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Background: Although many reports on the treatment of hepatocellular carcinoma (HCC) by microwave coagulation have been published recently, none have incorporated data for the long-term therapeutic efficacy of laparoscopic microwave coagulation (LMC). In the current study, the efficacy of LMC was assessed., Methods: The authors performed LMC under local anesthesia in 69 previously untreated patients with solitary HCCs < or = 4.0 cm in greatest dimension. The maximum diameter for the tumors averaged 22.6 +/- 7.4 mm. Long-time survival rate was evaluated according to the size and histologic grade of the tumor., Results: The 5-year overall cumulative survival rate for the 69 patients was 63.9%. The 5-year overall survival rate for patients with well differentiated HCC was 78.9%, whereas patients with moderately or poorly differentiated HCC had a 5-year overall survival rate of 38.9%. The 5-year cumulative survival rate for patients with HCCs < or = 2.0 cm in diameter was 76.0%, and 56.3% for patients with HCCs >2.0 cm. Twelve patients (17.4%) showed local tumor recurrence during the follow-up period. Local tumor recurrence was observed in 6 of 21 patients with moderately or poorly differentiated HCCs (28.6%) and in 6 of 40 patients with well differentiated HCCs (15.0%). The 3-year cancer-free survival rate for patients with well differentiated HCC was 44.4%, whereas it was 12.2% for patients with moderately or poorly differentiated HCC., Conclusions: A major factor that influenced outcome in LMC was tumor cell differentiation. LMC procedures were best suited for treatment of well differentiated HCC., (2005 American Cancer Society.)

We compared the findings of magnetic resonance (MR) images and pathological examination to determine whether or not MR images reflect pathological changes following microwave coagulation therapy (MCT) on liver tissue. We used microwave (generating frequency 2450 Mhz, wave length 12 cm, output 50 W, 60 second duration) to irradiate six canine livers under general anesthesia. After the animals were sacrificed, the livers were resected. The irradiated regions were cut with margins and divided into two pieces, one for MR study, and the other for pathological examination. The findings were compared. From the center to the marginal layer, the irradiated region presented 4/3 laminal patterns on T1/T2-weighted images: low/high, high/low, very high/high, and iso-low/high intensity. On gradient-echo imaging, the irradiated regions presented no decreasing signals using several echo time lengths. With hematoxylin and eosin stain, MR laminar patterns reflected the histopathological changes, as follows: a tissue loss area surrounding the inserted needle, low/high; decreased sinusoidal width with/without necrotic tissue, high/low; sinusoidal width dilation at the periphery, very high/high; and fatty degenerated tissue surrounding the irradiated area at the boundary of the normal hepatocytes, iso-low/high. The MR signal intensity, which reflected the histopathological changes, presented tissue characterization after MCT, and the macromolecular hydration effect influenced the high intensity on T1-weighted images.

Laparoscopic microwave coagulation (LMC) for hepatocellular carcinomas (HCCs) was performed on 26 HCCs in 17 patients. Contrast-enhanced CT (CECT) and MR images (T1-weighted imaging [T1WI], T2WI, gadolinium-diethylenetriamine pentaacetic acid [Gd-DTPA] T1WI) were obtained to determine changes over time. The irradiated center exhibited low to moderate intensity with surrounded high intensity (HI) on T2WI and Gd-DTPA T1WI. On T1WI, lesions showed four patterns of intensity: uniform HI (30.8%), arcuate HI (26.9%), mainly low with spot HI (30.8%), and isointensity to hypointensity (11.5%). Follow-up imaging at more than 170 days revealed isointensity to hypointensity on T1WI (96.2%) and reduced HI on T2-weighted imaging (T2WI) and Gd-DTPA T1WI. All lesions became less conspicuous and were reduced in volume. HCC shows time-related changes in signals and size after LMC. Identifying the irradiated lesion is necessary to estimate the adequacy of treatment by comparison with the pretherapeutic image.