Stomach cancer

Stomach cancer

Overview-

 Stomach cancer is one of the leading causes of cancer related morbidity and the second most common cause of cancer related deaths after Lung cancer.

Stomach cancer is a difficult disease to treat and even patients who present in most favorable conditions and undergo curative surgical resection often die of recurrent disease. Recent studies show that patients undergoing post-operative chemo radiation therapy have a better chance of survival.

 Majority of the cases are diagnosed late in the disease and the average 5 year survival rate is a poor 20%.

More than two thirds of these cases occur in the developing world (e.g. China, Chile, Korea and East European countries) and are linked to dietary habits and unhealthy food preservation practices in these countries. Japan, infamous for high stomach cancer incidence in the past, has largely controlled the disease morbidity and mortality because of early screening and changed dietary habits.

Stomach cancer may also extend through the stomach wall and spread to nearby lymph nodes, and to organs such as the liver, pancreas, and colon. It may spread to distant organs, such as the lungs, the lymph nodes above the collarbone, and to a woman’s ovaries.

There are various types of Stomach cancers, viz. gastric Lymphomas (cancer of gastric lymphatic tissue), Soft tissue sarcomas (e.g. Leiomyosarcomas) and carcinoids but the most common cancer of the stomach(approx. 90%) arise from the glandular cells of the stomach wall and are called Adenocarcinomas.

?Causes-

Stomach cancer has certain well defined risk factors and recognition of modifiable risk factors has gone a long way in reducing its incidence in recent times.

• Age- Most patients are between 55 to 70 years of age. People who present at a younger age have a more aggressive form of the disease.
• Sex- Males are twice as commonly affected as females.
• Race- Most of the cases occur in Asians, Hispanics, Pacific islanders and East Europeans
• Diet- Food preserved by drying, smoking, salting and pickling shows a direct link with stomach cancer. Dietary nitrites are broken down into N-nitroso compounds by the bacteria in the stomach and have been shown to have a carcinogenic effect in experimental animals. On the other hand, properly refrigerated and frozen Fresh fruits/vegetables and diet rich in Vitamin C appears to have a protective role.
• Helicobacter Pylori infection-People with H. Pylori bacteria infection of the stomach have greater risk.

·         Prior stomach surgery-People with a history of stomach surgery face a greater risk due to alteration in normal ph of the stomach.

• Stomach Disorders-Patients suffering from stomach diseases like Pernicious anemia, achlorhydria and atrophic gastritis are 6 times more prone to stomach cancer.

• Smoking
• Hereditary-Familial aggregates of stomach cancer patients have been reported but underlying genetic factors are poorly understood
• As a rule peptic ulcers are not considered premalignant, but rarely, some gastric ulcers may turn into cancer.

?Clinical features-

Early stages of the disease are usually asymptomatic.

Most patients present in an advanced stage and have non-specific symptoms like indigestion, nausea, vomiting and sometimes Pain.

They may also complain of a bloated feeling after eating, loss of appetite, dark colored stools (due to presence of blood) and feeling of tiredness (due to anemia). Presence of a primary mass from stomach is a rare finding.

Late features include peritoneal and pleural effusions, Jaundice and cachexia.

Hepatomegaly usually occurs and presence of an enlarged left supraclavicular lympnode (Virchow”s sign) is a typical finding.

Treatment-

Treatment depends on stage, extent and grade of the malignancy.

Surgery, Radiation and chemotherapy are the three commonest modalities of treatment.

Surgical intervention includes Partial/subtotal gastrectomy or Total gastrectomy (removal of stomach+lymphnodes+part of esophagus+part of small intestine +/- spleen) and making of a new stomach out of small intestine.

Surgery can be followed by radiation therapy using external beam radiation (5 days/week for 6 to 8 weeks). A new form of radiation therapy called Tomotherapy HI-ART (Tomotherapy highly integrated adaptive radiotherapy) is also available at some centers. Tomotherapy allows small and precise dosage of radiation to tumor and dramatically reduces radiation exposure to surrounding healthy tissue.

Chemotherapy using anticancer drugs given orally or intravenously is used alone or in combination with surgery and/or radiation. Fractionated dose chemotherapy is another option where chemotherapy is given in smaller doses spread over 3 to 5 days. It dramatically reduces side effects of chemotherapy like hair loss and nausea/vomiting.

Immunotherapy to boost the natural immune system of the body, nutritional therapy and physical therapy are some other treatment modalities used.