Focal ablation therapy for renal cancer in the era of active surveillance and minimally invasive partial nephrectomy

Exploring the Characteristics of Circulating Tumor DNA in Pt1a Clear Cell Renal Cell Carcinoma: A Pilot Study

Circulating tumor DNA (ctDNA) is a promising biomarker for clear cell renal cell carcinoma (ccRCC); however, its characteristics in small renal masses of ccRCC remain unclear. In this pilot study, we explored the characteristics of ctDNA in pT1a ccRCC. Plasma samples were collected preoperatively from 53 patients with pT1a ccRCC. The ctDNA of pT1a ccRCC was profiled using next-generation sequencing and compared with that of higher-stage ccRCC. The association of ctDNA in pT1a ccRCC with clinicopathological features was investigated. The positive relationship of mutations between ctDNA and matched tissues was evaluated. In pT1a ccRCC, the ctDNA detection rate, cell-free DNA concentration, and median variant allele frequency were 20.8%, 5.8 ng/mL, and 0.38%, respectively, which were significantly lower than those in metastatic ccRCC. The ctDNA gene proportions in pT1a samples differed from those in metastatic ccRCC samples. The relationships between ctDNA and tumor size, tumor grade, and patient age were not elucidated. The positive concordance between ctDNA and matched tissues was poor for pT1a ccRCC. Strategies are needed to increase sensitivity while eliminating noise caused by clonal hematopoiesis to increase the clinical utility of ctDNA analysis in small renal masses of ccRCC.

Thermal shielding performance of self-healing hydrogel in tumor thermal ablation

Thermal ablation therapy is widely used in the surgical treatment of tumors. Clinically, normal saline is generally used as an insulator to protect adjacent tissues from local high-temperature burns caused by thermal ablation. However, the flow of saline causes fluid loss, requiring frequent injections and complex operation, which is easy to lead to complications such as secondary injury and hematoma. Here, a self-healing chitosan-PEG (CP) hydrogel was proposed as a protective medium to challenge the clinical preparations. Compared with saline and non-self-healing hydrogel F127, CP hydrogel exhibited outstanding thermal shielding performance in the thermal ablation of thyroid nodule in a Beagle dog model. The transient plane source (TPS) method is used to measure thermal properties, including thermal conductivity, thermal diffusivity and specific heat capacity. The thermal shielding mechanism and clinical advantages including operability, biodegradability, and biological safety of self-healing hydrogel are then revealed in-depth. Therefore, self-healing hydrogel can achieve much better thermal management in tumor thermal ablation.

Tailoring Chemoimmunostimulant Bioscaffolds for Inhibiting Tumor Growth and Metastasis after Incomplete Microwave Ablation

Microwave ablation has attracted the most attention as a locoregional therapeutic method for solid neoplasms. However, the high incidence of incomplete ablation that could promote the rapid cancer progression still remains a challenge in clinic. Herein, we found that the high invasiveness of residual tumor following incomplete microwave ablation (iMWA) is mainly due to the myeloid cell-mediated immunosuppression. Accordingly, we develop a biohydrogel scaffold-enabled chemoimmunotherapeutic strategy by targeting myeloid cells with a phosphoinositide 3-kinase γ (PI3Kγ) inhibitor (IPI549) to synergize with immunostimulatory chemotherapy (Oxaliplatin, OX) for post-ablative cancer therapy. With several tumor mouse models, we reveal that OX&IPI549@Gel-based localized chemoimmunotherapy can substantially suppress the growth of tumor post-iMWA, simultaneously evoke robust systemic anticancer immunity to inhibit metastatic spread, and offer strong long-term immunological memory functions against tumor rechallenge. Besides, this work proposes a potential opportunity for precision medicine by utilizing a mechanism-based rationale to the adoption of our pre-existing arsenal of anticancer immunotherapeutic schedule.

Injectable Immunotherapeutic Thermogel for Enhanced Immunotherapy Post Tumor Radiofrequency Ablation

Tumor radiofrequency ablation (RFA) is a local and minimally invasive application using high temperature to induce coagulative necrosis of tumor, which has been commonly used in clinic. Although the tumor fragments generated by RFA can activate the host's immune system, it may be insufficient to inhibit cancer recurrence due to many factors such as the inefficient antigen presentation by dendritic cells (DCs). In this research, a convenient local administration strategy by blocking rho-associated kinases (ROCK) is applied to amplify the immune responses triggered by RFA via promoting the phagocytosis capacity of DCs. Briefly, ROCK inhibitor, Y27632, is successfully dispersed in the amphiphilic copolymer poly(D,L-lactide-co-glycolide)-b-poly(ethyleneglycol)-b-poly(D,L-lactideco-glycolide) (PLGA-PEG-PLGA) solution, which is sol at room temperature and forms hydrogel quickly at body temperature, obviously prolonging the retention of Y27632 after injection. Interestingly, in the melanoma tumor model, the generated tumor fragments after RFA treatment are swallowed by DCs and undergo reinforced antigen presentation process with the help of gradual released Y27632, further effectively activating T cell mediated anti-tumor immune responses and significantly improving the therapeutic efficiency of RFA. Overall, such strategy remarkably prolongs the survival of mice after RFA treatment, showing great potential for clinical translation as an improvement strategy for RFA.

Tumor-killing nanoreactors fueled by tumor debris can enhance radiofrequency ablation therapy and boost antitumor immune responses

Radiofrequency ablation (RFA) is clinically adopted to destruct solid tumors, but is often incapable of completely ablating large tumors and those with multiple metastatic sites. Here we develop a CaCO₃-assisted double emulsion method to encapsulate lipoxidase and hemin with poly(lactic-co-glycolic acid) (PLGA) to enhance RFA. We show the HLCaP nanoreactors (NRs) with pH-dependent catalytic capacity can continuously produce cytotoxic lipid radicals via the lipid peroxidation chain reaction using cancer cell debris as the fuel. Upon being fixed inside the residual tumors post RFA, HLCaP NRs exhibit a suppression effect on residual tumors in mice and rabbits by triggering ferroptosis. Moreover, treatment with HLCaP NRs post RFA can prime antitumor immunity to effectively suppress the growth of both residual and metastatic tumors, also in combination with immune checkpoint blockade. This work highlights that tumor-debris-fueled nanoreactors can benefit RFA by inhibiting tumor recurrence and preventing tumor metastasis.

Local anesthesia for percutaneous US/CT-guided bipolar radiofrequency ablation of small renal masses: A safe and feasible alternative

PURPOSE

This study is to evaluate the safety and feasibility of local anesthesia (LA) for percutaneous ultrasound/computed tomography (US/CT)-guided bipolar radiofrequency ablation (RFA) for small renal masses (SRMs) by comparing the LA with general anesthesia.

MATERIALS AND METHODS

A retrospective review was carried out between January 2018 to June 2020, 102 patients with SRMs were treated with US/CT-guided bipolar RFA. General anesthesia (GA) was performed in 42 and LA was performed in 60 patients. Demographics, tumor characteristics, peri-procedural data, pathologic and follow-up outcomes were analyzed. The factors associated with pain were also identified.

RESULTS

There was no significant difference in demographics and tumor characteristics between the LA and GA group. A statistically significant difference was observed in terms of procedural time (P = 0.010) and hospital stays (P < 0.001). The maximum perceived pain in LA group comprised 60.0% (36 of 60) mild, 40.0% (24 of 60) moderate. The anxiety in LA group comprised 65.0% (39 of 60) mild, 33.3% (20 of 60) moderate, 1.7% (1 of 60) severe. On multivariate analysis, tumor diameter was a significant predictor for pain in RFA procedure (OR 1.560, 95% CI 1.233-1.974, P < 0.001). All patients were followed up for a median (range) of 12 (2-24) months. Local recurrence occurred in 8.3% (5 of 60) of the LA group and in 7.1% (3 of 42) in GA group (P = 1.000).

CONCLUSION

Percutaneous bipolar RFA of SRMs using CT and ultrasound guidance under LA can be an effective and tolerable method for patients who are unfit for surgery and provide satisfactory oncologic control.

Real-Time US-CT fusion imaging for guidance of thermal ablation in of renal tumors invisible or poorly visible with US: results in 97 cases

PURPOSE

To assess the capability of ultrasound-computed tomography (US-CT) fusion imaging to guide a precise targeting of renal tumors invisible or poorly visible with US.

MATERIALS AND METHODS

From 2016 renal tumors poorly visible or inconspicuous/invisible at US were treated at our institution with the guidance of US/CT fusion in a room equipped with CT scanner. Feasibility of the procedure, accuracy of targeting, complications, and technique efficacy were evaluated.

RESULTS

Of 227 patients treated from 2016 to March 2020, 91 patients (65 males and 26 females, mean age 68.5 ± 10.1 years) with 97 renal lesions (mean maximum diameter 21.6 ± 9.4 mm) inconspicuous/invisible (29/97, 29.9%) or poorly visible (68/97, 70.1%) at US underwent treatment under US-CT fusion guidance. US-CT fusion imaging guidance was always technically feasible and enabled correct targeting in 97/97/(100%) of cases. Technical success was achieved in 93/97 lesions (95.9%). Three lesions were retreated during the same ablative session, while 1 was retreated in a subsequent session. Thus, primary efficacy was achieved in one session in 96/97 (98.9%) cases and secondary efficacy in 97/97 (100%) cases.

CONCLUSION

US-CT image fusion guidance allows for a correct tumor targeting of renal tumors poorly visible or inconspicuous/invisible with US alone, with a high rate of technical success and technique efficacy.

Oncological outcomes of active surveillance and percutaneous cryoablation of small renal masses are similar at intermediate term follow-up

BACKGROUND

Active surveillance (AS) and minimally invasive ablative therapies such as percutaneous cryoablation (PCA) are emerging as alternative treatment modalities in the management of small renal masses (SRMs).

METHODS

Fifty-nine patients underwent PCA since 2011 and 75 underwent AS since 2010 at two different institutions. Only patients with follow-up ≥ 6 months were included. All patients were followed with a standardized protocol. Treatment failure was defined by dimensional progression for AS and renal recurrence for PCA, in addition to stage and/or metastatic progression for both groups.

RESULTS

Treatment failure was observed in 14 cases (18,7%) during AS (mainly due to dimensional progression) and 12 patients (16%) underwent delayed intervention with a mean follow-up of 36,83 months. Seven patients (11,9%) in the PCA group experienced treatment failure with a mean follow-up of 33,39 months and 3 of them underwent re-ablation successfully. Cancer-specific-survival at 2 and 5 years was 100% and 95,8% in AS-group vs. 98,2% and 98,2% in PCA-group (p=0,831). One patient in both groups died from metastatic disease. Overall-survival at 2 and 5 years was 91,7% and 82,4% in the AS-group vs. 96,5% and 96,5% in the PCA-group (p=0,113). Failure-free survival at 2 and 5 years was 90,9% and 70,1% in the AS-group vs. 93,1% and 70,9% in the PCA-group (p=0,645).

CONCLUSIONS

AS and PCA provide similar survival outcomes and are safe and valid treatment options for elderly and comorbid patients with SRMs.

Local ablation vs partial nephrectomy in T1N0M0 renal cell carcinoma: An inverse probability of treatment weighting analysis

Objective

To compare the survival outcomes of local ablation (LA) and partial nephrectomy (PN) for T1N0M0 renal cell carcinoma (RCC).

Method

We identified 38,155 T1N0M0 RCC patients treated with PN or LA in 2004‐2016 from the retrospective Surveillance, Epidemiology, and End Results databases. Among them, there were 4656 LA and 33,499 PN. A Cox proportional hazards regression model, cause‐specific Cox regression and Fine and Gray sub‐distribution hazard ratio (sHR) with inverse probability of treatment weighting (IPTW) adjusting was utilized to compare the effects of LA vs PN on all‐, RCC‐, and non‐RCC–caused mortality.

Results

Within the IPTW analysis, patients who underwent PN experienced a better overall survival (OS) (HR, 1.56; 95% CI, 1.40‐1.74; P < .001) and cancer‐specific survival (CSS) (HR, 2.21; 95% CI, 1.62‐2.98; P < .001) than LA patients. In the subgroup of patients >85 years (HR, 1.14; 95% CI, 0.73‐1.79, P = .577), chromophobe RCC (HR, 1.68; 95% CI, 0.94‐3.00, P = .078), and tumor size <2 cm (HR, 1.21; 95% CI, 0.95‐1.53, P = .126), the OS showed no significant difference between LA and PN. No significant difference in CSS between LA and PN was observed in the subgroup of chromophobe RCC (HR, 0.34; 95% CI, 0.03‐3.97, P = .389), and tumor size <2 cm (HR, 1.83; 95% CI, 0.92‐3.64, P = .084). For patients >85 years (sHR, 0.89; 95% CI, 0.52‐1.27, P = .520) and tumor size <2 cm (sHR, 1.14; 95% CI, 0.94‐1.38, P = .200), the non‐RCC–specific mortality was not significantly different in PN and LA cohorts, however, for the chromophobe RCC, the LA showed a worse non‐RCC mortality than PN (HR, 1.72; 95% CI, 1.06‐2.79, P = .028).

Conclusion

PN showed a better prognosis than LA in T1N0M0 RCC treatment, but LA and PN showed a comparable OS in elderly patients (>85), small RCC (<2 cm) and chromophobe RCC.

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

Purpose: To evaluate feasibility, safety and efficacy of image-guided thermal ablations associated with retrograde pyeloperfusion in patients with centrally located renal tumors.Materials and methods: 48 patients (15 women, 33 men, mean age 69.1 ± 11.8) were treated with image-guided thermal ablation associated with pyeloperfusion for 58 centrally located renal tumors (mean diameter 32.3 ± 7.32 mm). 7 patients had a single kidney. Microwave and radiofrequency ablation were used. All treatments were performed with ultrasound, CT, or fusion imaging guidance under general anesthesia and simultaneous retrograde cold pyeloperfusion technique.Results: Procedure was feasible in all cases. Technical success and primary technical efficacy were reached in 51/58 (88%) and 45/54 tumors (83%). With a second ablation performed in 5 tumors, secondary technical efficacy was achieved in 50/50 (100%) tumors. Minor and major complications occurred in 8/58 (13%) and 5/58 (8%) tumors. No significative change in renal function occurred after treatment.During follow-up, 5 recurrences occurred, that were retreated with a second ablation. At last follow up (mean 32.2 ± 22.0 months), 41/48 (85%) treated patients were free from disease. The median TTP and PFS were 27.0 (range, 2.3-80.0) and 26.5 months (range, 2.3-80.0), respectively.Conclusion: Image-guided thermal ablation associated with protective pyeloperfusion is a feasible, safe, and effective treatment option for patients with central renal tumors with a minimal impact on renal function and relevant potential to avoid nephrectomy.

Percutaneous ablation techniques for renal cell carcinoma: current status and future trends

Percutaneous ablation is an increasingly applied technique for the treatment of localized renal tumors, especially for elderly or co-morbid patients, where co-morbidities increase the risk of traditional nephrectomy. Ablative techniques are technically suited for the treatment of tumors generally not exceeding 4 cm, which has been set as general consensus cutoff and is described as the upper threshold of T1a kidney tumors. This threshold cutoff is being challenged, but with still limited evidence. Percutaneous ablation techniques for the treatment of renal cell carcinoma (RCC) include radiofrequency ablation, cryoablation, laser or microwave ablation; the main advantage of all these techniques over surgery is less invasiveness, lower complication rates and better patient tolerability. Currently, international guidelines recommend percutaneous ablation either as intervention for frail patients or as a first line tool, provided that the tumor can be radically ablated. The purpose of this article is to describe the basic concepts of percutaneous ablation in the treatment of RCC. Controversies concerning techniques and products and the need for patient-centered tailored approaches during selection among the different techniques available will be discussed.

In situ thermal ablation augments antitumor efficacy of adoptive T cell therapy

Purpose: The aim of this study is to investigate whether radiofrequency ablation (RFA) improves the efficacy of adoptive T cell immunotherapy in preclinical mouse cancer models.Method: Mice implanted subcutaneously (sc) with syngeneic colon adenocarcinoma or melanoma were treated with sub-curative in situ RFA (90 °C, 1 min). Trafficking of T cells to lymph nodes (LN) or tumors was quantified by homing assays and intravital microscopy (IVM) after sham procedure or RFA. Expression of trafficking molecules (CCL21 and intercellular adhesion molecule-1 [ICAM-1]) on high endothelial venules (HEV) in LN and tumor vessels was evaluated by immunofluorescence microscopy. Tumor-bearing mice were pretreated with RFA to investigate the therapeutic benefit when combined with adoptive transfer of in vitro-activated tumor-specific CD8⁺ T cells.Results: RFA increased trafficking of naïve CD8⁺ T cells to tumor-draining LN (TdLN). A corresponding increase in expression of ICAM-1 and CCL21 was detected on HEV in TdLN but not in contralateral (c)LN. IVM revealed that RFA substantially enhanced secondary firm arrest of lymphocytes selectively in HEV in TdLN. Furthermore, strong induction of ICAM-1 in tumor vessels was associated with significantly augmented trafficking of adoptively transferred in vitro-activated CD8⁺ T cells to tumors after RFA. Finally, preconditioning tumors with RFA augmented CD8⁺ T cell-mediated apoptosis of tumor targets and delayed growth of established tumors when combined with adoptive T cell transfer immunotherapy.Conclusions: These studies suggest that in addition to its role as a palliative therapeutic modality, RFA may have clinical potential as an immune-adjuvant therapy by augmenting the efficacy of adoptive T cell therapy.

Stereotactic Body Radiotherapy for Stage I Renal Cell Carcinoma: National Treatment Trends and Outcomes Compared to Partial Nephrectomy and Thermal Ablation

PURPOSE

To assess use of stereotactic body radiotherapy (SBRT) for stage I renal cell carcinoma (RCC) and compare outcomes with thermal ablation and partial nephrectomy (PN).

MATERIALS AND METHODS

The 2004-2015 National Cancer Database was investigated for histopathologically proven stage I RCC treated with PN, cryoablation, radiofrequency (RF) or microwave (MW) ablation, or SBRT. Patients were propensity score-matched to account for potential confounders, including patient age, sex, race, comorbidities, tumor size, histology, grade, tumor sequence, administration of systemic therapy, treatment in academic vs nonacademic centers, treatment location, and year of diagnosis. Overall survival (OS) was evaluated with Kaplan-Meier plots, log-rank tests, and Cox proportional hazards models.

RESULTS

A total of 91,965 patients were identified (SBRT, n = 174; PN, n = 82,913; cryoablation, n = 5,446; RF/MW ablation, n = 3,432). Stage I patients who received SBRT tended to be older women with few comorbidities treated at nonacademic centers in New England states. After propensity score matching, a cohort of 636 patients was obtained with well-balanced confounders between treatment groups. In the matched cohort, OS after SBRT was inferior to OS after PN and thermal ablation (PN vs SBRT, hazard ratio [HR] = 0.29, 95% confidence interval [CI] 0.19-0.46, P < .001; cryoablation vs SBRT, HR = 0.40, 95% CI 0.26-0.60, P < .001; RF/MW ablation vs SBRT, HR = 0.46, 95% CI 0.31-0.67, P < .001). Compared with PN, neither cryoablation nor RF/MW ablation showed significant difference in OS (cryoablation vs PN, HR = 1.35, 95% CI 0.80-2.28, P = .258; RF/MW ablation vs PN, HR = 0.64, 95% CI 0.95-2.55, P = .079).

CONCLUSIONS

Current SBRT protocols show lower OS compared with thermal ablation and PN, whereas thermal ablation and PN demonstrate comparable outcomes.

Active surveillance and focal ablation for small renal masses: a better solution for comorbid patients

The natural history of small renal masses (SRM) is still not well understood and they are frequently incidentally diagnosed in elderly patients. Therefore, there is a need for less invasive options sparing the patient from the side-effects related to conventional surgical treatment. PubMed and Medline database search was performed to look for new findings on active surveillance and focal therapy for SRM. Sixty-one articles published between 2002 and 2018 were selected for the purpose of the review. There is growing evidence confirming the safety of active surveillance in patients at surgical risk and there appears to be a satisfactory intermediate-term outcome of focal treatment of SRM. In the group of elderly patients with a decreased life expectancy active surveillance appears to be the most appropriate approach. The future of minimally invasive therapy appears bright, especially with the improvement of new imaging modalities.

MRI-guided, transrectal, intraprostatic steam application as potential focal therapeutic modality for prostatic diseases in a large animal translational model: A feasibility follow-up study

Parallel to establishment of diagnostic surveillance protocols for detection of prostatic diseases, novel treatment strategies should be developed. The aim of the present study is to evaluate the feasibility and possible side effects of transrectal, MRI-targeted intraprostatic steam application in dogs as an established large animal translational model for prostatic diseases in humans. Twelve healthy experimental, intact, male beagle dogs without evidence of prostatic pathology were recruited. An initial MRI examination was performed, and MRI-targeted steam was applied intraprostatically immediately thereafter. Serum levels of C-reactive protein (CRP), clinical and ultrasonographic examinations were performed periodically following the procedure to assess treatment effect. Four weeks after treatment, all dogs underwent follow-up MRI examinations and three needle-core biopsies were obtained from each prostatic lobe. Descriptive statistics were performed. MRI-guided intraprostatic steam application was successfully performed in the study population. The first day after steam application, 7/12 dogs had minimal signs of discomfort (grade 1/24 evaluated with the short-form Glasgow Composite Measure Pain Scale) and no dogs showed any sign of discomfort by day 6. CRP elevations were detected in 9/12 dogs during the first week post steam application. Mild to moderate T2 hyperintense intraparenchymal lesions were identified during follow-up MRI in 11/12 dogs four weeks post procedure. Ten of these lesions enhanced mild to moderately after contrast administration. Coagulative necrosis or associated chronic inflammatory response was detected in 80.6% (58/72) of the samples obtained. MRI-targeted intraprostatic steam application is a feasible technique and displays minimal side effects in healthy dogs as translational model for human prostatic diseases. This opens the possibility of minimally invasive novel treatment strategies for intraprostatic lesions.

Retreatment after focal therapy for failure: a bridge too far?

PURPOSE OF REVIEW

To summarize the current knowledge about the evaluation of disease persistence and recurrence after focal therapy ablation (FTA) for small renal masses and to assess the outcomes and complications of related treatment options.

RECENT FINDINGS

FTA procedures continuously increased over the last 20 years, being now performed in more than one on 10 patients with T1a renal cell carcinoma. Disease recurrence seems to occur more often following radiofrequency ablation (RFA) compared with cryoablation. Evidence about the management of disease recurrence is scarce. Treatment options are similar to those available for de novo renal cell carcinomas, and include reablation, partial or radical nephrectomy and observation. Reablation is feasible, safe and can be easily done in the majority of cases. Oncological outcomes of repeated ablation, although encouraging, remain mostly uninvestigated and unreported.

SUMMARY

In case of disease persistence or recurrence after FTA, observation may be an acceptable approach, reserving repeated ablation or surgery only in those exhibiting significant tumor growth. In these patients repeated ablation with RFA is safe and noninvasive. Surgery after FTA presents technical difficulties related to perinephric scarring, especially with regards to nephron-sparing surgery. This should be taken into consideration in patients' counseling as well as in decision-making process.

Radiofrequency-Sensitive Longitudinal Relaxation Tuning Strategy Enabling the Visualization of Radiofrequency Ablation Intensified by Magnetic Composite

As a minimally invasive heat source, radiofrequency (RF) ablation still encounters potential damages to the surrounding normal tissues because of heat diffusion, high power, and long time. With a comprehensive understanding of the current state of the art on RF ablation, a magnetic composite using porous hollow iron oxide nanoparticles (HIONs) as carriers to load dl-menthol (DLM) has been engineered. This composite involves two protocols for enhancing RF ablation, that is, HION-mediated magnetothermal conversion in RF field and RF solidoid vaporation (RSV)-augmented inertial cavitation, respectively. A combined effect based on two protocols is found to improve energy transformation, and further, along with hydrophobic DLM-impeded heat diffusion, improve the energy utilization efficiency and significantly facilitate ex vivo and in vivo RF ablation. More significantly, in vitro and in vivo RSV processes and RSV-augmented inertial cavitation for RF ablation can be monitored by T₁-weighted magnetic resonance imaging (MRI) via an RF-sensitive longitudinal relaxation tuning strategy because the RSV process can deplete DLM and make HION carriers permeable to water molecules, consequently improving the longitudinal relaxation rate of HIONs and enhancing T₁-weighted MRI. Therefore, this RF-sensitive magnetic composite holds a great potential in lowering the power and time of RF ablation and improving its therapeutic safety.

Introduction of Microwave Ablation Into a Renal Ablation Practice: Valuable Lessons Learned

OBJECTIVE

The purpose of this study was to evaluate the early outcomes of percutaneous microwave ablation (MWA) for clinical stage T1 (cT1) renal masses when performed within a high-volume ablation practice with critical emphasis on procedural safety.

MATERIALS AND METHODS

A retrospective review of a percutaneous renal ablation registry identified 26 patients with a total of 27 cT1 renal masses treated with MWA between 2011 and 2017. Mean patient age was 63.8 years and 16 (61.5%) patients were male. Mean renal mass size ± SD was 2.3 ± 0.8 cm (range, 1.1-4.7 cm). The main outcome parameters investigated were technical success, local tumor progression, survival rates, and complications. Complications were categorized using the Clavien-Dindo classification system. Rates of local progression-free and cancer-specific survival (PFS and CSS, respectively) were estimated using the Kaplan-Meier method.

RESULTS

Technical success was 100% on contrast-enhanced CT or MRI performed immediately after renal MWA. Twenty-four patients (92%) with 25 tumors had follow-up imaging for 3 months or longer (mean, 20.6 ± 11.6 months), with no local tumor recurrences identified. Estimated 3-year local PFS and CSS were 96% and 94%, respectively. The overall complication rate was 19.2%; two patients (7.7%) experienced minor complications (grade I or II) and three patients (11.5%) experienced major bleeding or urinary-related complications (grade III or higher), including one death.

CONCLUSION

This study suggests that percutaneous MWA is a promising minimally invasive treatment option for cT1 renal masses. Nonetheless, major bleeding and urinary-related complications can occur, and further studies are needed to determine optimal patient and tumor selection for renal MWA.

The Role of Ablation and Minimally Invasive Techniques in the Management of Small Renal Masses

CONTEXT

Nephron-sparing approaches are increasingly recommended for incidental small renal masses. Herein, we review the current literature regarding the safety and efficacy of focal therapy, including percutaneous ablation, for small renal masses.

OBJECTIVE

To summarize the application of ablative therapy in the management of small renal masses.

EVIDENCE ACQUISITION

PubMed and Medline database search was performed to look for findings published since 2000 on focal therapy for small renal masses. After literature review, 64 articles were selected and discussed.

EVIDENCE SYNTHESIS

Radiofrequency ablation and cryotherapy are the most widely used procedures with intermediate-term oncological outcome comparable with surgical series. Cost effectiveness seems excellent and side effects appear acceptable. To date, no randomized trial comparing percutaneous focal therapy with standard surgical approach or active surveillance has been performed.

CONCLUSIONS

Focal ablative therapies are now accepted as effective treatment for small renal tumors. For tumors <3cm, oncological effectiveness of ablative therapies is comparable with that of partial nephrectomy. Percutaneous ablation has fewer complications and a better postoperative profile when compared with minimally invasive partial nephrectomy.

PATIENT SUMMARY

Focal ablative therapies are now accepted as effective treatment for small renal tumors. For tumors <3cm, oncological effectiveness of ablative therapies is comparable with that of partial nephrectomy.

Progression to chronic kidney disease in patients undergoing nephrectomy for small renal masses: a price to pay for a therapeutic success?

Nephrectomy, which constitutes a gold-standard procedure for the treatment of renal-cell carcinoma (RCC), has been widely discussed in the past decade as a significant risk factor of the development of chronic kidney disease (CKD). RCC is the third most common genitourinary cancer in the United States, with an estimated more than 65,000 new cases and 14,970 deaths. The aim of this review was to precisely and comprehensively summarize the status of current knowledge in CKD risk factors after nephrectomy, the advantages of minimally invasive vs. radical nephrectomy, post-nephrectomy biomarkers of CKD, ways of post-operative CKD prevention and, therefore, better understand why various aspects of CKD after nephrectomy. The majority of current studies indicated a better long-term kidney function preservation in patients undergoing partial nephrectomy in comparison to those after radical nephrectomy. Furthermore, a nephron-sparing surgery should be a preferred first-line procedure among young patients with small renal masses. As partial nephrectomy is followed by a greater risk of adverse outcomes relative to radical nephrectomy, a potential survival benefit should always be considered especially in the elderly or patients with comorbidities.

Intrarenal urothelial cancers confused as infiltrative renal masses: Report of 22 cases and literature review

Distinguishing infiltrative renal masses (IRMs) from intrarenal urothelial cancers (IUCs) is critically important, but may be challenging for any radiologist or urologist. The present study aimed to summarize the clinical, imaging and pathological characteristics of IRM, which were postoperatively confirmed as IUC. The analysis was performed using the records of 22 patients who were preoperatively diagnosed with IRM but the results of percutaneous biopsies or postoperative pathological analyses led to diagnoses of urothelial cancers (UCs) from January 2011 to December 2017. The demographic data, computed tomography (CT) imaging features and pathological characteristics were evaluated. The present study also reviewed the literature concerning the IRM and IUC. The mean age of patients was 62 years and 86.4% of them were >55 years. The sex and tumor side distributions were equal. Hematuria and/or flank pain were observed in 86.4% of patients. All patients exhibited endophytic solid renal masses with unclear tumor boundaries on CT images. The kidneys of 81.8% of patients maintained their normal shape while mild alternations were observed in 18.2% of cases. A total of 81.8% of patients maintained the reniform shape and 18.2% exhibited mild contour change. Of all patients, all tumors exhibited less or equal attenuation on unenhanced CT images and they were mildlyimproved on enhanced CT. A total of 6 cases were confirmed by biopsy, when patients underwent laparoscopic nephroureterectomy instead of radical nephrectomy. The remaining 16 patients underwent laparoscopic nephrectomy but the postoperative pathological diagnoses revealed the presence of UCs. All postoperatively confirmed cancers were stages T3 and T4 (62.5 and 37.5%, respectively). UCs should be suspected in middle aged or elderly middle-elderly patients presenting renal masses with endophytic solid unclear tumor boundary on unenhanced and slightly enhanced CT images, accompanied with hematuria and/or flank pain. Preoperative biopsy is preferred for complicated cases.

Radiofrequency ablation of small renal masses in comorbid patients

Introduction

Over the recent years, the progress in imaging techniques has led to increased detection of small renal masses (SRMs), including in elderly and high-risk patients. Partial nephrectomy (nephron-sparing surgery - NSS), the current standard of care in T1a kidney tumours, has some limitations in patients who are poor candidates for surgery, as it is associated with potential perioperative complications and possible renal function loss. Radiofrequency ablation (RFA), a minimally invasive method that can be performed percutaneously, is an option in such cases.

Aim

To present our experience in treatment of SRMs using RFA in comorbid patients.

Material and methods

In the years 2006-2012, 103 percutaneous, ultrasound-guided RFA procedures were performed in the Oncology Centre in Bydgoszcz in patients with an ASA score ≥ 3. Abdominal computed tomography and tumour biopsy were performed before the procedure. The average follow-up time was 46 months.

Results

The 1, 3 and 5-year overall survival rates were respectively 97%, 90% and 75%, while cancer-specific survival was 100%. No Clavien-Dindo grade ≥ 3 complications were observed.

Conclusions

Radiofrequency ablation performed percutaneously is a minimally invasive treatment and may be applied in patients who are, due to comorbidities, poor candidates for surgery. In comorbid patients, where other causes of death play an important role, the application of a minimally invasive treatment method with satisfactory oncological effectiveness is justified.