Treating Intact Cervical Cancer with Intensity-Modulated Radiotherapy: Maximized Bladder-Filling Change and Tumor Extent Are Associated with Organ Motion

子宮頸癌強度調控放射治療：最大膀胱體積變化量及腫瘤大小與器官移動顯著相關

呂紹綸(Shao-Lun Lu) ； 黃昭源(Chao-Yuan Huang) ； 成佳憲(Jason Chia-Hsien Cheng) ； 郭頌鑫(Sung-Hsin Kuo) ； 陳祈安(Chi-An Chen) ； 吳簡坤(Jian-Kuen Wu)

《放射治療與腫瘤學》 21卷3期 (2014/09) Pp. 211-221

https://doi.org/10.6316/TRO/201421(3)211

摘要

目的：評估子宮頸癌病人接受強度調控放射治療作為根除性治療時，膀胱體積變化對於目標器官移動的影響。材料與方法：連續22位子宮頸癌病人（FIGO分期IB-IVB）接受骨盆腔強度調控放射治療並納入分析。每位病人皆接受兩組治療計畫用電腦斷層，一組為漲尿狀態，另一組為排尿狀態。放射治療之目標與正常組織勾勒參照診斷用核磁共振與最新臨床指引，分別在兩組治療計畫電腦斷層上完成。其中最大膀胱體積變化量（DVB）定義為漲尿及排尿後兩組電腦斷層上的膀胱體積差異。子宮頸腫瘤及子宮體的幾何中心（centroid position）在兩組電腦斷層上經由治療計劃軟體運算決定。我們觀察子宮頸腫瘤及子宮體的幾何中心在兩組電腦斷層上的移動，並對其與膀胱體積變化量的關係進行分析。結果：經比較膀胱漲尿及排尿的兩組電腦斷層，子宮頸腫瘤及子宮體之幾何中心在頭腳軸向上有顯著的移動，且移動距離的多寡與膀胱體積變化量為顯著的正線性關係（adjusted R2= 0.49, p=0.0005）。其中8位病人其子宮頸腫瘤侵犯子宮體小於一半者，最大膀胱體積變化量與幾何中心移動距離的正向線性關係最為明顯（adjusted R2 = 0.61, p= 0.0008）；而對於腫瘤體積較大，侵犯超過子宮體積超過一半之病人，最大膀胱體積變化量與幾何中心移動距離的關係則不顯著。若子宮為前傾狀態，則子宮頸腫瘤與子宮體移動的距離和最大膀胱體積變化量呈現正向線性關係（adjusted R2 = 0.40, p= 0.022），若子宮後傾，則此線性關係不顯著。經考量病患年齡、疾病分期與子宮位置（前傾或後傾）等因素作多元回歸後，最大膀胱體積變化量及腫瘤大小為預測子宮頸腫瘤及子宮體中心移動的預測因子。結論：在此子宮頸癌強度調控放射治療的研究中，最大膀胱體積變化量及腫瘤大小與子宮頸腫瘤及子宮體在頭腳方向上的移動具顯著關聯。

關鍵字

子宮頸癌 ； 最大膀胱體積變化量 ； 強度調控放射治療 ； 器官移動

並列摘要

Introduction: The aim of the present study is to evaluate the impact of bladder filling on uterus-cervix mobility in patients with cervical cancer and an intact uterus treated by intensity-modulated radiotherapy (IMRT). Methods and Materials: Twenty-two consecutive women with cervical cancer (FIGO stage IB-IVB) receiving pelvic IMRT were selected for analysis. Two series of treatment planning CT scans, one with a full bladder and the other with an empty bladder, were acquired. The target volumes and normal tissues were contoured on each CT scan according to the updated guidelines and staging MRI. We determined the centroid positions of the cervical tumor and uterus, then correlated the centroid displacement to the delta volume of the bladder (DVB; defined as the volume difference between full and empty urinary bladders; the maximized bladder filling change). Results: A significant mobility of the uterus-cervix according to bladder filling was observed on the superior-inferior axis only. For all patients, displacement of the uteruscervix on the superior-inferior axis was significantly correlated with the DVB (adjusted R2= 0.49, p= 0.0005). Among 8 patients with cervical tumor invading less than onehalf of the uterus, the target displacement affected by DVB was well-described by linear regression (adjusted R2= 0.61, p= 0.0008). For those with bulky tumor extent, the correlation between target displacement and DVB was much less apparent. For patients have anteverted uterus (n= 11), the DVB was associated with cervix-uterus motion on superior-inferior axis (adjusted R2 =0.40, p= 0.022), while for those with retroverted or tip-up uterus, there was no significant correlation. After a multivariate linear regression analysis, DVB and tumor extent were significantly correlated with uterus-cervix motion. Conclusion: The maximized bladder filling change (DVB), and tumor extent, were significantly correlated with uterus-cervix centroid displacement on the superiorinferior axis of cervical cancer patients.

並列關鍵字

Cervical cancer ； Delta volume of bladder ； IMRT ； Organ motion