Combined Radiofrequency Ablation Research Articles

CO2‐enhanced sonographically guided radiofrequency ablation and transcatheter arterial chemoembolization for small hepatocellular carcinoma poorly defined on conventional sonography

We report a case of hepatocellular carcinoma located just below the right hemidiaphragm that was diagnosed as having hepatitis C virus-related cirrhosis 12 years ago. Although the lesion was not clear on conventional sonography, it was clearly defined on CO(2)-enhanced sonography, allowing safe and accurate radiofrequency ablation. By combining radiofrequency ablation with transcatheter arterial chemoembolization, extensive cauterization and complete tumor necrosis were obtained with only 1 session of treatment. The patient had no serious adverse effects and has shown no recurrence during 35 months of follow-up.

Combined radiofrequency ablation and doxorubicin‐eluting polymer implants for liver cancer treatment

Previously, biodegradable polymer implants (polymer millirods) to release chemotherapeutic agents directly into tumors have been developed. The purpose of this study is to evaluate local drug distribution from these implants in liver tumors treated with radiofrequency (RF) ablation and determine if the implants provide a therapeutic improvement over RF ablation alone. Cylindrical implants were fabricated using 65% poly(D,L-lactide-co-glycolide) (PLGA), 21.5% NaCl, and 13.5% doxorubicin. Control or drug-containing millirods were implanted inside VX2 liver tumors (11 mm diameter) in rabbits after RF ablation. Therapeutic efficacy was assessed 4 and 8 days after treatment using tumor size, histology, and fluorescence measurement of drug distribution. Tumors in both test groups recurred at the boundary of the ablated region. Therapeutic doxorubicin concentrations were found in more than 80% of the ablated area, but concentrations declined rapidly at the boundary between normal and ablated tissue. This region was characterized by a developing fibrous capsule with resolving inflammation, which restricted drug transport out of the ablated zone. The intratumoral doxorubicin implants delivered high concentrations of drug within the ablated region but only limited amounts outside the ablation zone. Future studies will focus on overcoming the fibrotic transport barrier and enhancing drug delivery to the periphery of the ablation region to prevent tumor progression.

Clinical Assessment of Percutaneous Radiofrequency Ablation for Painful Metastatic Bone Tumors

To investigate the pain-alleviating effects of radiofrequency ablation (RFA) on metastatic bone tumors in relation to tumor size, combined therapy, and percent tumor necrosis rate following RFA. Subjects comprised 24 patients with 28 painful metastatic bone tumors. A 17G internally cooled electrode was inserted into the tumor for CT guidance and ablation was performed. Bone cement was injected following RFA for 4 tumors involving a weight-bearing bone, while 5 tumors were treated using combined RFA and external irradiation. Percent necrosis rate of the tumor was measured using contrast-enhanced computed tomography 1 week after RFA. Improvement in the visual analog scale (VAS) score was 4.6 +/- 2.2 for large tumors (> 5 cm, n = 12), 3.7 +/- 1.8 for medium-sized tumors (3.1-5.0 cm, n = 11), and 3.5 +/- 1.7 for small tumors (< or = 3 cm, n = 4), with no significant differences noted among tumor sizes. Improvement in the VAS score was 3.5 +/- 1.3 for the 4 tumors in the RFA + bone cement group, 3.2 +/- 1.9 for the 5 tumors in the RFA + radiation therapy group, and 4.8 +/- 2.2 for the 18 tumors in the RFA group. No significant differences were identified between groups. The improvement in the VAS score was 3.8 +/- 2.3, 4.0 +/- 1.9, and 4.7 +/- 2.6 in patients with tumor necrosis rates of 0-49%, 50-74%, and 75-100%, respectively. No significant association was observed among these three groups. Percutaneous RFA therapy was effective in relieving pain due to metastatic bone tumors. No relationships appear to exist between initial response and tumor size, combined therapy, and percent tumor necrosis.

Efficient loading of dendritic cells following cryo and radiofrequency ablation in combination with immune modulation induces anti-tumour immunity

Dendritic cells (DC) are professional antigen-presenting cells that play a pivotal role in the induction of immunity. Ex vivo-generated, tumour antigen-loaded mature DC are currently exploited as cancer vaccines in clinical studies. However, antigen loading and maturation of DC directly in vivo would greatly facilitate the application of DC-based vaccines. We formerly showed in murine models that radiofrequency-mediated tumour destruction can provide an antigen source for the in vivo induction of anti-tumour immunity, and we explored the role of DC herein. In this paper we evaluate radiofrequency and cryo ablation for their ability to provide an antigen source for DC and compare this with an ex vivo-loaded DC vaccine. The data obtained with model antigens demonstrate that upon tumour destruction by radiofrequency ablation, up to 7% of the total draining lymph node (LN) DC contained antigen, whereas only few DC from the conventional vaccine reached the LN. Interestingly, following cryo ablation the amount of antigen-loaded DC is almost doubled. Analysis of surface markers revealed that both destruction methods were able to induce DC maturation. Finally, we show that in situ tumour ablation can be efficiently combined with immune modulation by anti-CTLA-4 antibodies or regulatory T-cell depletion. These combination treatments protected mice from the outgrowth of tumour challenges, and led to in vivo enhancement of tumour-specific T-cell numbers, which produced more IFN-γ upon activation. Therefore, in situ tumour destruction in combination with immune modulation creates a unique, ‘in situ DC-vaccine’ that is readily applicable in the clinic without prior knowledge of tumour antigens.

Long-term benefit of combined radiofrequency ablation and surgery in a patient with AJCC stage IV metastatic melanoma

Long-term benefit of combined radiofrequency ablation and surgery in a patient with AJCC stage IV metastatic melanoma

Combined hepatic resection and radiofrequency ablation for multiple hepatic adenomas

We describe the novel use of radiofrequency ablation (RFA) in combination with surgical resection for treatment of multifocal hepatic adenoma. We show three cases without recurrent lesions detected in follow-up examination. Two of the patients have subsequently gone on to carry pregnancies successfully to term.

Radiofrequency Ablation Followed by Conventional Radiotherapy for Medically Inoperable Stage I Non-small Cell Lung Cancer

The standard treatment of stage I non-small cell lung cancer (NSCLC) is surgical resection. Some patients are poor surgical candidates due to severe comorbid medical conditions. Radiotherapy alone has historically been used in this patient population with limited success. Radiofrequency ablation (RFA) is an image-guided, thermally mediated ablative technique recently applied to lung tumors. Combination therapy with both these treatments has not been previously performed. We report our experience with combined CT-guided RFA and conventional radiotherapy in 24 medically inoperable patients with a minimum of 2-year study follow-up in surviving patients. Twenty-four consecutive, medically inoperable patients with biopsy-proven, stage I NSCLC were treated with CT-guided RFA followed by radiotherapy to a dose of 66 Gy. RFA was performed with a single or cluster cool-tip F electrode; 21 patients were staged before therapy using fluorodeoxyglucose-positron emission tomography. There were 14 women and 10 men (median age, 76 years; range, 58 to 85 years). The histologic subtypes were squamous cell (n = 13), adenocarcinoma (n = 5), and undifferentiated (n = 6). All patients received RFA followed by three-dimensional conformal radiotherapy. There were no treatment-related deaths or grade 3/4 toxicities. Pneumothorax requiring chest tubes developed in three patients (12.5%). At a mean follow-up period of 26.7 months (range, 6 to 65 months), 14 patients (58.3%) died, with cumulative survival rates of 50% and 39% at the end of 2 years and 5 years, respectively. Ten of the deaths were cancer related. Two patients had local recurrence (8.3%), while nine patients had systemic metastatic disease. Three patients died of respiratory failure with no evidence of active disease, and one patient died of a cerebrovascular accident at 18-month follow-up. Pleural effusions developed after treatment in six patients (25%), which proved to be malignant in one patient. RFA followed by conventional radiotherapy is feasible in this population of medically inoperable stage I NSCLC patients. Procedural complication rates are low, and no additional major toxicities were seen despite the addition of RFA. Local control and survival rates appear to be better than with radiotherapy alone.

Radiofrequency Ablation Combined with Renal Arterial Embolization for the Treatment of Unresectable Renal Cell Carcinoma Larger Than 3.5 cm: Initial Experience

The purpose of the study was to evaluate the feasibility, safety, and therapeutic effects of the combination of renal arterial embolization and radiofrequency (RF) ablation to reinforce the anticancer effect on renal cell carcinomas (RCCs) measuring 3.5 cm or larger. This study was undertaken to evaluate this combined therapy on large RCCs-based tumor geometry. Eleven patients with 12 RCCs 3.5 cm or larger in diameter (3.5-9.0 cm) underwent combined therapy. Two were exophytic tumors, and the remaining 10 tumors had components extending into the renal sinus fat. Tumor vessels were selectively embolized in nine patients and the renal artery was completely embolized in two patients with polyvinyl alcohol or ethanol mixed with iodized oil. RF ablation was percutaneously done under the computed tomographic (CT)-fluoroscopic guidance. Response to treatment was evaluated by dynamic contrast-enhanced CT and magnetic resonance (MR) imaging. Tumor enhancement was eliminated after a single RF session in nine tumors (75%), after two sessions in two tumors (17%), and after four sessions in one tumor (8%). Both exophytic tumors (100%) and 7 of 10 tumors having components in the renal sinus fat (70%) were completely ablated with a single RF session. All tumors remained controlled during a mean follow-up period of 13 months and showed significant reduction in tumor sizes (5.2 +/- 1.7 cm to 3.6 +/- 1.4 cm, p < 0.001). A delayed abscess developed in the ablated lesion in a patient, which was percutaneously drainaged. Combined therapy as described in this report is a feasible, relatively safe, and promising treatment method for large RCCs regardless of tumor geometry.

A family of new instruments for laparoscopic radiofrequency ablation of malignant liver lesions

Primary and secondary liver tumors may be treated with radiofrequency ablation (RFA) to improve tumor control and to increase patient survival. Lesions are punctured percutaneously or during open surgery. However, not all of the lesions are accessible percutaneously due to their localization: Adjacent structures could be endangered and/or the treatment would cause severe pain. Open surgery is an option in these cases but significantly more invasive. Laparoscopic RFA (LRFA) is an additional possibility in those cases: It offers a better access to difficult lesions than via the percutaneous route and is also less invasive than open surgery. The precision of targeting, however, in LRFA still has to be improved. In an in‐vivo feasibility study we used a tumor mimic model in pigs to examine the applicability of laparoscopic RFA in combination with laparoscopic ultrasound using a set of dedicated new instruments to handle the RFA probe. To increase the ablation volume, the liver blood flow was reduced performing a Pringle maneuver. It is demonstrated that this set of specially designed instruments is indeed applicable and facilitates the targeting of liver lesions of any localization. Accordingly, it could significantly enlarge the applicability of LRFA.

The trans‐metastasis hepatectomy (through metastases previously ablated with radiofrequency): Results of a 13‐case study of colorectal cancer

Curative trans-metastasis liver resection immediately following radiofrequency (RF) destruction is a new technique that enables the proposition of a curative approach to patients with bilateral, unresectable liver metastases (LM), when the only possible future hepatectomy plane passes through a LM. Firstly, the ill-sited LM, which is located in the only feasible future hepatectomy plane, is ablated using RF; the hepatectomy is then performed through this ablated LM. The aim of this study is to report the feasibility and efficacy of this new approach, known as post-RF-trans-metastasis-hepatectomy (PRFTMH). Thirteen patients with colorectal primary cancer were treated with PRFTMPH between January 2000 and May 2004. The mean number of LMs per patient was 10.7. Preoperative hypertrophy of the future remaining liver was achieved by selective portal vein embolization in eight patients. The mortality rate was 7.6% (one death), and morbidity was 24%. No local recurrence was observed at the PRTMPH site after a mean follow-up of 19.4 months (range: 47-10), demonstrating the efficacy of this technique. All patients, except those who died postoperatively, are currently alive; the median survival has not yet been attained after a mean follow-up of 19.4 months. TMPRFH is a new and safe technique, combining RF ablation and trans-RF-hepatectomy, which makes it possible to propose a curative approach in certain patients with non-resectable bilateral LMs.

Radiofrequency Ablation for Cancer: Current Indications, Techniques and Outcomes

Radiofrequency Ablation for Cancer is an all-inclusive textbook solely devoted to the therapeutic modality, radiofrequency ablation (RFA), a popular and ever-increasing technique being applied in the treatment of solid tumors. The editors have assembled a cadre of recognized experts in their respective fields with extensive experience in the use of this therapeutic technique. Together, the editors and contributing authors have compiled an important overview of the state of the art for RFA, which is a must read for anyone currently using or contemplating incorporating this approach into their therapeutic armamentarium. The main target audience is comprised of those individuals who would use this innovative tool or who are involved in the management of patients treated by this modality, including surgeons, oncologists, and interventional radiologists. It will also prove useful for residents and fellows who want an understanding of the biologic basis and therapeutic implications of this procedure. The book is divided into 4 major sections. The first addresses the principles and generalized technique of RFA. The section is dedicated to RFA of both primary and secondary liver malignancies, those tumors that comprise the most common indication for this technique. The chapters in this section detail the current indications and techniques of ablation for hepatic metastasis and hepatocellular carcinoma. The authors provide scientifically derived results supporting the use of RFA but refreshingly point out the shortcomings of the procedure and the limited nature of the data serving as a foundation for its increased use in today's oncology care. Chapters are devoted to combined modality RFA with interarterial chemotherapy and the decision-making process regarding the use of resection versus RFA in the treatment of hepatic malignancy. The technique of laparoscopic RFA for hepatic tumors is also addressed. Finally, this section is completed by a thorough review of the complications associated with the technique and the lessons learned to safely apply this treatment device for liver tumors. The third section provides single chapter, state-of-the-art reviews on the use for RFA to solid tumors at various sites including breast, bone, kidney, lung, and thyroid. All of these chapters provide a concise and fair evaluation of the technique in the various settings described. The last section is dedicated to the role of imaging for appropriate application and follow-up of the technique. The book is well organized and easy to read. My only minor criticism is that the principles and technique of RFA, which are well outlined in the first chapter of the book, are frequently repeated in various chapters throughout the text. The book is peppered with wonderful, high-quality illustrations and photographs that complement the text well. Although the textbook does not replace the need for hands-on training and experience, it is a welcomed and necessary addition to the literature that provides a genuine summation of the art and science of this rapidly adopted and fashionable treatment modality.

Radiofrequency Ablation of Liver Tumors: A New Cause of Benign Portal Venous Gas

To retrospectively describe and categorize the presence of portal venous gas (PVG) from radiofrequency (RF) ablation of hepatic tumors. The study was HIPAA compliant, and informed consent was waived. Thirty-four consecutive computed tomography (CT)-guided percutaneous RF ablations of liver tumors in 26 patients (13 men, 13 women; mean age, 69 years) with five hepatocellular carcinomas and 21 metastatic liver tumors (13 colon, five other, and three unknown primary tumors) were performed with an institutional review board-approved protocol. Two treatment modalities were used: RF ablation alone (13 procedures) and combined RF ablation and ethanol injection (21 procedures). Presence of PVG was quantified with three parameters: maximum length of a portal venous branch with gas, number of Couinaud segments in which PVG was seen, and total number of portal venous branch points with gas. Then an overall PVG score from 0 to 5 was determined. Also, when tumoral gas was seen on CT scans, the largest cross-sectional area of gas was measured. The two ablation methods were compared for quantities of PVG and tumoral gas. The role of N(2)O anesthetic in PVG and tumoral gas formation during ablation also was studied. Statistical analyses were performed with Wilcoxon rank sum and Student t tests. In 25 procedures (74%), gas was found in portal vein branches; in 30 procedures (88%), gas was also found in tumoral and peritumoral tissues. There was no significant difference in frequency of PVG between the ablation methods. Combined therapy yielded significantly greater lengths of PVG (P < .002) and more portal venous branch points (P < .001) than did RF ablation alone. Mean PVG score was 2.4 +/- 0.4 (standard error of the mean) for combined therapy and 0.9 +/- 0.2 for RF ablation alone (P < .004). N(2)O anesthetic was associated with greater amounts of tumoral gas (P < .008) and PVG (P < .03). Tumoral gas, peritumoral gas, and PVG dissipated within 20 minutes after ablation in all patients. No morbidity or mortality was associated with PVG. RF ablation is a common yet benign cause of transient PVG, tumoral gas, and peritumoral gas. Combined RF and ethanol ablation was associated with more PVG than was RF ablation alone.

Combined Radiofrequency Ablation and Adjuvant Liposomal Chemotherapy: Effect of Chemotherapeutic Agent, Nanoparticle Size, and Circulation Time

To evaluate the effects of liposomal chemotherapeutic agent, nanoparticle size, and liposome circulation time on tissue coagulation and intratumoral drug uptake when radiofrequency (RF) ablation is combined with adjuvant intravenous liposomal chemotherapy in an animal breast tumor model. Ninety-one R3230 mammary adenocarcinoma nodules were implanted in 48 Fischer rats. First, standardized RF ablation was combined with intravenous liposomal doxorubicin, cisplatin, or 5-fluorouracil (35 tumors each). Second, three different-sized doxorubicin-containing nanoparticle preparations were combined with standardized RF ablation. Last, two doxorubicin-containing liposome preparations with different blood elimination half-lives were combined with RF ablation. Coagulation diameter and interstitial doxorubicin concentration were measured 48 hours after treatment and compared with use of statistical analysis. All combinations of RF with liposomal chemotherapy caused significantly greater tumor necrosis than RF alone (P<.05). Significantly increased necrosis was observed with intravenous liposomal RF/doxorubicin and RF/cisplatin compared with intravenous liposomal RF/5-fluorouracil (P<.01). Greater coagulation was observed with RF combined with 100-nm nanoparticles compared with 20-nm or 250-nm nanoparticles (P=.01 and P=.04, respectively). Additionally, greater intratumoral doxorubicin uptake was observed in the group treated with 20-nm nanoparticles compared with those treated with other sizes of nanoparticles (P<.05). RF plus liposomal doxorubicin produced greater coagulation and intratumoral doxorubicin uptake than RF plus 1,2-dipalmitoyl-sn-glycero-3-phosphatidic acid (P<.05). When combined with RF ablation, modification of adjuvant intravenous liposomal chemotherapy, including nanoparticle size, circulation time, and chemotherapeutic agent, can influence intratumoral drug accumulation and tissue coagulation.

Hepatocellular Carcinoma (HCC)

Purpose: Surgical approaches remain the only curative option for HCC but they are possible in only a minority of patients. The purpose of this study was to analyze the outcome of 38 patients treated with TACE at UIC. Methods: Information about all patients with HCC treated at UIC since 1998 was retrospectively collected by electronic chart review. Statistical Analysis was performed utilizing the SAS Biostatistical software. Results: A Total of 194 patients were identified. Of these, 38(19.6%) underwent at least one hepatic artery chemoembolization alone or with other interventions such as ethanol ablation (5), systemic chemotherapy (5), radiofrequency ablation (RFA) (3), or as a bridge to transplantation (2). The tumor size ranged between 2–15 cm. The stage distribution of the patients was: Stage I: 4, Stage II: 16, Stage III: 7, and Stage IV: 11. Almost half of the patients belonged to early stages (I-II) but could not receive surgical treatment due to comorbidities or logistic barriers to transplantation. The median survival for the whole cohort was 17 months, 95% confidence interval (95% CI) 12–24 months. The median survival for the TACE group was 25 months, 95% CI 10–35 months. The survival of the TACE group seems better than the historically reported 12 months for HCC but this may be due in part to selection of patients with better prognostic features for this treatment modality. Most patients did not have documentation of response, which precluded meaningful recurrence analysis. Of interest, one of the patients who underwent liver transplant following TACE was found to have no evidence of tumor in the explanted liver. This was a very atypical patient who survived from 1999 and past her transplant in 2003 maintained with multiple procedures (TACE, ethanol and RFA). Even though the possibility of a complete pathological remission of a tumor with very low aggressive potential exists, misdiagnosis cannot be excluded. One more patient treated with a combination of RFA, TACE five times followed by chemotherapy has had a survival of over 7 years. This patient had two 2cm biopsy proven tumors but could not undergo transplant due to cardiovascular disease. Conclusions: TACE with or without other local modalities appears to be a reasonable therapeutic alternative for selected patients with HCC where surgery is contraindicated.

Phase II study of a combination of radiofrequency ablation (RFA) and systemic chemotherapy for patients with colorectal liver metastases

3716 Background: More than 25% of patients (pts) with colorectal cancer (CRC) develop metastases confined to the liver (LM) without extra hepatic spread. In these pts surgery is the mainstay of tre...

Combination Radiofrequency Ablation with Intratumoral Liposomal Doxorubicin: Effect on Drug Accumulation and Coagulation in Multiple Tissues and Tumor Types in Animals

To determine whether use of radiofrequency (RF) ablation combined with intravenously (IV) administered liposomal doxorubicin, as compared with use of RF ablation or doxorubicin alone, facilitates increased tissue coagulation and interstitial drug accumulation in animal models. The institutional animal care and use committee approved this study. In experiment 1, multiple canine sarcomas were implanted in seven mildly immunosuppressed dogs and grown to a mean diameter of 4.8 cm. Tumors were assigned to three treatment groups: internally cooled RF ablation (12 minutes, 2000-mA pulsed technique) followed by IV liposomal doxorubicin (10 mg per animal) (n = 6), RF ablation alone (n = 6), and liposomal doxorubicin alone (n = 4). In experiment 2, the livers and kidneys of 10 rabbits and the thigh muscles of 10 rats were randomly assigned to one of two treatment groups: conventional RF ablation (90 degrees C +/- 2, 5 minutes) followed by IV liposomal doxorubicin (5 mg per rabbit, 1 mg per rat) or RF ablation alone (n = 5, each). Coagulation diameter and interstitial doxorubicin concentration (tissues were homogenized in acid alcohol, with doxorubicin extracted for 24 hours at 5 degrees C and quantified with fluorimetry) were measured 48 hours after treatment and compared. Multivariate analysis of variance and subsequent pairwise t tests (alpha = .05, two-tailed test) were performed. Data are means +/- standard errors of the mean. A larger diameter of tumor destruction was observed in canine sarcomas treated with RF ablation-liposomal doxorubicin (3.7 cm +/- 0.6) compared with that in tumors treated with RF ablation (2.3 cm +/- 0.1) or liposomal doxorubicin (0.0 cm +/- 0.0) alone (P < .01). A new finding was a completely necrotic red zone (1.6 cm +/- 0.7) surrounding the central RF ablation-induced white coagulation zone. Greater but nonuniform drug uptake was observed particularly in this red zone (77.0 ng/g +/- 18.2) compared with uptake in the central zone (15.1 ng/g +/- 3.2), peripheral area of untreated tumor (38.9 ng/g +/- 8.0), and tumors treated with liposomal doxorubicin alone (43.9 ng/g +/- 6.7 for all regions) (P < .01 for all individual comparisons). In experiment 2, use of combined therapy led to increased coagulation in all tissues (liver: 17.6 mm +/- 3.1, P = .03; kidney: 11.0 mm +/- 3.1, P = .03; muscle: 13.1 mm +/- 1.3, P < .01) compared with use of RF ablation alone (liver, 13.4 mm +/- 1.5; kidney, 7.9 mm +/- 0.7; muscle, 8.6 mm +/- 0.5). Combined therapy, as compared with liposomal doxorubicin therapy alone, was also associated with increased doxorubicin accumulation in liver, kidney, and muscle (1.56 microg/g +/- 0.34, 4.36 microg/g +/- 1.78, and 3.63 microg/g +/- 1.43, respectively, vs 1.00 microg/g +/- 0.18, 1.23 microg/g +/- 0.32, and 0.87 microg/g +/- 0.53, respectively) (P < or = .01 for all individual comparisons). Use of RF ablation combined with liposomal doxorubicin facilitates increased tissue coagulation and interstitial doxorubicin accumulation in multiple tissues and tumor types and may be useful for treatment of large tumors and achieving an ablative margin within the untreated tissue surrounding RF ablation-treated tumors.

Reduced Tumor Growth with Combined Radiofrequency Ablation and Radiation Therapy in a Rat Breast Tumor Model

To determine whether use of combined radiofrequency (RF) ablation and external-beam radiation therapy increases end-point survival beyond that with either RF ablation or radiation therapy alone in an animal tumor model. With a protocol approved by the institutional animal care and use committee, R3230 mammary adenocarcinoma (12.5 mm +/- 0.6 [standard deviation]) was implanted subcutaneously into 107 female Fischer 344 rats. Initially, 42 tumors were randomized into four treatment groups: (a) RF ablation (70 degrees C for 5 minutes) alone, (b) RF ablation followed by radiation therapy with a total dose of 20 Gy, (c) 20-Gy radiation alone, and (d) no treatment. Another 19 tumors were randomized to receive (e) RF ablation (70 degrees C for 5 minutes) followed by 5-Gy radiation, (f) 5-Gy radiation alone, or (g) no treatment. Animals were followed up until survival end point (either until tumor growth to 30 mm in diameter, or for 120 days if no tumor was seen in mammary fat pad or chest wall). Results were analyzed with the Kaplan-Meier method. Histopathologic analysis was performed in 15 additional tumors at survival end point and 18 other representative tumors at other specified end points. Combined RF ablation and 20-Gy radiation resulted in complete local control in nine (82%) of 11 tumors, compared with one (9%) of 11 tumors treated with RF ablation alone and one (17%) of six treated with RF ablation and 5-Gy radiation (P < .001). No local control was achieved in rats with radiation therapy alone or in controls. Median end-point survival was 12 days for controls, 20 days with RF ablation or 5-Gy radiation alone, 30 days with RF ablation plus 5-Gy radiation, 40 days with 20-Gy radiation alone, and 120 days with RF ablation plus 20-Gy radiation. Mean end-point survival was 13 days +/- 5 (standard deviation) for the control group, 34 days +/- 31 with RF ablation alone, and 43 days +/- 16 with 20-Gy radiation alone. Mean survival was significantly greater with 20-Gy radiation and RF ablation combined: 94 days +/- 34 (P < .001 compared with all other groups). Mean survival for rats that received 5-Gy radiation with RF ablation versus without was 46 days +/- 37 versus 24 days +/- 11, respectively. Combined RF ablation and external-beam radiation therapy increased animal survival compared with that with either of the treatments alone or with no treatment.

Three years experience with monopolar and bipolar radiofrequency ablation surgery in patients with permanent atrial fibrillation☆

In our population permanent atrial fibrillation (pAF) is a frequent concomitant problem in patients undergoing open heart surgery. A 3-year experience with a treatment strategy using mono- and bipolar radiofrequency (RF) ablation procedures in a heterogeneous group of patients is reported. In a prospective analysis the incidence of pAF among all patients undergoing open heart surgery in our department between February 2001 and July 2004 was evaluated. In a second step a selective group of 106 patients with pAF (primary mitral: n=63; aortic: n=24; CABG: n=16; aortic+mitral: n=3) underwent either monopolar (n=86) or bipolar (n=20) RF ablation procedures creating two encircling isolation lesions around the left and the right pulmonary veins (PVs) and a connection line between both. In addition amiodarone was given for 3 months after surgery. Regular follow-ups were performed 3, 6, 9, 12, 18, 24 and 36 months after surgery. The incidence of pAF in the total group of 4.110 patients was 3.6%. While the rate was low in cases without severe heart valve disease (1.1%), a significantly higher presence of pAF in patients scheduled for heart valve surgery (10.3%) was observed (P<0.0001). The incidence was 30-39% in patients with degenerative and rheumatic mitral valve (MV) disease, and further particularly high in the older aged compared to younger patients (4.2-8.3% at 70-99 years; P<0.001). Hospital mortality after combined open heart and RF ablation surgery was 1.9%. Whereas patients with small left atrial size (LA-diameters <56 mm; n=59) had SR in almost 90% at follow-up, LA enlargement (LA-diameter > or =56 mm; n=47) was associated with a significant risk of persisting pAF after surgery (P=0.033, 0.002 and 0.006 at 3, 6 and 9 months follow-up). The use of RF ablation procedures in combination with amiodarone therapy represents a safe and efficient option to cure pAF during open heart surgery in a selective group of patients. The preoperative LA size was of significant importance for the outcome in this investigation.

Combination radiofrequency thermal ablation and adjuvant IV liposomal doxorubicin increases tissue coagulation and intratumoural drug accumulation

There has been marked interest in minimally-invasive, image-guided radiofrequency (RF) tumour ablation (i.e. coagulating tumour using short duration heating (<15 min) by directly applying temperatures >50°C via needle electrodes) to treat focal liver, renal, breast, bone and lung tumours. In spite of advances in RF technology and improved understanding of tumour biophysiology that now enable experimental treatment of tumours up to 5 cm, investigators have been unable to achieve complete ablation in many cases, particularly at the tumour margins and adjacent to blood vessels. One strategy for overcoming these limitations has been to take advantage of complementary interactions between RF thermal ablation and chemotherapy, particularly liposomal doxorubicin preparations, to attempt more complete tumour destruction. This paper will review published laboratory investigations demonstrating that this combined treatment paradigm has the unique potential both to potentiate preferential delivery of cytotoxic agents in liposome vehicles and to maximize the completeness of ablation of a treated tumour. New confirmatory data describing increased tumour destruction with RF ablation combined with different liposome preparations, documenting increased lipid peroxidation and expanding on previously published tumour growth studies is presented. Additionally, early clinical data including a randomized, pilot clinical study on 10 patients with primary and metastatic liver tumours, in which a non-optimized combination of RF ablation and IV liposomal doxorubicin (Doxil) increased the volume of tumour destruction 25–30% compared to RF alone, will also be described in detail.

Combined Radiofrequency Ablation and Myxoma Resection Through a Port Access Approach

Myxomas are common cardiac tumors that are traditionally managed by complete excision through a median sternotomy approach with the use of cardiopulmonary bypass. We discuss a patient with left atrial myxoma and chronic atrial fibrillation who underwent surgical excision and combined irrigated radiofrequency ablation for atrial fibrillation through a Port Access approach. Minimally invasive operations constitute an expanding field for the treatment of many cardiac diseases and may be an alternative for the treatment of this pathology because of less surgical trauma and cosmetic superiority. In this case, both excision of the myxoma and radiofrequency ablation were feasible through this minimally invasive approach. The combination of direct and endoscopic views enabled both procedures to be performed safely and efficiently.