Early gastric cancer in Europe

Abstract

Despite mass population screening and an incidence of EGC in Japan that is at least double that of the West, there seem to be no genuine differences in the clinicopathological features of the disease between the two regions. The macroscopic appearance, size, depth of invasion, frequency of lymph node invasion, and histology of EGC are all remarkably similar in Japan, Europe and America, as are sex and age distributions. Patients with EGC are a number of years younger than those with advanced cancer. This is not surprising: Tsukuma et al followed 56 cases of EGC that were not surgically treated and estimated that the median "duration of EGC" before becoming advanced was 37 months. This suggests that EGC undergoes a period of slow growth before becoming advanced. Further differences between early and advanced cancers include a higher frequency of synchronous cancers and a longer symptom duration in EGC. Unfavourable prognostic factors in EGC include lymph node invasion, and invasion through the muscularis mucosae, though it is not clear whether these are independent. Repeated attempts have been made to identify other prognostic factors, but no clear pattern has emerged, with the possible exceptions of patient age, tumour size, and the presence of ulceration. The postsurgical outcome of EGC in the West is marginally less favourable than in Japan. In view of the similar clinical and pathological features in the two regions it seems likely, therefore, that this is because of the more aggressive surgical techniques traditionally used in Japan. Conversely, however, EMR has recently emerged as an important technique in Japan. Despite the advantages of low operative mortality and normal function of the postoperative stomach, there are also a number of potential disadvantages. It would seem sensible, therefore, to await the results of long term follow up studies before widespread adoption of EMR in Europe. Nevertheless, this technique should be considered for frail patients unfit for more radical surgery.

Figure 1

: Macroscopic classification of early gastric cancer according to the Japanese Research Society for gastric cancer.

Figure 2

: Macroscopic classification of early gastric cancer: per cent of lesions that are depressed or excavated, or a combination of the two (IIc, III, IIc + III).

Figure 3

: Early gastric cancer and depth of invasion: per cent of lesions that have invaded mucosa alone or have invaded into the submucosa.

Figure 4

: Early gastric cancer according to the Lauren classification: per cent of cases with intestinal, diffuse, or mixed histology.

Figure 5

: Lymphadenopathy in early gastric cancer: per cent of cases with involved lymph nodes detected at time of operation.

Figure 6

: Lymphadenopathy in early gastric cancer according to depth of invasion: per cent of cases with involved lymph nodes detected at time of operation, divided into cases of mucosal invasion alone and cases in which the submucosa has been invaded.

Figure 7

: Recurrence rate of early gastric cancer. The recurrence rate was calculated from data published in the relevant references. It includes patients with recurrence of early gastric cancer regardless of ultimate survival. Operative mortality is excluded. Numbers above columns represent follow up in years (mean or median, as reported in the publication).

Figure 8

: Five year survival of patients with early gastric cancer: prognosis according to presence or absence of lymphadenopathy at time of operation. *Ten year survival.

Figure 9

: Five year survival of patients with early gastric cancer: prognosis to depth of invasion (mucosal or submucosal) at time of operation. *p < 0.05.