Very few patients with gastric hepatic metastases are good candidates for hepatic resection because of multiple bilateral metastases, extrahepatic disease, or advanced cancer progressions such as peritoneal dissemination or extensive lymph node metastases
Satoshi Ambiru et al reviewed a single institutional study of 40 consecutive patients who had resection of hepatic metastases, in which numerous factors were examined and their relationship to outcome assessed, in order to determine the benefits and the limits of hepatic resection for gastric metastases.
Their univariate and multivariate analyses in this study demonstrated that only time of hepatic metastases was an indipendent prognostic determinant of survival.
Patients with metachronous metastases undergoing hepatic resection of resection margin greater than 10 mm had 37% 5 year survival rate, and all of the long term survivors underwent anatomical hepatic resection more extensive than segmentectomy, indicating that anatomical hepatic resection with sufficient resection margin of at last 10 mm is an important surgical consideration in cases of gastric hepatic metastases.
They had only 1 long-term survivor among patients with synchronous metastases. In particular patients with synchronous hepatic metastases undergoing hepatic resection of resection margin less than 10 mm had no 3-year survival. Therefore controindication to performing hepatic resection should be carefully considered if it is thought that a patient with synchronous metastases is unable to undergo the surgical procedure with sufficient hepatic resection margin.
Their previous study showed that significant prognostic factors were number of hepatic metastases and resection margin, which were results somewhat different from those of the present study. These differences are thought to be due to increase in the number of patients and difference in analytic methods
Keiichi Okano et al. affirm that solitary and metachronous metastases were significant determinants for a favorable prognosis after hepatic resection. Their study failed to find any significant association between survival and factors related to the primary gastric cancer in patients who underwent curative resection of their primary cancer
( 3 ). Also the Satoshi Ambiru's study on univariate analysis showed that any prognostic factors associated with primary tumor features were not significant
( 1 ). In fact Ochiai et al reported that the significant factor associated with survival was only the microscopic depth of invasion of primary tumor, and that hepatic resection should be attempted in patients with synchronous or metachronous metastases if there is no serosal invasion by the primary gastric tumor
( 4 ).
In addition in the Okano's study the surgical procedure and the surgical margin for the metastatic lesion were not significant prognostic factors
( 3 ). In the study of Ambiru et al resection margin was , by a narrow gap, an insignificant factor in multivariate analysis. But they think that the surgeon should strive to obtain an adequate margin if technically feasible, because among numerous analyzed factors the only one that the surgeon had any influence over was the resection margin
( 1 ).
Moreover Okano et al analyse whether synchronous resection of liver metastases provided any long-term survival benefit. In their study, synchronous resection resulted in one long-term survivor who had solitary metastases, and five patients survived with recurrent disease for about 2 years. In comparison with other treatments, it appears that gastrectomy combined with hepatectomy has a beneficial effect on short term prognosis. However they cannot as yet say whether synchronous hepatic resection in this setting can result in long-term cure
( 3 ).
Okano et al in a previous study showed that the presence of a fibrous pseudocapsule between colorectal metastases and the hepatic parenchyma was a promising indicator of a better prognosis after resection for this disease
( 5 ). In the current study they showed that the presence of a fibrous pseudocapsule around liver metastases from gastric cancer was also closely associated with patient survival. Pseudocapsule formation is considered to be a consequence of a protective immunoinflammatory reaction by the noncancerous liver against the metastastic nodule. The presence of a fibrous pseudocapsule may be valuable as a prognostic factor reflecting the host defence reaction in patients with liver metastases
( 3 ).
In approximately 70% of patients, recurrent disease developed after hepatic resection, most commonly in the liver. Recurrent tumours were more frequently distributed in both lobes than in resected lobe, suggesting that liver recurrence is more probably derived from multiple metastatic foci from the primary disease than from intrahepatic remetastases of the liver lesion. In addition, recurrence after hepatic resection is more strongly associated with systemic spread through vessel infiltration than with local spread through lymphatic or serosal invasion of the primary tumor
( 3 ). Also if Kazuhide Kumagai et al in a recent article consider that the lymphatic system is closely related to the establishment of liver metastases; in particular, extranodal invasion is a significant risk factor for liver metatastases in patient with gastric cancer
( 6 ). In recent years, post operative adjuvant chemotherapy for liver metastases has advanced, with some studies showing that arterial chemotherapy significantly prevents hepatic recurrence. To improve the results of surgical management for this disease, newer adjuvant treatments for systemic spread are thought to be required
Hepatic resection, a potentially curative approach for patients with liver metastases from colorectal carcinoma, carries a 5 year survival rate of 30% to 50%. The resection rate for hepatic metastases from colorectal carcinoma varies from 20% to 50%. In contrast, for hepatic resection for metastases from gastric carcinoma, only 10% to 20% of patients with metastases are suitable for surgical treatment, and the procedure has a median survival of 5 to 8 months, with 15% to 50% survival at 1 year and 19% survival at 5 years. Nonsurgical treatments, including systemic or hepatic artery infusion chemotherapy, do not achieve satisfactory results. In patients treated by gastrectomy and chemotherapy, median survival times are reported to range from 2.9 to 11.8 months; however, in the Okano's study, 3 patients survived more than 5 years after hepatic resection, and the median overall and disease-free survivals for all 19 patients were, respectively, 21 and 8.2 months. These results for a surgical approach for liver metastases from gastric cancer are better than those previously reported and may be due to proper patient selection and the use of a controlled procedure
( 3 ).
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