Value of percutaneous needle biopsy of small renal tumors in patients referred for cryoablation

Time course of complications after small renal mass biopsy: evaluation of initial follow-up images

PURPOSE

To retrospectively assess the time course of complications after image-guided small renal mass biopsy using initial follow-up imaging.

MATERIALS AND METHODS

A total of 190 masses (mean, 2.1 ± 0.70 cm; range, 0.6-3.8 cm) were assessed using initial computed tomography (43 non-enhanced and 141 enhanced) or magnetic resonance imaging (five non-enhanced and one enhanced) after biopsy. Initial follow-up imaging was classified into two groups (i.e., with or without hematoma) and various factors were compared.

RESULTS

The masses were histologically diagnosed in all patients except one. Post-procedural complications included 129 Grade I hematomas, 1 Grade I hemothorax, 9 Grade II hematomas, and 1 Grade IIIa pneumothorax. Residual 28 Grade I and 6 Grade II hematomas and 8 new complications (6 small hematomas, 1 pseudoaneurysm, and 1 arteriovenous fistula) were observed on the initial follow-up imaging obtained at a median of 21 days (3-90 days) after the biopsy. On the initial follow-up imaging, the groups with and without hematoma differed significantly in the following factors: age (P = 0.04), size (P = 0.02), guided images (P < 0.01), hematoma at the end of the procedure (P < 0.01), and days after biopsy (P < 0.01). Although three masses exhibited > 25% shrinkage, no significant change was observed in mass diameter on initial follow-up imaging (mean, 2.1 ± 0.71 cm; P = 0.90).

CONCLUSION

Initial follow-up imaging after a biopsy revealed improvements in most of the complications, a few new complications, and an unchanged mass diameter.

Computed Tomography-guided Core Needle Biopsy for Renal Tumors: A Review

Small renal tumors are sometimes challenging to diagnose accurately through imaging alone, and image-guided biopsies are performed when histological diagnoses are needed. Although ultrasound guidance is usually chosen for renal tumor biopsies, computed tomography guidance is preferred for selected cases; e.g., obese patients or when the target is undetectable by ultrasound (as those in the upper pole). In the 14 recently published studies covering ≥50 procedures, computed tomography-guided renal tumor biopsies had a wide range diagnostic yield (67.4%-97.4%). Complications often occurred; however, most were minor and asymptomatic. No biopsy-related deaths and tumor seeding occurred. This study aimed to review the advantages and disadvantages, procedure techniques, diagnostic yields, and complications of core needle biopsies for renal tumors under computed tomography guidance.

Percutaneous US-guided renal cryoablation using 3D modeling

INTRODUCTION

The article describes the first experience of performing percutaneous ultrasound (US)-guided cryoablation of renal tumor and assesses the safety and short-term results of treatment.

MATERIALS AND METHODS

Twelve patients were subjected to US-guided cryoablation of renal tumor in 2015. The tumor size in 11 patients was up to 3.0 cm (T1а); in one female patient, 4.5 cm (T1b). Tumors were assessed according to the PADUA score. In eight patients, it was 6-7 (low); in three patients, 8-9 (average); in one, 10 (high). All the patients underwent US examination using a FlexFocus 800 apparatus with convex abdominal transducers. Before surgery and 6 months later, all the patients underwent renal Doppler US and contrast-enhanced computed tomography.

RESULTS

The average cryoablation time was 60 min. Seven operations were performed under spinal anesthesia and five operations under local anesthesia. The follow-up period lasted 8 months on average. According to the ultrasonography and Doppler findings, after 6 months, the tumor (T1a) in 11 patients reduced in size by an average of 7-8 mm and had no blood supply.T1b patient's mass size reduces from 4.5 to 3.7 cm; however, a 1.5 cm area with a high attenuation gradient of the contrast medium was visualized. Later, the patient was subjected to laparoscopic renal resection. Histological finding revealed clear-cell carcinoma.

CONCLUSIONS

We consider percutaneous US-guided cryoablation as a method of choice for patients with stage T1a renal tumor localized on the posterior or lateral surface in the inferior or middle segment without sinus involvement and PADUA <9.