Fifty‐year history of biliary surgery

Abstract There has been enormous progress in the surgical treatment of biliary tract cancers in the past 50 years. In preoperative management, biliary drainage methods have changed from percutaneous transhepatic biliary drainage to endoscopic nasobiliary drainage, while the advent of multidetector‐row computed tomography in imaging diagnostics now enables visualization of three‐dimensional anatomy, extent of cancer progression, and hepatic segment volume. Portal vein embolization has also greatly improved the safety of extended hepatectomy, and indication of extended hepatectomy can now be objectively determined with a combination of the indocyanine green test and computed tomography volumetry. In terms of surgery, combined resection and reconstruction of the portal vein and/or hepatic artery can now be safely carried out at specialized centers. Further, long‐term survival can be attained with combined vascular resection if R0 resection can be achieved, even in locally advanced cancer. Hepatopancreatoduodenectomy, combined major hepatectomy with pancreatoduodenectomy, should be aggressively carried out for laterally advanced cholangiocarcinoma, whereas its indication for advanced gallbladder cancer should be carefully evaluated. Japanese surgeons have made a significant contribution to the progression of extended surgeries such as combined vascular resection and hepatopancreatoduodenectomy for biliary tract cancer.


| INTRODUC TI ON
Diseases treated by biliary surgery are broadly divided into biliary tract cancers such as cholangiocarcinoma, gallbladder cancer, and carcinoma of Vater's ampulla and benign diseases such as cholelithiasis, bile duct injury, and postoperative bile duct stricture.
As a result of the limited literature available, this article will review the history of surgical treatments for biliary tract cancers, focusing on preoperative management and extended surgical procedures in particular.

| Preoperative biliary drainage
In the 1980s, a number of randomized controlled trials (RCT) were conducted in Western countries on the clinical value of percutaneous transhepatic biliary drainage (PTBD). [1][2][3] Results of the RCT showed that preoperative drainage with PTBD had no favorable effects on surgical outcome, with no advantages in terms of cost. | 599 NAGINO However, the majority of the study cases involved palliative resections including bypass surgery, and only a small number of hepatectomy cases for biliary tract cancers were included. Furthermore, in many of the RCT, the incidence of complications caused by PTBD itself was extremely high, and drainage duration was insufficient, so Japanese surgeons did not accept these results. In Japan, preoperative biliary drainage with PTBD was widely implemented until approximately 2010 ( Figure 1). However, PTBD was found to cause so-called seeding metastasis, including sinus tract recurrence, 4 peritoneal dissemination, 5,6 or pleural dissemination; 7 thus, endoscopic nasobiliary drainage (ENBD) is commonly carried out as preoperative drainage before extended hepatectomy for biliary cancer. [8][9][10] Now, ENBD is recommended as first-line treatment in Japanese clinical practice guidelines for the management of biliary tract cancers. 11 As ENBD is external drainage where the drained bile is eliminated out of the body, it is recommended to return the bile to the intestinal tract. 10,12 ENBD is a superior method with few cholangitis complications, but it does present pharyngeal discomfort, 13 so, in the future, it is highly likely to be replaced with an inside stent. 14

| Preoperative diagnostic modality
Prior to 2000, along with direct cholangiography with percutaneous transhepatic cholangiography (PTC)/PTBD, abdominal angiography was also widely used to ascertain the anatomy of the hepatic artery (HA) and portal vein (PV) and to diagnose the extent of cancer as a preoperative diagnostic imaging modality (1). The advent of multidetector-row computed tomography (MDCT) in the 2000s drastically changed preoperative imaging diagnostics in the field of hepatobiliary-pancreatic medicine. MDCT used in combination with a workstation for image analysis easily generates a great deal of information within 1-2 hours after taking the CT scan, including diagnosis of the extent of cancer; 15-17 diagnosis of distant metastases in areas such as the peritoneum, liver, or lymph nodes, 18 D structure of the HA, PV and hepatic vein, [19][20][21][22] and volume of the hepatic segments. [21][22][23] Consequently, abdominal angiography was never implemented. In many cases, the resection procedure could be planned based on MDCT information alone. In our clinic, MDCT is routinely carried out on the day of admission and, based on this information, the site of biliary drainage is determined and portal vein embolization is scheduled. Magnetic resonance imaging (MRI) and positron emission tomography are used only for selected patients.
Around the time when PTBD was widely implemented, biopsy for biliary tract cancer was done by percutaneous transhepatic cholangioscopy (PTCS). 24 However, as mentioned above, due to concerns about seeding metastasis associated with PTBD, 4-7 PTCS is not used for preoperative biliary biopsy. Instead, an endoscopic transpapillary approach is now commonly used. 25 Externally drained bile has been used for bile cytology, but the accuracy of this method is modest, at approximately 50%. 26,27 Unlike stomach cancer and colon cancer, it is difficult to repeatedly take sufficient biopsy samples for bile duct cancers. Thus, surgery is often carried out when cancer is strongly suspected based on imaging findings, even without preoperative histological confirmation. Consequently, approximately 3% of cases resected as perihilar cholangiocarcinoma are so-called misdiagnoses, where the lesion is diagnosed as benign in final pathology. 28

| Liver function assessment and portal vein embolization
Loading test using indocyanine green (ICG) has traditionally been used in Japan as preoperative liver function tests for over 30 years.
Asialoscintigraphy and galactose tolerance tests are also used as liver function tests. However, there are no methods superior to the ICG test in terms of simplicity and reliability, and this test is still routinely carried out before hepatectomy ( Figure 1). The most important aspect from the perspective of clinical surgery is accurately predicting the extent of resection rate based on liver function, prior

| CHANG E S IN E X TENDED SURG ERY FOR B ILIARY TR AC T C AN CER S
Hepatectomy combined with vascular resection (combined resection of the PV and/or HA) and hepatopancreatoduodenectomy (HPD) are proposed as extended surgery for biliary tract cancers. Below, the changes in these procedures are described.

| Hepatectomy with combined vascular resection
Doctor Kajitani from the Cancer Institute Hospital carried out the world's first hepatectomy with PV resection for perihilar cholangiocarcinoma on August 6, 1965. 47 He resected the right hepatic lobe, but not the caudate lobe. The PV including portal bifurcation was resected and reconstructed by anastomosis between the upstream side of the PV and the inferior vena cava in an end-to-side method (Eck fistula). Operative time was 4 hours and 2 minutes, and blood loss was 4300 g. The patient developed no liver failure despite the Eck fistula and was discharged in good health, but died of cancer recurrence 3 years and 11 months later. Thereafter, until around 1990, Longmire, 48 Fortner, 49 Tsuzuki, 50 Blumgart,51 and Sakaguchi, 52 and respective colleagues reported their surgical experience with hepatectomy with PV resection, but there were only a few cases in each study. In 1981, Tsuzuki et al from Keio University reported two cases of left hepatectomy with simultaneous resection of the PV and HA. 50 Both patients tolerated the procedure but died of cancer recurrence at 1 year and 6 months and at 1 year and 3 months later, respectively. Nonetheless, these were the world's first successful cases of simultaneous resection of the PV and HA, and represented a groundbreaking report (Table 1).
By the 1990s, reports appeared on combined vascular resections for over 20 patients. 53,[55][56][57][58] In 1991, Nimura et al from Nagoya University described surgical outcomes of 29 cases of hepatectomy with PV resection for locally advanced biliary tract cancers; this was the first large series study on combined PV resection for biliary tract cancer. 53

| Major hepatopancreatoduodenectomy
Major HPD, which combines major hepatectomy with pancreatoduodenectomy, is the most difficult surgical procedure. The world's first case of major HPD was carried out on June 12, 1974, at the Cancer Institute Hospital for a bulky advanced gallbladder cancer involving the duodenum. The surgeon was Dr Kuno, the chief surgeon of the hospital. Operative time was 6 hours and 25 minutes, and blood loss was 3270 mL. The patient was discharged after 2 months but died of cancer recurrence 5 months postoperatively. Kasumi et al gave a brief report of this case, 70 whereas the first detailed report on major HPD was written by Takasaki et al from Tokyo Woman's Medical School. 71 They carried out major HPD on five patients with advanced gallbladder cancer. All patients underwent extended right hepatectomy, and all surgeries were advanced in a PD-first method. 71 Unfortunately, three of the five patients died of postoperative complications, while the remaining two patients survived recurrence-free for 16 months and 5 months, respectively. In the 1980s, major HPD was resolutely carried out by Japanese surgeons mainly for advanced gallbladder cancer, but the mortality rate was high and prognosis was poor (Table 2). [70][71][72][73][74][75] At that time, major HPD was not carried out outside of Japan, so the valuable and challenging achievements by Japanese surgeons in the early days of major HPD were all written in Japaneselanguage literature, [70][71][72][73][74][75] and it is extremely regrettable that these reports were not communicated to the rest of the world. (3), and the mortality rate has fallen below 20%. [76][77][78][79][80][81][82][83][84][85][86] An important finding identified in these reports was that, although major HPD could achieve good prognosis for cholangiocarcinoma, there was no improvement in prognosis when major HPD was carried out for advanced gallbladder cancer. Ebata et al from Nagoya University reported on the outcome of HPD for 85 cases of cholangiocarcinoma and found the mortality rate was low at 2% and the 5-year survival rate for all resected patients was 37%. 81 The long-term outcomes were extremely good with 5-year survival of 54% in 57 patients who underwent R0 resection, with no distant metastasis. 81    and/or pancreas that required major HPD. Therefore, the authors mentioned that upfront surgery is not indicated for such advanced gallbladder cancer and, instead, it is recommended to first carry out chemotherapy, then reassess the patient's condition before deciding on resection. 86 Indication for major HPD should be considered separately for cholangiocarcinoma and gallbladder cancer.

Several reports have been written since 2000
Although not mentioned in detail, it is evident that reduction of intraoperative blood loss has greatly contributed to the improvement of the safety of hepatobiliary surgery. 87 Extended hepatobiliary resections presented here are still associated with much intraoperative blood loss; thus, further reduction of blood loss is key to further improve surgical outcome after extended resection.

| CLOS ING REMARK S
In all modesty, undoubtedly Japanese surgeons ( Figure 2) have made significant contributions to the progression of biliary surgery, particularly difficult extended surgery for biliary tract cancers. Hepatectomy with PV resection, 47 hepatectomy with simultaneous resection of the PV and HA, 50 and major HPD, 70 all of which are still demanding to carry out, were successfully done for the first time by Japanese surgeons. We thus have great pride in these achievements. Japanese surgeons may be suited to surgical treatment of biliary tract cancers, which require careful pre-and postoperative management and meticulous surgical techniques.
Although we should express respect for the pioneers of these techniques, we must also strongly encourage further developments in biliary surgery.

D I SCLOS U R E
Conflicts of Interest: Author declares no conflicts of interest for this article.