Gastric cancer in the East: same disease, different patient

Two large case series describing risk factors for morbidity and mortality in gastric cancer surgery are published in this issue. The series from Japan (Kodera et al.) and Korea (Park et al.) report excellent short-term outcomes for radical gastric cancer surgery in Eastern populations. Although the authors do not profess any great claim to originality, they do make valuable comparisons with Western studies. Both papers provide surgeons in the West with the simple message that gastrectomy can be performed with excellent results, but that increasing age and additional resection of the pancreas are associated with an increased risk of complications. Further analysis of the data raises more important issues about the practice and outcome of gastric cancer surgery in the West. The in-hospital mortality rates of 0·8 and 0·6 per cent respectively for series of 523 and 719 patients are extraordinary and have never been achieved in the West. The Japanese data are particularly impressive as these studies included only patients with locally advanced gastric cancer who were randomized to D2 or ultraradical D3 resection. One of the main reasons that even D2 resections have not been adopted widely in the West has been the increased rates of complications and high mortality rates of 13 and 10 per cent respectively reported by the UK Medical Research Council (MRC) and Dutch Trials1,2. The two papers in this issue provide further insight into whether these differences reflect volume effects and surgical expertise, a disease with different behaviour or a different population in the West. Surgical expertise is clearly a factor. The Seoul National University Hospital recruited over 700 patients at a single centre during a 12-month period, equivalent to 30 per cent of all resections performed in the UK per annum3. The Gastric Cancer Surgery Study Group of Japan has provided multicentre data, but this almost certainly reflects the best practice in that country. Expertise in postoperative management is evident in both studies. Despite experiencing all the major surgical complications that occur in Western practice, albeit at a much lower incidence, this rarely translated into death. A major criticism of the MRC and Dutch trials is the low volume of the recruiting centres and the relative inexperience of surgeons in performing radical gastric resection. Despite increasing experience, adoption of Japanese surgical techniques and development of specialist centres in the West, the lowest reported mortality rates are in the region of 5 per cent4. It has been suggested previously that gastric cancer in the West may be a different disease to that in Japan5, although there is no evidence to support this. Comparison of the results of gastric cancer treatment in racially similar Tokyo and Honolulu Japanese demonstrates poorer results for those treated by Western methods. The natural history of the disease, modes of spread, areas of recurrence and most prognostic factors are similar. One potential factor of significance in short-term outcome is the increasingly high proportion of both proximal and diffuse tumours in the West, where total gastrectomy has been associated with twice the mortality of a subtotal resection. Neither Kodera et al. nor Park et al. found the extent of gastric resection to be an independent risk factor for the development of complications. The most important difference between East and West appears to be in the population undergoing resection, a point highlighted in these papers. They confirm previous reports that Western patients are on average 10 years older, have a higher incidence of cardiovascular disease, are significantly more overweight and have a higher risk of thromboembolic complications. Unfortunately insufficient information is provided by either study with regard to co-morbidity and the incidences of cardiorespiratory disease, diabetes and cigarette smoking. Certainly no formal risk assessment model, such as those validated in the UK, were applied or referred to in either paper. Nevertheless, the average American Society of Anesthesiologists grade of 1·6 in the Korean series is low and Kodera et al. reported only one cardiac complication in 523 patients, unrecognizable from any published Western series. The patients are also younger; Park et al. noted that patients aged over 50 years were at an increased risk, and the absence of such an association in the Japanese series was attributed to the exclusion of patients older than 75 years. It is well recognized that obesity makes extended lymph node dissection more difficult6 and Kodera et al. found an association between obesity and increased morbidity. The difference in body habitus is starkly demonstrated by the fact that only 14 per cent of Japanese patients had a body mass index of over 25 and that this was considered obese. At present nearly 60 per cent of patients undergoing oesophagogastric resection in the UK fall into this category. We have learned an enormous amount regarding surgical technique and perioperative care from Japan and the East in general. It appears that there is much more to learn about the different populations that this disease affects. Despite careful patient selection, the higher associated co-morbidity of Western patients both increases the risk of non-surgical complications and lowers the patient's ability to tolerate any major surgical complications. We should not, however, simply blame poor results on the population and must strive towards the outcomes reported by these series. Clearly, true comparisons between populations cannot be made until accurate risk assessment models become standard practice. Only then will it be possible to assess truly how far we have come in managing what is clearly the same disease in a different population.