Image-guided thermal ablation of central renal tumors with retrograde cold pyeloperfusion technique: a monocentric experience

Figures & data

Table 1. Characteristics of 48 patients who underwent thermal ablation for a centrally located renal lesion (n = 58).

Characteristic	Value
Mean Age (y)	69.1 ± SD 11.8 (37.1–89)^a
RFA	67.94 ± SD 9.85
MWA	69.88 ± SD 13.86
Mean body mass index (kg/m^2)	26.4 ± SD 4.76 (19.51–48.21)^a
Sex
M	33/48 (68%)
F	15/48 (32%)
Median lesion diameter (mm)	36.5 (16–48)^a
RFA	30.76 (16–43)^a
MWA	34.04 (17–48)
Lesion location (kidney)
Left	25/58 (43%)
Right	33/58 (57%)
Monorenal Status (patients)	7/48 (15%)
Chronic kidney disease (CKD) status (ml/min/1.73 m^2) [15]
normal GFR (G1; >90)	2/7 (29%)
mildly decreased GFR (G2; 60–90)	2/7 (29%)
moderately to severely decreased GFR (G3b; 30–44)	2/7 (29%)
severely decreased GFR (G4; 15–29)	1/7 (14%)
Histologic subtype
RCC	58/58 (100%)
Clear cells	34/58 (59%)
Papillary	12/58 (21%)
Not-defined RCC	12/58 (21%)
Median RENAL nephrometry score^a	9 (6–10)
Low (4–6)	5 (9%)
Moderate (7–9)	28 (48%)
High (10–12)	25 (43%)

^a Numbers in parentheses are the range.

Figure 1. Treatment of a left kidney central tumor with renal sinus extension with image-guided microwave ablation and retrograde pyeloperfusion. (a) T1-weighted, fat-saturated, contrast-enhanced MR image demonstrating a centrally located tumor (white arrow) with extension in close proximity of the renal sinus. (b) Retrograde pyeloperfusion was performed through a single j stent (white arrowheads) placed endoscopically the day of the ablation with the tip located in the renal pelvis (white arrow). (c) Microwave antenna (white arrowheads) was inserted under real-time US visualization. (d) CT confirmed the precise positioning of the microwave antenna at the level of the tumor. (e, f) Contrast-enhanced CT 6 months after treatment demonstrates the correct ablation of the tumor (white arrows) with no residual enhancing tumor either in the arterial phase (e, white arrowhead = arterial branch) or the excretory phase (f, white arrowhead = renal calyx). (g) Contrast-enhanced CT in the arterial phase 12 months after the ablation demonstrating complete ablation with tumor shrinkage (white arrow) and no complications.

Figure 2. Flowchart of the ablation results (per-lesion analysis). ¹1 total nephrectomy, 1 active surveillance, 2 untreated due to death of patients for unrelated reasons; ²1 total nephrectomy, 3 untreated due to death of patients for unrelated reasons.

Figure 3. Progression-free survival in a series of 48 patients with kidney lesions treated with thermal ablation. Dashed lines = 95% confidence intervals.

Table 2. Pretreatment and post-treatment characteristics of patients (n = 48) who underwent thermal ablation for a centrally located renal lesion (n = 58).

Variable	Pretreatment	Post-treatment^a	Δ	p Value
Serum creatinine level (mg/dL)	1.14 ± 0.60	1.12 ± 0.47	−0.01 ± 0.21	0.88
	(0.70–3.65)	(0.62–2.63)	(−1.10 to 0.30)
GFR (L/min/1.73 m^2)	68.92 ± 25.05	67.53 ± 25.69	−1.39 ± 7.89	0.79
	(0.82–112.00)	(0.85–111.90)	(−19.90 to 14.50)
Hemoglobin level (g/dL)	14.06 ± 1.57	12.66 ± 1.83	−1.39 ± 1.04	<0.05
	(8.90–17.10)	(7.50–16.30)	(−4.30 to 1.10)

Values are expressed in terms of mean ± SD; numbers in parentheses are the range; ^aat last follow-up.

Table 3. Pretreatment and post-treatment characteristics of mono-renal patients (n = 7) who underwent thermal ablation for a centrally located renal lesion (n = 8).

Variable	Pretreatment	Post-treatment^a	Δ	p Value
Serum creatinine level (mg/dL)	1.48 ± 0.67	1.50 ± 0.58	−0.02 ± 0.20	0.94
	(0.70–2.72)	(0.70–2.39)	(−0.33 to 0.25)
GFR (L/min/1.73 m^2)	56.27 ± 26.53	53.58 ± 25.31	−2.68 ± 6.04	0.83
	(21.00–91.40)	(25.00–91.00)	(−14.40 to 4.40)

Values are expressed in terms of mean ± SD; numbers in parentheses are the range; ^aat last follow-up.

Table 4. Complications among patients (n = 48) who underwent thermal ablation for a centrally located renal lesion (n = 58), classified according to SIR standards [17].

Grading	Number (%)	Type of complication	Details
A	6/58 (10%)	Minor urinary leakage	Resolved the day following the procedure; no further treatment
	1/58 (2%)	Transient hematuria	Mild event; no further treatment
B	1/58 (2%)	Abdominal pain	Minor pain; no further treatment
C	1/58 (2%)	Intraprocedural pneumothorax	Placement of a drainage catheter; 3-day hospitalization in total
D	1/58 (2%)	Hemothorax	Placement of a pleural drainage; longer hospitalization
	1/58 (2%)	Kidney hemorrhage	Embolization
	1/58 (2%)	Acute kidney failure and urinary leakage	Sudden episode on a stage 4 CKD patient; resolved after few days
	1/58 (2%)	Perirenal hematoma	5-day hospitalization

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