Areas of residual tumors after RFA or PEI therapy are not distinguishable from necrotic tissues on US. The sonographic findings of gray-scale, color Doppler and power Doppler scanning after RFA or PEI therapy do not correlate well with the overall necrotic shape, or with the volume or extent of coagulation necrosis induced. Therefore, contrast-enhanced CT or MRI is generally necessary to assess the efficacy of the treatment. The absence of intensified areas on contrast-enhanced CT indicates the disappearance of the blood supply and, by inference, a successful treatment. Conversely, focal areas of persistent contrast enhancement usually indicate viable tumor cells, and, therefore, warrant further treatment to achieve a complete tumor necrosis. Harmonic gray-scale images can extract only the blood flow echoes created by destruction of microbubbles, whilst echoes from tissue are effectively cancelled. This mode makes it possible to clearly depict residual blood flow in tumors after therapy. Because contrast-enhanced harmonic sonography is easy to perform and provides real-time needle insertion guidance, it may be favored in monitoring response to localized therapies, obviating unnecessary CT and treatment sessions. Although contrast-enhanced CT can clearly depict residual areas of tumors after RFA or PEI therapy, it does not make possible real-time guidance in percutaneous therapies. Furthermore, the retention of lipiodol in HCC lesions sometimes makes it difficult to distinguish the hyperattenuating area of contrast enhancement from that of lipiodol when the retention of iodized oil in tumors is incomplete. Contrast-enhanced harmonic gray-scale images can reveal the tumor vascularity in patients with HCC, after transcatheter arterial embolization and percutaneous therapies, with high sensitivity and accuracy in comparison with dynamic CT. This capability of harmonic imaging for depicting residual cancer cells in HCCs after treatment facilitates a correct guidance for the insertion of a needle on US monitoring, which cannot be achieved by any other imaging modalities including CT and MRI. The noninvasive vascular technique of contrast-enhanced harmonic imaging is an extremely sensitive tool for detecting the intranodular blood flow in hepatic tumors. This method is drastically changing the diagnostic and therapeutic strategy of hepatic tumors, especially HCC, resulting in an eventual improvement in the prognosis of patients with HCC.
Temperature changes in both an agar phantom and beef liver during microwave ablation for 10 minutes were consecutively monitored by MR temperature mapping using the proton resonance frequency method. Three kinds of MR-compatible needle-type electrodes (A : normal type with 2 mm gap, B : high output type with 6 mm gap, C : ball-tip type with 2 mm gap) and 2 output powers (80W and 110W) were used. Maximum temperature increases were obtained with electrode A at 110W in an agar phantom, but with electrode B at 110W in beef liver. This difference might have been caused by the condition of the water molecules around the electrode. The area with a temperature increase of more than 30°C showed good correspondence with the coagulated liver. This technique, which did not require cutting the sample and could continuously detect the temperature increase in the same sample, should be useful for the evaluation of electrodes and for the optimization of output power and duration in microwave ablation.
In order to increase the area of tissue coagulation in liver cancer, we developed a treatment called multi-channel microwave coagulation therapy (MMCT) using numerous Teflon-coated electrodes. However, during MMCT we found that it was extremely difficult to divided the electric current equally among the numerous electrodes. Therefore, in order to solve this problem, we developed a new type of distributor. We conclude that MMCT with this new distributor is a very safe therapy for liver cancer.
In order to increase the area of tissue coagulation in liver cancer, we developed a treatment called multi-channel microwave coagulation therapy (MMCT) using numerous Teflon-coated electrodes. However, during MMCT we found that it was extremely difficult to fix spacers on numerous electrodes both correctly and firmly. To overcome this we developed new spacers that were able to be fixed on the electrodes properly.
In recent few decades, various types of medical applications of microwaves have widely been investigated and reported. The authors have been studying the thin coaxial antennas for minimally invasive microwave thermal therapy, particularly, microwave coagulation therapy (MCT). The MCT is considered to be a very effective treatment for small size tumor. However, there are some problems to be improved for conventional MCT antennas. Particularly, there is a problem that length of the coagulated region becomes long and uncontrollable in the antenna insertion direction. In this paper, we improve the structure of the antenna to generate a localized heating region only around the tip of the antenna by using computer simulation.
It is difficult to reduce blood loss during hepatectomy with cirrhosis. We are using microwave tissue coagulation during hepatic resection. From June 1999 through January 2002, 118 consecutive patients with underwent hepatectomy with microwave tissue coagulation. The change in liver function was not so big and the post operative complication rate was low. We conclude that hepatectomy with microwave tissue coagulation is useful and safe, especially the case of cirrhosis.
We now evaluated our therapeutic outcomes of open microwave coagulo-necrotic therapy (MCT) for hepatocellular carcinoma (HCC). The subjects were 23 patients for whom we underwent open MCT from November 1992 to December 2000. Postoperative three-year survival rate in Stage III cases for which open MCT was performed was 45.5%. In a comparison of the cumulative survival rates, there is no significant difference between the cases of the open MCT and hepatic resection. Local recurrence of treated area was experienced in only one case. This result suggested that open MCT is good for local ablation therapy for HCC. However, we actually experienced the lethal complications such as hepatic failure and pyothorax. We must be careful for extending the indication of open MCT.
23 patients with solitary HCC were firstly treated by laparoscopic microwave coagulation (LMC) and 39 were initially treated by percutaneous ethanol injection (PEI). For these 63 cases, we analyzed the survival rates and compared the rates between LMC group and PEI group. Of these patients, the longest diameters of HCC were between 7 and 40 mm. 4-year survival rates were 86% in LMC group and 58% in PEI group. The differences of survival rates were not statistically significant between LMC and PEI group (p=0.15). When HCC were 20 mm or less, 4-year survival rates (82%) in LMC group were almost the same percentage as in those (65%) of PEI group (p=0.88). However, when HCC were larger than 20 mm, 4-year survival rates (90%) of LMC group were significantly higher than those (42%) of PEI group (p=0.04).
We have already reported the safety and efficacy of laparotomic microwave coagulation therapy (LMCT) for the patients of hepatocellular carcinoma (HCC) with impaired liver function. The aim of this study is to evaluate less invasiveness of laparoscopic assisted microwave assisted microwave coagulation therapy (LAMCT) compared with LMCT. Method : 18 patients of HCC with poor hepatic reserve underwent since April, 2001. 7 patients received LAMCT (LA group) and 11 patient received LMCT (L group). Clinical data ware analyzed before and after surgery in 18 patients. Results : Operative time, blood loss during surgery, and hospitalization were significant less in the LA group than those in the L group. No significant differences between the groups were recognized after surgery in regard to changes in the time course of levels of liver function (AST, ALT, Total bilirubin, Prothrombin time, and Albumin). The changes in the time course of levels of WBC and CRP, as postoperative inflammatory indicators, in the LA group were significantly lower than those in the L group (p<0.05). LAMCT might be useful treatment mordality for the patient of HCC with poor liver function, whose tumor number is not multiple and tumor size is 3cm or less, and further more, tumor location is not adjacent to Glissonn's sheath.
Although metastatic liver tumor after resection of cancer of the biliary tract occurs in a high frequency, no effective therapy has been established as yet. Microwave coagulation therapy (MCT) is beginning to be established as less invasive therapy, has been applied widely. Herein, we experienced a case of eventful recurrence of metastatic liver tumor after resection of ampullary carcinoma in which OMCT was extremely effective, resulting in improved survival and quality of life. There was no complication when OMCT was performed At present, the patient is doing well more than two years after first operation. We concluded that OMCT is an effective therapeutic method for recurrence of metastatic liver tumor from cancer of the biliary tract. However it was thought that MCT must be treated more carefully after surgical reconstruction of the biliary tract.
Ablation therapy (MCT and RFA) has been reported to be one of the useful approaches except for hepatic resection in the primary hepatic carcinoma with liver damage. In the present study, hepatic resection with intraoperative ablation therapy was performed on two cases of HCCs and a case of cholangiocarcinoma with liver cirrhosis and HCV positive. Case 1 : A 63-year-old man with liver damage, diabetic nephropathy and diabetic neuropathy underwent left hepatic lateral segmentectomy for large HCC (5 cm) and RFA for small HCC (exceeding 2 cm) in S8. Case 2 : A 62-year-old woman with liver cirrhosis underwent left hepatic lateral segmentectomy for large cholangiocarcinoma (4.5 cm) and MCT for small tumor (2 cm) in S5. Case 3 : A 69-year-old man with liver cirrhosis underwent partial caudate lobectomy of the liver for HCC (3 cm) in S1 and RFA for HCC (exceeding 3 cm) in S4. The efficiency of the coagulation was proven by employing postoperative enhanced computed tomography in all cases. All patients had an uneventful postoperative course. It was suggested that limited hepatic resection with multimodal minimally invasive treatment such as ablation therapy is effective when combined with interstinal therapy for multiple primary hepatic carcinomas with liver damage.
The optimal treatment for hepatocellular carcinoma (HCC) is surgical resection. However, only a small percentage of patients are operative candidates. Radiofrequency ablation (RFA) has been shown to be efficacious in treatment of unresectable HCC. We performed laparoscopic radiofrequency ablation therapy (LRAT) for HCC, which is located in touch with Gall Bladder. Despite poor hepatic reserve, postoperative recovery after LRAT was rapid. There were no intra-therapeutic complications. LRAT is a less invasive optional therapy for HCC, which is located in touch with other organs in cirrhotic patients.
A new curved microwave applicator was developed for microwave endometrial ablation for uteri with an enlarged and distorted cavity. The applicator was transcervically introduced into the uterine cavity of a resected specimen with a submucosal myoma node, and the endometrium was microwave-coagulated. The endometrium and neighboring myometrium 7 mm in depth were degenerated at a power of 70W with a duration of 50 sec for each coagulation site. Nitroblue tetrazolium staining revealed that coagulated areas lost activity of succinate dehydrogenase, a key enzyme in the Krebs cycle, while myometrium outside of coagulated areas maintained enzyme activity. Tissue temperature increased no more than 10 Celsius degrees at 10 mm from the surface of the applicator at the end of microwave coagulation procedure. In a case of hypermenorrhea caused by a submucosal myoma node 3.8 cm in diameter, heavy period was relieved and the submucosal node shrank by 50% three months after MEA. We concluded that this new curved applicator is useful for MEA in uteri enlarged with submucosal myoma.
From 1999, we have performed the partial nephrectomy for the size of ≤ 4cm in diameter of renal cell carcinoma using the microwave tissue coagulator in our institution. In this study, we examined the side effect and usefulness of the microwave tissue coagulator. Total 11 patients who had been treated the partial nephrectomy for renal tumor without the renal artery cramping at our institution between 1999 and June 2001 were enrolled in this study. We underwent the open surgery in 6 patients and laparoscopic surgery in 5 patients. There were no cases that shifted to the nephrectomy and trancefused due to bleeding from the tumor resection's side. We didn't have patients who were not pathologically diagnosed for using the microwave tissue coagulator. All patients didn't have serious side effect and renal disfunction post operation.
Two patients with lung cancer were successfully treated by Percutaneous Microwave Coagulation Therapy (PMCT) under CT guided condition. Using our CT guided device, PMCT can be carried out safely and accurately. The first patient survived for 15months after PMCT. At least 7 months he stayed home with his family. The second was followed by operation. The specimen resected revealed massive necrosis within whole tumor although a few residual cancer cells were observed around peripheral bronchiole. PMCT has the advantage of cost-benefit balance and also a minimal invasiveness treatment for patients. PMCT will be a potent option for lung cancer therapy.