Laparoscopic renal cryoablation: 8-year, single surgeon outcomes. J Urol. 2010;183:889-895. [PMID: 20089263 DOI: 10.1016/j.juro.2009.11.041]

Radiofrequency ablation of renal tumours with clinical, radiographical and pathological results

WHAT'S KNOWN ON THE SUBJECT? AND WHAT DOES THE STUDY ADD?: Radiological imaging is heavily relied on for follow up after renal ablative therapy. We show that while this is largely reliable, there are quantifiable false negative and false positive findings. A non-involuting zone of ablation should be considered for multisite-directed core biopsies even in the absence of detectable enhancement.

OBJECTIVE

To evaluate our experience with radiofrequency ablation (RFA) for renal masses and to report on clinical, radiological and post-RFA biopsy results.

PATIENTS AND METHODS

The study collected clinical, radiological and pathological data from 150 consecutive patients who were treated with RFA of a renal mass between 2002 and 2008 at a tertiary referral centre. Post-ablation biopsies were performed in patients with non-involuting lesions or suspicion of recurrence on imaging. Comparisons were performed using the Mann-Whitney U-test. Survival was estimated using the Kaplan-Meier method.

RESULTS

Renal malignancy was found in 72.1% of patients based on the initial diagnostic biopsy. Median tumour size was 2.6 cm, 22.7% of patients had a solitary kidney, and most were central tumours. The mean follow-up period was 40.1 month. There was no recurrence in 96.7% of the entire cohort. Cancer-specific survival for 106 patients with sporadic, localized, biopsy proven renal malignancy was 100% at 38.5 months. Biopsies were obtained in 43 patients for a median of 21 months after RFA. Among 38 patients who had biopsy for non-involuting, non-enhancing zones of ablation, three (7.9%) were positive.

CONCLUSIONS

Short-term cancer-specific survival after RFA remains excellent and most cases are successful based on a combination of imaging and post-ablation biopsies performed almost 2 years after treatment. There were four out of 150 (2.7%) patients who had recurrences with tissue confirmation; one of these patients was detected on imaging and three (2%) were radiologically occult. The absence of enhancement in the setting of non-involuting lesions is not always a guarantee of a successful ablation.

Laparoscopic cryoablation of renal masses: single-center long-term experience

OBJECTIVE

To evaluate perioperative and long-term functional and oncological outcomes of laparoscopic cryoablation (LCA) performed at Washington University.

METHODS

A retrospective chart review was performed evaluating 62 consecutive patients who underwent LCA at our institution between 2000 and 2005.

RESULTS

Mean age-adjusted Charlson Comorbidity Index (CCI) was 6.1 (SD, 2.1; 95% confidence interval [CI], 5.6-6.6). Mean tumor size was 2.52 cm (SD, 0.99; CI, 2.3-2.8). Mean operative time was 162.0 minutes (SD, 66.6; CI, 142.0-182.1). Mean estimated blood loss was 84.9 mL (SD, 102; CI, 58.6-111.2). Mean hospital stay was 2.6 days (SD, 1.90; CI, 2.1-3.1). The perioperative complication rate was 9.7% (Clavien 1-2). Among patients with biopsy proven, localized renal cell carcinoma, the 6-year Kaplan-Meier estimated disease-free survival (DFS) was 80%; cancer-specific survival (CSS) was 100%; and overall survival (OS) was 76.2%. Mean follow-up in this subset was 76.0 months (SD, 39.3; CI, 62.7-89.4; n = 35), whereas mean time to cancer recurrence was 27.6 months (SD, 11.2; CI, 15.9-39.3; n = 6). Tumor size ≥2.6 cm was the only predictor of cancer recurrence in a multivariate Cox proportional hazards model (hazard ratio [HR] = 28.9; P = .046; n = 35). Mean preoperative estimated glomerular filtration rate (eGFR) was 68.3 (SD, 22.3; CI, 62.1-74.5), compared to 64.5 mL/min/1.73 m(2) (SD, 28.9; CI, 56.5-72.6) at last follow-up (P = .12; n = 52). Excluding patients requiring secondary ablative or extirpative treatments for recurrent renal cell carcinoma, preoperative eGFR <60 mL/min/1.73 m(2) (odds ratio [OR] = 88.3; P = .036) and age-adjusted CCI ≥6 (OR = 32.4; P = .046) were the only factors predicting renal disease progression on multiple logistic regression (n = 47).

CONCLUSION

We report what is by far the longest follow-up to date of postlaparoscopic cryoablation changes in eGFR and note excellent long-term renal functional outcomes. For those willing to accept the potential need for retreatment for recurrent disease, LCA offers excellent long-term CSS.

Renal preservation therapy for renal cell carcinoma

Renal preservation therapy has been a promising concept for the treatment of localized renal cell carcinoma (RCC) for 20 years. Nowadays partial nephrectomy (PN) is well accepted to treat the localized RCC and the oncological control is proved to be the same as the radical nephrectomy (RN). Under the result of well oncological control, minimal invasive method gains more popularity than the open PN, like laparoscopic partial nephrectomy (LPN) and robot assisted laparoscopic partial nephrectomy (RPN). On the other hand, thermoablative therapy and cryoablation also play an important role in the renal preservation therapy to improve the patient procedural tolerance. Novel modalities, but limited to small number of patients, include high-intensity ultrasound (HIFU), radiosurgery, microwave therapy (MWT), laser interstitial thermal therapy (LITT), and pulsed cavitational ultrasound (PCU). Although initial results are encouraging, their real clinical roles are still under evaluation. On the other hand, active surveillance (AS) has also been advocated by some for patients who are unfit for surgery. It is reasonable to choose the best therapeutic method among varieties of treatment modalities according to patients' age, physical status, and financial aid to maximize the treatment effect among cancer control, patient morbidity, and preservation of renal function.

Population-based comparative effectiveness of nephron-sparing surgery vs ablation for small renal masses

OBJECTIVE

To determine, in a population-based cohort, if disease-specific survival (DSS) was equivalent in patients undergoing ablation vs nephron-sparing surgery (NSS) for clinical stage T1a renal cell carcinoma (RCC).

PATIENTS AND METHODS

A retrospective cohort study was performed using patients from the Surveillance, Epidemiology and End Results cancer registry with RCC < 4 cm and no evidence of distant metastases, who underwent ablation or NSS. Kaplan-Meier and Cox regression analyses were performed to determine if treatment type was independently associated with DSS.

RESULTS

Between 1998 and 2007, a total of 8818 incident cases of RCC were treated with either NSS (7704) or ablation (1114). The median (interquartile range) follow-up was 2.8 (1.2-4.7) years in the NSS group and 1.6 (0.7-2.9) years in the ablation group, although 10% of each cohort were followed up beyond 5 years. After multivariable adjustment, ablation was associated with a twofold greater risk of kidney cancer death than NSS (hazard ratio 1.9, 95% confidence interval 1.1-3.3, P= 0.02). Age, gender, marital status and tumour size were also significantly associated with outcome. The predicted probability of DSS at 5 years was 98.3% with NSS and 96.6% with ablation.

CONCLUSION

After controlling for age, gender, marital status and tumour size, the typical patient presenting with clinical stage T1a RCC, who undergoes ablation rather than NSS, has a twofold increase in the risk of kidney cancer death; however, at 5 years the absolute difference is small, and may only be realized by patients with long life expectancies.

The use of kidneys with small renal tumors for transplantation: who is taking the risk?

The ever-increasing disparity between the number of organs available for transplant and the need for organs drives further exploration into the use of compromised or marginal donors. There is now an emerging advocacy for the use of kidneys with existing tumors, which may be rendered tumor free after surgical excision and reconstruction. This practice is based on reliable data that renal cancers <3 cm in diameter behave with minimal malignant potential and likelihood of transmission to the immunosuppressed recipient. However, in the case of live donors this creates a potential ethical conflict between those treating patients with renal masses and those with an interest in renal donation. The best available treatment for patients with a small renal tumor is a form of nephron-sparing tumor excision or ablation, as this approach provides for the maximum amount of residual kidney function and enhances survival. Thus, patients newly diagnosed with small renal tumors should be referred to centers with expertise in nephron sparing techniques, not transplant centers. In the case of an individual undergoing a live donor evaluation in which a small renal tumor is detected, a careful analysis of risk and benefit for the potential donor and the recipient is indicated.

CT-guided percutaneous cryoablation of renal masses in selected patients

PURPOSE

We analysed our experience with computed tomography (CT)-guided percutaneous cryoablation (PCA) in patients who were not surgical candidates or refused surgery for small to medium-sized renal masses.

MATERIALS AND METHODS

Two freezing cycles were applied and separated by a passive warming cycle using 1.7- and 2.4-mm cryoprobes under either general anaesthesia or sedation based on patient positioning and respiratory status. Postoperative monitoring included haematological and biochemistry evaluation and CT scan 24 h after PCA. Follow-up consisted of a multislice CT scan at 1 month and every 3 months in the first year then every 6 months thereafter.

RESULTS

Thirty-seven patients (38 lesions) underwent 40 PCA procedures; 5/37 (13.5%) had a solitary kidney. Median mass size was 35 (range 12-70) mm. No complications occurred during the procedure. Clavien grade ≥2 anaemia occurred in two patients (5.4 %): one patient required 1 U of packed red blood cells; the other required an arterial embolisation. Serum creatinine did not increase in any case. Two patients showed persisting or recurrent disease at 1 and 9 months, respectively, and both could be re-treated with PCA. All other patients showed a hypodense mass 3 months after PCA, with no contrast enhancement. Subsequent examinations showed that lesion sizes decreased and CT densitometry remained stable or increased minimally, also with no contrast enhancement.

CONCLUSIONS

PCA proved relatively easy and safe and could be considered an effective alternative for patients who are not surgical candidates or refuse surgery, as well as in patients with medium-sized lesions.

Current status of ablative techniques for small renal masses

The past few decades have witnessed a steady increase in the number of newly diagnosed small renal masses. Although historically managed by surgical resection, many of these small renal masses are now noted to be amenable to less invasive treatment modalities including thermal ablation or active surveillance. Contemporary series suggest that renal thermal ablation (including cryoablation or radiofrequency ablation), when selectively employed, can maintain oncologic efficacy comparable to extirpation while minimizing complications and treatment morbidity. Therefore, as the incidence of small renal masses in elderly comorbid patients rises, it is likely we will see ablative techniques assume a greater role in management.

Results of laparoscopic cryoablation in the treatment of small renal masses

Context:

Study of clinical outcome in renal cryoablation.

Aims:

Laparoscopic cryoablation (LCA) is emerging as a reliable treatment option for small renal masses (SRMs) particularly in elderly patients. Our aim was to study the results of cryoablation for small renal masses in our cohort of patients.

Settings and Design:

We retrospectively studied all patients who underwent LCA for SRMs between September 2005 and July 2008.

Materials and Methods:

All patients were discussed in our multidisciplinary meeting prior to cryoablation. Our LCA protocol included two freeze-thaw cycles, achieving a core temperature of –70°C and a peripheral temperature of at least –40°C. Follow-up included serum creatinine measurements and pre- and postcontrast CT scans at 3, 6, 12, 18, and 24 months and yearly thereafter.

Statistical analysis used:

Paired samples t-test was used to study statistical difference.

Results:

Twenty-two patients underwent LCA with a mean (range) age of 68 (39–81 years) years. The mean (range) tumor size was 29 (19–45 mm) mm. Two patients required blood transfusions, one patient developed pneumonia, and another patient developed a small area of skin necrosis at the cryoneedle entry site. The average (range) hospital stay was 4 (2–14 days) days. Twenty-one patients have had CT follow-up at a mean (range) of 24 (4–42 months) months. Three of the 21 tumors showed central enhancement on follow-up CT scans, consistent with treatment failure.

Conclusions:

Laparoscopic cryoablation is a safe treatment option for SRM in a selected group of patients.

Treatment of localised renal cell carcinoma

CONTEXT

The increasing incidence of localised renal cell carcinoma (RCC) over the last 3 decades and controversy over mortality rates have prompted reassessment of current treatment.

OBJECTIVE

To critically review the recent data on the management of localised RCC to arrive at a general consensus.

EVIDENCE ACQUISITION

A Medline search was performed from January 1, 2004, to May 3, 2011, using renal cell carcinoma, nephrectomy (Medical Subject Heading [MeSH] major topic), surgical procedures, minimally invasive (MeSH major topic), nephron-sparing surgery, cryoablation, radiofrequency ablation, surveillance, and watchful waiting.

EVIDENCE SYNTHESIS

Initial active surveillance (AS) should be a first treatment option for small renal masses (SRMs) <4 cm in unfit patients or those with limited life expectancy. SRMs that show fast growth or reach 4 cm in diameter while on AS should be considered for treatment. Partial nephrectomy (PN) is the established treatment for T1a tumours (<4 cm) and an emerging standard treatment for T1b tumours (4-7 cm) provided that the operation is technically feasible and the tumour can be completely removed. Radical nephrectomy (RN) should be limited to those cases where the tumour is not amenable to nephron-sparing surgery (NSS). Laparoscopic radical nephrectomy (LRN) has benefits over open RN in terms of morbidity and should be the standard of care for T1 and T2 tumours, provided that it is performed in an advanced laparoscopic centre and NSS is not applicable. Open PN, not LRN, should be performed if minimally invasive expertise is not available. At this time, there is insufficient long-term data available to adequately compare ablative techniques with surgical options. Therefore ablative therapies should be reserved for carefully selected high surgical risk patients with SRMs <4 cm.

CONCLUSIONS

The choice of treatment for the patient with localised RCC needs to be individualised. Preservation of renal function without compromising the oncologic outcome should be the most important goal in the decision-making process.

Renal function and oncologic outcomes after cryoablation or partial nephrectomy for tumors in solitary kidneys

Purpose

Preservation of renal function is of paramount importance in patients with tumors in solitary kidneys. We compared the renal function and oncologic outcomes of patients treated by partial nephrectomy with those of patients treated by cryoablation for solitary kidney tumors.

Materials and Methods

All patients with solitary kidneys who were treated for renal tumors at our institution between 1997 and 2007 were included in the screen. We retrospectively identified 23 patients who underwent cryoablation and 15 patients who underwent partial nephrectomy.

Results

The two groups were similar with regard to age, gender, and tumor laterality. Patients in the partial nephrectomy group had a larger tumor size (3.4 cm vs. 2.5 cm, p=0.01), higher mean estimated blood loss (316 cc vs. 87 cc, p<0.001), longer duration of hospital stay (5.8 vs. 1.8 days, p<0.001), and a higher rate of perioperative complications (53.3% vs. 8.7% patients, p=0.03). Percentage changes in the glomerular filtration rate postoperatively and on follow-up were found to be similar in the two groups. Both the cryoablation and the partial nephrectomy groups with mean follow-ups of 31.2 months and 30.8 months, respectively, had evidence of local or distant recurrence in 3 patients each (13% and 20% respectively, p=0.7). Both groups had a similar mean overall survival (88.9 and 86.9 months in the cryoablation and partial nephrectomy groups, respectively, p=0.8).

Conclusions

For tumors in solitary kidneys, renal functional and clinical outcomes for cryoablation were not significantly different from those for partial nephrectomy. However, cryoablation has the distinct advantage of a lower morbidity rate and can be preferentially offered to selected cases.

Perioperative, oncologic, and functional outcomes of laparoscopic renal cryoablation and open partial nephrectomy: a matched pair analysis

PURPOSE

To directly compare perioperative, oncologic, and functional outcomes of laparoscopic renal cryoablation and open partial nephrectomy using a matched pair analysis.

PATIENTS AND METHODS

A total of 41 patients who underwent laparoscopic cryoablation for an incidental, solid clinical T(1a)N(0)M(0) renal tumor were matched with 82 patients who received partial nephrectomy in cold ischemia, using optimal matching based on propensity scores, which were created on the basis of preoperative aspects and dimensions used for an anatomic classification of renal tumors (PADUA) score, preoperative glomerular filtration rate, age-adjusted Charlson comorbidity index, and sex. Median follow-up was 33.6 months.

RESULTS

No differences in the overall incidence of complications (cryoablation, 20%; partial nephrectomy, 17%; P=0.739) and grade of complications (P=0.424) were observed. After cryoablation, local recurrence developed in four patients with renal-cell carcinoma (n=35) after a median duration of 14 months (range 6-18  mos), but none after partial nephrectomy. The 3-year recurrence-free survival probabilities after laparoscopic renal cryoablation vs open partial nephrectomy were 83% vs 100%, respectively (P=0.015). The average decrease of estimated glomerular filtration rate during follow-up was 7.8±3.1  mL/min/1.73  m(2) after laparoscopic cryoablation and 9.8±2.3  mL/min/1.73  m(2) after open partial nephrectomy, which was not statistically significant (P=0.602).

CONCLUSIONS

Perioperative complications and renal functional outcomes of laparoscopic cryoablation and open partial nephrectomy are similar; however, laparoscopic cryoablation confers a substantially higher local recurrence risk of about 17% after 3 years. Therefore, laparoscopic renal cryoablation should be reserved for high-risk patients with decreased life expectancy. Careful patient counseling is advocated. Study limitations include the small sample size, the lack of randomization, and the short follow-up.

The role of percutaneous renal biopsy in the management of small renal masses

The use of percutaneous renal mass biopsy (RMB) has increased in recent years, likely in parallel with the growing incidence of renal cell carcinoma and small renal masses in particular. Biopsy and imaging techniques are improving, and diagnostic sufficiency and accuracy of RMB now are much higher in large-volume, experienced centers. Overall morbidity is low. This has led to a significant expansion of the indications for biopsy beyond documenting renal involvement for patients with metastatic disease or other systemic illnesses. While there still are limitations to its use and clinical judgment is paramount, RMB is proving to be a valuable tool in the clinical diagnosis and management of small renal masses.

Active surveillance of renal cortical neoplasms: a contemporary review

INTRODUCTION

Over the past 2 decades, there has been a significant increase in the number of incidentally found small renal cortical neoplasms (RCNs). As more RCNs are being discovered in the elderly and infirmed patient populations, there has been a growing interest in the role of active surveillance (AS). Active surveillance is recommended for high surgical-risk patients and those with a reduced life expectancy. It is also an option for patients wishing to avoid surgery. We review the current literature on AS and highlight the natural history of disease, the important factors to evaluate during AS, and the contemporary role of biopsy.

METHODS AND MATERIALS

The MEDLINE database was searched using PubMed. Search terms included active surveillance, renal mass, natural history, and renal mass histology. From 1966 to present, 17 AS series were identified, all of which have been included in this summary. A summary was performed by compiling all available data and performing a weighted mean where applicable.

RESULTS

Initial tumor size does not correlate with growth rate or malignancy. The mean growth rate in large published series is low (0.28-0.34 cm/year). Tumors with high growth rates usually represent malignant lesions and typically undergo delayed intervention. Progression to metatatic disease is a low-probability event for tumors on AS (1.4%); however, this is still a risk that patients must be willing to accept. Larger tumors (cT1b and cT2) also demonstrate relatively low growth (0.57 cm/year); however, these tumors should be monitored carefully. Tumors followed for > 5 years demonstrate a low growth rate (0.15 cm/year), will not likely require intervention, and have a low chance of progression to metastatic disease.

CONCLUSION

For highly selected patients with RCN, AS is a reasonable treatment option. Age, surgical risk, comorbidities, and patient opinion must all factor into the final decision when considering a patient for AS.

Percutaneous cryoablation of renal tumors: patient selection, technique, and postprocedural imaging

Percutaneous cryoablation of renal tumors requires a number of important steps for success and relies heavily on imaging for treatment planning, intraprocedural guidance and monitoring, detection of untreated tumor, and surveillance for disease progression. Imaging-guided percutaneous cryoablation has several advantages over laparoscopic cryoablation. In particular, computed tomography (CT) and magnetic resonance (MR) imaging allow global evaluation of the ablation zone and an accurate depiction of the treatment margin. Ultrasonography allows real-time guidance of probe placement but cannot help depict ice ball formation as accurately as CT or MR imaging. Multiphasic CT or MR imaging should be performed at structured intervals following ablation. Treated tumors are expected to decrease in size over time, and lesion growth and internal or nodular enhancement are suspicious for tumor recurrence or progression. Complications include probe site pain, hematoma, incomplete ablation, and recurrent tumor. Current limitations of percutaneous cryoablation include the inability to control hemorrhage without intraarterial access and a lack of long-term follow-up data. Nevertheless, percutaneous cryoablation is an effective choice for minimally invasive nephron-sparing treatment of renal tumors.

Laparoscopic renal cryoablation using ultrathin 17-gauge cryoprobes: mid-term oncological and functional results

Study Type - Therapy (case series).

LEVEL OF EVIDENCE

4. What's known on the subject? and What does the study add? Laparoscopic Cryoablation of renal masses has a low persistence and recurrence rates at short term follow-up albeit higher than Partial Nephrectomy. Long term results are scarcely reported. It is however a NSS technique suitable for high-risk that preserves renal function. The study provides (1) mid-term oncological outcomes of laparoscopic cryoablation of renal masses stratified by primary pathology (RCC, benign mass or undetermined biopsy) and (2) data on renal function evolution up to one year of follow-up supporting the fact that the only predictor of (moderate)renal insufficiency development after Laparoscopic cryoablation is the eGFR at baseline.

OBJECTIVE

To present the functional and oncological mid-term results of laparoscopic cryoablation of renal masses using third generation ultrathin (17-gauge[G]) cryoprobes.

PATIENTS AND METHODS

• Consecutive patients with small renal masses treated by cryoablation from September 2003 to September 2008 were prospectively evaluated. The cryoablation was performed using multiple third generation 17-G cryoprobes after intraoperative mass biopsy. • Data on serum creatinine measurements and cross sectional imaging (computed tomography/magnetic resonance imaging) were regularly collected according to a previously determined protocol. Follow-up was censored in October 2009. • Renal function analysis was based on estimated glomerular filtration rate (eGFR) at 1 year compared with baseline. Residual (or persistent tumour) and recurrence were defined as the presence of residual enhancement at first follow-up and 'de novo' enhancement of a non-enhancing cryolesion at any time during follow-up. • Survival data were analysed using the Kaplan-Meier method. Best estimates for the overall survival (OS), recurrence-free survival (RFS), cancer-specific survival (CSS) and metastatic-free survival (MFS) were made for patients with renal cell carcinoma (RCC) and for patients with RCC or non-diagnostic biopsy.

RESULTS

• A total of 92 patients (100 tumours; mean size 2.5 ± 0.8 cm) were treated in 95 sessions. The mean follow-up was 30.2 ± 16.6 months (Mean values are ±SD). • Intraoperative biopsy showed RCC in 51 patients (53.7%), benign lesion in 23 patients (24.2%) and was non-diagnostic in 21 patients (22.1%). Three tumour persistences and four radiological recurrences were detected. • The estimated mean RFS time and 3-year OS and RFS in patients with RCC exclusively were 47.8 (95% confidence interval [CI]: 44.1-51.1) months, 86.1% (95% CI: 71.2-93.6) and 91.8% (95% CI: 76.3-97.3), respectively. The figures were slightly higher in the group of patients with RCC or unknown pathology. The actual CSS and MFS rates were 100%. • Renal function was preserved in 84.5% of patients with normal preoperative eGFR. • Baseline eGFR was the only predictor of renal insufficiency development at 1-year follow-up.

CONCLUSION

Laparoscopic cryoablation with multiple ultrathin cryoprobes is oncologically and functionally effective at mid-term follow-up.