High-risk clinical target volume delineation in CT-guided cervical cancer brachytherapy: Impact of information from FIGO stage with or without systematic inclusion of 3D documentation of clinical gynecological examination

Figures & data

Figure 1. Study design.

Figure 2. A) 3D clinical drawing of CGE for patient with large tumor in whole cervix with bilateral parametrial disease and vaginal infiltration along anterior and left wall reaching the lower third of vagina (FIGO stage IIIA) at diagnosis, Residual tumor after radiochemotherapy at time of BT was still in whole cervix with a central necrosis extending up to the right mid-parametrium and in the anterior-left upper third of vaginal wall. B) HR CTV delineation for the same patient on transverse CT section through the low cervix region with tandem applicator and interstitial needles: CT-based HR CTV_stage, CT-based HRCTV_{stage + 3Dclin} and MRI-based HR CTV_MRI.

Figure 3. Significant decrease of the volume ratios (VR) of HR CTV by adding of CGE diagrams, for all standardized uterine lengths (1/1, 2/3, 1/2) used in the study. VR_stage is the volume ratio of HR CTV_stage/HR CTV_MRI and _{VRstage + 3Dclin} is the volume ratio of CT-based HR CTV_{stage + 3Dclin}/HR CTV_MRI.

Table I. Mean, standard deviations and ranges of volume, height, width, and thickness of HR CTV_stage, HR CTV_{stage + 3Dclin} and HR CTV_MRI.

Parameters (mean ± SD [range])	Height (cm)	Width (cm)	Thickness (cm)	Volume (cm^3)
HR CTVstage 1/1 uterine height	6.6 ± 1.5 [4.0–10.8]	6.2 ± 0.8 [4.8–7.9]	3.9 ± 0.5 [2.9–4.8]	82 ± 27 [38–164]
HR CTVstage 2/3 uterine height	5.1 ± 1.3 [3.2–9.2]	*	*	71 ± 23 [32–149]
HR CTVstage uterine height	4.3 ± 1.1 [2.8–8.4]	*	*	60 ± 20 [28–131]
HR CTVstage + 3Dclin 1/1 uterine height	6.6 ± 1.5 [4.0–10.8]	5.4 ± 0.6 [4.2–6.5]	3.7 ± 0.5 [2.3–4.6]	66 ± 23 [32–141]
HR CTVstage + 3Dclin 2/3 uterine height	5.1 ± 1.3 [3.2–9.2]	*	*	56 ± 20 [27–127]
HR CTVstage + 3Dclin 1/2 uterine height	4.3 ± 1.1 [2.8–8.4]	*	*	47 ± 17 [21–111]
HR CTVMRI	4.1 ± 1.5 [2.0–8.0]	4.4 ± 0.7 [3.0–5.7]	3.2 ± 0.6 [2.0–4.1]	34 ± 15 [12–73]

*Asterisks indicate that width and thickness values are independent of uterine height. The heights for the two different CT-based HR CTV groups are identical when the same uterine standard length is used.

Figure 4. Significant decrease of the width ratio (WR) of HR CTV by adding of CGE diagrams. WR_stage is the width ratio of CT-based HR CTV_stage/HR CTV_MRI and _{WRstage + 3Dclin} is the width ratio of CT-based HR CTV_{stage + 3Dclin}/HR CTV_MRI.

Table II. Mean and standard deviations of the CT/MRI width ratios (WR_{x =} W_x/W_MRI) thickness ratios (TR_{x =} T_x/T_MRI) for all HR CTV_stage and HR CTV_{stage + 3Dclin}, and heights ratios (HR_{x =} H_x/H_MRI) for all standard uterine heights used for both CT-based contour types, grouped by different FIGO stages.

	x	FIGO stage
		IB (n = 8)	IIB (n = 18)	III (n = 9)	All (n = 35)
CT/MR width ratio WRx	HR CTVstage	1.5 ± 0.3	1.4 ± 0.1	1.4 ± 0.2	1.5 ± 0.2
(mean± SD)	HR CTVstage + 3Dclin	1.3 ± 0.2	1.2 ± 0.1	1.2 ± 0.2	1.2 ± 0.2
CT/MR thickness ratio TRx	HR CTVstage	1.2 ± 0.1	1.3 ± 0.2	1.1 ± 0.1	1.2 ± 0.2
(mean± SD)	HR CTVstage + 3Dclin	1.2 ± 0.1	1.2 ± 0.2	1.1 ± 0.1	1.2 ± 0.1
CT/MR height ratio HRx	1/1 uterine height	1.7 ± 0.2	1.9 ± 0.2	1.7 ± 0.6	1.7 ± 0.4
(mean± SD)	2/3 uterine height	1.3 ± 0.1	1.5 ± 0.2	1.3 ± 0.4	1.3 ± 0.3
	1/2 uterine height	1.1 ± 0.1	1.2 ± 0.2	1.1 ± 0.4	1.1 ± 0.3