Stomach Cancer – Is it Linked to Lifestyle Factors?
Stomach cancer has become quite an intriguing proposition both for the researchers and oncologist as its behaviour, propensity, subtleness during progression, advanced stage detection, inheritability, prolonged latency, upsurge manifestation, asymptomatic nature and versatility of causative factors are proving to be a challenging force to reckon.
Stomach cancer or gastric cancer is a type of cancer, in which the malignant cells develop in the mucosal cells (innermost cells that release mucus and other fluids) of the stomach. almost (90% to 95%) of stomach cancers are adenocarcinomas. The other types of stomach cancers include gastrointestinal stromal tumour (GIST) lymphomas and carcinoid tumours.
To begin with, cancer goes asymptomatic throughout the prolonged latency period – wherein the changes in the pre-cancerous cells that develop within the lining (mucosa) of the stomach take place rather slowly – rarely causing any warning signs and symptoms – owing to which, true cancer emerges only after several years.
Prior to carrying our discussion forward, you should know the following:
Cancers such as pancreatic cancer, liver cancer, colon cancer and cancers of the small intestine that occur in the abdomen have different symptoms, prognosis and treatments – they are different from stomach cancer and should not be confused with it.
In some individuals who inherit a mutated E-cadherin (CDH1) gene the risk of stomach cancer increases.
According to research studies, cagA strains of H. pylori are strongly linked to stomach cancer (adenocarcinoma & lymphoma).
Excess processed and preserved meats consumption and less intake of fresh fruits and vegetables have been linked to a higher risk of stomach cancer.
The risk associated with stomach cancers linked to H pylori infections can be reduced by taking healthy diet.
What causes stomach cancer?
Though the exact cause of stomach cancer is unknown, yet there are certain factors that can increase the risk including – the infections (ulcers) caused by a bacterium: H. Pylori; gastritis (gut inflammation); pernicious anaemia and presence of polyps in the stomach. In addition, there are other factors that may increase the risk, such as excessive consumption of red meat; obesity; smoking; eating salty, processed and pickled foods; reduced immunity; infections caused by Epstein-Barr viruses; gene mutations and exposure to certain chemicals.
Lifestyle factors are linked to 3 out of 4 stomach cancers.
Are there any symptoms of stomach cancer?
There are no early signs and symptoms associated with stomach cancer. However, an individual may have indigestion, loss of appetite, heartburn and bloating especially after having meals. You should remember that these symptoms do not always mean that you have cancer, but if you feel them consistently, then talk to your doctor. A Growing cancer may or may not cause these symptoms: abdominal pain, nausea, vomiting, blood in stool, diarrhoea or constipation, heartburn, fatigue and weight loss. However, they cannot be ignored as such.
How is stomach cancer diagnosed?
After physical examination and evaluation of the medical history of the patient, the doctor orders some tests to diagnose cancer. Initially, a CBP may be ordered to look for anaemia as cancer can cause internal bleeding. In addition, a faecal occult blood test helps in finding blood in the stool, which cannot be seen by the naked eye. The doctor may then take a note of the symptoms and risk factors, and then recommends endoscopy (a thin flexible tube with a camera & light at the end is passed down the throat into the stomach); during endoscopy tissue samples are taken (biopsy) and sent to the lab for detecting abnormalities in cells. Endoscopy can also be done as a part of a special imaging test (EUS – endoscopic ultrasound). EUS-guided needle biopsy test may help in determining the spread of cancer cells to nearby tissues and lymph nodes. Biopsy samples are checked under a microscope to detect cancer.
A CT scan is used to get detailed images of the soft tissues of the body and helps in confirming the location and extent of cancer. Similarly, a PET-CT scan is helpful in finding the areas where cancer has spread.
Can stomach cancer be detected early?
Screening is generally helpful in detecting cancer in individuals who are asymptomatic. However, routine screening is not recommended in relatively healthy individuals unless they are considered to be at an increased risk owing to the prominent risk factors as discussed. If you think that you are at risk owing to your lifestyle or strong family history, then it would be better to talk to your doctor regarding stomach cancer screening.
What is the treatment?
Treatment depends on the location of cancer and the extent of its spread. Early-stage cancer is treated by surgery (gastrectomy). Stage 1 and stage 2 cancers can be treated by subtotal gastrectomy or total gastrectomy. Chemotherapy and radiation therapy may be given prior to gastrectomy to shrink cancer. The treatment after surgery includes chemotherapy or a combination of chemoradiation therapy. For patients who cannot tolerate surgery chemoradiation therapy or chemotherapy alone or radiation therapy alone can be recommended.
The five-year survival rate for stomach cancer after treatment
Stage 1 cancer: 85% to 95%
Stage 2 cancer: 70% to 80%
Stage 3 cancer: 40% to 50%
Stage 4 cancer: 20%
MBBS, MD (General Medicine), DM (Gastroenterology – PGI)
Chief Gastroenterologist, Hepatologist & Therapeutic Endoscopist
Medical Director, Sunshine Hospitals