There are different classification schemes for gastric cancer, based on anatomic location within the stomach, histological subtype, as well as degree of invasion.

The most common symptoms at initial diagnosis of gastric cancer are weight loss (62 %) and persistent abdominal pain (52 %). Weight loss is often secondary to insufficient caloric intake that may be attributable to anorexia, nausea, early satiety, and dysphagia. Dysphagia is present in 26 % of patients and is a common symptom in cancers arising in the proximal stomach. Abdominal pain tends to be epigastric, vague and mild in early disease but more severe and constant as disease progresses. Nausea (34 %) is present in patients with linitis plastica with poor gastric distensibility or patients with gastric outlet obstruction due to an advanced distal tumor. Occult gastrointestinal bleeding is not uncommon and can be accompanied by iron deficiency anemia [26].

Tissue diagnosis and anatomic localization of the primary tumor are best obtained by upper gastrointestinal endoscopy. Although more invasive and more costly, upper endoscopy is also more sensitive and specific for diagnosing a variety of gastric, esophageal, and duodenal lesions than alternative diagnostic strategies (such as barium studies). The early use of upper endoscopy in patients presenting with gastrointestinal complaints may be associated with a higher rate of detection of early gastric cancers.

The ability to perform biopsy during endoscopy adds to the clinical utility of this modality. As up to 5 % of malignant ulcers appear benign grossly, it is imperative that all such lesions be evaluated by biopsy and histologic assessment [27]. A barium exam may be more useful is in patients with linitis plastica. The decreased distensibility of the stiff, “leather-flask”-appearing stomach is more apparent on a radiographic study, while the endoscopic appearance may be relatively normal.

The most widely used staging system in gastric cancer was developed jointly by the American Joint Committee on Cancer (AJCC) and the International Union Against Cancer (UICC). This classification system is most often used in the Western hemisphere and now commonly in Asian countries as well. The seventh edition was introduced in 2010 and the major differences compared to the sixth edition involved the depth of tumor invasion. Table 1 summarizes the TNM staging system for gastric cancer. Table 2 shows the 5-year survival rate according to stage.

Clinical staging is of high importance as it dictates the management of gastric carcinoma: Stage I–III tumors are potentially curable while stage IV disease is referred for palliative therapy based on the symptoms and functional status of the patient. All stages are best managed by a multidisciplinary team.

CT scan of the chest abdomen and pelvis is performed early in the preoperative evaluation after diagnosis of gastric cancer is made. It is best suited to stage the cancer, assessing for degree of local involvement as well as for metastatic disease (hepatic or adnexal metastases, ascites). Peritoneal metastases smaller than 5 mm are frequently missed by CT scan, even when using modern CT technology [28]. Burke et al. compared staging laparoscopy to CT in 103 patients with gastric adenocarcinoma and no evidence of metastatic disease on CT scan. In 31 % of the patients, laparoscopy identified biopsy-proven metastatic disease. The sensitivity and specificity of staging laparoscopy was 94 % and 100 %, respectively [29]. Karanicolas and colleagues reviewed the SEER database to analyze frequency of staging laparoscopy in the general population in the period between 1998 and 2005. Of 6388 patients, only 506 (8 %) underwent staging laparoscopy. Use of staging laparoscopy increased over time (5.5 % in 1998 to 11.1 % in 2005, P < 0.01), and patients tended to be young and white, living in the Northeast, and with proximal cancers, and they had fewer comorbidities than those who did not undergo staging laparoscopy. Although increasing in use, staging laparoscopy seems to remain underutilized in its potential benefit of avoiding unnecessary laparotomy [30].

Endoscopic ultrasonography (EUS) is considered the most reliable nonsurgical method available for evaluating the depth of invasion of gastric cancers [31]. The accuracy of EUS for differentiation of individual tumor stages (T1–T4) ranges from 77 to 93 %, with the experience of the operator markedly influencing these rates [32]. EUS is a more accurate predictor of the T stage compared to CT [33], although the accuracy for nodal staging is only slightly greater [34]. The advantage of EUS in the assessment of the nodal status is the ability to perform fine needle aspiration of suspicious nodes and areas, which adds to the accuracy of nodal staging.

The role of positron emission tomography (PET) is still in evolution. PET is more sensitive than CT scan in the detection of distant metastases [36]. An important caveat is that the sensitivity of PET scanning for peritoneal carcinomatosis is only 50 % [37]. Therefore PET cannot adequately replace staging laparoscopy for detection of peritoneal metastases. NCCN guidelines for preoperative evaluation of gastric cancer suggest integrated PET/CT. However, gastric cancer is not a reimbursable diagnosis for PET scanning in the US Medicare program.

After the initial introduction of laparoscopic gastrectomy for gastric cancer by Kitano et al. in 1993, the procedure has evolved significantly and is now considered one of the standard minimally invasive procedures for the treatment of early gastric cancer. There is a growing volume of literature comparing laparoscopic to open gastrectomy for early gastric cancer in the distal stomach. The first randomized studies published by Kitano, Huscher, Hayashi, and Lee were underpowered, with the number of patients recruited less than 50 [44–47], but with the same results and the same theme. The laparoscopic distal gastrectomy (LADG) group had less operative blood loss, shorter length of stay, quicker return to diet compared to the open distal gastrectomy group (ODG), and the perioperative morbidity and mortality as well as long-term survival was comparable in both laparoscopic and open gastrectomies. The largest and most notable randomized controlled study of laparoscopic vs. open distal gastrectomy for early gastric cancer is the Korean multicenter trial named KLASS (Korean Laparoendoscopic Gastrointestinal Surgery Study ). Included were patients with clinical stage I gastric adenocarcinoma. The primary endpoint was overall survival, and the secondary endpoints were disease-free survival, morbidity, mortality, quality of life, inflammatory and immune responses, and cost-effectiveness. A distal gastrectomy with D1 + β or D2 LN dissection was performed in both groups. Reconstruction was performed by Billroth I or Billroth II or Roux-en-Y fashion, depending on surgeon preference. To assure high surgical quality, surgery was performed by 15 surgeons, who had performed at least 50 cases each of LADG and ODG, at 12 high-volume institutions, which had performed more than 80 cases of distal gastrectomy per year. From February 2006 to August 2010, 1415 patients (704 LADG and 711 ODG) were enrolled, and the final results are expected to be reported in September 2015 [48]. The interim analysis of this KLASS-01 trial was published in 2010. A total of 342 patients were randomized (179 LADG and 161 ODG). There were no significant differences between the two groups concerning patient demographics. The postoperative complication rates of LADG and ODG groups were 10.5 % (17/179) and 14.7 % (24/163, p = 0.137). The postoperative mortality was 1.1 % (2/179) and 0 % (0/163) in the LADG and ODG groups (p = 0.497). The authors concluded that there was no significant difference in the morbidity and mortality between the two groups [49]. Another important Korean single-center RCT, conducted by Kim et al. [16], was published in 2008. This study aimed to evaluate the quality of life after LADG compared to ODG (n = 82 in each group) in patients with EGC. The LADG group showed better functional and symptom scales of EORCT QLQ-C30 and QLQ-STO22 at 3 months after surgery. Also, intraoperative blood loss, total amount of postoperative analgesics, and postoperative hospital stay were significantly less in the LADG group. The authors concluded that LADG resulted in improved quality of life outcomes after surgery in EGC patients compared to ODG. To evaluate the long term results of LADG Strong et al. from Memorial Sloan-Kettering Cancer Center reported a retrospective case–control study comparing 30 LADG with 30 ODG. Controls were matched for stage, age, and gender from 2005 to 2008. The mean number of resected LNs was 18 (range: 7–36) in the LADG group and 21 (range: 7–44) in the ODG group (p = 0.03). There were four recurrences (13.3 %) in the LADG group during 11 months of follow-up and five recurrences (16.6 %) in the ODG group during 13.8 months of follow-up (p = 0.71).

One of the most controversial areas in the surgical management of gastric cancer is the optimal extent of lymph node dissection. Japanese surgeons routinely perform extended lymphadenectomy, a practice that some suggest at least partially accounts for the better survival rates in Asian as compared to Western series. The term “extended lymphadenectomy” variably refers to either a D2 or a D3 lymph node dissection. Table 3 shows the different gastric lymph node stations, divided according to the Japanese classification [51]. Stations 1–6 are perigastric, and the remaining ten are located adjacent to major vessels, behind the pancreas, and along the aorta.