G. Scott Gazelle

PURPOSE: To describe the results of an ongoing radio-frequency (RF) ablation study in patients with hepatic metastases from colorectal carcinoma. MATERIALS AND METHODS: In 117 patients, 179 metachronous colorectal carcinoma hepatic metastases (0.9-9.6 cm in diameter) were treated with RF ablation by using 17-gauge internally cooled electrodes. Computed tomographic follow-up was performed every 4-6 months. Recurrent tumors were retreated when feasible. Time to new metastases and death for each patient and time to local recurrence for individual lesions were modeled with Kaplan-Meier analysis. Modeling determined the effect of number of metastases on the time to new metastases and death and effect of tumor size on local recurrence. RESULTS: Estimated median survival was 36 months (95% CI; 28, 52 months). Estimated 1, 2, and 3-year survival rates were 93%, 69%, and 46%, respectively. Survival was not significantly related to number of metastases treated. In 77 (66%) of 117 patients, new metastases were observed at follow-up. Estimated median time until new metastases was 12 months (95% CI; 10, 18 months). Percentages of patients with no new metastases after initial treatment at 1 and 2 years were 49% and 35%, respectively. Time to new metastases was not significantly related to number of metastases. Seventy (39%) of 179 lesions developed local recurrence after treatment. Of these, 54 were observed by 6 months and 67 by 1 year. No local recurrence was observed after 18 months. Frequency and time to local recurrence were related to lesion size (P < or =.001). CONCLUSION: RF ablation is an effective method to treat hepatic metastases from colorectal carcinoma.

Tumor ablation by using radio-frequency energy has begun to receive increased attention as an effective minimally invasive approach for the treatment of patients with a variety of primary and secondary malignant neoplasms. To date, these techniques have been used to treat tumors located in the brain, musculoskeletal system, thyroid and parathyroid glands, pancreas, kidney, lung, and breast; however, liver tumor ablation has received the greatest attention and has been the subject of a large number of published reports. In this article, the authors review the technical developments and early laboratory results obtained with radio-frequency ablation techniques, describe some of the early clinical applications of these techniques, and conclude with a discussion of challenges and opportunities for the future.

PURPOSE: To assess the feasibility and safety of using cooled-tip electrodes to increase the volume of coagulation necrosis obtained or reduce the number of treatment sessions necessary with percutaneous tumor radio- frequency (RF) ablation. MATERIALS AND METHODS: Twenty-nine patients with 44 hepatic metastases (1.3-5.1 cm diameter) from colorectal (n = 22), gastric (n = 5), pancreatic (n = 1), or breast (n = 1) carcinoma were treated with RF ablation using cooled-tip, 18-gauge electrodes with 2-3 cm tip exposure. Each tumor was treated in one or two treatment sessions. RESULTS: Technical success, ablation of all visualized tumor, was achieved in 40 (91%) metastases. Findings at computed tomography (CT) and magnetic resonance (MR) imaging performed 3-6 months after treatment confirmed complete necrosis of the entire metastasis in 66%. Disease-free survival was 50% at 12 months and 33% at 18 months, with localized progression of disease in 34% of treated lesions. Overall survival was 100%, 94%, and 89% at 6, 12, and 18 months, respectively. Only one complication, self-limited hemorrhage, was seen. CONCLUSION: Use of cooled-tip electrodes was a safe and feasible adjunct for tumor RF ablation therapy that produced larger volumes of coagulation necrosis with fewer electrode insertions than is produced with other RF ablation techniques

OBJECTIVE: To examine the hypothesis that elective laparoscopic repair should be routinely performed on patients with asymptomatic or minimally symptomatic paraesophageal hernias. SUMMARY BACKGROUND DATA: The management of asymptomatic paraesophageal hernias is a controversial issue. Most surgeons believe that all paraesophageal hernias should be corrected electively on diagnosis, irrespective of symptoms, to prevent the development of complications and avoid the risk of emergency surgery. METHODS: A Markov Monte Carlo decision analytic model was developed to track a hypothetical cohort of patients with asymptomatic or minimally symptomatic paraesophageal hernia and reflect the possible clinical outcomes associated with two treatment strategies: elective laparoscopic paraesophageal hernia repair (ELHR) or watchful waiting (WW). The input variables for ELHR were estimated from a pooled analysis of 20 published studies, while those for WW and emergency surgery were derived from the 1997 HCUP-NIS database and surgical literature published from 1964 to 2000. Outcomes for the two strategies were expressed in quality-adjusted life-years (QALYs). RESULTS: Analysis of the HCUP-NIS database showed that published studies overestimate the mortality of emergency surgery (17% vs. 5.4%). The mortality rate of ELHR was 1.4%. The annual probability of developing acute symptoms requiring emergency surgery with the WW strategy was 1.1%. For patients 65 years of age, ELHR resulted in reduction of 0.13 QALYs (10.78 vs. 10.65) compared with WW. The model predicted that WW was the optimal treatment strategy in 83% of patients and ELHR in the remaining 17%. The model was sensitive only to alterations of the mortality rates of ELHR and emergency surgery. CONCLUSIONS: If ELHR is routinely recommended, it would be more beneficial than WW in fewer than one of five patients. WW is a reasonable alternative for the initial management of patients with asymptomatic or minimally symptomatic paraesophageal hernias, and even if an emergency operation is required, the burden of the procedure is not as severe as was thought in the past.