Carcinoma Stomach remains a common disease worldwide with dismal prognosis. It represents the fourth most common malignancy and the second leading cause of cancer related death. In Japan gastric cancer remains the most common type of cancer among men. Its incidence, however, has been declining globally since World War II. Gastric cancer is one of the least common cancers in North America. The incidence of proximal gastric cancer is on the increase while the distal gastric cancer is declining in North America. The five year survival rate of gastric carcinoma is low (10-20%).
Ministry of Health and Family Welfare, Government of India has issued the Standard Treatment Guidelines for Carcinoma Stomach.
Following are the major recommendations :
Gastric Cancer refers to the malignant growth arising from the epithelial lining of the stomach. It is an aggressive tumor with vague early symptoms and spreads to the adjoining structures early in its course.
INCIDENCE IN INDIA
India falls in low incidence zone of gastric cancer. It is the fifth commonest cancer in males and seventh commonest in females in India. Age adjusted rate (AAR) of gastric cancer in six urban registries from India have reported the incidence 3.0-13.2/1,00,000 population which is lower to the world incidence of 4.1-15.5/1,00,000 population.
There is a regional variation in its incidence. It occurs four times more commonly in south India as compared to north India and also a decade earlier. Gastric cancer follows the global trend of declining incidence in India as well.
•Lower Esophageal Cancer
•Lower Esophageal Stricture
•Malignant Neoplasms of the Small Intestine
PREVENTION AND COUNSELING
Vast majority of Gastric Cancers are attributed to environmental factors, the most common being infection with Helicobacter Pylori. This organism has been found in almost 70% of the patients with Antral gastric cancer and is associated with nine fold increased risk of developing gastric cancer. Inoculation most likely occurs in childhood through the oro-fecal pathway and is transmitted from person to person.
Intake of certain food contents is also thought to be contributory; preserved diets with high salt contents, smoked foods and diets with low fresh fruits and vegetable contents have also been attributed to the increased incidence of gastric cancer.
Smoking and prolonged consumption of alcohol have also been attributed to the increased occurrence of gastric cancer. Better living standard, better dietary habits, eradication of Helicobacter Pylori infection, giving up of smoking and alcohol consumption may decrease the occurrence of gastric cancer.
1-3% of gastric cancers are associated with inherited gastric cancer predisposition syndromes. E-cadherin mutations occur in approximately 25% of families with an autosomal dominant predisposition to diffuse gastric cancers also called hereditary diffuse gastric cancer. This subset of persons may benefit from genetic counseling and prophylactic gastrectomy.
OPTIMAL DIAGNOSTIC CRITERIA, INVESTIGATIONS,TREATMENT & REFERRAL CRITERIA
Clinical diagnosis of Gastric Cancer, like all other diseases is based on astute history taking and thorough physical examination.
There are no pathognomic symptoms of early gastric cancer; rather they are vague and non-specific often mimicking peptic ulcer disease. Commonest complaint is epigastric discomfort. Patient often present with Aneamia, weight loss (Aesthenia) and loss of appetite (Anorexia), early satiety and rarely upper GI bleed.
Physical examination of early gastric cancer is usually uninformative. In late stage they may present with palpable epigastric mass, cachexia, bowel obstruction, ascites and pedal oedema. In advance cancers peritoneal seedling may involve ovaries leading to Krukenberg tumor, pelvic cul-de-sac (Blumer’s shelf) palpable on digital rectal examination, left supra clavicular lymphadenopathy (Virchow node), left anterior axillary lymphadenopathy (Irish’s node) or a periumbilical lymph node(Sister Mary Joseph node).
Upper GI Endoscopy is the mainstay of diagnosis, accounting for > 90% of Gastric Cancer diagnosis. Typically gastric cancer appears as irregular ulcer with raised margins or a polypoidal or fungating mass lesion. Multiple, at least 6 or more biopsies are to be taken for the best yield.
Barium UGI series is hardly required these days, though it may prove diagnostic in patient with Linitis Plastica, who have undistensible stomach.
Contrast Enhanced Computed Tomography (CECT), is required to stage the disease and evaluate the metastatic status.
Endoscopic Ultrasound (EUS) is used to asses the tumor depth and the adjacent lymphadenopathy. EUS guided FNAC of adjacent lymph nodes can also be performed.
Staging laparoscopy is the latest addition to the investigation armamentarium for carcinoma stomach.
PET scan is not routinely recommended to evaluate Gastric Cancer.
Tumor Markers: There are no specific tumor markers for Gastric cancer hence their assessment is not routinely advocated.
Multi-disciplinary treatment planning is mandatory for a better outcome of this rather dismal disease. Patients with Gastric cancer should be managed by an experienced team of Surgeons, Onco-physicians, Gastroenterologist, Radiation-Oncologist. Nutrion Specialist and Onco –Nurses.
Surgery remains the mainstay of treatment of gastric cancer. It is the only single modality treatment capable of curing the disease. The goal of surgical cure requires complete resection (R0). The standard recommendations for respectable gastric cancer are free margin surgery
(at least 5 cm clearance) with at least D1 lymph node dissection removing minimum of 15 lymph nodes.
Type of Gastectomy depends upon tumor location and its extent and consists of partial ( ProximaL/ Distal) or Total Gastrectomy addition of Splenectomy and distal Pancreatectomy significantly increases post operative mortality without significant survival advantage, hence should not be performed routinely.
Lymph Node Excision: Extent of lymph node dissection though an important issue, remains controversial. Results of D1 lymphadenectomy ( Perigastric nodes along the lesser and greater curvature) are comparable with D2 lymhadenectomy ( nodes along the coeliac trunk and its 3 branches), however more centres in even western world are now resorting to D2 gastrectomy for better post operative outcome.
Laparoscopic Surgery For Gastric Cancer:
Laparoscopy –assisted distal gastectomy(LADG) first developed by Kitano et al in Japan in 1991, has now become the standard of care in Japan for respectable Gastric Cancer.
Neo-Adjuvant/Adjuvant Therapy: Large number of randomized phase 3 studies have shown the efficacy of perioperative (pre & post operative) chemotherapy and post operative chemoradiotherapy in combination with R0 tumor resection and D1/D2 LN dissection.
Early Gastric Cancer: Endoscopic Mucosal Resection (EMR), and Endoscopic Sub-Mucosal dissection are the latest surgical option in the management of early gastric cancer (T1NoMo)., however such cancers are rarity in India and the western world.
Advanced Gastric Cancer:
In the treatment of advanced gastric Cancer (Unresectable, metastatic), surgery has no role except as palliative gastrojejunostomy for gastric Outlet Obstruction, control of bleeding or placement of feeding jejunostomy tube.
Multi disciplinary team, so necessary for the successful management of patients with Gastric Carcinoma, may not be available even in most of Indian Metro Hospitals their management at secondary Hospital/ Non-Metro situation is not advisable.
All patients of gastric cancer, who are deemed respectable at secondary hospitals, must be referred to super-specialty facility for a better post therapy outcome; however patients with advanced disease requiring palliation or emergency surgery can be tackled at secondary hospitals only.
Guidelines by The Ministry of Health and Family Welfare :
Gen RP Chaubey (retd)
Formerly from the Armed Forces Medical Services
Sri Balaji Action Medical Institute