Current treatment strategies for early gastric cancer

Abstract

Most surgeons in Japan have long considered extended lymphadenectomy (D2 dissection) as an essential part of surgical treatment for gastric cancer (GC) to clear completely the possible involved nodes.Accordingly,more than two-thirds gastrectomy is thought to be a necessary procedure, even for early gastric cancer (EGC). This radical surgery for EGC can,as a consequence,achieve excellent 5-year survival rates of greater than 90% [1,2]. The accumulation of EGC patient records undergoing a D2 dissection, both from individual institutional records [3-10] and from a nation-wide archive [11], subsequently revealed that the incidences of positive nodes among mucosal and submucosal GC, respectively, ranged from 1.8%-5% to 10%-25%. However, almost all node-positive mucosal GC patients and approximately 70% of node-positive submucosal GC patients exhibited perigastric node involvement, suggesting that EGC rarely spreads beyond the perigastric area. These site-specific analyses of positive nodes have subsequently changed the concept of surgical strategy for EGC in that a uniform D2 dissection is not always necessary. On the other hand, it has been established that various degrees of physiological and nutritional disorders develop in a large proportion of patients following gastrectomy. These postgastrectomy sequelae include early and late dumping syndromes, reflux esophagitis and gastritis, alkaline regurgitation, weight loss, malabsorption, vitamin and mineral deficiencies, anemia,and metabolic bone diseases [12]. These sequelae are often symptomatic and cannot be ignored. Gastrectomy in association with a certain amount of lymphadenectomy results in a loss or decreased reservoir size, abnormalities in gastric emptying (either too rapid or delayed), a loss of pyloric function that causes alkaline regurgitation, decreased caloric intake, and a loss of gastric motility. Each status, sometimes in combination or sometimes as a group, is responsible for the postgastrectomy sequelae,which often aggravate the patient's postoperative quality of life.Against the background of the above excellent surgical outcomes and preferential node involvement in most EGC patients, current surgical trends for EGC have shifted from an extensive resection to the preservation of as much tissue as possible to provide a better postoperative quality of life (Fig. 1). The preservation of tissues in this regard means an optimization of the resection amount, which has two different aspects: one is a "reduced" scope of lymphadenectomy, and the other is a "reduced" resection of the stomach. These concepts are termed a "less invasive" surgery. The Japanese Gastric Cancer Association (JGCA) published guidelines for the treatment of GC in 2001 [13]. Along with the foregoing shift in trends, the guideline introduces various types of treatment for EGC as "recommended options" as well as "allowed but investigational options." Minimizing surgical trauma (morbidity and mortality) while maximizing patient quality of life and therapeutic effects, which should be at least equal to the currently achieved patient survivals, forms the main goal of the less invasive strategies (Fig. 1); thus, such optimizations should be considered on a stage-specific and individual basis. Therefore, accurate staging performance and careful patient selection procedures are mandatory.However, it is also a fact that the current staging is not absolutely accurate even by the introduction of routine use (7.5MHz) or higher resolution (15-20MHz) endoscopic ultrasonography. Individually based treatment strategies therefore face practical but unavoidable problems where underestimation phenomenon do occur in some instances, that is, a certain lesser extent of surgery, which is preoperatively considered to be optimal, proves to be insufficient for those patients who were postoperatively proved to have more advanced diseases. Therefore, survival outcomes encompassing underestimated patients constitute a substantial concern for evaluating the actual rationality of each less invasive strategy. This chapter introduces a spectrum of current less invasive surgical strategies for EGC and their comprehensive evaluations, such as their indications, survival outcomes, surgical invasiveness, and quality of life. © 2005 Springer-Verlag Tokyo.