Microwave coagulation therapy (MCT) can usually be used to treat localized liver cancer less than 30 mm in diameter. In order to increase the area of tissue coagulation, we recently investigated the advantages of a water-cooled electrode, coated with Teflon. By cooling it with cold water, a larger area could be coagulated than with previous electrodes. Results of this study suggest that MCT with a water-cooled electrode may be a useful therapy for liver cancer of more than 31 mm in diameter.
In order to increase the area of tissue coagulation in liver cancer, we developed a multi-channel microwave coagulation therapy (MMCT) using numerous Teflon-coated electrodes. However, with MMCT we found that it was extremely difficult to treat tumors located deep in the liver. In this study we investigated the advantages of MMCT for cancer located deep in the liver, with a newly devised guidance needle. At first, the guidance needle under ultrasonographic guidance was used to puncture the resected livers of pigs. Numerous electrodes fixed up by spacers were then successfully inserted into the same part along the needle. We concluded that MMCT with the guidance needle was a very useful therapy for cancer located deep in the liver.
Conventionally, percutaneous microwave coagulation therapy has been performed under ultrasonical guidance using a real-time puncture transducer. Recently, development of open MR scaner and imaging technique allows interventional MRI. MR imaging can provide us with more useful intraoperative visualization in the PMCT field than is available to ultrasonical imaging. To establish MR Imaging guided-percutaneous microwave coagulation therapy, the specially designed MRI compatible percutaneous needle-electrode (percutaneous needle-electrode MRI) and the coaxial cable were used. MR images of several types of the needle-electrode MRI, inserted to the extracted pig liver, were evaluated. Then, the noises on the display in relation to microwave irradiation were studied. Desiable MR image could be got by using the percutaneous needle-electrode MRI. MR image were strongly influenced by the noises, caused by only connecting the percutaneous needle-electrode MRI to the microwave tissue coagulater with coaxial cable. A SEIWA noise shealding product protected the noises completely. With this materials the noises were also protected during microwave irradiation. Further more investigative efforts will be directed towards developing MR Imaging guided-percutaneous microwave coagulation therapy that assures us of better patient outcome in the treatment of small liver cancer.
For the image guidance in the interventional microwave surgery, ultrasonography has mainly been utilized. Recently, MR-guided thermotherapy has developed, because MRI can be used not only for image guidance, but also for temperature monitoring. It was reported that noises in MRI during microwave thermocoagulation are negligible under various magnetic fields. We started MR-guided microwave thermocoagulation therapy of liver tumors using a 0.5T GE SIGNA SP/i system. Real time MRIs were useful for image guidance during puncture. However, considerable noise interfered with MRI during microwave irradiation. Microtaze was fixed in a shielded box and a notch filter was inserted in the output line. Afterwards, the noise was reduced to a negligible level. Fluoroscopic monitoring and temperature mapping of MRI during microwave irradiation could be successfully carried out.
Tabuse reported that the microwave ablation elicited thermal damage of tissue that resulted in coagulation necrosis. While some researchers pointed out the possibility that some tumor cells remain viable in the ablated area. To clarify the sequential histologic of the microwave-irradiated tissue, we examined irradiated normal rat liver with enzyme histochemistry for acid phosphatase. The irradiated region was composed of histologically different two distinct areas : a central area adjacent to the electrode and a peripheral area. Cellular morphology and time sequence of tissue reaction in the peripheral area were consistent with coagulation necrosis. On the other hand, in the central area microwave caused tissue fixation. Because microwave fixed cells which were similar to normal cells in HE stain, enzyme histochemistry that enables us to distinguish fixed cells from viable cells may be useful to assess the effects of microwave irradiation.
We performed RFA for 718 nodules in 314 HCC patients between February 1999 and October 2000. Among them, 30 nodules in 25 patients who underwent fine needle biopsies after RFA were subjects in this study. Fine needle biopsies for targeting tumor were performed mainly from one week to one month after RFA. We investigated the specimens with hematoxylin-eosine (H-E) dyeing. Before RFA, all nodules were proven HCC by biopsies. At the early stage within one week after RFA, around 30% of the nodules didn't show necrosis from specimens with H-E dyeing and had discrepancy between CT findings and them. However, one month or more later, they would be considered to progress toward the necrosis. All nodules have had no local recurrence from any images in more than one year.
Radiofrequency ablation (RFA) therapy under interruption of the hepatic blood flow was performed on four patients with hepatocellular carcinoma and on one patient with primary malignant hepatic lymphoma. In this therapy, radiofrequency (RF) waves are delivered, while the hepatic artery is selectively blocked with gelatin sponge and the hepatic vein is selectively blocked with a balloon catheter. The RF wave generation device and electrodes used were 460kHz Leven needle electrode 26-207 (Boston scientific, Tokyo Japan), 2 mm in diameter, with 8 umbrella-shaped needles, and development widths of 20 mm and 30 mm were used. RF waves of 40W or 50W were delivered until roll off occurred or for up to 20 minutes. The patients were put under epidural anesthesia and additional local anesthesia. Efficacy judgment was made based on the postoperative dynamic CT findings. Tumors, in the range of 25 to 60 mm in diameter, could be coagulated in one session of therapy for all the patients except one. In 2 patients with hepatocellular carcinoma of 38 mm in diameter who underwent RFA with only hepatic artery interruption, dynamic CT immediately after the irradiation revealed peripheral shadow defect of the tumor. However, the portal blood flow in the tumor and the hepatic blood flow in the center of coagulation were detected. Dynamic CT at week 1 post-irradiation revealed no deep staining, indicating complete coagulation. No portal blood flow in the tumor was observed in the patients except in the aforementioned two cases. The findings that coagulation by RFA of the hepatic tumors controlled the hepatic blood flow, and the portal blood flow in particular, indicated that RFA therapy could allow strong heat coagulation of the tumor itself in addition to expansion of the coagulation area.
A curved microwave applicator was specifically developed for microwave endometrial ablation for the uterus with distorted cavity. The applicator was transcervically introduced to a uterine cavity of a surgical specimen with an intramural myoma node and adenomyosis, and 11 sites on the endometrium were coagulated by microwaves. The endometrium and neighboring myometrium 7mm in depth were degenerated at a power of 70W with a duration of 50sec. The endometrium at the cornus was found fully destroyed. Temperature increased less than three Celsius degrees on the serosal surface of the uterus at the end of microwave coagulation procedure. It is highly feasible to use the curved applicator for uteri enlarged with intramural or submucosal myomas in clinical setting.
We have examined the possibility of the percutaneous microwave coagulation therapy (PMCT) guided by CT for the lung tumors. Microwave coagulation therapy was performed for the normal lung tissues of beagles and human lung after resection of central type lung cancer in the conditions of power : 20, 40, 60W and treatment time : 1, 2, 3, 4 min at the each power. We investigated the diameter of maximum coagulation area and histopathological changes of normal lung tissue by H-E and Elastica von Gieson stain. Maximum coagulation of 22 mm was obtained in the condition of 60W, 4 min. for the normal lung of beagles and 25 mm was obtained in the condition of 40W, 3 min and 60W, 3 min for the resected normal human lung. Histopathological examination showed the coagulating changes, e. g., small picnotic nuclear, pooling of exudate in alveolar cavity, coiling of elastic fiber, abruption of vessel. In clinical case, we performed PMCT for the patient with lung metastatic tumor 2.0 cm in diameter from colon. More than 90% of tumor necrosis was observed by H. E. stain. Our results showed the utility of PMCT for the inoperable lung tumor or small peripheral lung tumor.
We performed microwave coagulation therapy (MCT) of liver on 130 patients with malignant hepatic tumor. Postoperative liver abscess was detected in seven patients, and five underwent open drainage and removal of the necrotic tissues, and their conditions were assessed. Remission was achieved in four patients who underwent open drainage and removal of the necrotic tissues of the microwave coagulation area, but one patient who developed hepatic abscess associated with hepatic hemorrhage following MCT for the deep multiple metastatic foci underwent laparotomy but ultimately died of multiple organ failure with recurrence of the hepatic hemorrhage. Large tumor size, old age, reconstruction of the biliary tract, performing MCT more than once (on the same patient), hepatic hemorrhage, and bile leakage are considered to be risk factors for post-MCT hepatic abscess.
Background : The objective of this study was evaluate the efficiency of chest tube insertion after trans-thoracic microwave coagulo-necrotic therapy for hepatic tumors. Methods : Twenty trans-thoracic microwave coagulo-necrotic therapy was performed in patients with hapatic tumors. The cases was divided into two groups ; Group I consisted of 10 patients with chest tube insertion. Group II consisted of 10 patients without chest tube insertion. Results : A comparison of pre-, intra- or post-operative data revealed that there was no significant differences in each group. A complication occured in 1 (5%) patient out of 20 cases. When a comparison was made with Group I and Group II, there was no significant differece in complication. The mean durations of hospitalization after treatment were 14.3 days in Group I and 21.1 days in Group II (p = 0.0871). Conclusions : Trans-thoracic microwave coagulo-necrotic therapy for hepatic tumors without chest tube insertion was performed safely.
The optimal treatment for hepatocellular carcinoma (HCC) is considered to be a surgical resection with curative intent. But, in the last decade, percutaneous local destructive treatments i.e. microwave coagulation therapy and radiofrequency ablation, have been developed and become widely accepted. In the present study, the outcome of our consecutive limited hepatectomies for HCC by using microwave coagulator (MTC) without vascular occulusion of injured remnant liver and desining a proper incision, since July 1994, in 42 patients was retrospectively analyzed. Our designed methods of limited hepatectomy clarified to be less invasive and have radicality. The feasibility of limited hepatectomy for HCC with MTC is demonstrated.
Results of ablation therapy was clinically evaluated for 38 hepatocellular carcinoma (HCC) patients. Their age, ICG, and tumor diameter was 68 years, 34%, 28 mm, respectively. Three-year survival rate was 77%. Ablation therapy was a good choice for poor risk patient with small sized tumor despite of remaining some problems such as liver abscess, needle tract burn and remnant viable cells due to radiator effect.
We underwent microwave coagulation therapy (MCT) for 24 patients with 31 liver cancer from Jan, 1998 to Mar, 2000 (including 23 patients with hepatocellular carcinoma and one with cholangiocellular carcinoma). The approach to the nodules were percutaneous (PMCT) in 19 patients, open surgical (OMCT) in 3 and both in two. Twenty-one nodules out of 23 were well controlled by these MCT therapies. However, two tumors by PMCT were not completely coagulated and required Lipiodol-TAE after PMCT. The OMCT effectively ablated in eight tumors out of 5 patients and no tumor recurrence was noted. There were four complications in three patients. Those included skin burn, bile leakage at the puncture site, obstructive jaundice due to bile duct stricture and infected biloma with bleeding. Infected biloma was occurred in the patient who had undergone a trisegmentectomy of the liver with the reconstruction of choledochojejunostomy for cholangiocellular carcinoma. PMCT and OMCT were the effective treatment of the patients with primary hepatic carcinoma, whose reserved liver function was poor. Attention should he taken to the patients who has a past history of biliary duct reconstruction.
Recently, microwave coagulation therapy (MCT) is performed as minimal invasive treatment for liver tumor, and many studies concerning MCT have been reported. However, the clinical study focusing on the relationship between the accurate amount of microwave irradiation and surgical stress after MCT has not been reported. In this report, we studied the relation between the amount of microwave irradiation and the postoperative results in 30 cases who had been received laparotomic MCT. The amount of irradiation was correlated with the volume of necrosis and postoperative transaminase and LDH concentration. Abscess formation was observed in two cases who had been received high amount of irradiation. However, the amount of irradiation did not correlate to the postoperative hospitalization, the average of which is 21.0 ± 1.0 days in cases which received irradiation less than 160.0 × 103 J. The amount of irradiation would be the useful factor for estimating necrotic volume and surgical stress. Although a lot of irradiation might complicate abscess, it was suggested that MCT was safely executed in appropriate and enough amount of irradiation.
We experienced a patient who underwent open MCT with the needle advanced via the middle hepatic vein for a metastatic liver tumor neighboring the paracaval portion. Open MCT was performed under hepatic inflow and outflow block to reduce the cooling effect by the blood flow. The operation was uneventfully performed, and no complications such as massive hemorrhage from middle hepatic vein, pulmonary infarction nor congestion in the drainage area of middle hepatic vein occurred. There was no evidence of local recurrence and other intrahepatic or extrahepatic metastases within 11 months after the operation. In conclusion, open MCT under hepatic inflow and outflow block is effective for tumors adjacent to a major hepatic vein. There was no complication when open MCT was performed by penetrating a major hepatic vein.
The possible use of percutaneous low output microwave tissue coagulation therapy (PLMCT) using ultra-sonography under local anesthesia for small solitary recurrent or metastatic liver cancer was studied. The subjects were 15 patients having recurrent or metastatic liver cancer with solitary liver tumor less than 4 cm in diameter. Consisting of 7 recurrent hepatocellular carcinoma and 8 metastatic liver cancers. PLMCT was performed at the output of 30 watt for 90 seconds at a time. Tumors less than 3 cm in diameter were completely coagulated by irradiation from 2 to 6 times judged by enhanced CT. No tumor recurrence was recognized in the coagulation area. Thus, the results suggested that PLMCT is a useful therapy for small solitary liver cancer especially, recurrence of hepatocellular carcinoma as a local control.
Microwave Ablation is one of the useful treatments of hepatic tumor. It has been used as an interventional device for thermoablation therapy under ultrasonographic or laparoscopic guidance. We have done clinical studies of MR-guided microwave ablation therapy of hepatic tumors since January 2000. From January through September 2000, 18 patients with liver tumors were hospitalized in the 1st Department of Surgery at Shiga University of Medical Science. There were 13 cases of metastatic hepatic tumor. All of which had previously had primary surgery. The other 5 cases were primary hepatic cancer. All patients were selected because percutaneous ethanol injection therapy (PEIT) or transcathetal arterial embolization (TAE) was ineffective, and surgical resection could not be done because of hepatic dysfunction. We had already performed MR-guided microwave ablation therapy to hepatic tumors located in every segment of the liver. However, percutaneous puncture of the tumors in the subphrenic area was not easy with the abdominal approach. In these cases, a combination of thoracoscopic and MR-guidance has been beneficial. MR compatible endoscope made us easily to puncture hepatic tumors located in every segment of the liver. MR-guided microwave ablation therapy is a feasible treatment for hepatic tumors.
We investigated the rates of the treatments and their prognoses in 450 patients with hepatocellular carcinoma (HCC), in order to determine the usefulness of percutaneous microwave coagulation therapy (PMCT) given the present situation of treatment for HCC. Rates of initial treatments were hepatectomy in 31%, percutaneous ethanol injection therapy (PEIT) in 19%, transarterial embolization (TAE) and PEIT in 16%, TAE in 14%, hepatic arterial chemotherapy (HAC) in 7%, PMCT in 7% and others in 6% of cases. The prognosis of PMCT in patients with a single tumor 3 cm in size or less was comparable to that with hepatectomy. Recurrence was found in about 59% of 387 patients who underwent radical treatment initially, and about 96% of these were intrahepatic recurrences. Rates of treatment for intrahepatic recurrence were TAE in 59%, PEIT in 33%, HAC in 31%, PMCT in 24% and hepatectomy in 4% of cases. Indications for use of PMCT were more restricted than for PEIT for reasons of safety. Therefore, the rate of use of PMCT as initial treatment was lower than that of PEIT. On the other hand, the rate of use of PMCT in treatment of recurrence was similar to that of PEIT. PMCT should be used not only as initial treatment but also in the treatment of recurrence, in which HCC is often found at a size 3 cm or less, considering the high incidence of intrahepatic recurrence of HCC as well as reliability of the therapeutic effect and low invasiveness attached to PMCT.
Percutaneous microwave coagulation therapy, one of the interdisciplinary therapies for hepatic tumors, is beginning to be established as less invasive therapy. Herein, we report on two patients with hepatic metastasis from gastric cancer who underwent percutaneous microwave coagulation therapy under interruption of the hepatic blood flow as a means of local control of the hepatic metastasis focus. Patient 1 : A 73-year-old male underwent distal gastrectomy and extended resection of the posterior hepatic region for a 10cm single hepatic metastasis focus in the posterior region of the right lobe of the liver. These operations were performed simultaneously in September 1997. Percutaneous microwave coagulation therapy under interruption of the hepatic blood flow was performed for isolated recurrence of cancer of the liver segment 4 and segment 8 in July 1998. Later, the patient had recurrence of cancer in the segment 8, and underwent hepatic arterial chemoembolization twice but the tumor continued to grow. He exhibited marked jaundice from November 1999 and died of hepatic failure in January 2000. Patient 2 : A 72-year -old male underwent total gastrectomy involving combined resection of the gallbladder, spleen, and transverse colon in June 1996. In May 1998, a 1cm metastasis focus in the liver segment 5 was detected and percutaneous microwave coagulation therapy under interruption of the hepatic blood flow was performed. In October 1999, a new metastasis focus in the liver segment 6 was resected. At present, the patient is doing well without any sign of recurrence of cancer. It was thought that the thermal coagulation area expanded by interruption of the hepatic blood flow made it possible to coagulate not only metastatic foci detected by imaging but also the metastatic foci detected by microscope. When hepatic metastasis focus develops in an isolated small area, percutaneous microwave coagulation therapy under interruption of the hepatic blood flow was considered to be a useful means for local control comparable to hepatectomy.
Nine cirrhotic patients with liver tumors underwent a gasless laparoscopic hepatic resection with a 5 cm minilaparotomy. To maintain the good visualization and working space during hepatic resections, we developed a simple retraction system. Tumors located in segment II through VI of the liver could be treated by the laparoscopic procedure. In three of the nine patients, laparoscopic microwave coagulation therapy was added for each HCC tumors that were detected by intraoperative sonography. No blood transfusion was necessary during the operations. No serious complications such as air embolism occurred. The procedure was also applicable to cirrhotic patients with some complications. The good indication of the laparoscopic procedure is for the patients with small HCCs associated with liver cirrhosis, who are not candidates for radical hepatic resection.
From April 1995 to January 2001, we treated 52 hepatocellular carcinomas (HCC) of 47 patients by laparoscopic microwave coagulation (LMC). The efficacy of LMC was evaluated by dynamic CT and 5 HCC were required for additional therapy. The other 45 HCC seemed to be coagulated sufficiently. The number of firstly treated cases with solitary HCC was 21 among 47 patients treated by LMC. In follow-up observation of these 21 cases, 4 cases developed local recurrences. In two of these four cases, HCC were located near large vessels, and local recurrences ware developed because viable portion of HCC were considered to be resisted near large vessels. Thus, HCC near large vessels is needed for careful coagulation because viable portion of HCC can be resisted near large vessels.
Thoracoscopic microwave coagulation therapy (MCT) is a new therapeutic approach for hepatocellular carcinoma (HCC) in a right subphrenic area of the liver (segments VII and VIII), which allows a minimal access to the tumor and complete tumor ablation. In this study, 19 patients with HCC in segments VII and VIII underwent thoracoscopic MCT as a less invasive therapeutic option due to their advanced liver cirrhosis and/or severe complications. Tumor sizes ranged from 15 to 50 mm in a maximum diameter and tumor differentiation was well differentiated in 3 patients, moderately or poorly in 16 patients. Patients recovered rapidly to preoperative conditions and no mortality was observed. Postoperative computed tomography (CT) showed complete tumor ablation with a cancer-free margin, which is thought to be equivalent to a limited hepatic resection. Postoperative course showed no local recurrence in all patients and no intrahepatic recurrence in 8 patients. This study suggests that thoracoscopic MCT might be a new less invasive option providing a cure for HCC in segments VII and VIII, in patients with advanced liver cirrhosis and severe complications.