Radiofrequency ablation of unresectable primary and metastatic hepatic malignancies: results in 123 patients

OBJECTIVE

To describe the safety and efficacy of radiofrequency ablation (RFA) to treat unresectable malignant hepatic tumors in 123 patients.

BACKGROUND

The majority of patients with primary or metastatic malignancies confined to the liver are not candidates for resection because of tumor size, location, or multifocality or inadequate functional hepatic reserve. Local application of heat is tumoricidal; therefore, the authors investigated a novel RFA system to treat patients with unresectable hepatic cancer.

PATIENTS AND METHODS

Patients with hepatic malignancies were entered into a prospective, nonrandomized trial. The liver tumors were treated percutaneously or during surgery under ultrasound guidance using a novel LeVeen monopolar array needle electrode and an RF 2000 generator. All patients were followed to assess complications, treatment response, and recurrence of malignant disease.

RESULTS

RFA was used to treat 169 tumors (median diameter 3.4 cm, range 0.5 to 12 cm) in 123 patients. Primary liver cancer was treated in 48 patients (39.1%), and metastatic liver tumors were treated in 75 patients (60.9%). Percutaneous and intraoperative RFA was performed in 31 patients (35.2%) and 92 patients (74.8%), respectively. There were no treatment-related deaths, and the complication rate after RFA was 2.4%. All treated tumors were completely necrotic on imaging studies after completion of RFA treatments. With a median follow-up of 15 months, tumor has recurred in 3 of 169 treated lesions (1.8%), but metastatic disease has developed at other sites in 34 patients (27.6%).

CONCLUSIONS

RFA is a safe, well-tolerated, and effective treatment to achieve tumor destruction in patients with unresectable hepatic malignancies. Because patients are at risk for the development of new metastatic disease after RFA, multimodality treatment approaches that include RFA should be investigated.

Hepatocellular carcinoma: US-guided percutaneous microwave coagulation therapy

PURPOSE

To evaluate the use of percutaneous microwave coagulation therapy for hepatocellular carcinoma, particularly with tumor nodules larger than 2 cm in diameter.

MATERIALS AND METHODS

Fifty patients with 107 hepatocellular carcinoma nodules (mean diameter, 2.7 cm +/- 1.5 [SD]; range, 0.8-6.4 cm) were treated with percutaneous microwave coagulation therapy. Single electrode insertion was used in 46 nodules (43.0%) 2 cm or smaller, whereas multiple electrode insertion was applied in 61 (57.0%) nodules larger than 2 cm.

RESULTS

At 1 month after therapy, technical success for tumors 2 cm or smaller and those larger than 2 cm was achieved in 45 (98%) and 56 (92%) nodules, respectively. After follow-up of 9 months or longer, local recurrence was found in one nodule (2%) sized 1.8 cm and in five nodules (8%) larger than 2 cm. At the end of the study, 26 (52%) of 50 patients were free of disease, and disease-free survival rates at 1 and 2 years were 55% and 41%, respectively. Overall survival rates at 1, 2, and 3 years were 96%, 83%, and 73%, respectively.

CONCLUSION

Percutaneous microwave coagulation therapy is an effective and safe therapeutic modality for hepatocellular carcinoma. A multiple electrode insertion technique can enhance the effectiveness of this therapy in tumors 6 cm or smaller.

Microwave Ablation: Results with a 2.45-GHz Applicator in ex Vivo Bovine and in Vivo Porcine Liver

PURPOSE

To characterize the relationship between applied power and treatment duration in their effect on extent of coagulation produced with a 2.45-GHz microwave applicator in both an ex vivo and a perfused in vivo liver model.

MATERIALS AND METHODS

All experimentation was approved by the Institute of Animal Care and Use Committee. Multiple tissue ablations were performed in ex vivo bovine liver (120 ablations) and in vivo porcine liver (45 ablations) with a 5.7-mm-diameter 2.45-GHz microwave applicator. The applied power was varied from 50 to 150 W (in 25-W increments ex vivo and 50-W increments in vivo), while treatment duration varied from 2 to 20 minutes (in eight time increments for ex vivo and five for in vivo liver). Three-dimensional contour maps of the resultant short- and long-axis coagulation diameters were constructed to identify the optimal parameters to achieve maximum coagulation in both ex vivo and in vivo models. Multivariate analysis was performed to characterize the relationship between applied power and treatment duration.

RESULTS

Power and treatment duration were both associated with coagulation diameter in a sigmoidal fashion (ex vivo, R(2) = 0.78; in vivo, R(2) = 0.74). For ex vivo liver, the maximum short-axis coagulation diameter (7.6 cm +/- 0.2 [standard deviation] by 12.3 cm +/- 0.8) was achieved at greatest power (150 W) and duration (20 minutes). In vivo studies revealed a sigmoidal relationship between duration and coagulation size, with a relative plateau in coagulation size achieved within 8 minutes duration at all power levels. After 8 minutes of treatment at 150 W, the mean short-axis coagulation diameter for in vivo liver was 5.7 cm +/- 0.2 by 6.5 cm +/- 1.7, which was significantly larger than the corresponding result for ex vivo liver (P < .05).

CONCLUSION

Large zones of ablation can be achieved with the 2.45-GHz microwave applicator used by the authors. For higher-power ablations, larger zones of coagulation were achieved for in vivo liver than for ex vivo liver with short energy applications, a finding previously not seen with other ablation devices, to the authors' knowledge.

Image-guided radiofrequency ablation of spinal tumors: preliminary experience with an expandable array electrode

PURPOSE

Metastases to the spine are a challenging problem. Percutaneous, image-guided tumor ablation with a thermal energy source, such as radiofrequency, has received increasing attention as a promising technique for the treatment of focal malignant disease. We used radiofrequency ablation for patients with unresectable, osteolytic spine metastases under computed tomographic and fluoroscopic guidance. The purpose of this study was to determine the feasibility, effectiveness, and safety of radiofrequency ablation as a palliative procedure to reduce pain and back pain-related disability in patients with vertebral and paravertebral spine tumors who were not able to benefit from radiotherapy, chemotherapy, or surgery.

PATIENTS AND METHODS

Between November 1999 and January 2001, 10 patients with unresectable spine metastases were treated with radiofrequency ablation. For the ablation we used a 50-W radiofrequency generator that is connected to an expandable electrode catheter (RITA Medical System Inc., Mountain View, CA). The mean patient age was 64.4 years. Metastases were ablated in the thoracic spine, the lumbar spine, and/or the sacral bone. Tumor diameter ranged from 1.5 to 9 cm. Combined computed tomographic and fluoroscopic guidance was used to guide the procedure. Operations were carried out without heavy sedation with the patient under local anesthesia only. The thermal lesion was produced by applying temperatures of 50 degrees to 120 degrees C for 8-12 minutes. Vertebroplasty was performed in four patients by use of 3 to 5.5 mL of polymethyl methacrylate. Therapy outcome was documented by magnet resonance imaging. Before the therapy and on follow-up of an average of 5.8 months, pain was assessed with the help of the Visual Analogue Scale. Back pain-related disability was measured with the Hannover Functional Ability Questionnaire. Neurologic and health status were documented on the Frankel score and the Karnofsky index.

RESULTS

At follow-up, 9 of 10 patients reported reduced pain (Visual Analogue Scale). In patients who experienced pain relief, there was an average relative pain reduction of 74.4%. Back pain-related disability was reduced by an average of 27%. Neurologic function was preserved in nine patients and improved in one. General health was stabilized in six patients, slightly increased (by 10%-20%) in two patients, significantly enhanced (by 50%) in one patient, and slightly reduced in one patient. No complications were reported. In the treated region, magnetic resonance imaging showed no further tumor growth after the therapy.

DISCUSSION

Radiofrequency ablation was successfully performed in all 10 patients. Needles were placed accurately under image guidance, and a controlled lesion was created. Pain- and back pain-related disability was clearly reduced, and neurologic function was preserved or stabilized. When confirmed by further investigation, this therapy may be a new option for patients with unresectable spine tumors that do not respond to radiotherapy and chemotherapy.

Transurethral microwave thermotherapy for management of benign prostatic hyperplasia: results of the United States Prostatron Cooperative Study

The primary objective of the study was to determine the safety and efficacy of transurethral microwave thermotherapy for the treatment of symptomatic benign prostatic hyperplasia. From March to August 1991, 150 patients were entered into a multi-site study and treated with transurethral microwave thermotherapy under a Food and Drug Administration approved protocol. Only patients with symmetrical trilobar or bilobar prostatic hypertrophy, peak flow rate of less than 15 cc per second (on 2 voided volumes of 150 cc or greater) and a total Madsen symptom score of more than 8 were treated. Transurethral microwave thermotherapy was performed with a 20F catheter and 1,296 MHz. microwave antenna for 60 minutes. The mean power achieved for this single session was 32.1 watts, with a mean power at maximum urethral temperature of 41.1 watts. Mean urethral temperature was 44.3C and the mean rectal temperature was 42.2C. The rectal and urethral temperatures were continuously monitored. Mean peak urinary flow rates, Madsen symptom score, post-void residual volume and improvement in motivating symptom to seek treatment were measured at 6 weeks, and 3, 6 and 12 months. Mean peak urinary flow rates improved 33% at 12 months (p < 0.0001). Overall, the mean Madsen symptom score improved 61% (p < 0.0001). The obstructive score and the irritative score improved 67% and 43%, respectively. Of 17 patients 12 (71%) reported improvement in weak stream when that was the motivating symptom to seek treatment. Of 28 men 18 (64%) reported improvement in nocturia, while 11 of 30 (37%) reported improvement in daytime frequency and 12 of 17 (71%) reported improvement in urgency. There was no statistically significant difference in post-void residual volume at 12 months from baseline. The treatment was well tolerated by all patients, and side effects were considered mild and transitory. Our study demonstrates the safety, effectiveness, patient tolerability and durability of transurethral microwave thermotherapy.

Clinical trial of a laser device called fractional photothermolysis system for acne scars

Ablative laser resurfacing is an effective treatment for acne scars. However, edema and prolonged erythema are common. Additionally, scarring and hyperpigmentation are often induced. A new concept of laser called fractional photothermolysis has been designed to create microscopic thermal wounds to achieve skin rejuvenation without significant side-effects. We treated 10 patients with acne scars using this laser system (Reliant Fraxel SR Laser). All the patients were successfully treated with minimal adverse effects. The fractional photothermolysis system represents an optional method for the treatment of acne scars.

Radiofrequency-induced hyperthermia: computer simulation of specific absorption rate distributions using realistic anatomical models

A description is given of a computer simulation technique which predicts the specific absorption rate (SAR) distribution within the human body resulting from the application of radiofrequency electromagnetic energy. The method uses an extension to the principle of over-relaxation of electric potentials and the basis of the simulation is a realistic three-dimensional model derived from both dielectric and anatomical data. Two of the principal means of applying radiofrequency hyperthermia, namely the use of capacitive electrodes and inductive coils, have been provided for. The accuracy of the simulation has been favourably tested using an agar split-phantom and an infrared thermograph camera. The simulations can be used to assist the design and clinical use of radiofrequency applicators, and examples are given of the application of both an inductive coil and switched capacitive electrodes to heat the thorax.

"Thermal mapping" in experimental cancer treatment with hyperthermia: description and use of a semi-automatic system

The regions of tumor which are least adequately heated during experimental hyperthermia treatments will most likely determine the ultimate probability of tumor control. Temperature inhomogeneity during local or regional hyperthermia is often marked, and stationary temperature probes yield very little information about the adequacy or inadequacy of tumor heating. Fine catheters can be placed through the tumor bearing region and temperatures recorded at various points within these catheters, thus yielding valuable data about temperature variations within the volume of interest. The "thermal mapping system" (TMS) described herein provides a method for remotely sampling these temperature variations in a semi-automatic manner in several catheters simultaneously. Its application in conjunction with a commercial hyperthermia system is described and clinical examples of its use and importance are provided.

Hepatocellular carcinoma: microwave ablation with multiple straight and loop antenna clusters--pilot comparison with pathologic findings

The purpose of this study was to evaluate the clinical implementation of triangular and spherical designs for simultaneous multiple-antenna ablation of human hepatocellular carcinoma (HCC) with a recently engineered microwave coagulation system. Institutional review board approval and informed consent were obtained, and the study was compliant with HIPAA requirements. Nine patients (five men, four women; age range, 53-79 years; mean age, 66.2 years) with resectable HCC (diameter, 2.9-6.0 cm; mean, 4.2 cm) underwent intraoperative ultrasonography-guided tumor ablation followed by resection and pathologic examination. Standard single-straight (n = 2), triangular triple-straight (n = 4), and spherical triple-loop (n = 3) antenna configurations produced mean estimated coagulation volumes of 16.7, 51.7, and 54.3 cm(3), respectively, during a single concurrent 5-10-minute ablation cycle. The triple-loop configuration yielded the most uniformly round ablation shape. Simultaneous activation of multiple straight or loop antennae is a potentially promising technique for rapid and effective treatment of large HCCs.

Treatment of cellulite with a bipolar radiofrequency, infrared heat, and pulsatile suction device: a pilot study

BACKGROUND

Very few therapeutic options have proven effective in the treatment of cellulite.

AIMS

To evaluate the effectiveness and adverse effects of a bipolar radiofrequency (RF), infrared (IR) heat and pulsatile suction device for the treatment of cellulite.

METHODS

Twelve subjects were treated with the RF-light-based device. All subjects were treated twice weekly for a total number of eight to nine treatments. Subjects were evaluated using standardized photographs, and measurements of body weight and circumference of treatment sites at baseline, immediately after the last treatment, and four weeks and one year after the last treatment. Clinical improvement scores of comparable photographs using a quartile grading scale (0 = <25%, 1 = 25-50%, 2 = 51-75%, 3 = >75% improvement) were judged independently by two non-treating dermatologists after the series of treatment.

RESULTS

The average body weights at baseline, immediately after the last treatment, and four weeks and one year after the complete treatment were 56.30, 56.05, 56.23, and 56.53 kg, respectively. The average circumferential reductions of the abdomen and thigh at the last treatment visit were 5.17 +/- 1.04 cm (6.32%+/- 1.82%) and 3.50 +/- 2.16 cm (6.23 +/- 3.58%), respectively. At four weeks after the last treatment, the average circumferential reductions of the abdomen and thigh were sustained at 3.17 +/- 2.75 cm (4.04%+/- 3.69%) and 3.50 +/- 2.04 cm (6.26%+/- 3.52%), respectively. At one year follow-up visit, the average circumferential reductions of the abdomen and thigh were maintained at 3.83 +/- 0.76 cm (4.64%+/- 1.15%) and 3.13 +/- 3.54 (5.50%+/- 6.12%), respectively. Average clinical improvement scores of the abdomen and thigh after the series of treatments were 0.75 (corresponding to approximately 25% improvement), and 1.75 (corresponding to approximately 50% improvement), respectively.

CONCLUSIONS

A bipolar RF, IR heat and pulsatile suction device provides a beneficial effect on reduction of abdomen and thigh circumference, and smoothening of the cellulite.

Use of a computer-controlled bipolar diathermy system in radical prostatectomies and other open urological surgery

BACKGROUND

Ligasure is a computer-controlled bipolar diathermy system, designed to optimally seal vessels < or = 7 mm in diameter. The aim of the present study was to evaluate its application to open urological surgery.

METHODS

The Ligasure device was used in 32 consecutive open surgical cases, including 25 radical prostatectomies, five radical nephrectomies, one partial nephrectomy and one nephro-ureterectomy. All procedures were performed using standard surgical techniques, with the exception that the Ligasure device was used for haemostasis. This included pelvic lymphatics and prostatic, adrenal, gonadal and aberrant obturator vessels, as well as vessels associated with the ureter, vasa, seminal vesicles, peri-renal fat, peritoneum and peri-adrenal tissues. Vessels > 7 mm in diameter, such as the renal artery, were ligated. In no patients were haemostatic clips used.

RESULTS

In all procedures, vessels and other structures < 7 mm were successfully sealed using the Ligasure device. For some structures, such as the prostatic pedicles and the seminal vesicles, the Ligasure device was much easier to apply than haemostatic clips. Use of the Ligasure device reduced the operating time (mean: 113 min vs 135.5 min; P < 0.001) and blood loss (mean: 529 mL vs 642 mL; P < 0.02) for radical prostatectomies. No intraoperative or postoperative blood transfusions were required. There were no postoperative haemorrhages, lymph leakage or lymphocoeles. Median inpatient hospital stay was 7 days (range: 6-9 days) and no patients required readmission.

CONCLUSION

The Ligasure, device was safe and easy to use in major urological procedures.

Bronchoscopic treatment of lung tumors

Several bronchoscopic techniques for the treatment of patients with tracheobronchial pathology have become available during the last decade. Technical development and additional instruments have provided the bronchoscopist with several alternatives for bronchoscopic therapeutic interventions. The majority of patients with malignant tracheobronchial neoplasm have a dismal prognosis. Palliation is the main aim of the treatment. However, in patients with an early-stage tumor, bronchoscopic treatment may have a curative potential. Resectability, after tumor reduction by a bronchoscopic treatment, may be improved. This article discusses various bronchoscopic techniques, the advantages and disadvantages of each method and the possible benefit which can be derived from such a treatment.

Continuous short-wave (radio-frequency) diathermy

Continuous shortwave diathermy is the technique of choice when uniform marked elevation of temperature is required in the deep tissues. This heating can be targeted accurately by using an appropriate applicator positioned correctly. SWD also allows superficial structures to be heated selectively, although for this the various methods of surface heating are usually preferable. Sub-acute or chronic conditions respond best to continuous shortwave diathermy which, when used properly, can be as effective as ultrasound. Acute lesions are better treated with pulsed shortwave diathermy. Continuous shortwave diathermy can help to relieve pain and muscle spasm, resolve inflammatory states and reduce swelling, promote vasodilation, increase the compliance of connective tissue, increase joint range and decrease joint stiffness.

An invasive microwave antenna for locally-induced hyperthermia for cancer therapy

A microwave system has been developed and characterized for delivering heat directly into tumors. This system employs a microwave power source (3-10W) operating in the 500 MHz to 1.3 GHz frequency range, coaxial transmission line, and a monopole antenna. Absorbed power was measured in saline, in tissue equivalent phantoms, and in tumors in live and dead mice. Antennas were designed to operate at 500 MHz and 1 GHz, and the critical design parameters have been identified for this system. Analytical and experimental results obtained in our laboratory suggest that this system is capable of providing controlled temperature distributions appropriate for hyperthermia in animal tumors. Theoretical results predict that 3 GHz may be an optimum choice for this system in animal tumors of approximately 1 cm diameter; the microwave antenna system provides a heat distribution superior to that obtained using a resistance heater of similar dimensions. We propose that further development of this approach may overcome some of the problems associated with other systems which use external radiation sources, and implications for clinical application of this system are discussed.

A microwave heating technique for the hyperthermic treatment of tumours in the eye, especially retinoblastoma

A special microwave stripline applicator (2450 MHz) has been designed for the hyperthermic treatment of eye tumours, especially retinoblastoma. The measured microwave absorbed power distribution was put into a thermal finite difference computer model of the human and rabbit eye to calculate the resulting temperature distributions. The temperature distributions have been experimentally verified on rabbit eyes, and satisfactory temperature distributions can be obtained. The anterior part as well as the posterior part of the eye can be heated uniformly to temperatures in the range of 37-44 degrees C. The complete hyperthermia system is described.

Interstitial temperature measurements during transurethral microwave hyperthermia

Microwave hyperthermia is presently being investigated as a treatment for alleviating the symptoms of urinary outlet obstruction associated with benign prostatic hyperplasia. Two clinical techniques using intracavitary microwave applicators are being evaluated for safety and efficacy at various institutions. The transrectal technique uses a directional microwave radiator that is inserted into the rectum adjacent to the prostate. The transurethral approach uses a symmetrically radiating applicator located within the prostatic urethra. Transrectal prostatic heating techniques require surface cooling to prevent hazardous temperatures in the intervening rectal mucosa. Since transurethral applicators radiate from within the prostatic urethra, heating is confined to the obstructive tissue immediately surrounding the applicator. Concern has been expressed regarding the possibility of thermal injury to the prostate and adjacent rectum during transurethral hyperthermia treatment. In this report we present interstitial temperature measurements of prostatic and rectal temperatures in 5 patients. Temperature was observed to decrease at a rate of about 6C/cm. outward from the applicator. No clinically significant temperature increase was observed beyond 1 cm, outside the prostatic capsule or in the rectal mucosa.

New device for endoscopic cystoenterostomy

A new device for endoscopic treatment of pancreatic pseudocysts is described. It aims to provide improved safety and ease of performance of endoscopic cystoenterostomy, even in difficult cases of massive compression of the intestinal wall with upper gastrointestinal obstruction. In this preliminary report, nine patients have been treated without complication.

Microwave thermotherapy for benign prostatic hyperplasia with the Dornier Urowave: results of a randomized, double-blind, multicenter, sham-controlled trial

OBJECTIVES

To study the efficacy and safety of a new transurethral microwave thermotherapy device (the Urowave) in the treatment of men with clinical benign prostatic hyperplasia (BPH) in a randomized, double-blind, sham-controlled trial.

METHODS

A total of 220 patients (mean age 66.2 years) with clinical BPH, an American Urological Association symptom index (AUA SI) of 13 points or more, and a peak flow rate of 12 mL/s or less were enrolled and randomized 2:1 for active versus sham treatment. All treatments were conducted as an outpatient procedure under local anesthesia, with oral sedation and analgesia only. Patients were followed up at 1 week and 1, 3, and 6 months after treatment.

RESULTS

The treatments were well tolerated, and no patient received general or spinal anesthesia. The AUA SI dropped from 23.6 to 12.7 points at 6 months (P < 0.05) in the active group and from 23.9 to 18.0 points in the sham-treated group (P < 0.05, between-group difference). Statistically significant improvements were also noted for peak flow rate (7.7 to 10.7 mL/s at 6 months for active treatment, 8.1 to 9.8 mL/s for sham treatment, P < 0.05, between-group difference) and for average flow rate. A decrease in AUA SI of more than 30% was achieved in 72% versus 38% of patients (active versus sham treatment, respectively) and more than 50% in 50% versus 19% of patients. In general, active Urowave-treated patients perceived "a lot" of improvement, whereas sham-treated patients perceived "a little" to "some" improvement. More of the actively treated patients had dysuria and urgency after treatment, and ejaculatory dysfunction (e.g., hematospermia) was more common in actively treated patients as well. Secondary urinary retention after removal of the catheter occurred in 8 patients (5.4%).

CONCLUSIONS

The Dornier Urowave transurethral microwave thermotherapy device for treatment of clinical BPH is effective in decreasing symptoms and bother and improving quality of life and flow rate and is superior to sham treatment. Patients perceive a great deal of improvement, independent of their baseline symptom severity. Adverse events are in general transient and mild in nature. Extended follow-up is necessary to document long-term durability of improvements.