CT fluoroscopy-guided closed-tip catheter placement before regional hyperthermia treatment of soft tissue sarcomas: 5-Year experience in 35 consecutive patients

Figures & data

Figure 1. Illustration of our calculated ratios through the example of a 54-year old man with an undifferentiated sarcoma in the right upper leg. (A) Contrast-enhanced planning CT scan in prone position clearly demarcates the vascularised tumour from the surrounding muscles. (B) Ratio 1 describes the proportion of the intratumoural catheter length (blue line) compared to the maximum tumour diameter in continuation of the catheter position (red line). In this example ratio 1 = 2.23:2.96 cm = 0.75. (C) Ratio 2 describes the proportion of the intratumoural catheter length (blue line in B) compared to the maximum total tumour diameter in any plane. In this example we reconstructed the coronary image via syngo.via® software (Siemens) because the maximum tumour extent is in this plane (white line). Here ratio 2 = 2.23:5.44 cm = 0.41.

Table 1. Population characteristics in patients with STS undergoing CT fluoroscopy-guided closed-tip catheter placement (N = 35).

Characteristic	Value N (% or range)
Age (years)
Mean ± standard deviation	52.4 ± 13.6 (24–75)
Sex
Female	13 (37.1)
Male	22 (62.9)
Tumour classification*
Undifferentiated sarcoma	15 (42.9)
Liposarcoma	5 (14.3)
Synovial sarcoma	3 (8.6)
MPNST	3 (8.6)
Myxofibrosarcoma	3 (8.6)
Leiomyosarcoma	2 (5.7)
Myofibroblastic sarcoma	1 (2.9)
Teleangiectatic osteosarcoma	1 (2.9)
PNET	1 (2.9)
Rhabdomyosarcoma	1 (2.9)
Tumour localisation
Extremity	17 (48.6)
Upper extremity	2 (5.7)
Lower extremity	15 (42.9)
Thorax	5 (14.3)
Thoracic wall	3 (8.6)
Intrapulmonary/thoracic spine	1 (2.9)
Supraclavicular	1 (2.9)
Abdomen	4 (11.4)
Anterior abdominal wall	1 (2.9)
Epigastric region	1 (2.9)
Renal bed	1 (2.9)
Psoas muscle	1 (2.9)
Pelvis	9 (25.7)
Sacrum	2 (5.7)
Iliac muscle	1 (2.9)
Inguinal region	4 (11.4)
Gluteal region	2 (5.7)
Tumour volume (cm^3)
Mean ± standard deviation	376.3 ± 319.4 (0–1042)**

*As in the WHO classification of soft tissue and bone tumours [19]. **Tumour volume of 0 cm³ was applied for cases in which catheters were placed into the tumour bed after incomplete surgical resection.

Table 2. Characteristics of CT fluoroscopy-guided closed-tip catheter placement.

Characteristic/parameter	Value N (range or %)
Number of catheters
Total	55
Per patient	1.7 ± 0.7 (1–4)
Number of RHT sessions until catheter removal
Mean ± SD (range)	1.9 ± 0.2 (1–2)
Duration of intracorporeal catheter placement
Mean ± SD (days)	4.1 ± 1.8 (2–10)
Intervention duration
Total* mean ± SD (range in min)	40.8 ± 13.5 (22.3–72.8)
Procedure duration mean ± SD (min)	14.5 ± 8.8 (5–39)
Mean procedure duration per catheter   (min)	8.7
Planning CT
Contrast enhanced	30 (85.7)
Unenhanced	5 (14.3)
DLP
Total mean ± SD (mGy*cm)	723.2 ± 355.9 (169–1826)
CT fluoroscopy-guided mean ± SD   (mGy*cm)	64.8 ± 81.8 (13–345)
Effective patient dose, mean ± SD (mGy*cm)
Thoracic sarcomas	8.0 ± 2.3
Abdominal sarcomas	8.3 ± 1.2
Pelvic sarcomas	11.1 ± 4.5

DLP, Dose-length product.

*Including CT topogram, planning CT and post-interventional CT.

Table 3. Technical outcome.

Characteristic/parameter	Value
Intratumoural catheter placement	34 (97.1)
Intra-interventional complications	0 (0)
Post-interventional complications	9 (25.7)
Ratio 1* mean ± SD	0.96 ± 0.08 (0.6–1.0)
Ratio 2** mean ± SD	0.66 ± 0.21 (0.2–1.0)

*Ratio 1, intratumoural catheter length to maximum tumour diameter in line.

**Ratio 2, intratumoural catheter length to maximum overall tumour diameter (maximum tumour diameter in any plane).

Figure 2. Closed-tip catheter placement in a 41-year old mn with a retroperitoneal malignant peripheral nerve sheath tumour (MPNST) (A) Contrast-enhanced planning CT scan shows the extent of the tumour in right psoas muscle. (B) Coronal reconstruction. (C) Intra-interventional CT fluoroscopy image. Final position of the closed-tip catheter.

Figure 3. Severe catheter dislocation in the same patient mentioned in Figure 2. (A–C) Catheter dislocated from its original retroperitoneal intratumoural position down to the upper leg along the fascial space. Arrows indicate the position of the catheter.

Table 4. Minor and major complications according to SIR quality improvement guidelines (20) and technical failure*.

	Patients affected	Catheters involved
Characteristic/parameter	N (%)	N (%)
Overall number of complications/technical failure	10 (28.6)	11 (20.0)
Major complications	2 (5.7)	2 (3.6)
Catheter-associated abscess formation^a	1 (2.9)	1 (1.8)
Severe post-procedural catheter dislocation^b	1 (2.9)	1 (1.8)
Minor complications	4 (11.4)	4 (7.2)
Fever of unknown origin^c	1 (2.9)	1 (1.8)
Inflamed puncture site^d	1 (2.9)	1 (1.8)
Irritation of a nerve root^e	1 (2.9)	1 (1.8)
Ichor out of catheter^f	1 (2.9)	1 (1.8)
Technical failure	4 (11.4)	5 (9.1)
Failed catheter insertion^g	1 (2.9)
Catheter kinking^h	3 (8.6)	5 (9.1)
No complications	25 (71.4)	44 (80.0)
30-day post-interventional mortality	0 (0.0)

^aNecessitated subsequent CT-guided drainage.

^bNecessitated consecutive surgery.

^cCatheter was removed and antibiotics were administered.

^dComplicated RHT treatment due to the applicator water bolus pressure on the inflamed puncture site.

^eNecessitated CT imaging to exclude post-interventional haematoma but did not show any pathological findings. Irritation vanished after slight pulling back of the catheter.

^fIncidental finding when catheter was removed. No further consequences.

^gDue to patient non-compliance.

^hDisturbed or impeded thermometry.

*Technical failure was defined as catheter not usable for thermometry

World Health Organization. WHO Classification of tumours of soft tissue and bone. 4th ed. Lyon: IARC; 2013

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