Computed Tomography-based Three-dimensional Image-guided Brachytherapy for Cancer of the Cervix Uteri

Full Article

RPY Tse, SWK Siu, A Chow, W Chan, F Tang, P Ho, TW Leung, P Kwong

Hong Kong J Radiol 2019;22:224-9

https://doi.org/10.12809/hkjr1916868

Objective: To clarify the treatment results of three-dimensional (3D) image-guided brachytherapy (IGBT) for cancer of the cervix uteri in Hong Kong.
Methods: Between January 2014 and June 2016, 52 patients underwent computed tomography (CT)-based 3D IGBT, in which three patients had interstitial needles inserted. Contouring was done with dose volume parameters recorded, as recommended by the GEC-ESTRO guidelines. Recorded parameters included HRCTV D90 mean dose (dose delivered to 90% of the high-risk clinical target volume), HRCTV V100 (percentage of HRCTV receiving 100% of the prescribed dose), and D_2cc (minimum dose in the most exposed 2 cm³ volume) of rectum, sigmoid colon, and bladder. One-way analysis of variance with Bonferroni’s multiple comparison post-hoc tests for normally distributed data or Dunn’s multiple comparisons test were used to assess any statistically significant differences.
Results: The HRCTV D90 mean doses in 2014, 2015, and 2016 were 75.1 Gy, 77.8 Gy and 82.1 Gy, respectively. The corresponding HRCTV V100 values were 88.7%, 91.6%, and 94.4%, respectively. The HRCTV D90 value in 2016 was found to be significantly higher than that in 2014. The D_2cc value of sigmoid colon in 2016 was significantly lower than that in 2014 or 2015. The D_2cc value of bladder in 2016 was significantly higher than that in 2015 but still within acceptable limits. None of the patients developed grade 3 to 4 acute radiation toxicities. There was one patient with persistent disease in the cervix after radiotherapy, three patients with distant failure, and one patient with both local and distant failure.
Conclusion: The CT-based 3D IGBT treatment for cancer of the cervix uteri with interstitial needle insertion is feasible in the local setting. There is potential to give higher dosages to the HRCTV by the 3D IGBT technique, while the doses to organs at risk can still be limited to acceptable levels.

Author affiliation(s):
RPY Tse, SWK Siu, A Chow, W Chan, F Tang, P Ho, TW Leung, P Kwong: Department of Clinical Oncology, Queen Mary Hospital, Pokfulam, Hong Kong

中文摘要

宮頸癌的電腦素描引導下近距離放射治療

謝佩楹、蕭偉君、周美君、陳穎樂、鄧年輝、何沛盈、梁道偉、鄺維基

目的：探討宮頸癌近距離放射治療在電腦素描引導下的治療成效。
方法：2014年1月至2016年6月期間共52名患者接受電腦素描引導下近距離放射治療，其中3名患者同時接受組織內針刺近距離放射治療。我們根據歐洲放射腫瘤學會（GEC-ESTRO）指引勾劃出高危靶區（HRCTV）和鄰近器官的體積。記錄的參數包括HRCTV D90（即可傳遞高風險臨床目標體積劑量的90%）平均劑量、HRCTV V100（接受100%處方劑量的HRCTV百分比），以及直腸、乙狀結腸和膀胱的D_2cc（即2cc危及器官的最低劑量）。使用Bonferroni對正態分佈數據的多重事後比較檢驗或Dunn多重比較檢驗的單向方差分析評估統計學的顯著差異。
結果：HRCTV D90平均劑量值於2014年、2015年及2016年分別是75.1 Gy、77.8 Gy和82.1 Gy。2016年的HRCTV D90值高於2014年。2016年的乙結腸D_2cc值顯著低於2014年及2015年。2016年的膀胱D_2cc值顯著高於2015年，但仍於可接受的安全範圍內。沒有患者產生第三或四級急性放射治療副作用。只有1位患者在放射治療後仍被檢測有腫瘤，另有3名患者有遠程轉移，另有1名患者同時有局部及遠程轉移。
結論：宮頸癌在電腦素描引導下作近距離放射治療及輔以組織內針刺是可行的。在三維圖像引導下 作近距離放射治療宮頸癌，HRCTV D90有可能予以更高劑量，另一方面能保持鄰近器官劑量在安全值內。