Review Article. Dig Dis 2015;33: DOI: /

Transcription

1 Review Article General Rules for the Clinical and Pathological Study of Primary Liver Cancer, Nationwide Follow-Up Survey and Clinical Practice Guidelines: The Outstanding Achievements of the Liver Cancer Study Group of Japan Masatoshi Kudo Masayuki Kitano Toshiharu Sakurai Naoshi Nishida Department of Gastroenterology and Hepatology, Kinki University School of Medicine, Osaka-Sayama, Osaka, Japan Key Words Primary liver cancer Hepatocellular carcinoma Practice guideline General rules Locoregional therapy Response evaluation criteria in cancer of the liver Abstract This review outlines the significance of establishing general rules, a nationwide follow-up survey, and clinical practice guidelines for liver cancer in Japan. The general rules are an essential part of hepatocellular carcinoma (HCC) treatment, enabling a common language to be used in daily clinical practice and for the nationwide follow-up survey. The Japanese General Rules for the Clinical and Pathological Study of Primary Liver Cancer, which provide detailed descriptions of HCC, are excellent and are unique to Japan. Items in the General Rules for the Clinical and Pathological Study of Primary Liver Cancer are used substantially in another important project, the Nationwide Follow-Up Survey of Primary Liver Cancer, which has been rigorously undertaken with great effort by the Liver Cancer Study Group of Japan biannually since Both evidence-based and consensus-based treatment algorithms for HCC are used to complement each other in clinical practice in Japan. karger@karger.com S. Karger AG, Basel /15/ $39.50/ S. Karger AG, Basel Introduction As for other cancers, general rules and clinical practice guidelines have been developed for hepatocellular carcinoma (HCC). Historically, the general rules for HCC have been published by the Liver Cancer Study Group of Japan (LCSGJ), under the title General Rules for the Clinical and Pathological Study of Primary Liver Cancer. After the publication of the first edition on June 20, 1983, subsequent editions were published in 1987 (2nd edition), 1992 (3rd edition), 2001 (4th edition) and 2008 (5th edition), followed by a revision of the current fifth edition on July 7, 2009 [1, 2]. The sixth edition is scheduled for publication in While the general rules for other cancers have been compiled primarily by the respective large medical societies, the general rules for primary liver cancer were published by the LCSGJ. In terms of the clinical practice guidelines for HCC, the Clinical Practice Guidelines Committee for Liver Cancer (Chairman, Dr. Masatoshi Makuuchi), sponsored by the Ministry of Health, Labour and Welfare, played a central role in establishing the first edition of the Evidence-based Clinical Practice Guidelines for HCC in The committee consisted mainly of executive council members of the LCSGJ. Thereafter, the Japan Society Masatoshi Kudo, MD, PhD Department of Gastroenterology and Hepatology Kinki University School of Medicine, Ohno-Higashi Osaka-Sayama, Osaka (Japan) med.kindai.ac.jp

2 of Hepatology (JSH) sponsored the publication of the second edition of the guidelines in 2009 and the latest edition in 2013 [3]. JSH also published the first and second editions of the Clinical Practice Manual for HCC, Management of Hepatocellular Carcinoma in Japan: Consensus- Based Clinical Practice Manual in 2007 and the revised version in 2010, respectively [4, 5]. The third edition was published in 2015 [6, 7]. This manual is useful as it incorporates recommendations with a high level of evidence that are presented in the aforementioned Evidence-based Clinical Practice Guidelines for HCC [8 10], while also explaining diagnoses and treatments relevant to routine clinical settings that are in line with expert opinion and consensus. 766 General Rules for the Clinical and Pathological Study of Primary Liver Cancer The first edition of General Rules for the Clinical and Pathological Study of Primary Liver Cancer was published to provide physicians specializing in liver cancer with specific terminology and abbreviations for noting the macroscopic findings of HCC, tumor stage, pathological findings, important terminology and the accompanying cirrhosis state and also for enabling discussions using common language. Every time a subsequent edition was published, the TNM classification system became unique to Japan, and owing to advances in pathological studies, the definition of pathological early welldifferentiated HCC [11] was clearly stated already in the third edition published in Moreover, Japan has adopted the liver damage to reflect degree of liver functional reserve, instead of the Child-Pugh classification, which is a global standard. This unique approach has arisen because the indocyanine green retention test is frequently performed before surgical resection in Japan. In that sense, liver damage is more of an HCCoriented liver functional reserve classification than Child-Pugh classification, where the latter was originally developed to predict the prognosis of cirrhotic patients [12, 13]. With the publication of the General Rules for the Clinical and Pathological Study of HCC and Intrahepatic Cholangiocarcinoma in Japanese and English, unique advances have been made. The TNM classification of HCC and intrahepatic cholangiocarcinoma is easy to remember and judge because the staging of T1 T4 tumors involves only 3 criteria: <2 or 2 cm, the presence or absence of vascular invasion and single or multiple tumors Table 1. Definitions of the TNM stage by the LCSGJ Stage I Stage II Stage III Stage IV-A Stage IV-B T1 (fulfilling 3 T factors) N0 M0 T2 (fulfilling 2 T factors) N0 M0 T3 (fulfilling 1 T factors) N0 M0 T4 (fulfilling 0 T factors) N0 M0 Any T N0 1 M1 T factor: (1) single, (2) <2 cm and (3) no vascular involvement. ( table 1 ). This innovative staging system is again unique to Japan and differentiates itself from the TNM classification system used worldwide that was developed by the Union for International Cancer Control (UICC) and American Joint Committee on Cancer. A study that used the TNM classification systems proposed by the LCSGJ and the UICC to examine Japanese patients showed that the former system allowed for more accurate stratification [14]. This also demonstrates that Japan s General Rules for the Clinical and Pathological Study of Primary Liver Cancer have developed in a unique way. These General Rules for the Clinical and Pathological Study of Primary Liver Cancer are important not only in providing a common language for hepatologists, surgeons, pathologists and radiologists involved in the treatment of liver cancer to use, but also in unifying the description of survey items in the Nationwide Follow- Up Survey of Primary Liver Cancer, which is another large project run by the LCSGJ since its establishment in This huge database is an extremely important asset that is not available in any other country. Because HCC was treated only by surgical resection [15 17] in the 1970s before locoregional therapy [18 22] was developed in the 1980s, the general rules describe surgeryrelated items and the macroscopic and histopathological findings of surgical specimens in immense detail. In contrast, descriptions of locoregional therapies, such as ablation [21] and transcatheter arterial chemoembolization (TACE) [13, 23, 24], were relatively scarce up until the fourth edition, which was published in However, due to the rapid progress of these therapies for HCC, there was an urgent need to introduce terminology or descriptions about locoregional therapy and to establish detailed response evaluation criteria for treatment. These changes were made in the 2009 revision of the fifth edition. The outcome of treatment for HCC has conventionally been evaluated using the Response Evaluation Criteria for the Solid Tumors (RECIST), which was developed to assess the treatment response of other solid tumors. RECIST is not suitable though for evaluat- Kudo/Kitano/Sakurai/Nishida

3 Super high-risk: US, tumor marker measurement, every 3 4 months, dynamic CT or MRI, 6 12 months High-risk US, tumor marker measurement, every 6 months Dynamic MDCT (when MRI is not available) Dynamic Gd-EOB-DTPA MRI Hypovascular Hypervascular with washout Hypervascular without washout Gd-EOB-DTPA MRI Hepatobiliary phase Optional exam. 1 HCC SPIO MRI Angiography-assisted CT (CTAP, CTHA) Highly sensitive tumor marker measurement Gd-EOB-DTPA MRI Hepatobiliary phase Hypointense 2 HCC Iso hyperintense Biopsy Hypointense CEUS (Sonazoid) Hypervascular and/or defect in Kuppfer phase 3 HCC Iso hyperintense Hypovascular and no defect in Kuppfer phase Small nodule ( cm) Small nodule (< 1.5 cm) Early HCC Biopsy DN borderline Gd EOB-DTPA MRI (dynamic CT) every 3 6 months Fig. 1. Surveillance and diagnostic algorithm of HCC (proposed by LCSGJ 2014). 1 Cavernous hemangioma may show hypointensity on equilibrium (transitional) phase of dynamic Gd-EOB- DTPA MRI (pseudo-washout). It should be excluded by other sequences of MRI and/or other imaging modalities. 2 Cavernous hemangioma usually shows hypointensity on hepatobiliary phase of Gd- EOB-DTPA MRI. It should be excluded by other sequences of MRI and/or other imaging modalities. 3 Biopsy may be considered for confirmation. ing the treatment response of HCC. Therefore, the LCSGJ has developed unique criteria to evaluate the direct treatment effects by locoregional therapies such as ablation or TACE. However, following recent advances in systemic chemotherapy using the molecular targeted agent, sorafenib, the fifth edition was revised to include the response evaluation of systemic therapy and was reissued under the title Response Evaluation Criteria in Cancer of the Liver (RECICL) [25] in order to apply the criteria and to evaluate the outcome of systemic chemotherapy. The forthcoming sixth edition of the general rules in 2015 will include the revision of the TNM classification system for intrahepatic cholangiocarcinoma, descriptions of lymph node metastasis and HCC rupture and General Rules and Practice Guidelines for HCC in Japan more sophisticated revised response evaluation criteria, namely, RECICL version 1.1 [26]. These revisions will also improve the descriptions used in the follow-up survey, thus making all the revision efforts worthwhile. Clinical Practice Guidelines The essential elements of the Evidence-Based Clinical Practice Guidelines for Liver Cancer are the surveillance, diagnostic and treatment algorithms for HCC. The guidelines also cover prevention, diagnosis, surveillance, surgery, ablation therapy, TACE, systemic chemotherapy [27, 28], radiation therapy [29, 30], post-treatment follow-up, prevention of recurrence after curative treatment 767

4 HCC Extrahepatic spread No Yes Liver function Child-Pugh A/B Child-Pugh C Child- Pugh B/C Child- Pugh A Vascular invasion No Yes No Yes 1, 2 Number Size Single 1~3 Hypovascular Early HCC*3 3 cm >3 cm 4 or more Within Milan 6 criteria and age 65 Exceeding Milan criteria or age >65 Treatment Intensive follow-up Ablation Resection Ablation Resection TACE TACE+ Ablation 4 TACE 5 HAIC 5 Resection 6 Ablation 6 Sorafenib 5 (TACE refractory, Child-Pugh A) HAIC (Vp1 4) 8 Sorafenib (Vp1 3) 8 TACE (Vp1,2) 9 Resection (Vp1,2) 9 Transplantation TACE/Ablation for Child-Pugh C pts 10 Palliative care Sorafenib Fig. 2. JSH-LCSGJ consensus-based treatment algorithm for HCC revised in Treatment should be performed as if extrahepatic spead is negative, when extrahepatic spread is not regarded as a prognostic factor. 2 Sorafenib is the first choice of treatment in this setting as a standard of care. 3 Intensive follow-up observation is recommended for hypovascular nodules by the Japanese Evidence-Based Clinical Practice Guidelines. However, local ablation therapy is frequently performed in the following cases: (1) when the nodule is diagnosed pathologically as early HCC; (2) when the nodules show decreased uptake on hepatocyte phase Gd- EOB-MRI; (3) when the nodules show decreased portal flow by CTAP or (4) decreased uptake is shown on Kupffer phase of Sonazoid enhanced US, since these nodules are known to frequently progress to the typical hypervascular HCC. 4 Even for HCC nodules exceeding 3 cm in diameter, combination therapy of TACE and ablation is frequently performed when resection is not indicated. 5 Transcathetherarterial chemoembolization (TACE) is the first choice of treatment in this setting. Hepatic arterial infusion chemotherapy (HAIC) using an implanted port is also recommended for TACE refractory patients. The regimen for this treatment is usually low-dose FP (5FU + CDDP) or intraarterial 5FU infusion combined with systemic interferon therapy. Sorafenib is also a treatment of choice for TACE refractory patients with Child Pugh A liver function. 6 Resection is sometimes performed even when numbers of nodules are over 4. Furthermore, ablation is sometimes performed in combination with TACE. 7 Milan criteria: Tumor size <3 cm and tumor numbers <3; or solitary tumor <5 cm. Even when liver function is good (Child-Pugh A/B), transplantation is sometimes considered for frequently recurring HCC patients. 8 Sorafenib and HAIC are recommended for HCC patients with Vp1,2 (minor portal vein invasion), Vp3 (portal invasion at the 1st portal branch). Sorafenib is not recommended for HCC patients with Vp4 (portal invasion at the main portal branch), whereas HAIC is recommended for such patients with tumor thrombus in the main portal branch. 9 Resection and TACE is frequently performed when portal invasion is minimum such as Vp1(portal invasion at the 3rd or more peripheral portal branch) or Vp2 (portal invasion at the 2nd portal branch). 10 Local ablation therapy or subsegmental TACE is performed even for Child-Pugh C patients when transplantation is not indicated when there is no hepatic encephalopathy, no uncontrollable ascites, and a low bilirubin level (<3.0 mg/dl). Although it is as a well accepted treatment in the routine clinical setting, there is no evidence of its survival benefit in Child-Pugh C patients. A prospective study is necessary to clarify this issue. Even in Child-Pugh A/B patients, transplantation is sometimes performed for relatively younger patients with frequently or early recurring HCC after curative treatments. 768 Kudo/Kitano/Sakurai/Nishida

5 Table 2. Definition of TACE failure/refractoriness (LCSGJ) 1 Intrahepatic lesion (i) Two or more consecutive insufficient responses within the treated tumors (viable lesion >50%) even after changing the chemotherapeutic agents and/or re-analysis of feeding artery can be seen by response evaluation CT/MRI after the 1 3 months following adequately performed selective TACE (ii) Two or more consecutive progression in the liver (tumor numbers even increase as compared to the tumor numbers before the previous TACE procedure) even after changing the chemotherapeutic agents and/or re-analysis of feeding artery can be seen by response evaluation CT/ MRI after the 1 3 months following adequately performed selective TACE 2 Tumor marker Continuous elevation of tumor markers right after TACE even though transient minor reduction is observed 3 Appearance of vascular invasion 4 Appearance of extrahepatic spread General Rules and Practice Guidelines for HCC in Japan and treatment for recurrence. These issues are introduced in a Clinical Questions format, in which questions routinely asked in daily clinical practice are answered based on facts with a high level of evidence that are reported in scientific articles selected during an extensive review of the literature. Evidence levels and recommended grades are listed to assist the diagnosis and treatment of HCC in daily clinical practice. The surveillance and diagnostic algorithm, the most important part of the clinical practice guidelines, recommends regular ultrasound and tumor marker screening using 3 markers (AFP, AFP-L3 and PIVKA-II) [31 33] or annual-to-semiannual CT or MRI depending on whether the patients are categorized as very high-risk or high-risk patients. The treatment algorithm presents treatment strategies that are in line with the severity of liver damage and the number and size of tumors [8, 9]. The 2013 edition states that the Child-Pugh classification can be used when non-surgical therapy is applied [3, 10]. But, it should be noted that, since the consensus-based surveillance and diagnostic algorithm is relatively complex, it is scheduled to be simplified considerably in the 2015 edition ( fig. 1 ) [7]. This was the results of consensus meeting at the 50th Annual Meeting of LCSGJ (Congress President: Prof. Masatoshi Kudo). In addition, the proposed treatment algorithm provides extremely useful guidance for daily clinical practice because it contains a list of practical treatment strategies that are being performed in accordance with current treatment policies developed based on expert opinion and consensus ( fig. 2 ). The criteria for TACE failure/refractoriness were also included in the third edition of the guidelines ( table 2 ) [34]. It was revealed at the 48th LCSGJ Congress (Congress President, Prof. Osamu Matsui, Kanazawa University) [35] that over 90% of physicians specializing in liver cancer who diagnose and treat liver cancer refer to the JSH s Evidence-based Clinical Practice Guidelines for HCC or Consensus-based Clinical Practice Guidelines for HCC. This indicates how well these guidelines complement each other and assist in optimizing diagnosis and treatment of liver cancer in Japan. Conclusion This review outlines the significance of establishing general rules, a nationwide follow-up survey and clinical practice guidelines for liver cancer in Japan. The general rules are an essential part of HCC treatment, enabling a common language to be used in daily clinical practice and for the nationwide follow-up survey. The Japanese General Rules for the Clinical and Pathological Study of Primary Liver Cancer [2], which provide detailed descriptions of HCC, are excellent and are unique to Japan. Items in the General Rules for the Clinical and Pathological Study of Primary Liver Cancer are used substantially in another important project, the Nationwide Follow-Up Survey of Primary Liver Cancer which has been rigorously undertaken with great effort by the LCSGJ biannually since Both the evidence-based and consensus-based treatment algorithms for HCC are used to complement each other in clinical practice in Japan. The most important point going forward is that prospective clinical trials are needed to accumulate solid evidence for the recommendations proposed in the consensus-based treatment algorithm, which are not included in the evidence-based clinical practice guidelines because of the lack of such evidence. In fact, clinical trials are now looking for evidence, and include the SURF trial (UMIN No. UMIN ), SILIUS trial (NCT Trial No ), TACTICS trial (NCT Trial No ) and DELICATE trial. Their results are eagerly awaited. Disclosure Statement The authors declare that they have no conflict of interest. 769

6 References 1 The Liver Cancer Study Group of Japan: The General Rules for the Clinical and Pathological Study of Primary Liver Cancer, ed 5, Rivised Version. Tokyo, Kanehara, Liver Cancer Study Group of Japan: General Rules for the Clinical and Pathological Study of Primary Liver Cancer, ed 3. Tokyo, Kanehara & Co., Ltd., Japan Society of Hepatology: Evidence-Based Clinical Practice Guidelines for Hepatocellular Carcinoma. Tokyo, Kanehara & Co., Japan Society of Hepatology: Management of Hepatocellular Carcinoma in Japan: Consensus-Based Clinical Practice Manual, ed 2. Tokyo, Igaku-Shoin, Kudo M, Izumi N, Kokudo N, Matsui O, Sakamoto M, Nakashima O, Kojiro M, Makuuchi M: Management of hepatocellular carcinoma in Japan: consensus-based clinical practice guidelines proposed by the Japan society of hepatology (JSH) 2010 updated version. Dig Dis 2011; 29: Chow PK: Intra-arterial radiotherapy for advanced HCC with vascular invasion. Liver Cancer 2014; 3: Kudo M, Matsui O, Izumi N, Iijima H, Kadoya M, Imai Y, Okusaka T, Miyayama S, Tsuchiya K, Ueshima K, Hiraoka A, Ikeda M, Ogasawara S, Yamashita T, Minami T, Yamakado K; Liver Cancer Study Group of Japan: JSH consensus-based clinical practice guidelines for the management of hepatocellular carcinoma: 2014 update by the Liver Cancer Study Group of Japan. Liver Cancer 2014; 3: Kokudo N, Makuuchi M: Evidence-based clinical practice guidelines for hepatocellular carcinoma in Japan: the J-HCC guidelines. J Gastroenterol 2009; 44(suppl 19): Makuuchi M, Kokudo N, Arii S, Igaki H, Ikai I, Kaneko S, Kawasaki S, Kudo M, Matsuyama Y, Ohtomo K, Okazaki M, Omata M, Takayama T, Takayasu K, Tateishi R: Surveillance algorithm and diagnostic algorithm for hepatocellular carcinoma. Hepatol Res 2010; 40: Kokudo N, Hasegawa K, Akahane M, Igaki H, Izumi N, Ichida T, Uemoto S, Kaneko S, Kawasaki S, Ku Y, Kudo M, Kubo S, Takayama T, Tateishi R, Fukuda T, Matsui O, Matsuyama Y, Murakami T, Arii S, Okazaki M, Makuuchi M: Evidence-based clinical practice guidelines for hepatocellular carcinoma: the Japan society of hepatology 2013 update (3rd JSH-HCC guidelines). Hepatol Res 2015; Kudo M: Early hepatocellular carcinoma: definition and diagnosis. Liver Cancer 2013; 2: Clinical practice guidelines for hepatocellular carcinoma differ between Japan, United States, and Europe. Liver Cancer 2015; 4: Kudo M: Surveillance, diagnosis, treatment, and outcome of liver cancer in Japan. Liver Cancer 2015; 4: Makuuchi M, Belghiti J, Belli G, Fan ST, Lau JW, Ringe B, Strasberg SM, Vauthey JN, Yamaoka Y, Yamasaki S: IHPBA concordant classification of primary liver cancer: working group report. J Hepatobiliary Pancreat Surg 2003; 10: Mise Y, Sakamoto Y, Ishizawa T, Kaneko J, Aoki T, Hasegawa K, Sugawara Y, Kokudo N: A worldwide survey of the current daily practice in liver surgery. Liver Cancer 2013; 2: Shindoh J, Kaseb A, Vauthey JN: Surgical strategy for liver cancers in the era of effective chemotherapy. Liver Cancer 2013; 2: Kubo S, Takemura S, Sakata C, Urata Y, Uenishi T: Adjuvant therapy after curative resection for hepatocellular carcinoma associated with hepatitis virus. Liver Cancer 2013; 2: Minami Y, Yagyu Y, Murakami T, Kudo M: Tracking navigation imaging of transcatheter arterial chemoembolization for hepatocellular carcinoma using three-dimensional conebeam CT angiography. Liver Cancer 2014; 3: Khajornjiraphan N, Thu NA, Chow PK: Yttrium-90 microspheres: a review of its emerging clinical indications. Liver Cancer 2015; 4: Kudo M: Locoregional therapy for hepatocellular carcinoma. Liver Cancer 2015; 4: Lin SM: Local ablation for hepatocellular carcinoma in Taiwan. Liver Cancer 2013; 2: Teng W, Liu KW, Lin CC, Jeng WJ, Chen WT, Sheen IS, Lin CY, Lin SM: Insufficient ablative margin determined by early computed tomography may predict the recurrence of hepatocellular carcinoma after radiofrequency ablation. Liver Cancer 2015; 4: Raoul JL, Gilabert M, Piana G: How to define transarterial chemoembolization failure or refractoriness: a European perspective. Liver Cancer 2014; 3: Edeline J, Gilabert M, Garin E, Boucher E, Raoul JL: Yttrium-90 microsphere radioembolization for hepatocellular carcinoma. Liver Cancer 2015; 4: Kudo M, Kubo S, Takayasu K, Sakamoto M, Tanaka M, Ikai I, Furuse J, Nakamura K, Makuuchi M: Response evaluation criteria in cancer of the liver (RECICL) proposed by the Liver Cancer Study Group of Japan (2009 revised version). Hepatol Res 2010; 40: Kudo M, Ueshima K, Kubo S, Sakamoto M, Tanaka M, Ikai I, Furuse J, Murakami T, Kadoya M, Kokudo N: Response evaluation criteria in cancer of the liver (RECICL) (2015 revised version). Hepatol Res 2015, Epub ahead of print. 27 Peck-Radosavljevic M: Drug therapy for advanced-stage liver cancer. Liver Cancer 2014; 3: Siegel AB, El-Khoueiry AB, Finn RS, Guthrie KA, Goyal A, Venook AP, Blanke CD, Verna EC, Dove L, Emond J, Kato T, Samstein B, Busuttil R, Remotti H, Coffey A, Brown RS Jr: Phase I trial of sorafenib following liver transplantation in patients with high-risk hepatocellular carcinoma. Liver Cancer 2015; 4: Lee DS, Seong J: Radiotherapeutic options for hepatocellular carcinoma with portal vein tumor thrombosis. Liver Cancer 2014; 3: Choi C, Choi GH, Kim TH, Tanaka M, Meng MB, Seong J: Multimodality management for Barcelona clinic liver cancer stage C hepatocellular carcinoma. Liver Cancer 2014; 3: Kudo M: Alpha-fetoprotein-L3: useful or useless for hepatocellular carcinoma? Liver Cancer 2013; 2: Toyoda H, Kumada T, Tada T, Sone Y, Kaneoka Y, Maeda A: Tumor markers for hepatocellular carcinoma: simple and significant predictors of outcome in patients with HCC. Liver Cancer 2015; 4: Song P, Gao J, Inagaki Y, Kokudo N, Hasegawa K, Sugawara Y, Tang W: Biomarkers: evaluation of screening for and early diagnosis of hepatocellular carcinoma in Japan and china. Liver Cancer 2013; 2: Kudo M, Matsui O, Izumi N, Kadoya M, Okusaka T, Miyayama S, Yamakado K, Tsuchiya K, Ueshima K, Hiraoka A, Ikeda M, Ogasawara S, Yamashita T, Minami T: Transarterial chemoembolization failure/refractoriness: JSH-LCSGJ criteria 2014 update. Oncology 2014; 87(suppl 1): Kudo M, Matsui O, Sakamoto M, Kitao A, Kim T, Ariizumi S, Ichikawa T, Kobayashi S, Imai Y, Izumi N, Fujinaga Y, Arii S: Role of gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging in the management of hepatocellular carcinoma: consensus at the symposium of the 48th annual meeting of the Liver Cancer Study Group of Japan. Oncology 2013; 84(suppl 1): Kudo/Kitano/Sakurai/Nishida