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Clinical Manifestations, Patient Evalution, Staging

Neither patient symptoms nor routine physical examination will lead to an early diagnosis of gastric cancer. The most common presenting symptoms and signs are loss of appetite, abdominal discomfort, weight loss, weakness (due to anemia), nausea and vomiting, and melena. The duration of symptoms is less than 3 months in nearly 40% of patients and longer than 1 year in only 20%.

Evaluation of the Patient


Positive findings on physical examination are those of advanced disease. Findings may include an abdominal mass (representing the primary tumor, hepatic metastasis, or ovarian metastasis [Krukenberg tumor]), remote node metastasis (left supraclavicular [Virchow node]; periumbilical [Sister Mary Joseph node]; or left axillary [Irish node]), ascites, or a rectal shelf (peritoneal seeding).

The diagnosis of gastric cancer is usually confirmed by upper GI endoscopy, or radiographs (see diagnostic algorithm in Table 75-1). Double-contrast radiographs may reveal small lesions limited to the superficial (inner) layers of the gastric wall. Endoscopy is now the preferred initial diagnostic test, because it allows direct tumor visualization, cytologic testing, and direct biopsy for histology that yield the diagnosis in 90% or more of patients with exophytic lesions. Ulcerated cancers and linitis plastica lesions may be harder to diagnose endoscopically, but multiple biopsies and gastric washings for cytology enhance the probability of accurate diagnosis. Endoscopic ultrasound (EUS) has a high degree of accuracy in determining depth of tumor invasion (i.e., does the lesion extend beyond the muscularis propria?) but is less accurate in detecting regional nodal metastasis.51-53 Ultrasound-guided fine-needle aspiration for cytologic test allows the assessment of regional lymph nodes and some distant metastatic sites (e.g., liver), further enhancing the ability of EUS to determine tumor stage and resectability.

The extent of disease at exploration or laparoscopy is usually more extensive than suggested on upper GI radiography or endoscopy. Abdominal CT scan is valuable in determining the abdominal extent of disease with regard to larger liver metastasis (1 cm or greater), involvement of celiac or periaortic nodes, or extragastric extension (may help determine which lesions extend to surgically unresectable structures). CT scan is of little value, however, in ruling out peritoneal metastases or small hepatic metastasis. Diagnostic laparoscopy allows visualization of small serosal or liver metastases and may give added information with regard to the amount of direct extension of the primary tumor.

Distant (hematogenous) metastases should be ruled out with a chest radiograph, serum liver chemistries, and abdominal CT scan, or liver ultrasound. We prefer CT scan to ultrasound because of the additional information concerning regional nodal status, extragastric extent of disease, and extension within the distal esophagus. CT scans also provide valuable tumor localization information should irradiation be indicated. If a proximal gastric tumor extends to involve the esophagus, CT scan of the chest is required in determining mediastinal node involvement or parenchymal lung metastases. Positron emission tomography fused with CT (PET/CT) is a valuable imaging tool to both rule out occult metastatic disease and to determine response to treatment.

Staging


With the development of laparoscopic general surgery, diagnostic laparoscopy is commonly used to assess for distant metastasis or unresectable locally advanced abdominal cancers. Several groups54,55 have reported the use of laparoscopy in stomach cancer patients. Metastatic disease was documented laparoscopically in 35% to 40% of patients.54-56 The sensitivity for metastases was 85% or greater55,56 and this technique was particularly sensitive in detecting liver and peritoneal disease. Laparoscopy is more sensitive and accurate in staging patients with regard to intraabdominal metastases than either ultrasound or CT scan.56,57 Many surgeons now routinely perform laparoscopy in all gastric cancer patients who are deemed candidates for surgical resection, to avoid nontherapeutic laparotomy. The current TNM (tumor, lymph node, metastasis) staging system is depicted in Table 75-2 and is acknowledged as the standard system for reporting outcomes in stomach cancer.58 Several comparison studies, including some from Japan,59,60 have shown better prediction of prognosis using the AJCC TNM system compared with other staging systems, including that of the Japanese Research Society for Gastric Cancer.