15 Vascular Resection for Hepatocellular Carcinoma 255 perform these resections. More importantly, such surgeons should understand the risks, benefits and limitations of these highly aggressive procedures and that they should be applied to a highly selected group of patients. An even smaller subset of patients with tumors involving major vasculature may be considered for resections utilizing cold preservations techniques. These extreme resections, performed by a handful of surgeons, offer the only hope for patients who would otherwise succumb to their liver cancers. The utility of these “extreme operations” must be carefully considered on a case-by-case basis. References 1. Llovet JM, Burroughs A, Bruix J (2003) Hepatocellular carcinoma. Lancet 362(9399): 1907–1917 2. Tsai TJ, Chau GY, Lui WY, Tsay SH, King KL, Loong CC, Hsia CY, Wu CW (2000) Clinical significance of microscopic tumor venous invasion in patients with resectable hepatocellular carcinoma. Surgery 127:603–608 3. Sugino T, Yamaguchi T, Hoshi N, Kusakabe T, Ogura G, Goodison S, Suzuki T (2008) Sinusoidal tumor angiogenesis is a key component in hepatocellular carcinoma metastasis. Clin Exp Metastasis 25:835–841 4. Al-Mehdi AB, Tozawa K, Fisher AB, Shientag L, Lee A, Muschel RJ (2000) Intravascular origin of metastasis from the proliferation of endothelium-attached tumor cells: a new model for metastasis. Nat Med 6:100–102 5. Mitsunobu M, Toyosaka A, Oriyama T, Okamoto E, Nakao N (1996) Intrahepatic metas- tases in hepatocellular carcinoma: the role of the portal vein as an efferent vessel. Clin Exp Metastasis 14:520–529 6. Inoue Y, Hasegawa K, Ishizawa T, Aoki T, Sano K, Beck Y, Imamura H, Sugawara Y, Kokudo N, Makuuchi M (2009) Is there any difference in survival according to the por- tal tumor thrombectomy method in patients with hepatocellular carcinoma? Surgery 145: 9–19 7. Liotta LA, Saidel MG, Kleinerman J (1976) The significance of hematogenous tumor cell clumps in the metastatic process. Cancer Res 36:889–894 8. Weiss L, Orr FW, Honn KV (1989) Interactions between cancer cells and the microvascula- ture: a rate-regulator for metastasis Clin Exp Metastasis 7:127–167 9. Kim BK, Han KH, Park YN, Park MS, Kim KS, Choi JS, Moon BS, Chon CY, Moon YM, Ahn SH (2008) Prediction of microvascular invasion before curative resection of hepatocellular carcinoma. J Surg Oncol 97:246–252 10. Matsuda M, Suzuki T, Kono H, Fujii H (2007) Predictors of hepatic venous trunk invasion and prognostic factors in patients with hepatocellular carcinomas that had come into contact with the trunk of major hepatic veins. J Hepatobiliary Pancreat Surg 14:289–296 11. Hagiwara S, Kudo M, Kawasaki T, Nagashima M, Minami Y, Chung H, Fukunaga T, Kitano M, Nakatani T (2006) Prognostic factors for portal venous invasion in patients with hepatocellular carcinoma. J Gastroenterol 41:1214–1219 12. Adachi E, Maeda T, Kajiyama K, Kinukawa N, Matsumata T, Sugimachi K, Tsuneyoshi M (1996) Factors correlated with portal venous invasion by hepatocellular carcinoma: univari- ate and multivariate analyses of 232 resected cases without preoperative treatments. Cancer 77:2022–2031 13. Poon RT, Fan ST, Lo CM, Liu CL, Lam CM, Yuen WK, Yeung C, Wong J (2004) Improving perioperative outcome expands the role of hepatectomy in management of benign and malig- nant hepatobiliary diseases: a nalysis of 1222 consecutive patients from a prospective database. Ann Surg 240:698–708 256 R.D. Kim and A.W. Hemming 14. Llovet JM, Schwartz M, Mazzaferro V (2005) Resection and liver transplantation for hepatocellular carcinoma. Semin Liver Dis 25:181–200 15. Farges O, Belghiti J, Kianmanesh R, Regimbeau JM, Santoro R, Vilgrain V, Denys A, Sauvanet A (2003) Portal vein embolization before right hepatectomy: prospective clinical trial. Ann Surg 237:208–217 16. Azoulay D, Castaing D, Krissat J, Smail A, Hargreaves GM, Lemoine A, Emile JF, Bismuth H (2000) Percutaneous portal vein embolization increases the feasibility and safety of major liver resection for hepatocellular carcinoma in injured liver. Ann Surg 232: 665–672 17. Hemming AW, Reed AI, Howard RJ, Fujita S, Hochwald SN, Caridi JG, Hawkins IF, Vauthey JN (2003) Preoperative portal vein embolization for extended hepatectomy. Ann Surg 237:686–691 18. Palavecino M, Chun YS, Madoff DC, Zorzi D, Kishi Y, Kaseb AO, Curley SA, Abdalla EK, Vauthey JN (2009) Major hepatic resection for hepatocellular carcinoma with or without portal vein embolization: Perioperative outcome and survival. Surgery 145: 399–405 19. Bruix J, Castells A, Bosch J, Feu F, Fuster J, Garcia-Pagan JC, Visa J, Bru C, Rodes J (1996) Surgical resection of hepatocellular carcinoma in cirrhotic patients: prognostic value of preoperative portal pressure. Gastroenterology 111:1018–1022 20. Llovet JM (2005) Updated treatment approach to hepatocellular carcinoma. J Gastroenterol 40:225–235 21. Noun R, Jagot P, Farges O, Sauvanet A, Belghiti J (1997) High preoperative serum alanine transferase levels: effect on the risk of liver resection in Child grade A cirrhotic patients. World J Surg 21:390–394 22. Eguchi H, Umeshita K, Sakon M, Nagano H, Ito Y, Kishimoto SI, Dono K, Nakamori S, Takeda T, Gotoh M, Wakasa K, Matsuura N, Monden M (2000) Presence of active hepatitis associated with liver cirrhosis is a risk factor for mortality caused by posthepatectomy liver failure. Dig Dis Sci 45:383–388 23. Lang H, Radtke A, Liu C, Fruhauf NR, Peitgen HO, Broelsch CE (2004) Extended left hep- atectomy – modified operation planning based on three-dimensional visualization of liver anatomy. Langenbecks Arch Surg 389:306–310 24. Rossi S, Ghittoni G, Ravetta V, Torello VF, Rosa L, Serassi M, Scabini M, Vercelli A, Tinelli C, Dal BB, Burns PN, Calliada F (2008) Contrast-enhanced ultrasonography and spiral com- puted tomography in the detection and characterization of portal vein thrombosis complicating hepatocellular carcinoma. Eur Radiol 18:1749–1756 25. Miyata R, Tanimoto A, Wakabayashi G, Shimazu M, Nakatsuka S, Mukai M, Kitajima M (2006) Accuracy of preoperative prediction of microinvasion of portal vein in hep- atocellular carcinoma using superparamagnetic iron oxide-enhanced magnetic resonance imaging and computed tomography during hepatic angiography. J Gastroenterol 41: 987–995 26. Togo S, Shimada H, Kanemura E, Shizawa R, Endo I, Takahashi T, Tanaka K (1998) Usefulness of three-dimensional computed tomography for anatomic liver resection: sub- subsegmentectomy. Surgery 123:73–78 27. Yamanaka J, Saito S, Fujimoto J (2007) Impact of preoperative planning using virtual segmental volumetry on liver resection for hepatocellular carcinoma. World J Surg 31: 1249–1255 28. Lang H, Radtke A, Hindennach M, Schroeder T, Fruhauf NR, Malago M, Bourquain H, Peitgen HO, Oldhafer KJ, Broelsch CE (2005) Impact of virtual tumor resection and computer-assisted risk analysis on operation planning and intraoperative strategy in major hepatic resection. Arch Surg 140:629–638 29. Chen H, Merchant NB, Didolkar MS (2000) Hepatic resection using intermittent vascu- lar inflow occlusion and low central venous pressure anesthesia improves morbidity and mortality. J Gastrointest Surg 4:162–167 15 Vascular Resection for Hepatocellular Carcinoma 257 30. Soonawalla ZF, Stratopoulos C, Stoneham M, Wilkinson D, Britton BJ, Friend PJ (2008) Role of the reverse-Trendelenberg patient position in maintaining low-CVP anaesthesia during liver resections. Langenbecks Arch Surg 393:195–198 31. Huguet C, Gavelli A, Bona S (1994) Hepatic resection with ischemia of the liver exceeding one hour. J Am Coll Surg 178:454–458 32. Hannoun L, Delriviere L, Gibbs P, Borie D, Vaillant JC, Delva E (1996) Major extended hepatic resections in diseased livers using hypothermic protection: preliminary results from the first 12 patients treated with this new technique. J Am Coll Surg 183:597–605 33. Man K, Fan ST, Ng IO, Lo CM, Liu CL, Wong J (1997) Prospective eva luation of Pringle maneuver in hepatectomy for liver tumors by a randomized study. Ann Surg 226: 704–711 34. Clavien PA, Selzner M, Rudiger HA, Graf R, Kadry Z, Rousson V, Jochum W (2003) A prospective randomized study in 100 consecutive patients undergoing major liver resection with versus without ischemic preconditioning. Ann Surg 238:843–850 35. Serafin A, Fernandez-Zabalegui L, Prats N, Wu ZY, Rosello-Catafau J, Peralta C (2004) Ischemic preconditioning: tolerance to hepatic ischemia-reperfusion injury. Histol Histopathol 19:281–289 36. Gurusamy KS, Kumar Y, Pamecha V, Sharma D, Davidson BR (2009) Ischaemic pre- conditioning for elective liver resections performed under vascular occlusion. Cochrane Database Syst Rev Jan 21(1):CD007629 37. Nakashima T, Okuda K, Kojiro M, Jimi A, Yamaguchi R, Sakamoto K, Ikari T (1983) Pathology of hepatocellular carcinoma in Japan. 232 Consecutive cases autopsied in ten years. Cancer 51:863–877 38. Anthony PP (1973) Primary carcinoma of the liver: a study of 282 cases in Ugandan Africans. J Pathol 110:37–48 39. Sung AD, Cheng S, Moslehi J, Scully EP, Prior JM, Loscalzo J (2008) Hepatocellular carci- noma with intracavitary cardiac involvement: a case report and review of the literature. Am J Cardiol 102:643–645 40. Agelopoulou P, Kapatais A, Varounis C, Grassos C, Kalkandi E, Kouris N, Pierakeas N, Babalis D (2007) Hepatocellular carcinoma with invasion into the right atrium. Report of two cases and review of the literature. Hepatogastroenterology 54:2106–2108 41. Kubota K, Makuuchi M, Kobayashi T, Sakamoto Y, Inoue K, Torzilli G, Takayama T (1997) Reconstruction of the inferior vena cava using a hepatic venous patch obtained from resected liver. Hepatogastroenterology 44:378–379 42. Miyazaki M, Ito H, Kimura F, Shimizu H, Togawa A, Ohtsuka M, Yoshidome H, Kato A, Yoshitomi H, Sawada S, Ambiru S (2004) Hepatic vein reconstruction using autologous vein graft for resection of advanced hepatobiliary malignancy. Hepatogastroenterology 51: 1581–1585 43. Ohwada S, Ogawa T, Kawashima Y, Ohya T, Kobayashi I, Tomizawa N, Otaki A, Takeyoshi I, Nakamura S, Morishita Y (1999) Concomitant major hepatectomy and inferior vena cava reconstruction. J Am Coll Surg 188:63–71 44. Iwatsuki S, Todo S, Starzl TE (1988) Right trisegmentectomy with a synthetic vena cava graft. Arch Surg 123:1021–1022 45. Kumada K, Shimahara Y, Fukui K, Itoh K, Morikawa S, Ozawa K (1988) Extended right hepatic lobectomy: combined resection of inferior vena cava and its reconstruction by EPTFE graft (Gore-Tex). Case report. Acta Chir Scand 154:481–483 46. Bower TC, Nagorney DM, Cherry KJ, Jr., Toomey BJ, Hallett JW, Panneton JM, Gloviczki P (2000) Replacement of the inferior vena cava for malignancy: an update. J Vasc Surg 31: 270–281 47. Risher WH, Arensman RM, Ochsner JL, Hollier LH (1990) Retrohepatic vena cava recon- struction with polytetrafluoroethylene graft. J Vasc Surg 12:367–370 48. Miller CM, Schwartz ME, Nishizaki T (1991) Combined hepatic and vena caval resection with autogenous caval graft replacement. Arch Surg 126:106–108 258 R.D. Kim and A.W. Hemming 49. Hashimoto T, Minagawa M, Aoki T, Hasegawa K, Sano K, Imamura H, Sugawara Y, Makuuchi M, Kokudo N (2008) Caval invasion by liver tumor is limited. J Am Coll Surg 207:383–392 50. Smyrniotis V, Kostopanagiotou G, Lolis E, Theodoraki K, Farantos C, Andreadou I, Polymeneas G, Genatas C, Contis J (2003) Effects of hepatovenous back flow on ischemic- reperfusion injuries in liver resections with the pringle maneuver. J Am Coll Surg 197: 949–954 51. Fortner JG, Shiu MH, Kinne DW, Kim DK, Castro EB, Watson RC, Howland WS, Beattie EJ Jr (1974) Major hepatic resection using vascular isolation and hypothermic perfusion. Ann Surg 180:644–652 52. Pichlmayr R, Bretschneider HJ, Kirchner E, Ringe B, Lamesch P, Gubernatis G, Hauss J, Niehaus KJ, Kaukemuller J (1988) [Ex situ operation on the liver. A new possibility in liver surgery]. Langenbecks Arch Chir 373:122–126 53. Hemming AW, Nelson DR, Reed AI (2002) Liver transplantation for hepatocellular carci- noma. Minerva Chir 57:575–585 54. Hemming AW, Reed AI, Langham MR, Jr., Fujita S, Howard RJ (2004) Combined resection of the liver and inferior vena cava for hepatic malignancy. Ann Surg 239:712–719 55. Azoulay D, Eshkenazy R, Andreani P, Castaing D, Adam R, Ichai P, Naili S, Vinet E, Saliba F, Lemoine A, Gillon MC, Bismuth H (2005) In situ hypothermic perfusion of the liver versus standard total vascular exclusion for complex liver resection. Ann Surg 241:277–285 56. Gubernatis G, Pichlmayr R, Lamesch P, Grosse H, Bornscheuer A, Meyer HJ, Ringe B, Farle M, Bretschneider HJ (1990) HTK-solution (Bretschneider) for human liver transplantation. First clinical experiences. Langenbecks Arch Chir 375:66–70 57. Kalayoglu M, Sollinger HW, Stratta RJ, D’Alessandro AM, Hoffmann RM, Pirsch JD, Belzer FO (1988) Extended preservation of the liver for clinical transplantation. Lancet 1(8586): 617–619 58. Melendez J, Ferri E, Zwillman M, Fischer M, DeMatteo R, Leung D, Jarnagin W, Fong Y, Blumgart LH (2001) Extended hepatic resection: a 6-year retrospective study of risk factors for perioperative mortality. J Am Coll Surg 192:47–53 59. Oldhafer KJ, Lang H, Schlitt HJ, Hauss J, Raab R, Klempnauer J, Pichlmayr R (2000) Long- term experience after ex situ liver surgery. Surgery 127:520–527 60. Gotohda N, Kinoshita T, Konishi M, Nakagohri T, Takahashi S, Furuse J, Ishii H, Yoshino M (2006) New indication for reduction surgery in patients with advanced hepatocellular carcinoma with major vascular involvement. World J Surg 30:431–438 61. Minagawa M, Makuuchi M, Takayama T, Ohtomo K (2001) Selection criteria for hepatectomy in patients with hepatocellular carcinoma and portal vein tumor thrombus. Ann Surg 233: 379–384 62. Imamura H, Matsuyama Y, Tanaka E, Ohkubo T, Hasegawa K, Miyagawa S, Sugawara Y, Minagawa M, Takayama T, Kawasaki S, Makuuchi M (2003) Risk factors contributing to early and late phase intrahepatic recurrence of hepatocellular carcinoma after hepatectomy. J Hepatol 38:200–207 63. Ercolani G, Grazi GL, Ravaioli M, Del Gaudio M, Gardini A, Cescon M, Varotti G, Cetta F, Cavallari A (2003) Liver resection for hepatocellular carcinoma on cirrhosis: univariate and multivariate analysis of risk factors for intrahepatic recurrence. Ann Surg 237:536–543 64. Koo J, Fung K, Siu KF, Lee NW, Lett Z, Ho J, Wong J, Ong GB (1983) Recovery of malig- nant tumor cells from the right atrium during hepatic resection for hepatocellular carcinoma. Cancer 52:1952–1956 65. Portolani N, Coniglio A, Ghidoni S, Giovanelli M, Benetti A, Tiberio GA, Giulini SM (2006) Early and late recurrence after liver resection for hepatocellular carcinoma: prognostic and therapeutic implications. Ann Surg 243:229–235 66. Shirabe K, Kanematsu T, Matsumata T, Adachi E, Akazawa K, Sugimachi K (1991) Factors linked to early recurrence of small hepatocellular carcinoma after hepatectomy: univariate and multivariate analyses. Hepatology 14:802–805 15 Vascular Resection for Hepatocellular Carcinoma 259 67. Vauthey JN, Lauwers GY, Esnaola NF, Do KA, Belghiti J, Mirza N, Curley SA, Ellis LM, Regimbeau JM, Rashid A, Cleary KR, Nagorney DM (2002) Simplified staging for hepatocellular carcinoma. J Clin Oncol 20:1527–1536 68. Nanashima A, Sumida Y, Abo T, Nagasaki T, Ohba K, Kinoshita H, Tobinaga S, Kenji T, Takeshita H, Hidaka S, Sawai T, Yasutake T, Nagayasu T (2008) Surgical treatment and adju- vant chemotherapy in hepatocellular carcinoma patients with advanced vascular involvement. Hepatogastroenterology 55:627–632 Chapter 16 Radiofrequency Ablation for Hepatocellular Carcinoma E. Ramsay Camp, Nestor F. Esnaola, and Steven A. Curley Keywords Radiofrequency ablation · HCC treatment strategy · Open RFA laparoscopic RFA · RFA outcomes HCC Hepatocellular carcinoma (HCC) is the most frequent primary hepatic tumor and the fifth most common cancer worldwide. The incidence continues to rise world- wide due to its association with hepatitis B and C viral infections. Cirrhosis is present concurrently with HCC in approximately 90% of the identified cases [1, 2]. Furthermore, the incidence of HCC increases with the severity of cirrhosis. Follow- up studies have identified HCC as one of the most common causes of death in the cirrhotic patient [3, 4]. The management of HCC, therefore, is based both on the stage of the malignancy and on the underlying functional status of the liver. Local tumor ablative techniques remain a reasonable treatment consideration for patients with disease confined to the liver who are not candidates for resection or transplantation. Radiofrequency Ablation Surgical resection or orthotopic transplantation s hould still be considered the gold standard for patients with hepatocellular carcinoma (HCC), with reported 5-year survival rates exceeding 70% in appropriately selected patients [5, 6]. However, surgical resection is only possible in the minority of patients with HCC confined to the liver due to the degree of cirrhosis, the tumor burden, and/or the anatomical location of the tumors. Transplantation is limited by the paucity of donor organs. For non-surgical candidates with no evidence of extra-hepatic disease, radiofrequency ablation (RFA) should be considered as a viable treatment option. RFA may be delivered from a percutaneous, laparoscopic, or by an open approach based on mul- tiple patient and technical factors. The ideal patients for RFA are cirrhotic patients E.R. Camp (B) Department of Surgery, Medical University of South Carolina, Charleston, SC, USA 261 K.M. McMasters, J N. Vauthey (eds.), Hepatocellular Carcinoma, DOI 10.1007/978-1-60327-522-4_16, C Springer Science+Business Media, LLC 2011 262 E.R. Camp et al. with small tumors who are not surgical candidates based on their underlying hep- atic function. RFA in appropriate selected patients can produce durable long-term survival with minimal procedure-related complications. Combination of RFA with other treatment strategies, particularly transarterial chemoembolization (TACE), can be effectively used to treat patients with advanced multifocal HCC or as a bridge to liver transplantation [7–9]. As the technique and experience improves, the indications for RFA to treat patients with HCC will likely continue to increase. Technical Considerations for Radiofrequency Ablation Radiofrequency ablation (RFA) may be considered as a treatment strategy for HCC patients who are not appropriate surgical resection candidates. RFA produces ther- mal tissue damage through the use of high-frequency alternating currents moving from the tip of an intra-tumoral electrode into the targeted surrounding tissue. The patient is part of a closed loop circuit that includes the RF generator, electrode nee- dle, and grounding pads placed on the patient. Frictional heating of the targeted tissue results from the movement of ions within the tissue following the alternating currents. As temperatures rise above 60 ◦ C surrounding the electrode, tissue coagu- lative necrosis is achieved in the tumor and surrounding hepatic parenchyma. The region of necrosis is relatively consistent with a zone of ablation within the first few millimeters of the electrode–tissue interface. The final size of the ablative region is proportional to the square of the radiofrequency current referred to as the radiofre- quency power density. Early RFA probes were simple straight unipolar needles, limiting the size of the tumor ablated to less than 2 cm in diameter. These unipo- lar probes have been replaced with multi-array probes that create a l arger region of necrosis. These modern expandable probes have multiple tines that are deployed once the needle electrode is inserted within the tumor. The curved electrodes are then deployed to a desired distance based on the size of the tumor. Reliable tis- sue destruction can only be expected 5–10 mm away from the multiple array hook electrodes. RFA can be successfully performed via either a percutaneous, laparoscopic, or open approach [10]. Using image guidance from either transcutaneous or intra- operative ultrasonography visualization, the RFA needle electrode is inserted into the targeted tissue and the needle tines are deployed. RF energy is then applied following an established algorithm [11]. Generally, small lesions (<2.5 cm) can be treated with a single deployment targeted at the center of the tumor (Fig. 16.1). Larger tumors (>2.5 cm) generally require multiple deployments to achieve com- plete tumor necrosis. Strategic deployment of the electrodes is planned so the regions of necrosis overlap to ensure complete tumor destruction. Typically, the most posterior portion is treated first followed by reapplication more anteriorly at 2–2.5 cm intervals within the tumor. The appropriate technique for RFA whether percutaneous, laparoscopic, or open approach depends on multiple variables. A percutaneous approach should be consid- ered for cirrhotic patients with small (<3 cm), early staged HCC tumors especially 16 Radiofrequency Ablation for Hepatocellular Carcinoma 263 Fig. 16.1 The upper left i mage demonstrates the use of intra-operative ultrasound (IOUS) on the surface of the liver to visualize tumors within the hepatic parenchyma. The radiofrequency needle electrodes are placed within the tumor under IOUS guidance. The upper right image demonstrates deployment of the multiple array secondary electrodes within the tumor. For tumors 2 cm in diam- eter or smaller, a single placement of the multiple array electrode is usually adequate to produce a 4–5 cm diameter zone of coagulative necrosis completely destroying the targeted tumor (lower inset illustration)[10] in the periphery of the liver. Lesions in the dome of the liver are often not acces- sible from a percutaneous approach. Patients undergoing a percutaneous approach usually require monitored sedation and are discharged from the hospital within 24 hours of the procedure. A laparoscopic approach utilizes laparoscopic ultrasonography which has the advantage of improved resolution relative to transcutaneous visualization. Intra- operative ultrasound may better define the location of the tumors and allow more precise positioning of the RFA probes close to major vasculature near a given tumor. This approach is appropriate for patients with no prior history of abdominal surgery and centrally located tumors less than 4.0 cm in size. Open RFA should be considered for larger tumors (>4.0 cm), multiple tumors, if the tumor is close to major hepatic blood vessels, or if dense adhesions prevent a laparoscopic approach. One major advantage of open RFA is that it allows for temporary hepatic inflow occlusion. This technique may improve the effectiveness in RFA of large hypervascular tumors and tumors in close proximity to major blood vessels by improving the RFA temperature response. Increased blood flow in the targeted RFA region leads to heat loss or a cooling effect limiting the degree of tissue necrosis and, therefore, the effectiveness of RFA. Hepatic inflow occlusion minimizes this cooling effect during RFA application. A second advantage of the open RFA approach is the ability to combine RFA with hepatic resection strategies to address multiple tumors. Tumor position can impact treatment decisions regarding RFA. Tumor not amenable to a margin-negative resection such as tumors abutting the junction of the inferior vena cava and the hepatic veins can often be treated with RFA (Fig. 16.2). 264 E.R. Camp et al. A B Fig. 16.2 (a) CT scan image of a hepatocellular tumor abutting the inferior vena cava (open arrows)andthe hepatic veins (closed arrows). For adequate ablation, serial deployments of the multiple array electrode probes are necessary beginning just outside of the inferior vena cava, and then sequentially withdrawn to treat the more anterior portions of the tumor. Blood flow through the inferior vena cava and hepatic veins p revents thermal damage of these major vessels. (b) CT scan 6 months after radiofrequency ablation reveals a larger necrotic cavity than the original tumor with patent hepatic veins (closed arrows)[10] Conversely, tumors located in the region of the hilar plate where the portal vein and hepatic artery branches enter the liver should not be treated with RFA. The large bile ducts in this region are susceptible to thermal injury resulting in secondary biliary strictures or fistulas. Imaging Considerations A critical component to the effective use of RFA is preoperative planning and tumor surveillance with appropriate imaging studies [12]. Typically, serial dynamic MRI or multiphasic helical CT scans are used to plan RFA treatment and evalu- ate response. The goal of RFA is to produce a necrotic cavitary lesion greater in size than the pretreatment HCC lesion when compared by CT/MRI. This compari- son is both to assess complete tumor ablation and to evaluate for tumor recurrence. . Resection for Hepatocellular Carcinoma 255 perform these resections. More importantly, such surgeons should understand the risks, benefits and limitations of these highly aggressive procedures and that. treatment and adju- vant chemotherapy in hepatocellular carcinoma patients with advanced vascular involvement. Hepatogastroenterology 55:627–632 Chapter 16 Radiofrequency Ablation for Hepatocellular Carcinoma E Sugimachi K, Tsuneyoshi M (1996) Factors correlated with portal venous invasion by hepatocellular carcinoma: univari- ate and multivariate analyses of 232 resected cases without preoperative treatments.