| International Session (Symposium) 7 (JSGS・JSGE・JSH) |
| Sat. November 3rd 14:00 - 17:00 Room 4: Portopia Hotel South Wing Portopia Hall |
| For further expanding limitations of liver resection for colorectal liver metastases -Arguments for and against ALPPS- | |||
| Kuniya Tanaka1, Yohei Ota1, Sayuri Matsushima1 | |||
| 1Yokohama Municipal Citizen’s Hospital | |||
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| Recent advances in procedural technique and perioperative chemotherapy now allow numerous patients to have potentially curative hepatectomy for colorectal liver metastases (CRLM). Although many independent risk factors for long-term survival are identified, contraindications for liver resection from the oncological point of view is not decided so far. On the contrary, technical limitation is definitively decided by volume of future liver remnant (FLR) after hepatectomy. Nowadays, other than parenchyma-sparing multiple partial resections can be applied, severe prehepatectomy chemotherapy followed by complex hepatectomy, such as staged liver resection combining portal vein occlusion become standard measure for aggressive liver metastases. Parenchyma-sparing resections can only be applied when almost all liver nodules are not attached or invaded major intrahepatic vascular pedicles. Therefore, extended hepatectomy following chemotherapy is more popular and necessitated strategy. During this strategy, however, severe chemo-toxicity within noncancerous liver parenchyma induced by frequent administration of chemotherapy which reduce liver hypertrophy ability and tumor progression during interval of staged resections are negative considerations. ALPPS were introduced as an innovative technique to overcome these subjects. Rapid and excessive liver hypertrophy by ALPPS makes liver hypertrophy possible even in damaged liver induced by chemotherapy and avoids interval tumor progression during staged resections because of short interval between 2 surgeries. Therefore, ALPPS initially was considered to be able to resolve the drawbacks of staged resection. However, 6 years past after the initial report of ALPPS, several problems of this treatment measure are evident. These are high morbidity due to difficulty of the procedure, high mortality from septic complication and postoperative liver failure, poor functional recovery of FLR with a histological immaturity of both hepatocyte regeneration and biliary-network formation, and histological similarity that after liver transplantation using a small-for-size graft (mismatch between blood inflow volume and FLR). Portal pedicle interruption during parenchymal transection may cause parenchymal necrosis that has possibility of septic focus. Poor functional volume gaining of FLR as compared to morphological volume increase that is caused as a result of immaturity of liver regeneration and/or mismatch between inflow and FLR volume may become main cause of postoperative liver failure. To establish safety of this procedure and to make sure this treatment as a standard for CRLM treatment, such the drawbacks should always be paid special care. Modified techniques to avoid parenchyma necrosis should be devised, which signal pathway of liver regeneration is related to less functional recovery of FLR should be clarified, and modification of blood inflow such as splenectomy may be considered. In order to further expand the limits of liver resection for CRLM, we need to explore mechanisms of liver regeneration, functional recovery, histopathologic changes of hepatocytes, and blood distribution during ALPPS simultaneously to developing and evaluating modifications of the procedure. |
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Index Term 1: liver metastases Index Term 2: ALPPS |
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