3D margin assessment predicts local tumor progression after ablation of colorectal cancer liver metastases

Figures & data

Figure 1. Measurement of ablation margins in 3 D in a patient with colorectal liver metastasis in segment 8. Pre-ablation contrast-enhanced CT scan 2 days before the procedure (A). Segmentation of the tumor (red) in the pre-ablation CT scan of the day of the procedure (B). General view of the software interface for ablation margin assessment (C). Detail of the tumor (red) and the ablation zone (green) in axial, sagittal, and coronal plane (D–F), showing adequate ablation margins in all three planes.

Figure 2. 3 D margin assessment in a patient with colorectal liver metastasis in segment 8. Pre-ablation PET/CT scan showing the tumor (A). Tumor segmentation (red) in a pre-ablation CT scan (B). Ablation zone segmentation (green) in a post-ablation contrast-enhanced CT scan (C). Tumor (red) and ablation zone (green) registration without target movement showing ablation margins <5mm (D). Tumor (red) and ablation zone (green) registration with target movement to match anatomic landmarks (E). Tumor (red) and ablation zone (green) registration with target movement and tissue contraction algorithm applied (F).

Table 1. Patient and tumor characteristics.

Patient (n = 68) and Tumor (n = 104) characteristics
Characteristic	Value
Age (y)*	57.5 (32–78)
Gender
Female	23 (34)
Male	45 (66)
Race
Asian/Far East/Indian Subcontinent	3 (4)
Black/African American	4 (5)
Patient refused to answer	2 (3)
White	59 (88)
Tumor size (cm)**	1.9 (0.8–4.0)
Time between diagnosis of colorectal cancer and ablation (mo)*	31.5 (8–163)
No. of tumors treated per patient**	1.5 (1–5)

Unless otherwise indicated, data represent the number of patients, and data in parentheses are percentages.

* Data are median values, and data in parentheses represent the range.

** Data are mean values, and data in parentheses represent the range.

Figure 3. Colorectal metastasis (red) ablation in the liver dome. Ablation zone (green) with adequate margins in the axial plane (A), but suboptimal margins in sagittal plane examination (B). Local tumor progression is evident on a 10-month PET/CT follow-up scan (C).

Table 2. Performance of ablation margin assessment methods.

	LTP (total 40)	No LTP (total 64)	Total number of tumors	Sensitivity	Specificity	Accuracy
Minimal margin <5mm − 3 D with tissue contraction	20	14	34	50% (95% CI: 35,65)	78% (95% CI: 68,88)	67% (95% CI: 58,76)
Minimal margin ≥5mm − 3 D with tissue contraction	20	50	70
Minimal margin <5mm − 3 D without tissue contraction	37	37	74	93% (95% CI: 84,100)	42% (95% CI: 30,54)	62% (95% CI: 52,71)
Minimal margin ≥5mm − 3 D without tissue contraction	3	27	30
Minimal margin <5mm − 2 D	8	9	17	20% (95% CI: 7,32)	86% (95% CI: 77,94)	61% (95% CI: 51,70)
Minimal margin ≥5mm − 2 D	32	55	87
Total number of tumors	40	64

Data availability statement

The data that support the findings of this study are available from the authors on reasonable request.