Evaluation of positive ductal margins of biliary tract cancer in intraoperative histological examination
- Authors:
- Published online on: September 21, 2018 https://doi.org/10.3892/ol.2018.9479
- Pages: 6677-6684
Abstract
Introduction
Biliary tract cancer, including cancers of the gallbladder and extrahepatic bile duct, is rare but highly fatal (1), and complete surgical resection is the only treatment that offers a chance of cure in patients (2). Although preoperative diagnosis has been improved by modern imaging techniques, it is still difficult to diagnose the extent of cholangiocarcinoma infiltration (3). Currently, the only method to confirm microscopic infiltration of cancer into ductal resection margins during surgery is intraoperative histological examination. However, some reports have revealed that prognosis for patients with positive bile duct stumps does not differ significantly from that of negative patients (4). Moreover, recent studies have shown that additional resection of a positive proximal bile duct margin does not offer any survival advantage (4,5). It remains controversial whether additional resection of the bile duct has a favorable impact on the patient outcomes (5). The impact of remnant carcinoma in situ (CIS) at the bile duct stump on on postoperative course remain unclear (4). In this study, surgical margin status and postoperative course were evaluated in 93 patients with biliary tract cancer to determine any correlation between remnant carcinoma and postoperative survival. Positive margin cases were divided into two groups, invasive carcinoma and carcinoma in situ, and the postoperative survival and recurrence-free survival were evaluated. Immunohistochemical staining targeting Ki67 and p53 for positive margins and invasion portion was conducted to evaluate the correlation between expression of these proteins and prognosis.
Patients and methods
Patients
All consecutive patients who underwent resection for biliary tract cancer at our institution between January 2004 and May 2012 were identified from a database. The number of cases was 93. Patients with carcinoma of the ampulla of Vater and intrahepatic cholangiocarcinoma were excluded. Data collection and analysis were performed according to institution guidelines in conformance with the ethical standards of the Declaration of Helsinki. The present study was approved by the Ethics Committee of Nippon Medical School Tamanagayama Hospital (Tokyo, Japan), and a consent form signed by patients prior to the start of the study.
Margin status
In practice, margins of at least 5 mm are recommended to achieve curative resection. Intraoperative histological examination is routinely used to assess the bile duct margin. If evidence or possibility of a tumour-positive margin is observed during this examination, additional resection of the proximal duct is performed, but only as far as it is technically feasible. All duct margins submitted for intraoperative histological examination are then re-evaluated later by permanent pathology. Margin status is classified as negative, positive with CIS, or positive with invasive carcinoma.
Immunostaining and scoring
In this study we used the cancer tissues in ductal margin. The paraffin-embedded serial tissue sections (3.5-µm thick) were subjected to immunostaining using Histofine Simple Stain Max-PO kits. Antigen Activation Liquid (pH 9.0; Nichirei Biosciences, Inc., Tokyo, Japan) at 121°C for 15 min. Endogenous peroxidase was blocked in 0.3% hydrogen peroxide and methanol for 30 min. Sections were then incubated with antibodies for p53 (cat. no. 20050705; dilution, 1:50) and Ki-67 (MIB1; cat. no. 20049476; dilution, 1:500; both Dako; Agilent Technologies, Inc., Santa Clara, CA, USA) in phosphate-buffered saline containing 1% bovine serum albumin (Sigma-Aldrich; Merck KGaA, Darmstadt, Germany) for 16 h at 4°C. The sections were further incubated with the Histofine Simple Stain™ MAX-PO (R; Nichirei Biosciences, Inc.) for 30 min, and peroxidase activity was visualized by 3,3′-diaminobenzidine. The sections were then counterstained with hematoxylin. Evaluation of the degree and positive ratio of p53 and ki-67 immunostaining was conducted using the following scale: 0, no staining; 1+, mild staining; 2+, moderate staining; and 3+, intense staining; and 0, no staining; 1+, 1–30% positive ratio in cancer cells; 2+, 31–60%; and 3+, >60% (6).
Clinicopathological features
Clinicopathological data included age, sex, location of the main tumour, surgical dissection margin, pathological depth of invasion (pT), major vessel invasion (A, PV), minor vein invasion (v), lymph duct invasion (ly), pathological lymph node metastasis category (pN), pancreas invasion (Panc), duodenal invasion (Du), hepatic invasion (Hinf), neural invasion (ne), bile duct distal margin (pDM), horizon margin (pHE), patholoical dissected margin (pEM), stage characterized according to the Japanese Society of Biliary Surgery Classification (7), date of recurrence, recurrence site, and date and cause of death. Sites of disease recurrence were confirmed by computed tomography and/or magnetic resonance imaging and/or positron emission tomography/computed tomography. When new findings of suspected cancer appeared, and cancer progression was observed by serial imaging, radiologic evidence of tumour recurrence was accepted without a biopsy. The date of the first radiologic finding of suspected cancer was recorded as the date of initial disease recurrence.
Statistical analysis
Statistical analysis was performed using the statistical software package SPSS, version 16.0 (SPSS, Chicago, IL, USA). Categorical variables were compared using the χ2 test or Fisher's exact test. Survival was calculated using the Kaplan-Meier method and compared by the log-rank test and Cox-regression analysis. P<0.05 was considered to indicate a statisticaly significant difference.
Results
During the study, 93 patients underwent curative intent resection. The clinical and pathological characteristics of the study participants are shown in Table I. The mean age of the patients was 69 years. The age range was 35–85 years and 61 patients were male (65.6%) and 32 patients were female (34.4%). There were 20 cases (21.5%) of positive-margin intraoperative histological examination and permanent pathological findings. The distribution of disease was as follows: 46 cases (49.5%) of common bile duct cancer (CBD), 25 cases (26.9%) of hiller cholangiocarcinoma (HCCA), and 22 cases (23.6%) of gall bladder cancer (GB). Operative procedures included 34 cases of pancreaticoduodenectomy, 32 cases of hemihepatectomy with bile duct resection, 16 cases of partial hepatectomy with bile duct resection, 8 cases cholecystectomy with bile duct resection, and 3 cases of hepatopancreatoduodenectomy. Next, patients were divided into two groups, a positive margin group (positive) and a negative margin group (negative). Clinicopathological findings were comparatively evaluated between the positive and negative groups (Table II). Cases with major vessel invasion were significantly higher in the positive group than in the negative group (P=0.0218). We focused on the positive group and further divided these patients into two subgroups according to resected margin status: CIS at the bile duct stump (CIS group, n=8) (Fig. 1A) and invasive carcinoma at any surgical margin (Invasive group, n=12) (Fig. 1B). No significant difference in clinicopathological findings between the two groups was observed. Recurrence and survival were significantly lower and higher, respectively, in the CIS group than in the Invasive group (Fig. 2). Immunohistochemical staining targeting p53 and Ki67 was conducted in the positive margins (Fig. 3). The expression levels of p53 and Ki67 in ductal margins were significantly higher in the Invasive group (P=0.035) (Table III). However, the expression levels in the invasion portion were not significantly different between the two groups. Moreover, no statistical correlations between the expression levels of p53 and Ki67 and survival and recurrence were observed (Fig. 4). In the positive group, resected margin status was the most important factor for recurrence-free survival according to Cox-regression analysis (Table IV).
 | Table III.No statistical correlation between the clinicopathological findings and expression of p53 and Ki67 was observed in the CIS and invasive groups. |
Discussion
Although histologically negative margins have been recognized as the most important independent determinant of survival, the additional resection of a diagnosed positive proximal bile duct is still controversial (4). Many studies have reported positive surgical margins as an important predictor of poor prognosis (8–11). According to several reports, however, the prognosis for patients with positive bile duct stumps does not differ significantly from that of carcinoma-negative patients. Moreover, some studies have even described long-term survival for patients with a positive surgical bile duct stump (12,13). Histologically positive surgical bile duct stumps can be further subclassified into two subtypes: Invasive carcinoma and CIS (4). Some reports have shown the survival rate of CIS groups to be no less than that of margin negative groups and higher than that of invasive groups (4). In this study, bile duct stumps were also divided into the same two groups. The recurrence and survival rates in the CIS group were not lower than those in the negative group (data not shown). The recurrence and survival rates were significantly lower and higher in the CIS group than in the Invasive group. The biological nature of main tumours with extensive superficial spread, which is likely to be responsible for remnant CIS, tends to be less malignant than that of conventional cholangiocarcinoma (4). Main tumours of extrahepatic bile duct carcinoma with extensive superficial spreading tend to have shallower invasion, more localized type gross appearance, and a more defined histological differentiation than conventional cholangiocarcinoma (14–16). Despite the usefulness of intraoperative histological examination in assessing tumour involvement in the bile duct, there are limitations to this method (17,18). A common feature of tumour spread is a submucosal pattern extending from 1 to 2 cm beyond the abnormal lesions, as observed in an imaging study (19). Intraoperative examination of margin status can be difficult due to the biological characteristics of this tumour, which involve the proximal microscopic spread of the disease along the bile duct, extending beyond the palpable macroscopic boundaries (17,20). Intraoperative histological examination may inaccurately differentiate between invasive carcinoma from epithelial atypia or dysplasia, especially in cases of inflammation of the ducts due to obstruction or a biliary drainage procedure (21). These factors lead to inaccurate diagnosis. Moreover, in our study, major vessel invasion was significantly more frequent in the carcinoma-positive group than in the carcinoma-negative group. When a positive surgical margin is identified, the state of the positive surgical margin must be examined more closely. The bile duct stump was also examined using immunohistochemical staining targeting Ki67 and p53. Ki67 is a prognostic marker of tumour proliferation that has been extensively researched in retrospective studies (22). Its cellular location is strongly cell cycle dependent (23,24). Ki67 levels are low during G1 and early S phase and peak during mitosis (22). p53 functions as a transcription factor involved in cell-cycle control, DNA repair, apoptosis and cellular stress responses (25). The tumour suppressor gene p53 was the first identified cancer gene (26). During cell cycle arrest, p53 functions by upregulating cyclin-dependent kinase (cdk) inhibitor p21, which can be detected as an immunohistochemical overexpression (27–29). Inactivation of p53 caused by missense mutations or interaction with oncogenic viral proteins results in a selective growth advantage for cancer cells (30,31). Most p53 gene mutations stop tumour suppressor activity (32). The frequency of p53 overexpression in cholangiocarcinoma is reported to vary from 19 to 58% (32–37). In this study, immunohistochemical staining targeting Ki67 and p53 in surgical bile duct stumps did not show a correlation with overall survival or recurrence-free survival. The histopathological findings of surgical bile duct stumps, whether positive with CIS or positive with invasive carcinoma, were more important than immunohistochemical staining findings.
In this study, we did not perform the experiment using the cell lines. Further studies were recommended to verify our results.
Some report showed the radiotherapy for biliary tract cancer (38). However, the radiotherapy for biliary tract cancer is not established. Some report showed the benefit of disease-free survival (39), but the evidence is insufficient due to the small number (<10) of 5-year survivors and retrospective study (38). Moreover, some reports have revealed the effectiveness of chemotherapy for biliary tract cancer (40). However, adjuvant chemotherapy for biliary tract cancer has not been investigated. Some reports evaluating the impact of adjuvant treatment with systemic chemotherapy suggested a benefit for high-risk patients with positive lymph nodes or positive resection margins (41,42). Prospective studies are needed. A large multi-national study (ACTICCA-1) is evaluating the combination of gemcitabine plus cisplatin for adjuvant chemotherapy with results expected within the next years (40,43).
Intraoperative histological examination of the surgical margin of the bile duct is essential during biliary tract cancer surgery. The status of the resected margin in the positive group was the most important factor for postoperative survival and recurrence in biliary tract cancer.
Acknowledgements
Not applicable.
Funding
No funding was received.
Availability of data and materials
The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.
Authors' contributions
JU, HY and EU designed the study, performed the experiments and wrote the manuscript. YMa, NT, MY, AH, YK, YMi, TS, TK, HT and RK performed the experiments. All authors read and approved the final manuscript.
Ethics approval and consent to participate
The present study was approved by the Ethics committee of Nippon Medical School, Tamanagayama Hospital (approval no. 407) and written informed consent was obtained from all participants.
Patient consent for publication
Not applicable.
Competing interests
The authors declare that they have no competing interests.
References
|
Castro FA, Koshiol J, Hsing AW and Devesa SS: Biliary tract cancer incidence in the United States-demographic and temporal variations by anatomic site. Int J Cancer. 133:1664–1671. 2013. View Article : Google Scholar : PubMed/NCBI | |
|
Konishi M, Ochiai A, Ojima H, Hasebe T, Mano M, Ohta T, Ito I, Sasaki K, Yasukawa S, Shimada K, et al: A new histological classification for intra-operative histological examination of the ductal resection margin in cholangiocarcinoma. Cancer Sci. 100:255–260. 2009. View Article : Google Scholar : PubMed/NCBI | |
|
Konishi M, Iwasaki M, Ochiai A, Hasebe T, Ojima H and Yanagisawa A: Clinical impact of intraoperative histological examination of the ductal resection margin in extrahepatic cholangiocarcinoma. Br J Surg. 97:1363–1368. 2010. View Article : Google Scholar : PubMed/NCBI | |
|
Nakanishi Y, Kondo S, Zen Y, Yonemori A, Kubota K, Kawakami H, Tanaka E, Hirano S, Itoh T and Nakanuma Y: Impact of residual in situ carcinoma on postoperative survival in 125 patients with extrahepatic bile duct carcinoma. J Hepatobiliary Pancreat Sci. 17:166–173. 2010. View Article : Google Scholar : PubMed/NCBI | |
|
Ribero D, Amisano M, Lo Tesoriere R, Rosso S, Ferrero A and Capussotti L: Additional resection of an intraoperative margin-positive proximal bile duct improves survival in patients with hilar cholangiocarcinoma. Ann Surg. 254:776–783. 2011. View Article : Google Scholar : PubMed/NCBI | |
|
Matsuda Y, Yamamoto T, Kudo M, Kawahara K, Kawamoto M, Nakajima Y, Koizumi K, Nakazawa N, Ishiwata T and Naito Z: Expression and roles of lumican in lung adenocarcinoma and squamous cell carcinoma. Int J Oncol. 33:1177–1185. 2008.PubMed/NCBI | |
|
Miyazaki M, Ohtsuka M, Miyakawa S, Nagino M, Yamamoto M, Kokudo N, Sano K, Endo I, Unno M, Chijiiwa K, et al: Classification of biliary tract cancers established by the Japanese Society of Hepato-Biliary-Pancreatic Surgery: 3(rd) English edition. J Hepatobiliary Pancreat Sci. 22:181–196. 2015. View Article : Google Scholar : PubMed/NCBI | |
|
Kayahara M, Nagakawa T, Ohta T, Kitagawa H, Tajima H and Miwa K: Role of nodal involvement and the periductal soft-tissue margin in middle and distal bile duct cancer. Ann Surg. 229:76–83. 1999. View Article : Google Scholar : PubMed/NCBI | |
|
Burke EC, Jarnagin WR, Hochwald SN, Pisters PW, Fong Y and Blumgart LH: Hilar Cholangiocarcinoma: Patterns of spread, the importance of hepatic resection for curative operation and a presurgical clinical staging system. Ann Surg. 228:385–394. 1998. View Article : Google Scholar : PubMed/NCBI | |
|
DeOliveira ML, Cunningham SC, Cameron JL, Kamangar F, Winter JM, Lillemoe KD, Choti MA, Yeo CJ and Schulick RD: Cholangiocarcinoma: Thirty-one-year experience with 564 patients at a single institution. Ann Surg. 245:755–762. 2007. View Article : Google Scholar : PubMed/NCBI | |
|
Kondo S, Takada T, Miyazaki M, Miyakawa S, Tsukada K, Nagino M, Furuse J, Saito H, Tsuyuguchi T, Yamamoto M, et al: Guidelines for the management of biliary tract and ampullary carcinomas: Surgical treatment. J Hepatobiliary Pancreat Surg. 15:41–54. 2008. View Article : Google Scholar : PubMed/NCBI | |
|
Bhuiya MR, Nimura Y, Kamiya J, Kondo S, Nagino M and Hayakawa N: Clinicopathologic factors influencing survival of patients with bile duct carcinoma: Multivariate statistical analysis. World J Surg. 17:653–657. 1993. View Article : Google Scholar : PubMed/NCBI | |
|
Jarnagin WR, Fong Y, DeMatteo RP, Gonen M, Burke EC, Bodniewicz BS J, Youssef BA M, Klimstra D and Blumgart LH: Staging, resectability, and outcome in 225 patients with hilar cholangiocarcinoma. Ann Surg. 234:507–519. 2001. View Article : Google Scholar : PubMed/NCBI | |
|
Igami T, Nagino M, Oda K, Nishio H, Ebata T, Yokoyama Y and Shimoyama Y: Clinicopathologic study of cholangiocarcinoma with superficial spread. Ann Surg. 249:296–302. 2009. View Article : Google Scholar : PubMed/NCBI | |
|
Nakanishi Y, Zen Y, Kawakami H, Kubota K, Itoh T, Hirano S, Tanaka E, Nakanuma Y and Kondo S: Extrahepatic bile duct carcinoma with extensive intraepithelial spread: A clinicopathological study of 21 cases. Mod Pathol. 21:807–816. 2008. View Article : Google Scholar : PubMed/NCBI | |
|
Ojima H, Kanai Y, Iwasaki M, Hiraoka N, Shimada K, Sano T, Sakamoto Y, Esaki M, Kosuge T, Sakamoto M and Hirohashi S: Intraductal carcinoma component as a favorable prognostic factor in biliary tract carcinoma. Cancer Sci. 100:62–70. 2009. View Article : Google Scholar : PubMed/NCBI | |
|
Endo I, House MG, Klimstra DS, Gonen M, D'Angelica M, Dematteo RP, Fong Y, Blumgart LH and Jarnagin WR: Clinical significance of intraoperative bile duct margin assessment for hilar cholangiocarcinoma. Ann Surg Oncol. 15:2104–2112. 2008. View Article : Google Scholar : PubMed/NCBI | |
|
Okazaki Y, Horimi T, Kotaka M, Morita S and Takasaki M: Study of the intrahepatic surgical margin of hilar bile duct carcinoma. Hepatogastroenterology. 49:625–627. 2002.PubMed/NCBI | |
|
Baton O, Azoulay D, Adam DV and Castaing D: Major hepatectomy for hilar cholangiocarcinoma type 3 and 4: Prognostic factors and longterm outcomes. J Am Coll Surg. 204:250–260. 2007. View Article : Google Scholar : PubMed/NCBI | |
|
Sakamoto E, Nimura Y, Hayakawa N, Kamiya J, Kondo S, Nagino M, Kanai M, Miyachi M and Uesaka K: The pattern of infiltration at the proximal border of hilar bile duct carcinoma: A histologic analysis of 62 resected cases. Ann Surg. 227:405–411. 1998. View Article : Google Scholar : PubMed/NCBI | |
|
Lee JH, Hwang DW, Lee SY, Park KM and Lee YJ: The proximal margin of resected hilar cholangiocarcinoma: The effect of microscopic positive margin on long-term survival. Am Surg. 78:471–477. 2012.PubMed/NCBI | |
|
Konstantinos K, Marios S, Anna M, Nikolaos K, Efstratios P and Paulina A: Expression of Ki-67 as proliferation biomarker in imprint smears of endometrial carcinoma. Diagn Cytopathol. 41:212–217. 2013. View Article : Google Scholar : PubMed/NCBI | |
|
Isola J, Helin H and Kallioniemi OP: Immunoelectron-microscopic localization of a proliferation-associated antigen Ki-67 in MCF-7 cells. Histochem J. 22:498–506. 1990. View Article : Google Scholar : PubMed/NCBI | |
|
Verheijen R, Kuijpers HJ, Schlingemann RO, Boehmer AL, van Driel R, Brakenhoff GJ and Ramaekers FC: Ki-67 detects a nuclear matrix-associated proliferation-related antigen. I. Intracellular localization during interphase. J Cell Sci. 92:123–130. 1989.PubMed/NCBI | |
|
Rufini A, Tucci P, Celardo I and Melino G: Senescence and aging: The critical roles of p53. Oncogene. 32:5129–5143. 2013. View Article : Google Scholar : PubMed/NCBI | |
|
Basu A and Haldar S: The relationship between BcI2, Bax and p53: Consequences for cell cycle progression and cell death. Mol Hum Reprod. 4:1099–1109. 1998. View Article : Google Scholar : PubMed/NCBI | |
|
Greenblatt MS, Bennett WP, Hollstein M and Harris CC: Mutations in the p53 tumor suppressor gene: Clues to cancer etiology and molecular pathogenesis. Cancer Res. 54:4855–4878. 1994.PubMed/NCBI | |
|
Hussain SP and Harris CC: Molecular epidemiology of human cancer: Contribution of mutation spectra studies of tumor suppressor genes. Cancer Res. 58:4023–4037. 1998.PubMed/NCBI | |
|
Kang YK, Kim WH and Jang JJ: Expression of G1-S modulators (p53, p16, p27, cyclin D1, Rb) and Smad4/Dpc4 in intrahepatic cholangiocarcinoma. Hum Pathol. 33:877–883. 2002. View Article : Google Scholar : PubMed/NCBI | |
|
Harris CC: Structure and function of the p53 tumor suppressor gene: Clues for rational cancer therapeutic strategies. J Natl Cancer Inst. 88:1442–1455. 1996. View Article : Google Scholar : PubMed/NCBI | |
|
Levine AJ: The p53 tumor-suppressor gene. N Engl J Med. 326:1350–1352. 1992. View Article : Google Scholar : PubMed/NCBI | |
|
Diamantis I, Karamitopoulou E, Perentes E and Zimmermann A: p53 protein immunoreactivity in extrahepatic bile duct and gallbladder cancer: Correlation with tumor grade and survival. Hepatology. 22:774–779. 1995. View Article : Google Scholar : PubMed/NCBI | |
|
Jan YY, Yeh TS, Yeh JN, Yang HR and Chen MF: Expression of epidermal growth factor receptor, apomucins, matrix metalloproteinases, and p53 in rat and human cholangiocarcinoma: Appraisal of an animal model of cholangiocarcinoma. Ann Surg. 240:89–94. 2004. View Article : Google Scholar : PubMed/NCBI | |
|
Ohashi K, Nakajima Y, Kanehiro H, Tsutsumi M, Taki J, Aomatsu Y, Yoshimura A, Ko S, Kin T, Yagura K, et al: Ki-ras mutations and p53 protein expressions in intrahepatic cholangiocarcinomas: relation to gross tumor morphology. Gastroenterology. 109:1612–1617. 1995. View Article : Google Scholar : PubMed/NCBI | |
|
Tannapfel A, Engeland K, Weinans L, Katalinic A, Hauss J, Mössner J and Wittekind C: Expression of p73, a novel protein related to the p53 tumour suppressor p53, and apoptosis in cholangiocellular carcinoma of the liver. Br J Cancer. 80:1069–1074. 1999. View Article : Google Scholar : PubMed/NCBI | |
|
Teh M, Wee A and Raju GC: An immunohistochemical study of p53 protein in gallbladder and extrahepatic bile duct/ampullary carcinomas. Cancer. 74:1542–1545. 1994. View Article : Google Scholar : PubMed/NCBI | |
|
Washington K and Gottfried MR: Expression of p53 in adenocarcinoma of the gallbladder and bile ducts. Liver. 16:99–104. 1996. View Article : Google Scholar : PubMed/NCBI | |
|
Labib PL, Davidson BR, Sharma RA and Pereira SP: Locoregional therapies in cholangiocarcinoma. Hepat Oncol. 4:99–109. 2017. View Article : Google Scholar : PubMed/NCBI | |
|
Shinohara E, Mitra N, Guo M and Metz J: Radiation therapy is associated with improved survival in the adjuvant and definitive treatment of intrahepatic cholangiocarcinoma. Int J Radiat Oncol Biol Phys. 72:1495–1501. 2008. View Article : Google Scholar : PubMed/NCBI | |
|
Siebenhüner AR, Seifert H, Bachmann H, Seifert B, Winder T, Feilchenfeldt J, Breitenstein S, Clavien PA, Stupp R, Knuth A, et al: Adjuvant treatment of resectable biliary tract cancer with cisplatin plus gemcitabine: A prospective single center phase II study. BMC Cancer. 18:722018. View Article : Google Scholar : PubMed/NCBI | |
|
Horgan AM, Amir E, Walter T and Knox JJ: Adjuvant therapy in the treatment of biliary tract cancer: A systematic review and meta-analysis. J Clin Oncol. 30:1934–1940. 2012. View Article : Google Scholar : PubMed/NCBI | |
|
McNamara MG, Walter T, Horgan AM, Amir E, Cleary S, McKeever EL, Min T, Wallace E, Hedley D, Krzyzanowska M, et al: Outcome of adjuvant therapy in biliary tract cancers. Am J Clin Oncol. 38:382–387. 2015. View Article : Google Scholar : PubMed/NCBI | |
|
Stein A, Arnold D, Bridgewater J, Goldstein D, Jensen LH, Klümpen HJ, Lohse AW, Nashan B, Primrose J, Schrum S, et al: Adjuvant chemotherapy with gemcitabine and cisplatin compared to observation after curative intent resection of cholangiocarcinoma and muscle invasive gallbladder carcinoma (ACTICCA-1 trial)-a randomized, multidisciplinary, multinational phase III trial. BMC Cancer. 15:5642015. View Article : Google Scholar : PubMed/NCBI |
