Image-guided percutaneous renal cryoablation for stage 1 renal cell carcinoma with high surgical risk

Safety and effectiveness of percutaneous renal cryoablation with conscious sedation

OBJECTIVE

To investigate complications and treatment failure rates of percutaneous renal cryoablation (PRC) for small renal masses under local anaesthesia and conscious sedation (LACS), to assess the safety and effectiveness of this approach, as PRC is typically performed under general anaesthesia (GA).

PATIENTS AND METHODS

We retrospectively reviewed PRC under LACS from 2003 to 2017. We analysed perioperative parameters between patients who successfully underwent PRC under LACS and patients with post-procedural complications or treatment failure (renal mass enhancement after successful intraoperative tumour ablation). Two-sided non-parametric and Fisher's exact tests were performed to compare uncomplicated or disease-free PRC with the complication or treatment failure group, respectively.

RESULTS

A total of 100 PRCs under LACS were performed during the study period. Of these patients, six patients had at least one postoperative complication (6%), and treatment failure was diagnosed in nine patients (9%) after PRC [mean (SD) follow-up of 42.7 (26.6) months]. The procedural failure rate was 1%. No ablations were converted to GA. The mean tumour size was smaller in patients who had no complications during PRC compared to those who did, at a mean (SD) of 2.2 (0.6) cm vs 3.0 (1.0) cm (P = 0.039). The use of more intraoperative probes during the PRC was also associated with complications, at a mean (SD) 3.0 (1.4) vs 1.8 (0.8) (P = 0.021).

CONCLUSIONS

PRC under LACS is an effective and safe procedural approach for managing small renal masses with low complication, treatment failure, and procedural failure rates. Larger renal masses and intraoperative use of multiple probes is associated with an increased risk of PRC complications.

ABBREVIATIONS

BMI: body mass index; CCI: Charlson Comorbidity Index; GA: general anaesthesia; LACS: local anaesthesia and conscious sedation; PRC: percutaneous renal cryoablation; R.E.N.A.L.: Radius, Exophytic/Endophytic, Nearness, Anterior/Posterior, Location.

[Percutaneous renal ablation: Pre-, per-, post-interventional evaluation modalities and adapted management]

OBJECTIVES

Ablative treatment (AT) rise is foreseen, validation of steps to insure good proceedings is needed. By looking over the process of the patient, this study evaluates the requirements and choices needed in every step of the management.

METHODS

We searched MEDLINE^®, Embase^®, using (MeSH) words and we looked for all the studies. Investigators graded the strength of evidence in terms of methodology, language and relevance.

RESULTS

Explanations of AT proposal rather than partial nephrectomy or surveillance have to be discussed in a consultation shared by urologist and interventional radiologist. Per-procedure choices depend on predictable ballistic difficulties. High volume, proximity of the hilum or of a risky organ are in favor of general anesthesia, cryotherapy and computed tomography/magnetic resonance imaging (CT/MRI). Percutaneous approach should be privileged, as it seems as effective as the laparoscopic approach. Early and delayed complications have to be treated both by urologist and radiologist. Surveillance by CT/MRI insure of the lack of contrast-enhanced in the treated area. Patients and tumors criteria, in case of incomplete treatment or recurrence, are the key of the appropriate treatment: surgery, second session of AT, surveillance.

CONCLUSION

AT treatments require patient's comprehension, excellent coordination of the partnership between urologist and radiologist and relevant choices during intervention.

Renal Cell Carcinoma: Alternative Nephron-Sparing Treatment Options for Small Renal Masses, a Systematic Review

BACKGROUND

The standard treatment of T1 renal cell carcinoma (RCC) is (partial) nephrectomy. For patients where surgery is not the treatment of choice, for example in the elderly, in case of severe comorbidity, inoperability, or refusal of surgery, alternative treatment options are available. These treatment options include active surveillance (AS), radiofrequency ablation (RFA), cryoablation (CA), microwave ablation (MWA), or stereotactic body radiotherapy (SBRT). In the present overview, the efficacy, safety, and outcome of these different options are summarized, particularly focusing on recent developments.

MATERIALS AND METHODS

Databases of MEDLINE (through PubMed), EMBASE, and the Cochrane Library were systematically searched according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria. The search was performed in December 2016, and included a search period from 2010 to 2016. The terms and synonyms used were renal cell carcinoma, active surveillance, radiofrequency ablation, microwave ablation, cryoablation and stereotactic body radiotherapy.

RESULTS

The database search identified 2806 records, in total 73 articles were included to assess the rationale and clinical evidence of alternative treatment modalities for small renal masses. The methodological quality of the included articles varied between level 2b and level 4.

CONCLUSION

Alternative treatment modalities, such as AS, RFA, CA, MWA, and SBRT, are treatment options especially for those patients who are unfit to undergo an invasive treatment. There are no randomized controlled trials available comparing surgery and less invasive modalities, leading to a low quality on the reported articles. A case-controlled registry might be an alternative to compare outcomes of noninvasive treatment modalities in the future.

The additional utility of apparent diffusion coefficient values of clear-cell renal cell carcinoma for predicting metastasis during clinical staging

BACKGROUND

The apparent diffusion coefficient (ADC) value is known to be an indicator of tumor activity. The ADC value of high-grade clear-cell renal cell carcinoma (RCC) is significantly lower than that of low-grade clear-cell RCC.

PURPOSE

To investigate the utility of ADC values of clear-cell RCC by comparing ADC values between groups with T1a RCC (tumor size ≤ 4 cm) without metastasis and the group with metastasis.

MATERIAL AND METHODS

A retrospective review was performed on 51 patients with 51 RCCs who underwent 1.5 T magnetic resonance imaging (MRI) for evaluating a renal mass confirmed pathologically to be clear-cell RCC between January 2010 and August 2014. We compared ADC values between group A (T1a RCC without metastasis, T1aN0M0) and group B (RCC with metastasis) using the Mann-Whitney U test.

RESULTS

The patients were divided into group A (n = 30; tumor size: median, 24.5 mm; range, 8-40 mm; ADC value [×10^-3 mm²/s]: median, 1.71; range, 1.23-2.24) and group B (n = 21; tumor size: median, 87.5 mm; range, 18-150 mm; ADC value [×10^-3 mm²/s]: median, 1.35; range, 0.91-1.94). The ADC value differed significantly between the two groups. The area under the receiver operating characteristic curve was 0.869. Using the optimum cutoff value (1.552 × 10^-3 mm²/s), ADC had a sensitivity of 80.0% and specificity of 81.0%.

CONCLUSION

There was a statistically significant difference in the ADC between group A (T1a clear-cell RCC without distant metastasis) and group B (advanced clear-cell RCC with lymph node metastasis or distant metastasis).

Diagnostic accuracy of contrast-enhanced computed tomography and contrast-enhanced magnetic resonance imaging of small renal masses in real practice: sensitivity and specificity according to subjective radiologic interpretation

Background

The aim of this study was to investigate the diagnostic accuracy of contrast-enhanced computed tomography (CT) and contrast-enhanced magnetic resonance imaging (MRI) of small renal masses in real practice.

Methods

Contrast-enhanced CT and MRI were performed between February 2008 and February 2013 on 68 patients who had suspected small (≤4 cm) renal cell carcinoma (RCC) based on ultrasonographic measurements. CT and MRI radiographs were reviewed, and the findings of small renal masses were re-categorized into five dichotomized scales by the same two radiologists who had interpreted the original images. Receiver operating characteristics curve analysis was performed, and sensitivity and specificity were determined.

Results

Among the 68 patients, 60 (88.2 %) had RCC and eight had benign disease. The diagnostic accuracy rates of contrast-enhanced CT and MRI were 79.41 and 88.23 %, respectively. Diagnostic accuracy was greater when using contrast-enhanced MRI because too many masses (67.6 %) were characterized as “4 (probably solid cancer) or 5 (definitely solid cancer).” The sensitivity of contrast-enhanced CT and MRI for predicting RCC were 79.7 and 88.1 %, respectively. The specificities of contrast-enhanced CT and MRI for predicting RCC were 44.4 and 33.3 %, respectively. Fourteen diagnoses (20.5 %) were missed or inconsistent compared with the final pathological diagnoses. One appropriate nephroureterectomy and five unnecessary percutaneous biopsies were performed for RCC. Seven unnecessary partial nephrectomies were performed for benign disease.

Conclusions

Although contrast-enhanced CT and MRI showed high sensitivity for detecting small renal masses, specificity remained low.

Utility of virtual unenhanced images and split-bolus injection using spectral multidetector CT for the assessment of renal cell carcinoma conspicuity and radiation dose

OBJECTIVE

The aim of this study was to evaluate the radiation dose and renal cell carcinoma conspicuity with virtual unenhanced images and split-bolus injection from spectral multidetector CT (MDCT).

MATERIAL AND METHODS

This prospective study was approved by the Ethics Committee, and informed consent was obtained. Ninety suspected patients of renal cell carcinoma diagnosed by abdominal ultrasonography and CEUS were randomly divided into two groups by a radiographer. Patients of the first group underwent spectral MDCT with virtual unenhanced imaging and split-bolus injection, while patients in the second group underwent conventional unenhanced as well as tri-phasic enhanced CT. Group A (split-bolus spectral MDCT group): The contrast material was administered at a dose of 1.5 mL/kg body weight at a flow rate of 4 mL/s, with a ratio of 7 to 5 before the CT scan with an interval of 60 seconds. Virtual unenhanced images were generated using a standard three-material decomposition algorithm, and the best mono-energy (keV) was calculated to show the tumour, renal artery and renal vein. Group B (conventional tri-phasic enhanced CT group): the contrast agent was injected with a dose of 1.5 mL/kg body weight at a flow rate of 4 mL/s. The corticomedullary phase scanning was performed once the arterial CT value reached 100 HU; the nephrographic phase was scanned 60 seconds later. And the excretory phase was scanned 5 min after onset of contrast injection. The LKR (lesion kidney ratio), CNR, and CT value of the corticomedullary and nephrographic phase were measured. The opacification of the renal collection system (including calices, infundibula and renal pelvis) was scored. The radiation dose was recorded. Statistical analysis was performed using Student's t-test, Fisher's exact test, the Mann-Whitney U-test, and k statistics.

RESULTS

There were no statistically significant differences between the two groups in age, sex and body mass index (BMI), but there was significant difference in treatment methods. The best mono-energy was 58 keV for showing the tumour and renal artery and 67 keV for showing the renal vein. There were no differences in the mean attenuations of normal renal parenchyma, renal tumour, CNR, and imaging quality between true unenhanced images and virtual unenhanced images from the combined corticomedullary and nephrographic phase. The LKR of the mono-energy at 58 keV from the combined corticomedullary and nephrographic phase was significantly better than the corticomedullary phase of the conventional enhanced CT scan (0.74±0.18 vs 1.08±0.34, P<.01), but there was no difference in CNR (2.31±1.74 vs 2.79±1.83, P>.05). There were no differences in the CT values of the renal tumour, normal renal parenchyma and renal artery between the two groups (P>.05). The CT value of the renal vein at mono-energy (67 keV) (200.55±43.38) from the combined corticomedullary and nephrographic phase was higher than the conventional CT scan (140.90±42.64) in the nephrographic phase. The Kappa scores of the rate of the renal collection system for the conventional CT and spectral CT were 0.68 (95% confidence interval [CI]: 0.35-0.89) and 0.54 (95% CI: 0.30-0.88), respectively. The radiation dose (735±162 mGy·cm) of Group A was significantly less than that of Group B (1032±324 mGy·cm) (P<.01).

CONCLUSION

Conspicuity with virtual unenhanced imaging and split-bolus injection from spectral multidetector CT is better than or equal to the conventional three-phase enhanced CT scan in showing the RCC, renal artery and renal vein, while the radiation dose can be reduced by 28.78%.