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| Japanese Journal of Clinical Oncology | Pages |
Letters
Gastric Cancer Staging in Japan: a Comparison with British Practice
To the Editor:
I have recently had the opportunity and privilege of visiting the National Cancer Centre Hospital (NCCH), Tokyo, for four weeks in February 1997.
This was my second visit to Japan. I had previously visited Kyoto Prefectural University of Medicine for one week in 1994 and during this short visit I was so impressed with the overall approach to the management of gastric cancer that I was determined to visit Japan again.
The NCCH has previously received several visitors from Britain and organisation of the visit was fairly straightforward.
On my arrival at the NCCH it soon became apparent that it is a popular unit to visit as there were three other visitors (from Singapore, Italy and Uruguay) in the Gastric Cancer Division alone.
The main objective of my visit to the NCCH was to observe at first hand the techniques of the Japanese extended lymphadenectomy for gastric cancer. My primary objective was easily fulfilled as I had the opportunity to observe a large number of standard D2 resections as well as some D3 and D4 dissections.
Although all four surgeons employ basically the same technique, each had their own small variations, all of which were of help in clarifying some of the technical difficulties I have encountered in my own practice in Britain.
There are several important differences between the Japanese and British approaches to the management of gastric cancer and some of these have been described by other British surgeons who have had the opportunity to visit the NCCH (1,2).
The area that I personally feel needs to be emphasised is the large differences in the pre-operative staging of gastric cancer.
The reason for these differences largely stems from the different disease patterns seen in the respective countries. In Japan, more than 50% of all gastric cancers are Early Gastric Cancer (EGC), whereas in Britain, EGC accounts for less than 10% of all gastric cancers. The aim of the staging process is therefore quite different. Staging in Japan is performed so that other treatment modalities such as Endoscopic Mucosal Resection (EMR) can be considered, or if the patient is to undergo surgery then the appropriate level of lymph node dissection can be carried out. In Britain the primary aim of staging is to determine if the patient has disseminated disease and to therefore avoid ineffective surgery. The last point is particularly relevant as gastric cancer in Britain is a disease of the elderly, often with significant co-existing morbidity, with the highest incidence occurring in the eighth decade. This contrasts with the Japanese patients who on average are at least ten years younger and do not appear to suffer the same degree of cardio-respiratory disease as the British.
Endoscopy and barium meal examination are the main staging tools employed in Japan, whereas in Britain these tools are largely used for diagnosis alone.
Endoscopy at the NCCH is performed by specialists, the procedure is meticulously recorded by routine photography and indigo-carmine spray is used to enhance minor mucosal irregularities. Once a mucosal irregularity is found it is carefully assessed by noting its elevation or depression, its surface regularity and the absence or presence of ulceration. The surrounding mucosa is then closely examined. Particular note is made of the pattern of the converging folds and bank formation. Using these careful endoscopic techniques it is possible to accurately differentiate between EGC and advanced gastric cancer in over 90% of cases.
In contrast, endoscopy in Britain is carried out by a variety of practitioners, including trainee gastro-enterologists, surgeons and general practitioners. Many of these will not be aware of EGC and their primary aim is to diagnose `gross' disease.
There is a growing tendency for the introduction of specialist nurse endoscopists in Britain. They are usually nurses who work in the endoscopy unit and will have received specific training in diagnostic endoscopy. This may allow the development of a group of endoscopists who may be able to recognise the often subtle mucosal changes associated with EGC.
Barium meal examination is also extensively used as a staging tool and using careful radiological techniques gastric cancer can be accurately staged in up to 80% of cases.
The technique employs double contrast radiology using a barium meal with a high concentration and low viscosity. The patient's position is changed frequently and rapidly allowing the barium to flow onto the gastric mucosal surface at high speed resulting in effective coating of the mucosal surface. It is of note that at the NCCH both endoscopy and barium meals are used to stage gastric cancers and their accuracy is very similar. To an overseas visitor, like myself, it may appear that endoscopy would be the investigation of choice, particularly as endoscopy also provides tissue for histological examination. However, I think that the barium meal is an important examination as it provides the surgeon with a `road map' to guide him to the extent of the resection margins. This is particularly important in EGC as the lesion is often impalpable.
Barium meal examination is rarely used by British surgeons and is mainly used as an investigation to detect `gross' disease by general practitioners who may not have easy access to endoscopy. Many British radiologists have little knowledge of EGC and may not routinely employ the careful radiological techniques needed to detect EGC.
Endoluminal ultrasound (EUS) is used for selected patients at the NCCH and in most instances simply confirms the endoscopic and radiological staging. EUS in Britain is still very much in its infancy but it is gradually being introduced as a staging tool for gastric cancer. Its use in Britain is perhaps more appropriate given that we deal mainly with advanced gastric cancer and EUS may help to detect those patients in whom the tumour invades adjacent organs.
Trans abdominal ultrasound is routinely performed to detect distant and local metastases. Although there are differences in the actual techniques employed, the examination appears to be carried out with similar frequency, expertise and accuracy in both Britain and Japan.
At the NCCH, computed tomography (CT) is reserved for those patients who are likely to have advanced gastric cancer as predicted by endoscopy and barium meal examinations. As most British patients present with advanced disease, CT is performed in virtually all patients. However, it is only recently that special techniques, such as filling the stomach with water and altering the position of the patient, have been introduced into British radiological practice.
Despite the fact that British patients tend to have several investigations in an attempt to stage the tumour as accurately as possible, most surgeons have found that the tests performed are not sensitive enough to detect peritoneal carcinomatosis. At the NCCH, patients with advanced gastric cancer who may have peritoneal carcinomatosis undergo a double contrast barium enema investigation, which in their hands is an extremely sensitive method of detecting peritoneal dissemination.
In Britain, laparoscopy, often with laparoscopic ultrasound, is increasingly being used prior to laparotomy to detect peritoneal carcinomatosis. This procedure can detect peritoneal dissemination in 20-30% of patients in whom other staging techniques described above have failed to detect disseminated disease.
In summary, the surgeons at the NCCH will have a fairly accurate pre-operative assessment of the gastric tumour and will tailor their operation accordingly. In Britain, however, it is only with the use of invasive procedures, such as laparoscopy, that we are able to stage tumours with some degree of accuracy.
It is only with the use of meticulous endoscopic and radiological techniques which the Japanese have perfected that we can improve the pre-operative assessment of our British patients. Furthermore, it is important that we, like the doctors at the NCCH, have regular meetings with endoscopists and radiologists to provide essential feedback.
Finally I wish to thank all those involved in arranging and supporting this extremely useful visit and I am most grateful for the financial support of the British Council.
Sukhbir S Ubhi
Consultant Surgeon
Leicester Royal Infirmary
Leicester, United Kingdom
References
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Copyright© Japanese Journal of Clinical Oncology, 1997.