Image-guided core biopsy of 2-cm or smaller renal tumors

Renal mass biopsy - a practical and clinicopathologically relevant approach to diagnosis

Advancements in imaging modalities have increased the frequency of renal mass discovery. Imaging has typically been considered sufficient to guide management for a large proportion of these tumours, but renal mass biopsies (RMBs) have an increasing role in determining malignancy and can be a valuable tool for preventing unnecessary surgery in patients with benign tumours. A structured approach should be used to help to navigate the expanding repertoire of renal tumours, many of which are molecularly defined. In terms of tumour subtyping, the pathologist's strategy should focus on stratifying patients into clinically different prognostic groups according to our current knowledge of tumour behaviour, including benign, low-grade or indolent, intermediate malignant or highly aggressive. Crucial pathological features and morphological mimicry of tumours can alter the tumour's prognostic group. Thus, pathologists and urologists can use RMB to select patients with tumours at a reduced risk of progression, which can be safely managed with active surveillance within a tailored imaging schedule, versus tumours for which ablation or surgical intervention is indicated. RMB is also crucial in the oncological setting to distinguish between different high-grade tumours and guide tailored management strategies.

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.

Prospective evaluation of core number of biopsy for renal tumor: are multiple cores preferable?

PURPOSE

This single-center, single-arm, prospective, open-label study was conducted to evaluate the optimal number of cores (single or multiple) in renal tumor biopsy.

MATERIALS AND METHODS

Forty-four biopsies of 44 tumors (mean diameter, 2.7 ± 1.0 cm; range, 1.6-5.0 cm) were included. Biopsy was performed under ultrasound or computed tomography fluoroscopy guidance using an 18-gauge cutting needle and the co-axial method. Two or more specimens were obtained, which were divided into first and subsequent specimens. "First specimen" and "all specimens" were histologically evaluated (i.e., appropriateness of specimen, histological diagnosis, subtype, and Fuhrman grade of renal cell carcinoma [RCC]) blindly and independently by two board-certified pathologists.

RESULTS

Multiple specimens were successfully and safely obtained in all the biopsies. All tumors were histologically diagnosed; 40 malignancies included 39 RCCs and 1 solitary fibrous tumor, and 4 benign lesions included 2 angiomyolipomas, 1 oncocytoma, and 1 capillary hemangioma. In all RCCs, the subtype could be determined (32 clear cell RCCs, 4 chromophobe RCCs, and 3 papillary RCCs), and the Furman grade was determined in 38 RCCs. When only the first specimen was evaluated, 22.7% of the specimens were inappropriate for diagnosis, and 34 (77.3%) were histologically diagnosed. The diagnostic yield was significantly lower than that of all specimens (P = 0.0044). Univariate analysis revealed that smaller lesions were a significant predictor of diagnostic failure (P = 0.020).

CONCLUSION

Biopsy with multiple cores significantly improved diagnostic yield. Thus, operators should obtain multiple cores during renal tumor biopsy.

The impact of tumor size on the survival of patients with small renal masses: A population-based study

Background

Active surveillance (AS) with delayed intervention has gained acceptance as a management strategy for small renal masses (SRMs). However, during AS, there is a risk of tumor growth. Thus, we aim to investigate whether tumor growth in patients with SRMs leads to tumor progress.

Methods

In this study, we enrolled 16,070 patients from the Surveillance, Epidemiology, and End Results database with T1a renal cell carcinoma (RCC) between 2004 and 2017. The 16,070 patients were divided into three groups: 10,526 in the partial nephrectomy (PN) group, 2768 in the local ablation (LA) group, and 2776 in the AS group. Associations of tumor size with all‐cause and cancer‐specific mortality were evaluated using Kaplan–Meier analyses and Cox regression models.

Results

Four tumor size categories were delineated (≤1, >1–2, >2–3, and > 3–4 cm in diameter), and 10‐year all‐cause and cancer‐specific mortality both significantly increased with increasing tumor size in the PN, LA, and AS groups (all p < 0.05). Tumors were substaged based on diameter: T1aA (≤2 cm) and T1aB (>2–4 cm). All‐cause and cancer‐specific mortality were significantly higher in T1aB tumors than T1aA tumors in each group (hazard ratio = 1.395 and 1.538, respectively; all p < 0.05).

Conclusions

Tumor growth relates to worse prognosis of T1a RCC, and 2 cm serves as a size threshold that is prognostically relevant for patients with T1a RCC. Because of the lack of accurate predictors of tumor growth rate, AS for patients with SRMs incurs a risk of tumor progression.

CT fluoroscopy-guided biopsy of pulmonary lesions contacting the interlobar fissure: An analysis of 72 biopsies

PURPOSE

The purpose of this study was to evaluate retrospectively the safety and diagnostic yield of computed tomography (CT) fluoroscopy-guided biopsy for pulmonary lesions with interlobar fissure contact.

MATERIALS AND METHODS

Seventy-two lesions showing interlobar fissure contact (mean size, 15.2 ± 5.3 [SD] mm [range: 5.3-27.0 mm]; mean length of interlobar fissure contact, 8.9 ± 3.6 [SD] mm [range: 2.6-17.5 mm] in 72 patients (33 men, 39 women; mean age, 69.7 ± 10.3 [SD] years; age range: 37-91 years) were evaluated. Multiple variables were assessed to determine the risk factors for diagnostic failure and pneumothorax. Additionally, these variables were compared between these 72 lesions and randomly selected controls (i.e., non-contact lesions).

RESULTS

All biopsies were technically successful using the transfissural (n = 14) or conventional routes (the route into the lung lobe with the target) with (n = 35) or without (n = 23) possible risk of needle insertion into the interlobar fissure after penetrating the target lesion. Sixty-eight (94.4%) procedures succeeded diagnostically and four (5.6%) failed. There were 27 grade I pneumothorax (37.5%), one (1.4%) grade II bleeding, and five (6.9%) grade IIIa pneumothorax requiring chest tube placement. Groups with and without pneumothorax did not differ significantly in patient-, lesion-, or procedure-related variables. Diagnostic yields and pneumothorax occurrence showed no significant differences between lesions with interlobar fissure contact and controls.

CONCLUSION

CT fluoroscopy-guided biopsy of pulmonary lesions with interlobar fissure contact is a safe procedure with a high diagnostic yield. Furthermore, because of potential complications, the transfissural route should be used only when a safer route is not possible.

Biocompatible nanomicelles for sensitive detection and photodynamic therapy of early-stage cancer

The lack of sensitive detection techniques and agents for early-stage tumors, which are characterized by small size, juvenile blood vessels and scarce secreted markers, has hampered timely cancer therapy and human well-being. Herein, the natural product pyropheophorbide-a (PPa) and FDA-approved Pluronic F127 are organized to develop F127-PPa nanomicelles with favorable size, red-shifted fluorescence and decent biocompatibility. After intravenous (i.v.) injection, the F127-PPa nanomicelles could not only accurately identify early-stage xenografted tumors, but also sensitively detect cancer metastasis in lungs through near-infrared (NIR) fluorescence imaging. The fluorescence signals are consistent with radionuclide imaging, photoacoustic (PA) imaging and bioluminescence imaging of tumors, consolidating the reliability of using F127-PPa nanomicelles for sensitive cancer diagnosis in a non-invasive and low-cost manner. Moreover, the fluorescence intensity of small tumors is linearly correlated with the tumoral mass ranging from 10 to 120 mg with a fluorescence coefficient of 4.5 × 10⁷ mg^-1. Under the guidance of multimodal imaging, the tumors could be thoroughly eradicated by F127-PPa under laser irradiation due to efficient reactive oxygen species (ROS) generation. These findings may provide clinically translatable agents and strategies for sensitive diagnosis of early-stage tumors and timely cancer therapy.

Image-guided marking techniques in interventional radiology: A review of current evidence

Precise marking of lesions using image-guided techniques is essential, as imprecise targeting of a tumor can result in either insufficient excision/treatment with an increased risk of recurrence, or excessive removal of healthy tissue. Most frequent indications include localization of nonpalpable lesions before surgical resection (i.e., hook-wire localization of pulmonary nodules before video-assisted thoracoscopy) and definite marking of liver metastasis before neoadjuvant therapy. Other indications include marking of hepatocellular carcinomas that are not visible on ultrasound and unenhanced computed tomography before thermal ablation, of bone lesions before surgical excision, and of different visceral tumors before stereotactic radiotherapy. This review presents the different existing indications, assesses their usefulness, gives systematic details on the technique and lastly analyzes the current literature with emphasis on results and complications.

CT evaluation of patent artery after percutaneous cryoablation of renal cell carcinoma

PURPOSE

The purpose of this retrospective study was to determine the incidence of persistent patent artery after percutaneous cryoablation of renal cell carcinoma (RCC) and the relationship between patent arteries one month after cryoablation and early tumor progression.

MATERIALS AND METHODS

One hundred and fifty-nine patients (112 men, 47 women; mean age, 63.6±14.6 [SD] years; age range: 21-91 years) who underwent percutaneous cryoablation for 186 RCCs (mean diameter, 1.9±0.6 [SD] cm; range: 0.7-4.0cm) were retrospectively included. After cryoablation, patients underwent contrast-enhanced computed tomography (CT) with ≤2-mm slice thickness within one week from cryoablation, and at one, three, and six months. The time course of patent artery in the ablated renal parenchyma after cryoablation was the primary endpoint. The relationships between patent arteries one month after cryoablation and treatment effectiveness, tumor vascularity, tumor enhancement one month after cryoablation, tumor subtype, and renal function changes were evaluated as secondary endpoints.

RESULTS

CT showed patent arteries in the ablated renal parenchyma within one week in 166 RCCs (89.2%), at one month in 54 RCCs (29.0%), at three months in 8 RCCs (4.3%), and at six months in 2 RCCs (1.1%). The presence of patent artery one month after cryoablation was significantly associated with tumor enhancement at the same time point (P=0.015). There was no association between patent arteries one month after cryoablation and treatment effectiveness (P=0.693).

CONCLUSION

Patent arteries in the ablated renal parenchyma are commonly observed on CT examination after percutaneous cryoablation of RCC. However, they gradually disappear and do not require specific treatment.

Safety and oncologic efficacy of percutaneous MRI-guided cryoablation of intraparenchymal renal cancers

PURPOSE

The purpose of this study was to evaluate the safety and oncologic efficacy of percutaneous magnetic resonance imaging (MRI)-guided cryoablation of intraparenchymal renal cancer.

MATERIALS AND METHODS

Between February 2009 and August 2019, 31 consecutives patients with 31 entirely intraparenchymal biopsy-proven renal cancers were treated with cryoablation under MRI-guidance in our institution, and were retrospectively included. There were 20 men and 11 women with a mean age of 68.5±12.5 (SD) (range: 40-91years). Patient, tumor- and procedure-related, and follow-up data were retrospectively collected and analyzed. Local recurrence free (LRFS), metastasis free (MFS), disease free (DFS), cancer specific (CSS), and overall survivals (OS) were calculated.

RESULTS

Primary and secondary technical efficacy rates were 94% and 100%, respectively. Median follow-up was 27months. Seven (7/31; 23%) minor complications were noted in 7 patients. Patients showed a significant decline of the estimated glomerular filtration rate (eGFR) between baseline and nadir (mean basal eGFR 65.9±22.4 [SD] mL/min/1.73m²vs. mean nadir eGFR 52.8±26.0 [SD] mL/min/1.73m²; P<0.001), but only two showed a clinically significant renal function decline. Three-year estimates of primary and secondary LRFS, MFS, and DFS were 64% (95% confidence interval [CI]: 47-87%), 89% (95% CI: 78-99%), 83% (95% CI: 77-98%), and 45% (95% CI: 28-73%), respectively. No patients died due to renal cancer evolution (three-year CSS of 100%; 95% CI: 100-100%). One patient died 52months after the percutaneous treatment due to cryoablation-unrelated causes (three-year OS of 100%; 95% CI: 100-100%).

CONCLUSION

MRI-guided percutaneous cryoablation for intraparenchymal renal cancer offers good oncologic outcomes with acceptable complication rates and renal function worsening.

Needle artifact characteristics and insertion accuracy using a 1.2T open MRI scanner: A phantom study

PURPOSE

To evaluate the characteristics of needle artifacts and the accuracy of needle insertion using a 1.2 Tesla open magnetic resonance imaging (MRI) system in a phantom.

MATERIALS AND METHODS

First, the apparent width of the needle on the MRI and the needle tip position error of 16- and 18-gauge MRI-compatible introducer needles and a 17-gauge cryoneedle were examined with different needle angles (0°, 30°, 45°, 60°, and 90°) to the main magnetic field (B0), sequence types (balanced steady-state acquisition with rewound gradient echo [BASG] and T2-weighted fast spin echo [FSE] sequence), and frequency encoding directions. Second, the accuracy of needle insertion was evaluated after 10 MRI fluoroscopy-guided insertions in a phantom.

RESULTS

The apparent needle widths was larger when the angle of the needle axis relative to B0 was larger. The needles appeared larger on BASG than on T2-weighted FSE images, with the largest apparent widths of 16-, 17-, and 18-gauge needles of 14.3, 11.6, and 11.0mm, respectively. The apparent needle tip position was always more distal than the actual position on BASG images, with the largest longitudinal error of 4.0mm. Meanwhile, the 16- and 18-gauge needle tips appeared more proximal on T2-weighted FSE images with right-to-left frequency encoding direction. The mean accuracy of MRI fluoroscopy-guided needle insertion was 3.1mm.

CONCLUSION

These experiments clarify the characteristics of needle artifacts in a 1.2 Tesla open MRI. With this system, the MRI fluoroscopy-guided needle insertion demonstrated an acceptable accuracy for clinical use.