Ablative therapies for renal tumors

Recent Advances and Applications of Ambient Mass Spectrometry Imaging in Cancer Research: An Overview

Cancer metabolic variability has a significant impact on both diagnosis and treatment outcomes. The discovery of novel biological indicators and metabolic dysregulation, can significantly rely on comprehension of the modified metabolism in cancer, is a research focus. Tissue histology is a critical feature in the diagnostic testing of many ailments, such as cancer. To assess the surgical margin of the tumour on patients, frozen section histology is a tedious, laborious, and typically arbitrary method. Concurrent monitoring of ion images in tissues facilitated by the latest advancements in mass spectrometry imaging (MSI) is far more efficient than optical tissue image analysis utilized in conventional histopathology examination. This article focuses on the "desorption electrospray ionization (DESI)-MSI" technique's most recent advancements and uses in cancer research. DESI-MSI can provide wealthy information based on the variances in metabolites and lipids in normal and cancerous tissues by acquiring ion images of the lipid and metabolite variances on biopsy samples. As opposed to a systematic review, this article offers a synopsis of the most widely employed cutting-edge DESI-MSI techniques in cancer research.

Phase 2 Trial of Stereotactic Ablative Radiotherapy for Patients with Primary Renal Cancer

BACKGROUND

Most renal cell carcinomas (RCCs) are localized and managed by active surveillance, surgery, or minimally invasive techniques. Stereotactic ablative radiation (SAbR) may provide an innovative non-invasive alternative although prospective data are limited.

OBJECTIVE

To investigate whether SAbR is effective in the management of primary RCCs.

DESIGN, SETTING, AND PARTICIPANTS

Patients with biopsy-confirmed radiographically enlarging primary RCC (≤5 cm) were enrolled. SAbR was delivered in either three (12 Gy) or five (8 Gy) fractions.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary endpoint was local control (LC) defined as a reduction in tumor growth rate (compared with a benchmark of 4 mm/yr on active surveillance) and pathologic evidence of tumor response at 1 yr. Secondary endpoints included LC by the Response Evaluation Criteria in Solid Tumors (RECIST 1.1), safety, and preservation of kidney function. Exploratory tumor cell-enriched spatial protein and gene expression analysis were conducted on pre- and post-treatment biopsy samples.

RESULTS AND LIMITATIONS

Target accrual was reached with the enrollment of 16 ethnically diverse patients. Radiographic LC at 1 yr was observed in 94% of patients (15/16; 95% confidence interval: 70, 100), and this was accompanied by pathologic evidence of tumor response (hyalinization, necrosis, and reduced tumor cellularity) in all patients. By RECIST, 100% of the sites remained without progression at 1 yr. The median pretreatment growth rate was 0.8 cm/yr (interquartile range [IQR]: 0.3, 1.4), and the median post-treatment growth rate was 0.0 cm/yr (IQR: -0.4, 0.1, p < 0.002). Tumor cell viability decreased from 4.6% to 0.7% at 1 yr (p = 0.004). With a median follow-up of 36 mo for censored patients, the disease control rate was 94%. SAbR was well tolerated with no grade ≥2 (acute or late) toxicities. The average glomerular filtration rate declined from a baseline of 65.6 to 55.4 ml/min at 1 yr (p = 0.003). Spatial protein and gene expression analyses were consistent with the induction of cellular senescence by radiation.

CONCLUSIONS

This clinical trial adds to the growing body of evidence suggesting that SAbR is effective for primary RCC supporting its evaluation in comparative phase 3 clinical trials.

PATIENT SUMMARY

In this clinical trial, we investigated a noninvasive treatment option of stereotactic radiation therapy for the treatment of primary kidney cancer and found that it was safe and effective.

Comparison of the Results of Therapy for cT1 Renal Carcinoma with Nephron-Sparing Surgery (NSS) vs. Percutaneous Thermal Ablation (TA)

Implementation of ultrasonography (USG), computed tomography (CT) and magnetic resonance imaging (MRI) into abdominal cavity diagnostics enabled early detection of cT1 graded renal cancers. According to European Association of Urology (EAU) and Polish urological Association (PUA) recommended method of treatment is sparing resection of renal parenchyma with tumour—nephron-sparing surgery (NSS). In selected cases other methods such as thermal ablation (TA) or cryoablation can be introduced /1/. Objectives: To evaluate the results of treatment of cT1 renal tumours with the use of NSS and TA methods. Material and methods: 140 patients with cT1 renal carcinoma were treated in 2nd Department of Urology of Medical University of Lodz between 2014 and 2017. Neuron-sparing surgery was performed in 56 cases (40%), while percutane-ous thermal ablation (TA) in 84 cases (60%). Demographic data, clinical data (lab results, Charlson index), nephrometry data (tumour size, location, R.E.N.A.L. score) post-operative data (Clavien-Dindo classifica-tion) were investigated. Histopathology results, Fuhrman malignancy grading, as total three-year survival of patients were evaluated. The following methods were used for statistical evaluation: Chi2, Fisher, W Shapiro-Wilk, U Mann-Whitney tests, Kaplan-Meier’s curve and Cox model. The results were displayed in a form of median and upper and lower quartile values (25–75%). Results: No statistical differences in gender nor left/right kidney location were observed. Patients, who underwent TA were at average 10 years older and had multiple comorbidities (median age for TA was 79, for NSS 68; median Charlson index for TA was 5 and for NSS was 3). TA patients had lesser haematological values (Hb, Ht). R.E.N.A.L. scoring demonstrated comparable nephrometry in both groups. NSS procedure was open laparotomy without temporary clamping of renal vessels. Surgical margins of resected tumours were negative. TA was performed with Cool-Tip Covidienequipment with the use of Cluster electrode and was ultraso-nography-guided. Post-treatment complications evaluated with the use of Clavien-Dindo classification were slightly more frequent for NSS method. Patients after NSS were discharged at average after 8.5 days and after TA after 3 days. Histopathological type and Fuhrman malignancy grading were comparable in both groups. TA treated patients’ death risk was 9-fold of that observed in NSS treated patients. There was 1 death for each group in perioperative period. Conclusion: 1. NSS was associated with slightly higher side effect rate but resulted in prolonged survival. 2. TA was applied to elderly patients with comorbidities. Despite less invasive treatment this group had poorer/reduced survival. 3. Charlson Comorbidity Index (CCI) and the treatment method were relevant survival factors in patients treated due to cT1 renal cancer tumours.

Identification of diagnostic metabolic signatures in clear cell renal cell carcinoma using mass spectrometry imaging

Clear cell renal cell carcinoma (ccRCC) is the most common and lethal subtype of kidney cancer. Intraoperative frozen section (IFS) analysis is used to confirm the diagnosis during partial nephrectomy. However, surgical margin evaluation using IFS analysis is time consuming and unreliable, leading to relatively low utilization. In our study, we demonstrated the use of desorption electrospray ionization mass spectrometry imaging (DESI-MSI) as a molecular diagnostic and prognostic tool for ccRCC. DESI-MSI was conducted on fresh-frozen 23 normal tumor paired nephrectomy specimens of ccRCC. An independent validation cohort of 17 normal tumor pairs was analyzed. DESI-MSI provides two-dimensional molecular images of tissues with mass spectra representing small metabolites, fatty acids and lipids. These tissues were subjected to histopathologic evaluation. A set of metabolites that distinguish ccRCC from normal kidney were identified by performing least absolute shrinkage and selection operator (Lasso) and log-ratio Lasso analysis. Lasso analysis with leave-one-patient-out cross-validation selected 57 peaks from over 27,000 metabolic features across 37,608 pixels obtained using DESI-MSI of ccRCC and normal tissues. Baseline Lasso of metabolites predicted the class of each tissue to be normal or cancerous tissue with an accuracy of 94 and 76%, respectively. Combining the baseline Lasso with the ratio of glucose to arachidonic acid could potentially reduce scan time and improve accuracy to identify normal (82%) and ccRCC (88%) tissue. DESI-MSI allows rapid detection of metabolites associated with normal and ccRCC with high accuracy. As this technology advances, it could be used for rapid intraoperative assessment of surgical margin status.

Use of hemostatic agents for surgical bleeding in laparoscopic partial nephrectomy: Biomaterials perspective

In recent years, there was an abrupt increase in the incidence of renal tumors, which prompt up the appearance of cutting-edge technology, including minimally invasive and organ-preserving approaches, such as laparoscopic partial nephrectomy (LPN). LPN is an innovative technique used to treat small renal masses that have been gaining popularity in the last few decades due to its promissory results. However, the bleeding control remains the main challenge since the majority of currently available hemostatic agents (HAs) used in other surgical specialities are inefficient in LPN. This hurried the search for effective HAs adapted for LPN surgical peculiarities, which resulted on the emergence of different types of topical HAs. The most promising are the natural origin HAs because of their inherent biodegradability, biocompatibility, and lowest toxicity. These properties turn them top interests' candidates as HAs in LPN. In this review, we present a deep overview on the progress achieved in the design of HAs based on natural origin polymers, highlighting their distinguishable characteristics and providing a clear understanding of their hemostat's role in LPN. This way it may be possible to establish a structure-composition properties relation, so that novel HAs for LPN can be designed to explore current unmet medical needs.

Diagnostic value of imprint cytology testing in kidney tumors: review of 200 cases

INTRODUCTION

Previous investigations have studied the importance of imprint cytology (IC) testing of core needle biopsy (CNB) from various organs. We have presented the largest series, to the best of our knowledge, of IC testing of CNB for patients with kidney tumors.

MATERIALS AND METHODS

The present retrospective study (January 1, 2015, through January 30, 2016) identified laboratory information through a computer search of the cytology archived reports for 200 consecutive IC testing with CNB for renal tumors cases. A board-certified cytopathologist and cytology-trained fellow reviewed the IC testing and CNB slides and rendered them as nondiagnostic, positive for malignancy, negative for malignancy, positive for neoplasm, or atypical. The tumors were graded using the International Society of Urological Pathology grading system. The sensitivity, specificity, positive predictive value, and negative predictive value were calculated.

RESULTS

The IC testing cases classified as atypical (n = 53) or positive for neoplasm (n = 28) were evaluated separately because of the ambiguous morphologic characteristics. Of the other 119 cases, IC testing classified 95 (80%) as positive for malignancy, 5 (4%) as negative for malignancy, and 19 (16%) as nondiagnostic. The corresponding CNB histologic diagnoses showed that 85 of 95 cases (89%) were true positive for malignancy. Of these 85 cases, 45 (53%) were low grade, 21 (25%) were high grade, and 19 (22%) were ungraded. The corresponding sensitivity, specificity, and accuracy were 85%, 11%, and 58%, respectively. The 53 IC-identified atypical cases were more likely to be malignant (n = 40; 75%). Of the remaining IC testing atypical cases, 12 (23%) were negative for malignancy and 1 (2%) was nondiagnostic. Of the 28 cases positive for neoplasm using IC, 13 (46%) were positive and 15 (54%) were negative for malignancy.

CONCLUSIONS

The relatively low diagnostic value of IC testing for renal tumors showed it to be less powerful for screening than its use in other organs.

SEER study of ablation versus partial nephrectomy in cT1A renal cell carcinoma

Aim: Compare ablation versus partial nephrectomy (PN) in T1A renal cell carcinoma (RCC) treatment, using the SEER database. Methods: Patients with diagnosed T1A RCC from 2004 to 2013 were identified. Propensity matching paired subjects with similar background variables. Kaplan–Meier and Cox proportional hazards regression were performed before and after matching. Results: Cohort included 4592 patients (809 ablation, 3783 PN). PN compared with ablation group had significantly increased overall survival (OS; 93.6% vs 81.9% 5-year survival; p < 0.0001) and cancer-specific survival (CSS; p < 0.0001). After matching (1222 pairs), PN group had significantly increased OS (91.0% vs 86.3% 5-year survival; p = 0.0457) but similar CSS (p = 0.4023). Conclusion: Ablation offers similar CSS but lower OS as PN for T1A RCC in this SEER database.

Bioluminescence Image as a Quantitative Imaging Biomarker for Preclinical Evaluation of Cryoablation in a Murine Model

PURPOSE

To employ bioluminescence imaging (BLI) as a quantitative imaging biomarker to assess preclinical evaluation of cryoablation in a murine model.

MATERIALS AND METHODS

In vitro, Colon26-Luc (C26-Luc) cells were seeded at 6 different concentrations in 35-mm dishes. These were divided into 6 groups: group 0 (G0), a control group without treatment; and groups 1-5 (G1-G5) according to the number of freeze-thaw cycles, with each cycle consisting of freezing at -80°C for 10 min followed by thawing at room temperature for 5 minutes. BLI and flow-cytometric analysis were performed after cryotherapy. In vivo, 20 tumor-bearing mice with C26-Luc cells were divided into 4 groups: group 0 (G0), a control group; and groups 1-3 (G1-G3) according to the number of freeze-thaw cycles. Each cryoablation procedure was performed for 30 seconds with liquid nitrogen (-170°C) applied with cotton-tipped applicators. BLI was acquired at 6 hours and 1, 3, and 7 days after treatments.

RESULTS

In vitro, BLI signal showed a negative correlation with the number of freeze-thaw cycles (r = -0.86, P = .02). In vivo, there was no difference in tumor volume at 1 day after cryoablation among all groups, but the BLI signals were significantly different between G0 and G2/G3 (P = .03 and P = .02, respectively) and between G1 and G3 (P = .04). BLI signals reflected tumor growth speed and survival ratio.

CONCLUSIONS

This study demonstrates the direct validation of BLI as a quantitative tool for the early assessment of therapeutic effects of cryoablation.

Thermal ablation of a confluent lesion in the porcine kidney with a clinically available MR-HIFU system

The incidence of small renal masses (SRMs) sized  <4 cm has increased over the decades (as co-findings/or due to introduction of cross sectional imaging). Currently, partial nephrectomy (PN) or watchful waiting is advised in these patients. Ultimately, 80-90% of these SRMs require surgical treatment and PN is associated with a 15% complication rate. In this aging population, with possible comorbidities and poor health condition, both PN and watchful waiting are non-ideal treatment options. This resulted in an increased need for early, non-invasive treatment strategies such as MR-guided high intensity focused ultrasound (MR-HIFU). (i) To investigate the feasibility of creating a confluent lesion in the kidney using respiratory-gated MR-HIFU under clinical conditions in a pre-clinical study and (ii) to evaluate the reproducibility of the MR-HIFU ablation strategy. Healthy pigs (n  =  10) under general anesthesia were positioned on a clinical MR-HIFU system with integrated cooling. A honeycomb pattern of seven overlapping ablation cells (4  ×  4  ×  10 mm³, 450 W, <30 s) was ablated successively in the cortex of the porcine kidney. Both MR thermometry and acoustic energy delivery were respiratory gated using a pencil beam navigator on the contralateral kidney. The non-perfused volume (NPV) was visualized after the last sonication by contrast-enhanced (CE) T ₁-weighted MR (T ₁ w) imaging. Cell viability staining was performed to visualize the extent of necrosis.

RESULTS

a median NPV of 0.62 ml was observed on CE-T ₁ w images (IQR 0.58-1.57 ml, range 0.33-2.75 ml). Cell viability staining showed a median damaged volume of 0.59 ml (IQR 0.24-1.35 ml, range 0-4.1 ml). Overlooking of the false rib, shivering of the pig, and too large depth combined with a large heat-sink effect resulted in insufficient heating in 4 cases. The NPV and necrosed volume were confluent in all cases in which an ablated volume could be observed. Our results demonstrated the feasibility of creating a confluent volume of ablated kidney cortical tissue in vivo with MR-HIFU on a clinically available system using respiratory gating and near-field cooling and showed its reproducibility.

Multipoint Thermal Sensors Associated with Improved Oncologic Outcomes Following Cryoablation

INTRODUCTION

Cryoablation (CA) is a minimally invasive modality for the management of small renal cortical neoplasms (RCN). Effective ablation is dependent on achieving target temperatures during CA that result in tumor cell death. We investigated long-term oncologic outcomes following CA using multipoint thermal sensors (MTS), which allow precise temperature determination at four points along the needle.

METHODS

We performed a retrospective review of 20 patients with <4 cm RCN who underwent de novo CA from 2005 to 2009. In 11 procedures, MTS needles were deployed with the goal of obtaining -20°C at the tumor margin, while 9 were done without MTS. Patient demographics, tumor characteristics, and CA procedure data were retrieved and analyzed. Follow-up CT or MRI was used to assess recurrence status.

RESULTS

With a mean follow-up of 45 months, none of the 11 patients experienced a recurrence in the MTS group, compared with 4 of 9 (44.4%) patients in the non-MTS group (p = 0.026). Of the biopsy-confirmed renal cancers, none of the 6 in the MTS group, compared with 3 of 6 (50%) in the non-MTS group, recurred (p = 0.182). Age, tumor size, surgical approach, tumor histopathology, grade, follow-up time, and skin-to-tumor distance were similar between the MTS and non-MTS groups. The MTS group was also associated with increased total length of freeze (p = 0.041), procedure time (p = 0.020), cryoprobe utilization (p = 0.049), and a greater ratio of cryoprobes used per cm diameter of tumor (p = 0.003).

CONCLUSIONS

In this small renal mass pilot study, the use of MTS needles to monitor temperature and guide cryoneedle deployment was associated with improved oncologic outcomes.

Contemporary Status of Percutaneous Ablation for the Small Renal Mass

Renal cell carcinoma is the tenth most common malignancy in the USA, with upwards of 61,000 new cases and resulting in more than 14,000 deaths annually. Although partial nephrectomy remains the standard treatment, image-guided nephron-sparing ablative techniques including cryoablation, radiofrequency ablation, and microwave ablation have emerged as treatment options in certain patient populations. Ablative therapies have high technical successes, low tumor recurrence rates, and preserve renal parenchymal volume. The purpose of this article is to provide an update on ablation therapies for small renal masses.

Emerging needle ablation technology in urology

PURPOSE OF REVIEW

Thermal ablation of urologic tumors in the form of freezing (cryoablation) and heating (radiofrequency ablation) have been utilized successfully to treat and ablate soft tissue tumors for over 15 years. Multiple studies have demonstrated efficacy nearing that of extirpative surgery for certain urologic conditions. There are technical limitations to their speed and safety profile because of the physical limits of thermal diffusion.

RECENT FINDINGS

Recently, there has been a desire to investigate other forms of energy in an effort to circumvent the limitations of cryoblation and radiofrequency ablation. This review will focus on three relatively new energy applications as they pertain to tissue ablation: microwave, irreversible electroporation, and water vapor. High-intensity-focused ultrasound nor interstitial lasers are discussed, as there have been no recently published updates.

SUMMARY

Needle and probe-based ablative treatments will continue to play an important role. As three-dimensional imaging workstations move from the advanced radiologic interventional suite to the operating room, surgeons will likely still play a pivotal role in the +-application of these probe ablative devices. It is essential that the surgeon understands the fundamentals of these devices in order to optimize their application.