Murakami Naoya, Ueno Takao, Yatsuoka Wakako, Okamoto Hiroyuki, Tselis Nikolaos, Masui Koji, Yoshida Ken, Takahashi Kana, Inaba Koji, Okuma Kae, Igaki Hiroshi, Nakayama Yuko, Itami Jun
Department of Radiation Oncology, National Cancer Center Hospital, Chuo-ku, Tokyo, Japan.
Department of Oral Health and Diagnostic Sciences, National Cancer Center Hospital, Chuo-ku, Tokyo, Japan.
J Contemp Brachytherapy. 2018 Oct;10(5):486-491. doi: 10.5114/jcb.2018.79471. Epub 2018 Oct 31.
When squamous cell carcinoma of the buccal mucosa (BSCC) extends surrounding anatomical sites such as gingiva, retromolar triangle, or hard palate, it might be challenging to ensure adequate tumor coverage by sole interstitial brachytherapy due to the complexity of catheter implantation. By combining interstitial catheters with an enoral placed, individually assembled "oral spacer plus embedded catheters" device (hybrid of intracavitary-interstitial brachytherapy), it should be easier to deliver the necessary tumoricidal dose to irregular-shaped tumor volumes (clinical target volume - CTV) with improved conformity. The purpose of this analysis was to compare the dose distribution created by the hybrid of intracavitary-interstitial brachytherapy (HBT) with the dose distribution of an interstitial catheter only-approach, based on the interstitial catheters used for HBT (ISBT-only) by evaluating respective treatment plans (HBT plan vs. ISBT-only plan) for the treatment of early stage BSCC.
A retrospective analysis was performed for patients with localized BSCC treated between April 2013 and October 2017. All patients received sole HBT without additional external beam radiation therapy or planned neck dissection. Dosimetric parameters taken into account for comparison between actual HBT and virtual ISBT-only were CTV D, CTV V, CTV V, CTV V, mandible D, and mucosal surface D.
Dosimetrically, HBT showed a trend toward better CTV D compared to ISBT-only. In addition, HBT demonstrated statistically better CTV V coverage compared to ISBT-only. There was no statistically significant difference with respect to CTV V, CTV V, and mucosal surface D, while a trend was seen in better mandible D between HBT and ISBT-only.
The HBT approach appears to enable improved dose coverage of irregular-shaped enoral tumor volumes compared to ISBT-only for patients with early stage BSCC.
当颊黏膜鳞状细胞癌（BSCC）扩展至周围解剖部位，如牙龈、磨牙后三角或硬腭时，由于导管植入的复杂性，仅采用组织间近距离放射治疗确保肿瘤得到充分覆盖可能具有挑战性。通过将组织间导管与经口放置的、单独组装的“口腔间隔器加嵌入式导管”装置（腔内-组织间近距离放射治疗的混合方式）相结合，应该能够更轻松地向不规则形状的肿瘤体积（临床靶体积-CTV）输送必要的杀肿瘤剂量，并提高适形性。本分析的目的是基于用于腔内-组织间近距离放射治疗（HBT）的组织间导管（仅组织间近距离放射治疗-ISBT），通过评估早期BSCC治疗的各自治疗计划（HBT计划与仅ISBT计划），比较腔内-组织间近距离放射治疗混合方式（HBT）与仅组织间导管方法的剂量分布。
对2013年4月至2017年10月间接受治疗的局限性BSCC患者进行回顾性分析。所有患者均接受单纯HBT，未接受额外的外照射放疗或计划性颈部清扫。实际HBT与虚拟仅ISBT之间比较时考虑的剂量学参数为CTV D、CTV V、CTV V、CTV V、下颌骨D和黏膜表面D。
在剂量学方面，与仅ISBT相比，HBT显示出CTV D更好的趋势。此外，与仅ISBT相比，HBT在统计学上显示出更好的CTV V覆盖。在CTV V、CTV V和黏膜表面D方面没有统计学显著差异，而在HBT和仅ISBT之间下颌骨D有更好的趋势。
对于早期BSCC患者，与仅ISBT相比，HBT方法似乎能够改善口腔内不规则形状肿瘤体积的剂量覆盖。
