Journal Review for July

Recent journal articles dealing with tumor ablation therapy compare the effectiveness of different ablation methods, evaluate side effects and other dangers inherent in the procedure, look at the uses of the procedure in treating bone, liver, and kidney tumors, and more. Following is a roundup of the news.

Comparative studies

Outcome of regional and local ablative therapies for hepatocellular carcinoma: a collective review

Eur J Surg Oncol

2005 May;31(4):331-347
A Netherlands-based team reviewed the literature to evaluate the effectiveness of five tumor ablation techniques in treating HCC: transcatheter arterial (chemo) embolization (TACE), cryoablation (CA), percutaneous ethanol injection (PEI), radiofrequency ablation (RFA), and interstitial laser coagulation (ILC). The researchers found that complete tumor necrosis could be achieved in 60% to 100% of patients. For those treated with PEI, complete tumor necrosis occurred in 70% to 100% of patients, with cryoablation, 60% to 85%, with RFA, 80% to 90%, and with ILC, 70% to 97%. With TACE, significant tumor response was achieved in 17% to 61.9%, but complete tumor response was rare (zero to 4.8%) RFA was associated with fewer treatment sessions and a higher complete necrosis rate. All techniques had low morbidity and mortality, but cryoablation seemed to produce a higher morbidity rate.

Liver

Percutaneous radiofrequency ablation of hepatocellular carcinoma as a bridge to liver transplantation

Hepatology

2005 May;41(5):1130-1137
A UCLA study examined the use of RFA to keep patients eligible for orthotopic liver transplantation (OLT) as treatment for hepatocellular carcinoma (HCC). They studied the outcomes of 52 consecutive patients with 87 HCC nodules accepted for OLT and treated with percutaneous RFA. After a mean of 12.7 months (range, 0.3 to 43.5 months) on the waiting list, 41 patients had undergone transplantation, with one- and three-year post-OLT survival rates of 85% and 76%, respectively. The researchers found percutaneous RFA an effective bridge to OLT for patients with compensated liver function and safely accessible tumors. Tumor-related dropout rate and post-OLT outcome compared favorably with published controls of patients with early-stage disease.

Significant long-term survival after radiofrequency ablation of unresectable hepatocellular carcinoma in patients with cirrhosisAnn Surg Oncol 2005 June 21; [E-pub ahead of print]
Researchers at M.D. Andersen Cancer Center evaluated the use of RFA to treat patients with unresectable hepatocellular carcinoma (HCC) whose disease was confined to the liver. A total of 194 patients with a median age of 66 years underwent RFA of 289 sonographically detectable HCC tumors. All patients were followed up for at least 12 months. The median diameter of tumors treated with RFA was 3.3 cm. Disease recurred in 103 (53%) of the patients, including 69 (49%) of 140 patients treated percutaneously and 34 (63%) of 54 treated with open RFA (not significant). Local recurrence developed in nine patients (4.6%). Most recurrence was intrahepatic. The overall complication rate was 12%. Overall survival rates at one, three, and five years for all 194 patients were 84.5%, 68.1%, and 55.4%, respectively. The authors of the study concluded that treatment with RFA can produce significant long-term survival rates for cirrhotic patients with early-stage, unresectable HCC, and randomized trials are warranted.

Bone

Combination treatment of vertebral metastases using image-guided percutaneous radiofrequency ablation and vertebroplasty: a case report

Surg Neurol

2005 May;63(5):469-474; discussion 474-475
A Northwestern University study describes a case of vertebral metastases treated with a combination of percutaneous radiofrequency ablation (RFA) and vertebroplasty in a single session. Both procedures were performed without complications, and the patient was discharged the same day without complaints. The study concludes that these minimally invasive procedures can be used in combination to treat spinal metastases. Pain relief is often immediate. RFA can also minimize procedure-related complications during the vertebroplasty. In properly selected patients, it may increase the duration of local spinal stabilization afforded by vertebroplasty alone. Long-term studies are needed to assess the efficacy and durability of this unique approach.

Percutaneous radiofrequency treatment of osteoid osteoma using cool-tip electrodesEur J Radiol 2005 June 15; [E-pub ahead of print]
A Spanish study reports on the use of percutaneous cool-tip radiofrequency ablation of osteoid osteomas and evaluates clinical outcome. Of 38 patients treated by CT-guided percutaneous radiofrequency ablation, primary success was obtained in 37 (97%), with a 100% secondary success rate. All patients are currently pain-free. No major complications occurred, and patients could resume unrestricted normal activity within 24 hours. The researchers recommend that percutaneous RFA of osteoid osteomas be considered the procedure of choice for most cases.

Radiofrequency thermal ablation of non spinal osteoid osteoma: remarks on methodRadiol Med (Torino) 2005 May-June;109(5-6):555-562.
An Italian study assessed 117 patients affected by osteoid osteoma, treated by radiofrequency thermal ablation between June 2001 and November 2003. The article describes the patient recruitment procedure, CT-guided technique, percutaneous approach, thermal ablation, and the instruments used. Data were analyzed thoroughly, and modifications that have improved the effects of treatment are highlighted. The results achieved since the method was perfected have been encouraging, confirming that the technique is highly effective if performed correctly. RFA has become the treatment of choice for nonspinal osteoid osteoma at Rizzoli Orthopaedic Institute.

Kidney

Radiofrequency ablation of renal cell carcinoma: Part 1, indications, results, and role in patient management over a 6-year period and ablation of 100 tumors

AJR

2005;185:64-71
A Boston-based team reviewed its experience treating 100 renal tumors in 85 patients over a six-year period. All 52 small (3-cm) and all 68 exophytic tumors underwent complete necrosis regardless of size, although many large tumors (>3 cm) required a second ablation session. The researchers found that both small size (p

Radiofrequency ablation of renal cell carcinoma: Part 2, lessons learned with ablation of 100 tumors

AJR

2005;185:72-80
The Boston team reviewed radiofrequency ablation of 100 renal tumors and lessons learned with respect to electrode approach, effects on collecting system, bowel proximity, and patterns of residual disease. They found that initial electrode position at and parallel to the tumor-kidney interface did not result in less difficult or more successful ablations. Contiguity of tumor or zone of ablation to the collecting system did not increase the risk of complications, but obscuration of calyces did. Bowel complications were rare, and protection with hydrodissection is becoming more common. Residual tumor presents as nodules or crescents of persistent enhancement.

Percutaneous transthoracic radiofrequency ablation of renal tumors using an iatrogenic pneumothorax

AJR

2005; 185:86-88
A team from M. D. Anderson Cancer Center reports on a new technique for percutaneous radiofrequency ablation of tumors in the upper pole of kidneys in the presence of intervening lung parenchyma, using a transthoracic approach through an iatrogenic pneumothorax. This technique allows for precise placement and repositioning of the radiofrequency electrode under CT guidance without repeated puncture of the visceral pleura.

Complications and side effects

Percutaneous radiofrequency ablation of hepatic tumors: postablation syndrome

AJR

2005;185:51-57
A Texas study defines the spectrum and possible predictors of symptoms that occur in patients after percutaneous radiofrequency ablation of hepatic tumors. They performed 50 consecutive percutaneous radiofrequency ablation sessions on 39 patients with a total of 89 liver tumors. Approximately one-third of patients who underwent percutaneous radiofrequency ablation of hepatic tumors developed delayed, transient, flulike symptoms that could be treated conservatively and were significantly related to the volume of tissue ablated.

Liver abscess after percutaneous radiofrequency ablation for hepatocellular carcinomas: frequency and risk factors

AJR

2005;184:1860-1867
A Korean study attempted to clarify the frequency and risk factors of liver abscess formation after percutaneous radiofrequency ablation in patients with hepatocellular carcinoma. The study involved 603 patients with 831 hepatocellular carcinomas measuring 5 cm or less in maximum diameter, who underwent a total of 751 percutaneous radiofrequency ablation procedures. The investigators discovered that liver abscess formation was infrequent, but risk factors existed that could predict the development of abscesses: preexisting biliary abnormality prone to ascending biliary infection, tumor with retention of iodized oil, and treatment with an internally cooled electrode system. No patient died of liver abscess, and all successfully recovered with parenteral antibiotics and percutaneous clearance of pus.

New methods

Sonography-guided percutaneous microwave ablation of high-grade dysplastic nodules in cirrhotic liver

AJR

2005;184:1657-1660
A Chinese team evaluated the effect of sonographically guided percutaneous microwave ablation of high-grade dysplastic nodules in the cirrhotic liver. They used microwave ablation to treat 49 histologically proven high-grade dysplastic nodules in 30 patients with liver cirrhosis. The mean size of the nodules was 1.8 cm (range, 0.9 to 4.6 cm). Sixty-eight insertions with 78 applications were administered to the 49 nodules. Over the follow-up period of 12 to 82 months, all nodules showed decreased density on unenhanced CT. Post-treatment biopsy performed in 16 patients with 18 nodules one to three months after microwave ablation showed no evidence of viable tissue but replacement by fibrotic tissue in all nodules. The researchers recommend further randomized trials.

High-intensity focused ultrasound ablation: Will image-guided therapy replace conventional surgery?

Radiology

2005;235:345-346
A Thomas Jefferson University Hospital radiologist profiles high-intensity focused ultrasound ablation, which offers a noninvasive treatment method with no skin incision. The method enables practitioners to target high-intensity focused ultrasound to specific tissue, causing the temperature of the targeted tissue to rise. Unlike other thermal ablation techniques, little heating of adjacent tissues occurs. Focused ultrasound therapy may be used alone or in combination with other therapies for cancer.