Treatment of invasive breast carcinoma with ultrasound-guided radiofrequency ablation

BACKGROUND: Radiofrequency ablation (RFA) is a minimally invasive thermal ablation technique. This study reports the safety and efficacy of RFA as a minimally invasive strategy for breast cancers <3 cm diameter in postmenopausal women. METHODS: Twenty-two postmenopausal women (aged 60 years or older) with clinical T-1N0 core biopsy proven breast cancers were studied. Thermocoagulation was undertaken using a sonographically guided RF probe under local anesthesia and sedation. The ablated tumor was resected between 1 and 2 weeks later. Endpoints were technical success, completeness of tumor kill, marginal clearance, skin damage, and patient reports of pain and procedural acceptability. RESULTS: The procedure was well tolerated and cosmesis was excellent. Pathology revealed a central ablation zone surrounded by hyperemia. Coagulative necrosis was complete in 19 of 22 patients. Disease at the ablation zone margin was found in 3 patients and 5 patients had disease distant to the ablation zone consisting of multifocal tumors (2), in-transit metastasis (1), and extensive ductal carcinoma in situ with microinvasive carcinoma (2). Ninety-five percent of patients would be willing to have RFA again. CONCLUSIONS: Radiofrequency ablation can be safely applied in an outpatient setting with acceptable patient tolerance. By itself, RFA cannot be considered effective local therapy. Trials to evaluate RFA complemented with breast irradiation are justified.     

A Phase II Trial of Image-Guided Radiofrequency Ablation of Small Invasive Breast Carcinomas: Use of Saline-Cooled Tip Electrode

Background Local ablative therapy of breast cancer represents the next frontier in the evolution of minimally-invasive breast conservation therapy. We performed this Phase II trial to determine the efficacy and safety of Radiofrequency (RF) ablation of small invasive breast carcinomas. Methods Seventeen patients with biopsy-proven invasive breast cancer, ≤ 1.5 cm in diameter were enrolled in this trial. Under ultrasound guidance, the tumor and a 5 mm margin of surrounding breast tissue were ablated with saline-cooled RF electrode followed by surgical resection. Pathologic and immunohistochemical stains were performed to assess tumor viability. We examined whether loss of ER, PR receptor and pancytokeratin expression following RF ablation would correlate with non-viability. Results Fifteen patients completed the treatment. The mean tumor size was 1.28 cm. The mean ablation time was 21 minutes using a mean power of 35.5 watts. During ablation, the tumors became progressively echogenic that corresponded with the region of severe electrocautery injury at pathological examination. Of the 15 treated patients, NADPH viability staining was available for 14 patients and in 13 (92.8%), there was no evidence of viable malignant cells. ER, PR expression and pancytokeratin immunohistochemistry analysis were unreliable surrogates for determining non-viability. Following RF ablation, 2 patients developed skin puckering. Conclusions RF ablation is a promising minimally invasive treatment of small breast carcinomas, as it can achieve effective cell killing with a low complication rate. Further research is necessary to optimize this image-guided technique and evaluate its future role as the sole local therapy.     

Cryoablation of Early-Stage Breast Cancer: Work-in-Progress Report of a Multi-Institutional Trial

Background With recent improvements in breast imaging, our ability to identify small breast tumors has markedly improved, prompting significant interest in the use of ablation without surgical excision to treat early-stage breast cancer. We conducted a multi-institutional pilot safety study of cryoablation in the treatment of primary breast carcinomas.Methods Twenty-nine patients with ultrasound-visible primary invasive breast cancer 2.0 cm were enrolled. Twenty-seven (93%) successfully underwent ultrasound-guided cryoablation with a tabletop argon gas-based cryoablation system with a double freeze/thaw cycle. Standard surgical resection was performed 1 to 4 weeks after cryoablation. Patients were monitored for complications, and pathology data were used to assess efficacy.Results Cryoablation was successfully performed in an office-based setting with only local anesthesia. There were no complications to the procedure or postprocedural pain requiring narcotic pain medications. Cryoablation successfully destroyed 100% of cancers <1.0 cm. For tumors between 1.0 and 1.5 cm, this success rate was achieved only in patients with invasive ductal carcinoma without a significant ductal carcinoma-in-situ (DCIS) component. For unselected tumors >1.5 cm, cryoablation was not reliable with this technique. Patients with noncalcified DCIS were the cause of most cryoablation failures.Conclusions Cryoablation is a safe and well-tolerated office-based procedure for the ablation of early-stage breast cancer. At this time, cryoablation should be limited to patients with invasive ductal carcinoma 1.5 cm and with <25% DCIS in the core biopsy. A multicenter phase II clinical trial is planned.     

Treatment of Renal Tumors by Percutaneous Ultrasound-Guided Radiofrequency Ablation Using a Multitined Electrode: Effectiveness and Complications

Background

Radiofrequency ablation (RFA) is a minimally aggressive, therapeutic alternative for renal tumors. It can be an alternative to nephrectomy in patients with previous nephrectomy, bilateral tumors, von Hippel-Lindau disease, or small renal carcinomas and in those with contraindications for surgery.

Objective

To assess the effectiveness of the treatment of renal tumors by RFA in the short and medium term and to identify the possible complications and the factors that determine therapeutic success.

Design, setting, and participants

A retrospective review of patients with renal tumors treated with RFA between May 2005 and December 2008 was performed in a tertiary academic hospital. Patients were selected among those with previous nephrectomy, bilateral neoplasms, von Hippel-Lindau disease, surgical risk, comorbidity, advanced age, or patient's refusal to surgery. Tumors with evidence of extrarenal extension were excluded. Patients were followed up for 10–50 mo using computed tomography and magnetic resonance imaging.

Intervention

Ultrasound-guided RFA was performed on 65 tumors (range: 1.2–5.3 cm) of 58 patients using multitined electrodes.

Measurements

Incomplete ablation rate, therapeutic success rate, and complications rate.

Results and limitations

Therapeutic success was achieved in 59 of 65 tumors (91%): 53 in a single session, 5 in two sessions, and 1 in three sessions. A significant relationship was observed between size and growth pattern of the tumor and both therapeutic success and incomplete ablation rates. Therapeutic success in tumors >5 cm was 60%. Complications were detected in 10 patients (13%); 5% were considered major complications.Limitations include the lack of pathologic studies to confirm a complete ablation and the lack of a control group to compare with the results of those who underwent nephrectomy.

Conclusions

RFA is safe and effective in renal tumors. Corticomedullary lesions and tumors >3 cm have greater possibility of incomplete ablation. In tumors >5 cm, RFA has a significant failure rate.     

Radiofrequency ablation followed by resection of malignant liver tumors.

BACKGROUND: Radiofrequency ablation (RFA) has recently been used to treat liver tumors, but few clinical reports have described the pathological characteristics of radiofrequency ablation in human specimens. This study delineates the gross pathologic and histochemical changes induced by RFA in benign and malignant human liver tissue and confirms the tumor necrosis described in early clinical reports. METHODS: Ten patients with metastatic tumors of the liver received a single treatment of ultrasound-guided percutaneous RFA to 12 tumors. Hepatic resection was carried out within 6 weeks of RFA. Specimens were stained with standard hematoxylin and eosin stain followed by oxidative stain to determine if there was evidence of viable tumor within the zone of ablation. RESULTS: Nine of the 12 ablations were resected. Microscopic examination within the zone of ablation showed successful ablation in 8 of the 9 resected ablations. CONCLUSIONS: Percutaneous RFA creates well-circumscribed areas of tumor necrosis with apparent cell death using an oxidative stain. Further investigation is encouraged to determine the clinical effectiveness of radiofrequency ablation in the complete destruction of liver tumors for palliative or curative intent.     

射频消融联合腔镜微创保乳治疗早期乳腺癌的医学美学评价

目的评价射频消融（radiofrequency ablation,RFA）联合腔镜微创保乳治疗早期乳腺癌的医学美学效果。方法选择早期乳腺癌（T1-2N0-1M0）单侧单发病例,在术前常规化疗的同时,对乳腺肿瘤局部行B超引导下RFA治疗,然后行病变乳腺叶段切除和腔镜下前哨淋巴结染色活检与选择性腋窝淋巴结微创清扫术。术后随访3年以上,通过问卷法自我评价医学美学效果,并与传统保乳手术进行比较。结果直径≤3cm[平均（2．10±0．83）cm,最小1．20cm,最大3．00cm]的早期乳腺癌单侧单发共23例,肿瘤完全消融率95．6％（22／23）,成功完成微创保乳术22例。RFA联合腔镜微创保乳治疗不仅瘢痕微小,而且乳房外形和腋窝形态明显优于传统手术,患者自我评分满意率100％,医学美学评分优良率95．5％（21／22）。结论RFA联合腔镜微创保乳治疗早期乳腺癌可获得更好的医学美学效果。     

Percutaneous Radiofrequency Ablation versus Partial Hepatectomy for Multicentric Small Hepatocellular Carcinomas: A Nonrandomized Comparative Study

Background  

The aim of this study was to compare the results of percutaneous radiofrequency ablation (RFA) with those of partial hepatectomy (PH) in the treatment of multicentric small hepatocellular carcinomas (HCCs). With advances in RFA, it is not known whether the minimally invasive approach with percutaneous RFA could attain comparable survival outcomes but with a lower morbidity in patients with multicentric HCCs.     

超声引导下射频消融治疗肝转移瘤的疗效观察

目的评价超声引导下射频消融（RFA）治疗结直肠癌肝转移瘤（MLC）的疗效。方法采用超声引导下RFA治疗结直肠癌MLC患者60例134个病灶,其中91个病灶≤3.0 cm,43个〉3.0 cm。术前39例血清癌胚抗原（CEA）增高,21例正常。采用CEUS检查结合增强CT、穿刺活检及CEA值的动态变化综合评价肿瘤治疗效果。结果术后3个月复查CEA,37例增高,23例正常。术后30 min CEUS检查显示127个射频消融病灶呈无灌注区,近期有效率达94.78%（127/134）。术后1个月CEUS检查显示8个病灶局部增强,考虑复发,经超声引导下穿刺活检及细胞学检查证实而行第2次治疗。术后1个月增强CT复查显示126个（126/134,94.03%）射频消融病灶呈无灌注区,为完全坏死的转移病灶;部分坏死病灶为8个,与CEUS结果一致。结论超声引导下RFA是治疗MLC的一种安全有效的局部微创治疗方法。     

Ultrasound-Guided Laser-Induced Thermal Therapy for Small Palpable Invasive Breast Carcinomas: A Feasibility Study

Background  The next step in breast-conserving surgery for small breast carcinomas could be local ablation. In this study, the feasibility of ultrasound-guided laser-induced thermal therapy (LITT) is evaluated. Methods  Patients with large-core needle biopsy-proven invasive, palpable breast carcinoma (clinically ≤2 cm) underwent ultrasound-guided LITT, followed by surgical excision. Completeness of ablation was determined by both hematoxylin and eosin staining and nicotinamide adenosine diaphorase staining. Results  Fourteen patients completed the treatment. The mean histological tumor size was 17 mm (range, 8–37 mm); 6 of 14 tumors were histologically larger than the clinical entry threshold of 2 cm. The power applied in all patients was 7 W, and the mean treatment time was 21.4 min (range, 15–30 min). In one patient, a skin burn occurred, and one patient had a localized pneumothorax that could be treated conservatively. In 7 (50%) of 14 patients, the tumor was completely ablated, as confirmed by nicotinamide adenosine diaphorase staining. In 11 cases, extensive in-situ carcinoma was present. In one case, the in-situ carcinoma was also completely ablated. A total of seven (88%) of eight tumors <2 cm in size were completely ablated versus one (17%) of six tumors that were ≥2 cm in size (P = .026). Conclusions  Successful LITT of invasive breast cancer seems to be feasible when confined to small (<2 cm) nonlobular carcinomas without surrounding extensive in-situ component and angioinvasion. However, to implement LITT in a curative setting, improvements in imaging to more reliably preoperatively assess tumor size and monitoring of fiber tip placement and treatment affect are essential.     

eRFA: Excision Followed by RFA—a New Technique to Improve Local Control in Breast Cancer

Introduction Excision followed by RFA (eRFA) may allow improved cosmesis while ensuring negative margins in patients with breast cancer. This technique utilizes heat to create an additional tumor-free zone around the lumpectomy cavity. We hypothesized that eRFA will decrease the need for re-excision of inadequate margins.Methods Between July 2002 and January 2005, we conducted a multiphase trial of RFA of prophylactic mastectomy specimens and of women desiring lumpectomy. In both models, a lumpectomy was performed, the RFA probe was deployed 1 cm circumferentially into the walls of the lumpectomy cavity and maintained at 100°C for 15 min. Whole mount slides were used to measure the zone of ablation for ex vivo specimens. Hematoxylin and eosin staining of in vivo lumpectomy margins <3 mm was considered inadequate.Results Nineteen prophylactic mastectomy ablations revealed a consistent perimeter of ablation. Forty-one patients (mean age 63 ± 14 years) had an average tumor size of 1.6 ± 1.5 cm underwent in vivo eRFA, and 25% had inadequate margins: one focally positive, one <2 mm, eight <1 mm and one grossly positive. Only the grossly positive margin was re-excised. Overall complication rate of in vivo ablations was 7.5%. Twenty-four of 41 patients did not have post-eRFA XRT. No in-site local recurrences have occurred during a median follow-up of 24 months (12–45 months). Two patients have occurred elsewhere.Conclusions The ex vivo ablation model reliably created a 5–10 mm perimeter of ablation. In vivo, this zone reduced the need for re-excision for inadequate margins by 91% (10/11). Short-term follow-up suggests that eRFA could reduce re-excision surgery and local recurrence.     

Tubular Carcinoma of the Breast: A Histologic Subtype Indicative of Breast-Conserving Therapy

We reviewed the clinical and pathologic features of pure tubular carcinoma of the breast with particular emphasis on the reported risk factors associated with local recurrences and survival following breast-conserving therapy. Of 1653 cases of invasive breast cancer, 12 (0.7%) were identified as pure tubular carcinoma. Clinical/pathologic features of pure tubular carcinoma were compared with those of T1 invasive carcinoma of all other histologic types (T1 IC). Of the 12 patients with pure tubular carcinoma (median tumor diameter 1.4 cm; range 0.5–3.0 cm), a multicentric association was identified in one patient while a multifocal association was seen in two. One patient had nodal metastatic disease out of the ten who underwent axillary dissection. No lymphatic vessel invasion was identified in any tumors (P < 0.1 vs T1 IC). In addition, extensive intraductal spread was not present in any tumors (P < 0.05 vs T1 IC). This study shows that patients with pure tubular carcinoma are appropriate candidates for breast-conserving therapy based on the clinical/pathologic features. When a multifocal association is suspected preoperatively, either a wide local excision or a quadrantectomy which includes other lesions is thus recommended. Received: January 21, 2000 / Accepted: July 25, 2000     

Eligibility of patients for minimally invasive breast cancer therapy based on MRI analysis of tumor proximity to skin and pectoral muscle

There is growing interest in minimally invasive breast cancer therapy. Eligibility of patients is, however, dependent on several factors related to the tumor and treatment technology. The aim of this study is to assess the proportion of patients eligible for minimally invasive breast cancer therapy for different safety and treatment margins based on breast tumor location. Patients with invasive ductal cancer were selected from the MARGINS cohort. Semiautomatic segmentation of tumor, skin, and pectoral muscle was performed in Magnetic Resonance images. Shortest distances of tumors to critical organs (ie, skin and pectoral muscle) were calculated. Proportions of eligible patients were determined for different safety and treatment margins. Three‐hundred‐forty‐eight patients with 351 tumors were included. If a 10 mm safety margin to skin and pectoral muscle is required without treatment margin, 72.3% of patients would be eligible for minimally invasive treatment. This proportion decreases to 45.9% for an additional treatment margin of 5 mm. Shortest distances between tumors and critical organs are larger in older patients and in patients with less aggressive tumor subtypes. If a 10 mm safety margin to skin and pectoral muscle is required, more than two‐thirds of patients would be eligible for minimally invasive breast cancer therapy.     

Combined Hepatectomy and Radiofrequency Ablation for Multifocal Hepatocellular Carcinomas: Long-term Follow-up Results and Prognostic Factors

Background For multifocal hepatocellular carcinomas (HCCs) that are untreatable with resection only, locoregional therapies added to hepatectomy have been introduced. However, some preliminary reports have documented average survival results and relatively high complication rates. We evaluated the long-term survival results and safety of combined hepatectomy and radiofrequency ablation (RFA) in patients with HCCs and assessed the prognostic factors affecting their survival. Methods A total of 53 patients who had 148 HCCs in their livers underwent hepatectomy combined with ultrasound-guided intraoperative RFA. The mean diameter of the 82 resected tumors was 4.8 cm (range 1.3–21.0 cm) and that of 66 ablated tumors was 1.5 cm (range 0.8–3.5 cm). We evaluated the primary effectiveness rates, survival rates, and complications. In addition, we assessed the prognostic factors associated with the survival rates using Cox proportional hazard models. Results The primary effectiveness rate of RFA was 98% (65 of 66). Local tumor progression was observed in two (3%) ablation zones of 65 tumors with complete primary effectiveness. The cumulative survival rates at 1, 2, 3, 4, and 5 years were 87, 83, 80, 68, and 55%, respectively. Patients with smaller resected tumors (≤5 cm) demonstrated better survival results (P = 0.004). No procedure-related deaths occurred. We observed hepatectomy-related complications in 4 patients (8%, 4 of 53) and an RFA-related complication in 1 patient (2%, 1 of 53). Conclusions Combined hepatectomy and RFA is an effective and safe treatment modality for multifocal HCCs. Resected tumor size was a significant prognostic predictor of long-term survival.     

Laser therapy for small breast cancers

BACKGROUND: Widespread mammography has resulted in the increased detection of breast cancer <1.5 cm. It may be possible to treat these small tumors with in-situ laser ablation. Prior to ablation tumor size is determined by ultrasound and mammogram. Histologic diagnosis and determination of prognostic factors are obtained from image-guided needle core samples. Invasive and in-situ tumors may be percutaneously ablated by a stereotactically guided laser needle and subsequently evaluated by imaging methods and needle biopsy. METHODS: Fifty-four patients (50 invasive, 4 in-situ); 51 mass, 3 microcalcification; mean diameter 12 (5 to 23) mm were treated by a stereotactically guided 805 nm laser beam via a fiber in a 16G needle delivered to the cancer. One to 8 weeks later the coagulated lesions were surgically removed for pathologic evaluation. In 2 additional patients, the laser-treated tumors were not removed but were monitored by mammography, ultrasonography, and needle core biopsy. RESULTS: None of the patients sustained any adverse effect. The average treatment time was 30 minutes. Pathology analysis revealed a 2.5 to 3.5 hemorrhagic ring surrounding the necrotic tumor. Under steady conditions, in two groups of 14 patients, 93% and 100% of the tumors showed complete destruction, with no residual cancer report. In the 2 unresected cases kept under surveillance for 6 to 24 months, the laser-treated tumors first showed shrinkage, followed by a 2 to 3 cm oil cyst. Fibrosis was demonstrated on needle core biopsies. CONCLUSIONS: Laser energy delivered through a stereotactically guided needle appears to ablate mammographically detected breast cancer. A multicenter clinical trail is planned.     

Radio-frequency ablation of renal cell carcinoma: early clinical experienc.

Purpose: To report the authors' early experience with radio-frequency (RF) ablation of renal cell carcinoma.Materials and Methods: Twenty-four percutaneous RF ablation treatments for nine tumors were performed in eight patients with renal cell carcinoma. Indications included coexistent morbidity, previous surgery, or solitary kidney in patients with a life expectancy shorter than 10 years. Smaller (⩽3-cm) peripheral lesions (n = 3) were treated with single electrodes. All but one of the larger (>3 cm) and/or central lesions (n = 6) were treated with cluster or multiple electrodes. Patients returned for a second treatment when follow-up imaging depicted tumor enhancement. Follow-up imaging was performed at 1 and 3 months and then at 6-month intervals, with a mean follow-up of 10.3 months. Seven patients were alive at least 6 months after their initial treatment.Results: All five exophytic tumors were free of enhancement. One of three central tumors was free of enhancement. One tumor had both central and exophytic components and was free of enhancement. Three tumors were 3 cm or smaller and free of enhancement. Of the six tumors larger than 3 cm, four were free of enhancement.Conclusion: Percutaneous RF ablation is a promising treatment for select patients with renal cell carcinoma. The ultimate role of this modality will continue to evolve and warrants further study.CommentaryNew minimally invasive technologies are currently being applied to the field of nephron-sparing surgery (NSS) for renal cell carcinoma (RCC) in an effort to decrease operative time, pain, morbidity and hospital stay. Methods of tumor ablation have included cryotherapy, radio-frequency ablation (RFA), high intensity focused ultrasound (HIFU), laser and microwave coagulation. These new modalities are currently being administered laparoscopically or percutaneously; ultimately, completely extracorporeal techniques may be feasible.The primary mechanism of tissue destruction with RFA is thermonecrosis. Radio-frequency energy causes high frequency current flow from the needle electrode into the surrounding tissue. This causes ionic agitation, molecular friction, cellular warming with rapid dessication and cell death. The size and configuration of the lesion are related to the amount of energy delivered, ablation time, tissue impedance, electrolyte content of the tissue and surface area of the electrode. It is a major technical challenge to control for each of these variables independently.The major concern with RFA and related ablative technologies is the ability to image the destructive process precisely as it is being administered, thereby minimizing injury to normal adjacent parenchyma while assuring complete tumor ablation. Since a surgical specimen is not removed for pathologic study, histologic documentation of complete tumor destruction and accurate tumor staging/grading are not available. Meticulous long-term clinical and radiographic follow-up of treated patients is ultimately needed to validate the efficacy of ablative techniques such as RFA for treating renal malignancy.Andrew C. Novick, M.D.     

Radiofrequency Ablation in 447 Complex Unresectable Liver Tumors: Lessons Learned

Background: Radiofrequency ablation (RFA) is a promising technique for unresectable hepatic malignancies. We reviewed our RFA experience to identify variables affecting local recurrence.Methods: Patients undergoing RFA between 1997 and 2001 were reviewed for demographics, tumor size, pathology, diagnosis, recurrence, procedures, survival, and complications.Results: The 447 unresectable liver tumors were ablated in 198 procedures. The 153 patients averaged 61.9 years of age and 1.25 RFA procedures per patient. Follow-up averaged 11 months. Serial ablations were performed in 28 patients, 8 of whom are without evidence of disease. Tumors were most commonly carcinomas of colorectal, hepatocellular, breast, and melanoma histologies. Colorectal carcinomas and hepatomas individually recurred more frequently than all other tumor types combined in univariate analyses (P = .009 and P = .008, respectively). Patients with multiple tumors ablated recurred significantly more frequently (P = .001). Size was also significant in univariate and multivariate analyses (P = .0032 and &<.0001, respectively). Eighteen patients experienced 36 complications.Conclusions: Size has the highest correlation with local recurrence, but multiple tumors and pathology may also predict local recurrence risk. Large, complex lesions can be safely serially ablated, but because of morbidity and recurrence, RFA should not replace resection as the primary treatment of resectable liver tumors.Presented at the 55th Annual Cancer Symposium of the Society of Surgical Oncology, Denver, Colorado, March 14–17, 2002     

Intraoperative Ablation for Small HCC not Amenable for Percutaneous Radiofrequency Ablation in Child A Cirrhotic Patients

Background

Radiofrequency ablation (RFA) was initially started by radiologists as a percutaneous treatment, but surgeons started to use RFA by surgical approach for patients with tumors at locations difficult for the percutaneous procedure. The aim was to evaluate the results of intraoperative RFA for small hepatocellular carcinomas (HCCs) (<3 cm) in locations difficult for a percutaneous approach.

Methods

Two hundred forty-seven patients with small solitary HCC (<3 cm) were treated; 196 via percutaneous RFA while 51 patients presented at sites not amenable for percutaneous route. Twenty-seven out of 51 patients underwent surgical resection, while 24/51 patients underwent intraoperative RFA.

Results

The location and depth of the tumor from the liver capsule was the only significant factors in the choice of the surgeon between resection and RFA. RFA was successful in all tumors (complete ablation rate of 100 %). In the surgery group, all patients achieved R0 resection. Complication rate was comparable (p?=?1.0). After a median follow-up of 37 months (range, 10–45 months), no tumors showed neither local progression nor local recurrence and no significant difference was observed between two groups as regards early recurrence and number of de novo lesions (p?=?0.49). One-year and 3-year survival rates were 93 % and 81 %, respectively, in the resection group comparable to the corresponding rates of 92 % and 74 % in the RFA group (p?=?0.9).

Conclusion

For small HCC in locations difficult for a percutaneous approach, intraoperative RFA can be an alternative option for deep-seated tumors necessitating more than one segmentectomy achieving similar tumor control, and overall and disease-free survival.     

Nicotinamide adenine dinucleotide staining immediately following radio frequency ablation of renal tumors-is a positive stain synonymous with ablative failure?

PURPOSE: Nicotinamide adenine dinucleotide diaphorase staining is arguably the standard for assessing tissue viability following radio frequency ablation, yet the accuracy of this test is questionable. Thus, it is imperative to examine the reliability of nicotinamide adenine dinucleotide to predict ablation success. To evaluate the observation that immediate nicotinamide adenine dinucleotide staining may not be clinically reliable, we compared results from immediate post-ablation biopsies of renal tumors to radiological and clinical followup. MATERIALS AND METHODS: Laparoscopic radio frequency ablation was performed in 9 patients and 10 tumors using a temperature modulated radio frequency system. Cold cup biopsies were taken immediately following ablation, and processed for nicotinamide adenine dinucleotide and hematoxylin and eosin staining. Patients were then followed using contrast enhanced computerized tomography at regular intervals. RESULTS: Median tumor size was 2.3 cm. Hematoxylin and eosin stain diagnosed 8 renal cell carcinomas and 2 angiomyolipomas. A quarter of the renal cell carcinomas and both angiomyolipomas stained positive for scattered nicotinamide adenine dinucleotide diaphorase activity immediately after RFA. Mean followup for the nicotinamide adenine dinucleotide positive tumors was 28.5 months (range 24 to 30) and for the nicotinamide adenine dinucleotide negative tumors was 25 months (range 18 to 30). There was no evidence of local tumor recurrence in any patient. CONCLUSIONS: Four lesions had nicotinamide adenine dinucleotide diaphorase activity on post-ablation biopsy suggesting retained viable tissue, yet there has been no recurrence during an average 2-year followup. While negative nicotinamide adenine dinucleotide staining is consistent with nonviability, these results suggest that false-positive staining can occur immediately following RFA, making the predictive value of positive nicotinamide adenine dinucleotide diaphorase staining unclear.     

Thermal ablation for small renal masses: Identifying the most appropriate tumor size cut-off for predicting perioperative and oncological outcomes

ObjectivesTo test TRIFECTA achievement [1) absence of CLAVIEN-DINDO ≥3 complications; 2) complete ablation; 3) absence of ≥30% decrease in eGFR] and local recurrence rates, according to tumor size, in patients treated with thermal ablation (TA: radiofrequency [RFA] and microwave ablation [MWA]) for small renal masses.MethodsRetrospective analysis (2008–2020) of 432 patients treated with TA (RFA: 162 vs. MWA: 270). Tumor size was evaluated as: 1) continuously coded variable (cm); 2) tumor size strata (0.1–2 vs. 2.1–3 vs. 3.1-4 vs. >4 cm). Multivariable logistic regression models and a minimum P-value approach were used for testing TRIFECTA achievement. Kaplan-Meier plots depicted local recurrence rates over time.ResultsOverall, 162 (37.5%) vs. 140 (32.4%) vs. 82 (19.0%) vs. 48 (11.1%) patients harboured, respectively, 0.1 to 2 vs. 2.1 to 3 vs. 3.1 to 4 vs. >4 cm tumors. In multivariable logistic regression models, increasing tumor size was associated with higher rates of no TRIFECTA achievement (OR:1.11; P< 0.001). Using a minimum P-value approach, an optimal tumor size cut-off of 3.2 cm was identified (P< 0.001). In multivariable logistic regression models, 3.1 to 4 cm tumors (OR:1.27; P< 0.001) and >4 cm tumors (OR:1.49; P< 0.001), but not 2.1 to 3 cm tumors (OR:1.05; P= 0.3) were associated with higher rates of no TRIFECTA achievement, relative to 0.1 to 2 cm tumors. The same results were observed in separate analyses of RFA vs. MWA patients. After a median (IQR) follow-up time of 22 (12–44) months, 8 (4.9%), 8 (5.7%), 11 (13.4%), and 5 (10.4%) local recurrences were observed in tumors sized 0.1 to 2 vs. 2.1 to 3 vs. 3.1 to 4 vs. >4 cm, respectively (P= 0.01).ConclusionA tumor size cut-off value of ≤3 cm is associated with higher rates of TRIFECTA achievement and lower rates of local recurrence over time in patients treated with TA for small renal masses.     

Image-guided Percutaneous Ablation of Renal Tumors: Outcomes,Technique, and Application in Urologic Practice

The recent increase in detection of small (≤4 cm) renal cortical neoplasms has engendered changes in the management of these incidental renal tumors. There is increased interest in new forms of minimally invasive therapies, including focal renal mass ablation with cryotherapy and radiofrequency ablation (RFA). Percutaneous cryoablation (PCA) and percutaneous RFA are among the newest approaches to minimally invasive renal surgery offering excellent patient recovery, lower rates of procedure-related complications, and promising oncologic outcomes. Ablative techniques were once considered a treatment option only in highly selected cases. However, with excellent efficacy of ablative technologies having been demonstrated with intermediate-term follow-up, renal ablation has expanded to a larger patient population. Percutaneous renal ablative procedures are optimized when performed in a combined fashion, with urologists and interventional radiologists collaborating to optimize the chance of success of the ablation. This article reviews the recent advances in PCA and percutaneous RFA and offers suggestions for patient selection in contemporary urologic practice.