Robert H. Oishi

Ultrasound-guided radiofrequency thermal ablation of liver tumors: percutaneous, laparoscopic, and open surgical approaches

Only 10% to 20% of patients with primary and colorectal metastatic liver tumors are candidates for curative surgical resection. Even after curative treatment, tumors recur commonly in the liver. As a less invasive therapy, radiofrequency thermal ablation (RFA) of primary, metastatic, and recurrent liver tumors was performed under percutaneous, laparoscopic, or open intraoperative ultrasound guidance. The safety and local control efficacy of RFA were investigated. RFA was performed mostly in patients with unresectable hepatomas or metastatic liver tumors. Patients with large tumors, major vessel or bile duct invasion, limited extrahepatic metastases, or liver dysfunction were not excluded. An RFA system with a 15-gauge electrode-cannula with four-pronged retractable needles was used. All patients were followed for more than 8 months to assess morbidity and mortality, and to determine tumor recurrence. Sixty RFA operations were performed in 46 patients: 11 patients underwent repeat RFA once or twice. A total of 204 tumors were treated: 70 hepatomas and 134 metastatic tumors. Tumor size ranged from 5 mm to 180 mm (mean 36 mm). RFA was performed in 29 operations for 81 tumors percutaneously, in seven operations for 14 tumors laparoscopically, and in 24 operations for 109 tumors by open surgery. Combined colorectal resection was carried out in five operations and combined hepatic resection was carried out in three operations. There was one death (1.7%) from liver failure, and there were three major complications (5%): one case of bile leakage and two biliary strictures due to thermal injury. There were no intra-abdominal infectious or bleeding complications. The length of hospital stay ranged from 0 to 2, 1 to 3, and 4 to 7 days for percutaneous, laparoscopic, and open surgical RFA, respectively. During a mean follow-up period of 20.5 months, local tumor recurrence at the RFA site was diagnosed in 18 (8.8%) of 204 tumors. The risk factors for local recurrence included large tumor size and major vessel invasion: recurrence rates for tumors less than 4 cm, 4 to 10 cm, and greater than 10 cm, and for those with vessel invasion were 3.3%, 14.7%) 50%) and 47.8%) respectively. Ten of 18 tumors recurring locally were retreated by RFA, and eight of them showed no further recurrence. Ultrasound-guided RFA is a relatively safe, well-tolerated, and versatile treatment option that offers excellent local control of primary and metastatic liver tumors. The appropriate use of percutaneous, laparoscopic, and open surgical RFA is beneficial in the management of patients with liver tumors in a variety of situations.

Long-term Outcome of Radiofrequency Ablation for Unresectable Liver Metastases from Colorectal Cancer: Evaluation of Prognostic Factors and Effectiveness in First- and Second-line Management

PURPOSELong-term follow-up data of radiofrequency ablation (RFA) for patients with unresectable metastatic liver tumors from colorectal cancer have rarely been reported. This study was undertaken to evaluate long-term outcome of RFA in relation to its timing opposite chemotherapy, and to identify prognostic factors associated with survival. PATIENTS AND METHODSPatients undergoing RFA from 1997 to 2003 were monitored. Data were prospectively collected and retrospectively reviewed. RESULTSRFA was performed for 100 patients in 146 procedures to ablate 507 colorectal metastatic tumors. All patients were followed up for at least 18 months or until death, up to 84 months: the median follow-up was 24.5 months. The overall median survival was 28 months, and 1-, 3-, and 5-year survival was 90.0%, 42.0%, and 30.5%, respectively. The recurrence-free median survival was 13 months. Median survival was 48 months among 55 patients (55%) who received RFA (first-line) before initiation of chemotherapy, versus 22 months among 45 patients (45%) who received RFA (second-line) for residual or progressive metastatic disease after chemotherapy. Significant factors affecting overall survival were carcinoembryonic antigen level (200 ng/mL), total tumor size (sum diameter of tumors, 100 mm), RFA approach, previous therapeutic chemotherapy by a univariate analysis, age (70 years) by a multivariate analysis, and ex-trahepatic metastasis by both analyses. DISCUSSIONRFA can contribute to encouraging long-term survival. Prognostic factors have been identified. Compared with historical survival, RFA appears to confer a survival benefit over systemic chemotherapy alone, particularly when it is offered as part of first-line therapy.

Laparoscopic ultrasonography versus operative cholangiography during laparoscopic cholecystectomy: review of the literature and a comparison with open intraoperative ultrasonography

BACKGROUND Laparoscopic ultrasonography (LUS) has been used increasingly over the last several years as a new imaging modality. To define the role of LUS during laparoscopic cholecystectomy, we evaluated LUS by prospectively comparing it with operative cholangiography (OC), by reviewing the literature on LUS, and by retrospectively comparing it with intraoperative ultrasonography performed during open cholecystectomy. STUDY DESIGN LUS and OC were compared prospectively in 100 consecutive patients during laparoscopic cholecystectomy. The success rate of examination, the time required, the accuracy in diagnosing bile duct calculi, and the delineation of biliary anatomy were evaluated. RESULTS The success rate of examination was 95% for LUS and 92% for OC. The main reason for unsatisfactory LUS was incomplete visualization of the distal common bile duct. The time required was 8.2 minutes for LUS and 15.9 minutes for OC (p<0.0001). Nine patients had bile duct calculi. LUS had one false-negative result and OC had two false-positives and one false-negative. The accuracies of LUS and OC were comparable except for a slightly better positive predictive value of LUS (100% versus 77.8%; p>0.1). In a literature review, 12 recent prospective studies comparing LUS and OC and three studies on open intraoperative ultrasonography were reviewed. Twelve studies of LUS with a total of 2,059 patients demonstrated results similar to the present study. The success rate was 88% to 100% for both tests. The time for LUS was approximately 7 minutes, about half of the time needed for OC. Overall, LUS was associated with fewer false-positive results than OC; the positive predictive value and specificity of LUS were better, while the sensitivity and negative predictive value of LUS and OC were comparable. OC detected ductal variations or anomalies more distinctly than LUS. Compared with open intraoperative ultrasonography, LUS had a slightly lower success rate and required a slightly longer time because it was technically more demanding, but the two procedures had a similar accuracy for diagnosing bile duct calculi. CONCLUSIONS Because of their different advantages and disadvantages, LUS and OC can be used in a complementary manner. There is a learning curve for LUS because of its technical difficulty. Once learned, however, LUS can be used as the primary screening procedure for bile duct calculi because of its safety, speed, and cost-effectiveness. OC can be used selectively, particularly when ductal anatomic variations or anomalies or bile duct injuries are suspected.

In vitro B-mode ultrasonographic criteria for diagnosing axillary lymph node metastasis of breast cancer.

Axillary lymph node status is an important factor for staging and treatment planning in breast cancer. Our study was performed in vitro on a node‐by‐node basis to evaluate the ability of B‐mode ultrasonographic images to distinguish metastatic from nonmetastatic nodes. Immediately prior to histologic examination, individual dissected axillary nodes were scanned in a water bath using a 10 MHz B‐mode ultrasonographic transducer. Four B‐mode features (size, circularity, border demarcation, and internal echo) were evaluated for their ability to distinguish metastatic from nonmetastatic lymph nodes. Lymph node metastasis was indicated by (1) a large size (i.e., a length of the longest axis of 10 mm or greater); (2) a circular shape (i.e., the ratio of the shortest axis to the longest axis between 0.5 and 1.0); (3) a sharply demarcated border compared with surrounding fatty tissue; and (4) a hypoechoic internal echo, with obliteration of the fatty hilum. The sensitivity and specificity were compared for all combinations of features. We examined 84 histologically characterized axillary nodes from 27 breast cancer patients, including 64 nonmetastatic and 20 metastatic nodes. Of the criteria cited, circular shape was the best single feature for distinguishing metastatic from nonmetastatic nodes (sensitivity, 65%; specificity, 73%). The best combination of sensitivity (85%) and specificity (73%) was obtained using the criterion that a lymph node contained cancer when at least three positive features were present. The present in vitro study demonstrated that the sensitivity and specificity of B‐mode ultrasonography for diagnosing lymph node metastasis were lower than 90%. Therefore, B‐mode ultrasonography may not be an optimal noninvasive screening method for diagnosing axillary lymph node metastasis in breast cancer patients, particularly under in vivo clinical conditions.

In vitro diagnosis of axillary lymph node metastases in breast cancer by spectrum analysis of radio frequency echo signals

Axillary lymph node status is of particular importance for staging and managing breast cancer. Currently, axillary lymph node dissection is performed routinely in cases of invasive breast cancer because of the lack of accurate noninvasive methods for diagnosing lymph node metastasis. We investigated the diagnostic ability of ultrasonic tissue characterization based on spectrum analysis of backscattered echo signals to detect axillary lymph node metastasis in breast cancer in vitro compared with in vitro B-mode imaging. Immediately after surgery, individual lymph nodes were isolated from axillary tissue. Each lymph node was scanned in a water bath using a 10-MHz instrument, and radio frequency data and B-mode images were acquired. Spectral parameter values were calculated, and discriminant analysis was performed to classify metastatic and nonmetastatic lymph nodes. Forty histologically characterized axillary lymph nodes were enrolled in this study, including 25 nonmetastatic and 15 metastatic lymph nodes. A significant difference existed in the spectral parameter values (slope and intercept) for metastatic and nonmetastatic lymph nodes. Spectral parameter-based discriminant function classification of metastatic vs. nonmetastatic lymph nodes provided a sensitivity of 93.3%, specificity of 92.0%, and overall accuracy of 92.5%. In comparison, B-mode ultrasound images of in vitro lymph nodes provided a sensitivity of 73.3%, specificity of 84.0%, and overall accuracy of 80.0%. Receiver operating characteristic (ROC) analysis comparing the efficacy of both methods gave an ROC curve area of 0.9888 for spectral methods, which was greater than the area of 0.8980 for B-mode ultrasound. Hence, this in vitro study suggests that the diagnostic ability of spectrum analysis may prove to be markedly superior to that of B-mode ultrasound in detecting axillary lymph node metastasis in breast cancer. Because of these encouraging results, we intend to conduct an investigation of the ability of spectral methods to classify metastatic axillary lymph nodes in vivo.

Hand-assisted laparoscopic ultrasound-guided radiofrequency thermal ablation of liver tumors: a technical report.

Ultrasound-guided radiofrequency thermal ablation has been performed for liver tumors by percutaneous, laparoscopic, or open surgical approaches. Each approach has specific advantages and disadvantages. Herein we describe a new technique for hand-assisted laparoscopic ultrasound-guided radiofrequency thermal ablation of liver tumors. A hand-access device is placed at the right or central portion of the abdomen, in addition to standard trocars. A conventional intraoperative ultrasound probe, with an ultrasound guidance system attached, is inserted into the peritoneal cavity together with the surgeons hand. After pneumoperitoneum is established, an electrode-cannula for thermal ablation is introduced subcostally or intercostally, and advanced into a liver tumor under direct guidance by intraoperative ultrasound. We have used this technique in eight patients with unresectable liver tumors. Precise guidance of the cannula into tumors was possible. All tumors were well ablated. The postoperative recovery of patients was of shorter duration compared with that of an open surgical approach. A hand-assisted laparoscopic ultrasound-guided method has advantages of both laparoscopic and open surgical approaches for radiofrequency thermal ablation treatment of liver tumors. Accurate cannula insertion is possible with the ultrasound guidance system. The hand-assisted laparoscopic approach can become an additional useful technique, particularly as a valuable alternative to an open surgical method, for performing radiofrequency thermal ablation.

Sonographically guided radio frequency thermal ablation for unresectable recurrent tumors in the retroperitoneum and the pelvis.

Objective. To evaluate the feasibility of sonographically guided radio frequency thermal ablation as a minimally invasive method for treatment of unresectable recurrent or metastatic tumors in the retroperitoneum and the pelvis, which often pose difficult surgical problems. Methods. Radio frequency thermal ablation was performed on 7 patients with unresectable recurrent retroperitoneal or pelvic tumors from colorectal (n = 4), renal (n = 2), and prostate (n = 1) cancers. Under sonographic guidance, a total of 11 radio frequency thermal ablation operations were performed by a percutaneous or transanal approach. Results. Three patients were asymptomatic, whereas 4 patients were symptomatic. The sizes of the tumors ranged from 29 to 100 mm (mean, 50.5 mm). Radio frequency thermal ablation was technically completed in all operations without intraoperative complications. The ablation time ranged from 25 to 238 minutes depending on the tumor size. There was no mortality. There were postoperative complications in 3 operations (27.3%): an enterovesical fistula, a skin burn, and fecal incontinence. The hospital stay was generally 0 to 1 day. Tumor marker levels decreased after radio frequency thermal ablation in all operations. Symptoms of 4 patients were controlled by radio frequency thermal ablation. One patient with recurrent renal cancer and uncontrollable hypercalcemia became asymptomatic immediately after radio frequency thermal ablation. Local recurrence at the radio frequency thermal ablation site occurred in 2 patients (28.6%), but these local recurrent tumors were treated effectively by additional sonographically guided radio frequency thermal ablation. Conclusions. Minimally invasive sonographically guided radio frequency thermal ablation is technically feasible for local treatment of unresectable recurrent retroperitoneal and pelvic tumors from different origins. Care should be taken to avoid thermal injury to surrounding organs. Further study is needed to evaluate its safety and efficacy.