toxicity rates using three dose-rate systems. Lower OS rates were observed in LDR group for stage III patients compared with patients in HDR and PDR groups. Therefore, we suggest that LDR should be used with caution while treating stage III patients.
对于宫颈癌患者，腔内近距离放疗（ICBT）可采用多种剂量率系统，如低剂量率（LDR）、高剂量率（HDR）和脉冲剂量率（PDR）。本回顾性分析旨在比较接受LDR-、HDR-或PDR-ICBT治疗的宫颈癌患者的治疗效果。
共有613例患者接受盆腔外照射放疗（EBRT），随后分别接受LDR-（271例患者）、HDR-（259例患者）或PDR-（83例患者）ICBT。LDR患者根据正交X线片进行基于点的计划，HDR和PDR患者根据计算机断层扫描（CT）成像进行计划。ICBT规定剂量如下：LDR治疗为单次30 Gy；HDR为7 Gy×3次分割（每周一次分割）；PDR为每小时70 cGy脉冲给予27 Gy，所有剂量均在A点规定。LDR使用的放射源为铯-137，HDR和PDR治疗使用铱-192。
LDR、HDR和PDR组的局部区域控制（LRC）率分别为74%、75%和77%（P = 0.80）。三组（即LDR、HDR和PDR）的5年总生存率（OS）分别为63%、64%和68%（P = 0.77）。三组的严重晚期毒性（RTOG 3级及以上）率相当（LDR为12%；HDR为8%；PDR为8.9%，P = 0.36）。
我们的研究表明，使用三种剂量率系统时，LRC、5年OS和晚期毒性率相当。与HDR和PDR组患者相比，LDR组III期患者的OS率较低。因此，我们建议在治疗III期患者时应谨慎使用LDR。
