Interstitial Tumor Ablation Research Articles

Technical aspects and effectiveness of percutaneous fetal therapies for large sacrococcygeal teratomas: cohort study and literature review.

The objectives of this study were to evaluate the efficacy of minimally invasive ablation of high-risk large sacrococcygeal teratomas (SCT) and to compare the efficacy of vascular and interstitial tumor ablation. This was a retrospective multicenter study including a cohort of fetuses with high-risk large SCTs between 2004 and 2010. In addition, we performed a systematic literature review of all cases that underwent tumor ablation in order to compare the survival rates after 'vascular' and 'interstitial' ablation. Statistical analysis was conducted using Bayesian methods. In our cohort, a total of 13 fetuses had high-risk large SCT and five of them underwent tumor ablation. The estimated difference in hydrops resolution rate between the fetal intervention and the no fetal intervention groups was 44.6% (95% credibility interval, 1.5 to 81.0%; Pdiff> 0 = 97.9%). The estimated difference in survival rate between the fetal intervention and the no fetal intervention groups was 31.0% (13.9 to 48.1%; Pdiff> 0 = 99.9%). We analyzed our five cases together with 28 cases from the literature and estimated the difference in survival rate between the vascular and interstitial ablation groups as 19.8% (-13.1 to 50.1%; Pdiff> 0 = 88.3%). The estimated difference in hydrops resolution rate between the vascular and the interstitial ablation groups was 36.7% (-5.7 to 72.7%; Pdiff> 0 = 95.5%). Minimally invasive surgery seems to improve perinatal outcome in cases of high-risk large fetal SCT. Our findings suggest that 'vascular' ablation may improve outcome and may be more effective than 'interstitial' tumor ablation, but this hypothesis needs further investigation in a larger multicenter prospective study. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

Image-based 3D modeling and validation of radiofrequency interstitial tumor ablation using a tissue-mimicking breast phantom

Minimally invasive treatment of solid cancers, especially in the breast and liver, remains clinically challenging, despite a variety of treatment modalities, including radiofrequency ablation (RFA), microwave ablation or high-intensity focused ultrasound. Each treatment modality has advantages and disadvantages, but all are limited by placement of a probe or US beam in the target tissue for tumor ablation and monitoring. The placement is difficult when the tumor is surrounded by large blood vessels or organs. Patient-specific image-based 3D modeling for thermal ablation simulation was developed to optimize treatment protocols that improve treatment efficacy. A tissue-mimicking breast gel phantom was used to develop an image-based 3D computer-aided design (CAD) model for the evaluation of a planned RF ablation. First, the tissue-mimicking gel was cast in a breast mold to create a 3D breast phantom, which contained a simulated solid tumor. Second, the phantom was imaged in a medical MRI scanner using a standard breast imaging MR sequence. Third, the MR images were converted into a 3D CAD model using commercial software (ScanIP, Simpleware), which was input into another commercial package (COMSOL Multiphysics) for RFA simulation and treatment planning using a finite element method (FEM). For validation of the model, the breast phantom was experimentally ablated using a commercial (RITA) RFA electrode and a bipolar needle with an electrosurgical generator (DRE ASG-300). The RFA results obtained by pre-treatment simulation were compared with actual experimental ablation. A 3D CAD model, created from MR images of the complex breast phantom, was successfully integrated with an RFA electrode to perform FEM ablation simulation. The ablation volumes achieved both in the FEM simulation and the experimental test were equivalent, indicating that patient-specific models can be implemented for pre-treatment planning of solid tumor ablation. A tissue-mimicking breast gel phantom and its MR images were used to perform FEM 3D modeling and validation by experimental thermal ablation of the tumor. Similar patient-specific models can be created from preoperative images and used to perform finite element analysis to plan radiofrequency ablation. Clinically, the method can be implemented for pre-treatment planning to predict the effect of an individual's tissue environment on the ablation process, and this may improve the therapeutic efficacy.

Conceptual Basis for Focal Therapy in Prostate Cancer

The proportion of men with low- to intermediate-risk prostate cancer is rising with the increasing use of formal and informal prostate-specific antigen screening. The risk-to-benefit ratio of radical therapy is large with many men suffering genitourinary side effects compared with the small degree of cancer control that they derive from surgery or radiotherapy. On the other hand, the current alternative, active surveillance, carries risk of progression as well as some psychological and healthcare burdens. Focal treatment may be an acceptable alternative: in aiming to destroy only the areas of prostate cancer, focal therapy could deliver cancer control while at the same time avoid damage to surrounding structures. This may reduce incontinence, impotence, and rectal toxicity. Improvements in localization of cancer such as template transperineal prostate-mapping biopsies as well as state-of-the-art imaging such as multiparametric MRI and novel ultrasound-based tissue characterization tools have made the delivery of focal therapy possible. Minimally invasive ablative technologies such as cryotherapy, high-intensity focused ultrasound, photodynamic therapy, photothermal therapy, or radiofrequency interstitial tumor ablation can precisely treat to within a few millimeters. Early studies evaluating focal therapy have found a lower side-effect profile with acceptable short- to medium-term cancer control rates. If these promising results are confirmed in future prospective trials, focal therapy could start to challenge the current standard of care.

Radiofrequency ablation of renal tumors: Practical aspects and results

ObjectivesTo report our experience in percutaneous radiofrequency ablation of renal tumors, emphasizing technical aspects and indications and analyzing our results. Material and methodsWe retrospectively analyzed 20 tumors in 13 patients (10 with a single kidney, 2 who had refused surgical treatment, and 1 with severe comorbidities). All procedures were performed using the radiofrequency interstitial tumor ablation (RITA) technique under general anesthesia and CT guidance. All patients underwent follow-up CT examination with and without intravenous contrast administration; the absence of enhancement was considered complete necrosis. ResultsThe mean size of the tumors was 2.8cm. Complete necrosis was achieved in 17 tumors (85%); complete necrosis was achieved in 100% of the exophytic tumors and in 50% of the tumors with mixed location after 14 months’ follow-up. Complete ablation was achieved in 15 of the 16 tumors measuring ≤ 3.5cm. In 9 of the 10 patients with a single kidney (four of whom had more than one tumor), renal function remained normal after the procedure; the other patient developed hydronephrosis after a urinary tract lesion and died. The patient who died also developed a subcapsular liver hematoma that did not require transfusion when another tumor was treated transhepatically. ConclusionIn experienced hands and with careful selection of patients (exophytic tumors ≤ 3.5cm), radiofrequency ablation of renal tumors can achieve excellent oncologic results with minimal morbidity and mortality.

The Current Use and Future Trends of Focal Surgical Therapy in the Management of Localized Prostate Cancer

The current treatment algorithms for management of localized prostate cancer are mainly extirpative in nature. Treatment varies from expectant management to radical prostatectomy or radiation therapy. However, the ever-increasing emphasis on achieving the best survival benefit while better preserving quality of life, coupled with the introduction of new, safer, and efficacious minimally invasive ablative technologies, has led to the increased popularity of minimally invasive treatment (MIT). MIT refers to the use of a wide range of techniques for local target ablation of the prostate gland with minimal damage to the surrounding tissue. Currently these include cryotherapy and high-intensity focused ultrasound. However, other experimental technologies such as photodynamic therapy, interstitial prostate brachytherapy, and microwave and radiofrequency interstitial tumor ablation are also currently under investigation in early clinical trials. To date, the overall interim results for these relatively new modalities of treatment appear comparable to those for surgical and radiation therapies. However, randomized, controlled studies are needed to support use of these modalities as an alternative to surgery and radiation. In this review, we will address the current rationale for and knowledge of MIT with regard to its safety and efficacy in the treatment of localized prostate cancer. In addition, we will discuss future promising tools in MIT such as photodynamic therapy and the target focal therapy approach as a new trend for the treatment of organ-confined low-volume disease.

MP-14.11: Histopathological findings after radiofrequency in treatment for prostate cancer

Radiofrequency Interstitial Tumor Ablation (RITA) is a thermal ablation method that uses needles and low radiofrequency energy.

Histopathological findings after radiofrequency (RITA) treatment for prostate cancer

Radiofrequency interstitial tumor ablation (RITA) is a thermal ablation method that uses needles and low radiofrequency (RF) energy. The aim of our study was to evaluate the histopathology of thermal lesions induced by RF energy delivered interstitially in prostate cancer patients who subsequently underwent prostatectomy, and to determine the feasibility, effectiveness and safety of this new method in a pilot study.

Incomplete renal tumor destruction using radio frequency interstitial ablation.

We evaluate the efficacy of temperature based radio frequency ablation as a potential treatment modality for small (less than 3.5 cm.) renal tumors. We treated 15 patients with a total of 20 tumors with radio frequency ablation through an open surgical approach immediately before partial nephrectomy. All tumors were biopsied before radio frequency ablation treatment. Tumors were heated to 90 to 110C for 6 to 16 minutes (mean 9.1). Tumor ablation was monitored by direct vision and ultrasound. Partial nephrectomy was performed in standard fashion. All specimens were stained with hematoxylin and eosin, and 5 specimens were stained for nicotinamide adenine dinucleotide (NADH) diaphorase activity. Tumors ranged from 1.5 to 3.5 cm. (mean 2.4) in greatest dimension. All 20 specimens had evidence of morphologically unchanged tumor and normal renal parenchyma on standard hematoxylin and eosin staining. Of the 5 specimens 4 stained positively for NADH in areas confirmed to be tumor in hematoxylin and eosin stained neighboring sections. There was 1 intraoperative renal pelvic thermal injury requiring pyeloplasty and 2 postoperative caliceal leaks requiring stent placement. In our series radio frequency therapy did not result in total tumor destruction when specimens were examined with hematoxylin and eosin or NADH staining. We believe that radio frequency interstitial tumor ablation of renal cell carcinoma without subsequent tissue resection should continue to be an investigational treatment modality for those who would otherwise undergo partial or radical nephrectomy.

Pilot study of radiofrequency interstitial tumor ablation (RITA) for the treatment of radio‐recurrent prostate cancer

To prospectively evaluate the feasibility, safety, morbidity, and preliminary efficacy of radiofrequency interstitial tumor ablation (RITA) for the focal treatment of patients with local prostate cancer recurrence. Eleven patients with biopsy-proven, hormone-naïve, clinically localized prostate cancer were enrolled in a prospective phase I/II trial. Eight patients had failed prior radiation therapy and three were not candidates for curative primary therapy (median Gleason score 7 and 6, respectively). Median follow-up was 20 months. All patients were treated with RITA in an office setting, under intravenous sedation and were discharged after the procedure. Radiofrequency energy was applied via needles placed transperineally under transrectal ultrasound guidance. The placement of 1/4 lesions was aborted in two patients due to increasing rectal temperature. Complications included transient macrohematuria (19%), bladder spasms (9%), and dysuria (9%). Serum PSA levels decreased after RITA >50% in 90% of patients, > 70% in 72% of patients, and > 80% in 46% of patients. The mean PSA doubling time after RITA was slower than that before RITA (37 +/- 22 months vs. 14 +/- 13 months, P = 0.008). At 12 months after RITA, 50% of patients with sufficient follow-up had no residual cancer on repeat systematic 12-core biopsy cores and 67% were cancer-free in biopsy cores sampled from the RITA-treated areas. RITA treatment is a minimal invasive, rapid, user-friendly, office-based procedure that is well tolerated. Focal ablation with RITA results in effective local disease control in patients with non-metastatic prostate cancer recurrence. Larger, prospective, multicenter clinical studies are needed to confirm these findings.

Radiofrequency interstitial tumor ablation: dry electrode.

With the shift in the treatment of small renal tumors from radical extirpative surgery to nephron-sparing approaches, dry-electrode radiofrequency ablation (RFA) has emerged as one potential modality. This application of RF energy leads to the production of heat within the treatment zone secondary to the native impedance of living tissue. Animal studies and human clinical series have demonstrated that RFA can create controlled, targeted, reproducible, and lethal lesions. Most clinical series have reported promising results, although some authors question the totality of tumor destruction by RFA. With time, the efficacy of RFA, as measured by patient survival, will be determined. Once this is known, RFA may be compared with other therapeutic modalities for small renal tumors to determine its place.

Alternative therapies for localized prostate cancer.

Prostate cancer is the leading malignancy in men; an increase in detected localized prostate cancers is expected in the years to come. Radical prostatectomy, although effective, is associated with a considerable morbidity. The aim of minimal invasive alternative treatment options should be equal efficacy, but a decrease in side effects. Cryosurgical ablation of the prostate, brachytherapy, high-intensity focused ultrasound, and radiofrequency interstitial tumor ablation were evaluated after a literature review from a MEDLINE search (1966-2002). When compared with treatments in the 1960s and 1970s, increased safety is observed in all of the alternative treatments available today. Sophisticated technology, including the latest ultrasonography devices for exact planning and monitoring of treatment, contributes largely to this safety. Five-year results of cryosurgical ablation of the prostate show a prostate-specific antigen lower than 1 ng/mL in 60% of the cases; in the third generation, there are no long-term data available on cryosurgical ablation of the prostate. Recent outcome data of brachytherapy come close to results of radical prostatectomy series. Brachytherapy is the only true alternative at this point in time. High-intensity focused ultrasound and radiofrequency interstitial tumor ablation are promising new technologies that have proven to be able to induce extensive necrosis; however, follow-up is too short to determine their definite places in the treatment of prostate cancer.

In-vivo evaluation of a simulation model for interstitial tumor ablation by radiofrequency therapy in porcine liver with normal and interrupted hepatic perfusion

In-vivo evaluation of a simulation model for interstitial tumor ablation by radiofrequency therapy in porcine liver with normal and interrupted hepatic perfusion

Perkutane Radiofrequenzablation - klinische Indikationen und Ergebnisse

Percutaneous interstitial tumor ablation therapy is a relatively new and steadily growing field within interventional radiology. Radiofrequency ablation (RFA) became one of the most accepted techniques among hyperthermal ablation procedures, presumably due to its superior relation between probe diameter and efficacy. The first part of this review provided an overview of the underlying principles, technical background and application techniques. This second part describes the indications, techniques and results of clinical RFA applied to primary and secondary liver tumors as well as experiences with extrahepatic RFA applied to kidney, bone and lung, together with a discussion of the current literature.

Incomplete Renal Tumor Destruction Using Radio Frequency Interstitial Ablation

We evaluate the efficacy of temperature based radio frequency ablation as a potential treatment modality for small (less than 3.5 cm.) renal tumors. We treated 15 patients with a total of 20 tumors with radio frequency ablation through an open surgical approach immediately before partial nephrectomy. All tumors were biopsied before radio frequency ablation treatment. Tumors were heated to 90 to 110C for 6 to 16 minutes (mean 9.1). Tumor ablation was monitored by direct vision and ultrasound. Partial nephrectomy was performed in standard fashion. All specimens were stained with hematoxylin and eosin, and 5 specimens were stained for nicotinamide adenine dinucleotide (NADH) diaphorase activity. Tumors ranged from 1.5 to 3.5 cm. (mean 2.4) in greatest dimension. All 20 specimens had evidence of morphologically unchanged tumor and normal renal parenchyma on standard hematoxylin and eosin staining. Of the 5 specimens 4 stained positively for NADH in areas confirmed to be tumor in hematoxylin and eosin stained neighboring sections. There was 1 intraoperative renal pelvic thermal injury requiring pyeloplasty and 2 postoperative caliceal leaks requiring stent placement. In our series radio frequency therapy did not result in total tumor destruction when specimens were examined with hematoxylin and eosin or NADH staining. We believe that radio frequency interstitial tumor ablation of renal cell carcinoma without subsequent tissue resection should continue to be an investigational treatment modality for those who would otherwise undergo partial or radical nephrectomy.

Evaluation of a 3-D computer-simulated irradiation model for interstitial tumor ablation in porcine liver in vivo

Evaluation of a 3-D computer-simulated irradiation model for interstitial tumor ablation in porcine liver in vivo

Evaluation of a 3-D computer-simulated irradiation model for interstitial tumor ablation in porcine liver in vivo

Evaluation of a 3-D computer-simulated irradiation model for interstitial tumor ablation in porcine liver in vivo

A PHASE 2 STUDY OF RADIO FREQUENCY INTERSTITIAL TISSUE ABLATION OF LOCALIZED RENAL TUMORS

Small renal tumors are frequently detected during the screening of patients with a hereditary type of renal cancer. The development of nonsurgical treatment modalities would greatly improve quality of life in these patients. We present our experience with radio frequency interstitial tissue ablation, a heating device approved by the Food and Drug Administration for treating soft tissue tumors. Patients underwent radio frequency interstitial tissue ablation of small renal tumors just before surgical excision. Pathological examination of the renal tumors was done to evaluate the treatment effect. Computerized tomography and renal function testing were performed before and after therapy to evaluate toxicity. Four patients underwent treatment of a total of 14 tumors with the radio frequency interstitial tissue ablation device just before surgical removal of the tumors. All lesions were brown after ablation, in contrast to the normal pink appearance of untreated lesions that were resected. On color Doppler ultrasound blood flow to each tumor evident before was not visualized after treatment. The Wilcoxon rank sum test demonstrated no difference preoperatively and postoperatively in blood urea nitrogen, serum creatinine, creatinine clearance or differential renal function. We identified no toxicity associated with radio frequency interstitial tissue ablation. Of the excised tumors 11 were renal cell carcinoma and 3 fibrotic hemorrhagic cysts. For renal cell carcinoma the treatment effect involved the loss of nuclear detail and nonvisualization of nucleoli. These changes were not observed in any tumors resected without radio frequency interstitial tissue ablation. The treatment effect was noted in 10 of the 11 lesions, and in 1 case the treatment effect involved 35% of the tumor. No toxicity was associated with radio frequency interstitial tissue ablation. Percutaneous treatment of renal tumors is planned to evaluate the treatment effect better and further evaluate toxicity.

Transperineal radiofrequency interstitial tumor ablation of the prostate: Correlation of magnetic resonance imaging with histopathologic examination

Objectives Radiofrequency (RF) energy has recently been employed to destroy human tissue in vivo. The purpose of this study was to investigate the safety of this approach in localized carcinoma of the prostate (CaP) and specifically, the predictability of lesions obtained with radiofrequency interstitial tumor ablation (RITA). Methods Using RITA, a total of 21 lesions were induced in 10 patients with localized CaP (mean age 70.4 years). RF was delivered transperineally under transrectal ultrasound (TRUS) guidance. All patients underwent endorectal magnetic resonance imaging (MRI) before and after treatment. Radical prostatectomy was performed in all patients 1 to 7 days after RITA. Three of the patients were treated with local anesthesia only. The predictability of the thermal lesion was assessed by correlating the findings of intraoperative TRUS, preand post-RITA endorectal MRI, and the histologic examination of the specimen. Results Postoperatively, patients were catheterized for an average of 1.8 days (1 to 3 days). Lesions of 2 × 2 × 2 cm were targeted. Average lesion diameters obtained on MRI were 2.08 ± 0.23 × 2.09 ± 0.36 × 2.28 ± 0.21 cm. Average lesion diameters defined by coagulative necrosis at histologic examination were 2.20 ± 0.23 × 2.10 ± 0.31 × 2.38 ± 0.14 cm. There were no statistically significant differences ( P = 0.377) between average lesion volume on MRI (5.37 ± 1.83 cm 3) and average lesion volume at histology (5.86 .63 cm 3). No complications or adverse events were noted. Conclusions In this Phase I study, RITA was shown to be safe and feasible, and to result in lesions that were predictable in size and location. MRI accurately visualized and verified the area of coagulative necrosis as documented at histology. The procedure is technically simple and can even be performed under local anesthesia.

Radiofrequency interstitial tumor ablation (RITA) is a possible new modality for treatment of renal cancer: ex vivo and in vivo experience.

Small renal tumors are increasingly diagnosed and are frequently treated by nephron-sparing surgery. Tumors can be ablated by radiofrequency (RF) energy, which allows the operator to create very localized necrotic lesions. Radiofrequency interstitial tumor ablation (RITA) has been used in human kidneys in an ex vivo experiment to assess the necrotic lesions produced in a model close to physiologic conditions and then in three patients with localized renal cancer prior to radical nephrectomy. In the ex vivo model, four freshly removed kidneys were treated. Bipolar RF energy was delivered by a generator connected to two needles introduced parallel to each other into the renal parenchyma. A thermocouple was inserted between the two active electrodes. The renal artery at physiologic conditions was maintained at a constant temperature of perfusion of 37 degrees C by a computer-assisted Hot-line monitor. Two lesions were produced in each pole of each kidney including the cortex and the medulla. In an initial human study focusing on safety, feasibility, and pathology, three patients were treated by RITA with bipolar and monopolar energy. One patient with a peripheral 2-cm upper-pole tumor was treated percutaneously under ultrasound guidance with local anesthesia only 1 week prior to surgery. The other patients, with 3- and 5-cm tumors, were treated during surgery under general anesthesia just before nephrectomy. Ex vivo, the maximum temperature at the active needles ranged from 84 degrees C to 130 degrees C with 10 to 14 W applied during 10 to 14 minutes. Lesions were on average 2.2 x 3 x 2.5 cm.3 Microscopic examination showed stromal edema with intensive pyknosis. No damage was seen to adjacent untreated tissue. In the in vivo procedure, tolerance of RTA as an anesthesia-free procedure was excellent. The size of the observed lesions was comparable to the forecast size depending on the needle deployment. No side effects were noted, and no adjacent structures were affected by the RF ablation. These preliminary studies demonstrate the ability of RITA to produce localized extensive necrosis in kidney parenchyma and tumors safely under local anesthesia. Further studies could evaluate this new minimally invasive treatment in small kidney tumors considered for nephron-sparing surgery.