Dr Ruchi Shah
Esophageal cancer is the eighth most common cancer and sixth most common cancer for mortality in the world. About 90% of esophageal cancers globally are squamous cell carcinoma (ESCC). Its frequency is highly variable due to geographical locations. Highest incidences are reported in regions of central Asia including Asian esophageal cancer belt, spreading from eastern Turkey through the southernmost former-Soviet Union (Kazakhstan, Turkmenistan, Uzbekistan, northern China. In North India, Jammu and Kashmir is another region in Asia where esophageal cancer is the second leading cancer after lung carcinoma. There are a number of etiological factors that are associated with esophageal cancers; including poor lifestyle resulting in a deficiency of essential vitamins and minerals, use of tobacco and alcohol, dietary habits and genetic factors.
Risk factors linked to ESCC
Diet: In the state of Jammu and Kashmir, people have peculiar dietary habits.The dietary habits include food prepared by using heavy amount of spices, salt and oil. The preparation of food involves deep frying and usage of large amount of spices and salt in higher concentration . Boiled rice and “haakh” form the main part of the meals taken by the people twice a day in Kashmir valley and there is a beverage that is pink in colouration, commonly known as “noon chai”. It includes milk and salt too. Salt is considered as the common irritant of the stomach epithelium . All these food materials have high nitrite and nitrate contents like NDMA (N- nitrosodimethylamine). It has been observed that NDMA is an exogenous source that contributes to a number of cancers which includes ESCC.
Obesity: Obesity is the critical risk factor commonly linked with EAC. BMI (body mass index) is used to determine general obesity. It has also been observed that BMI also affects disease outcome and toxicities related to treatment in case of esophageal carcinoma A better understanding of actual mechanism that relates cancer and BMI is yet to be explored.
Alcohol: In a study in Japanese population, it has been observed that alcohol increases the risk of esophageal carcinoma. It has been studied that acetaldehyde that is present in alcohol is a carcinogen that causes cancer in human beings. It has been observed that acetaldehyde gets easily mixed up with saliva. Ethanol is also considered as a group 1 carcinogen but it is less toxic than acetaldehyde. These enzymes influence activity of acetaldehyde. Relation of ESCC with polymorphism of alcohol-metabolizing enzymes is well explored in Asian population. Alcohol consumption is considered as one of the main risk factors in ESCC. In Kashmir valley, the consumption of alcohol is very less as compared to the other parts of country because of religious constraints). No study has been done so far which could investigate a relationship between alcohol and the risk of ESCC in Kashmir valley so far. In Jammu region alcohol consumption is on a larger scale. In a study it has been observed that in urban areas of Jammu, alcohol consumption among adolescents is on a larger scale than in the rural areas.
Smoking: ESCC involves smoking as one of the crucial risk factors in the development of disease. It has been observed that both moderate and heavy chain smokers are at risk of both ESCC and EAC (esophageal adenocarcinoma). When a person inhales smoke it condenses and it produces nitrosoamines which are carcinogenic and it comes in direct contact with the esophageal epithelium.
Low income demographic profile of the population studies: In perspective of Socio-economic status of the patients, it was found to be linked to various cancers including ESCC. Economic status, alcohol intake and tobacco consumption are the main risk factors associated with the increased risk of esophageal squamous cell carcinoma worldwide. Lower socioeconomic status deprives people from having a healthy diet comprising of fresh fruits and vegetables. People having good education and government jobs can easily have food with higher nutritional value than the people working in smaller regions with lower wages.
Barretts esophagus (BE): It is a premalignant condition observed in GERD (gastroesophageal reflux disease) and later can develop into EAC. In Barett’s esophagus the columnar mucosa which is present in intestines replaces stratified squamous epithelium of the distal esophagus. There is a sequence of molecular and pathological events like metaplasia, dysplasia which is followed by carcinoma, it is believed that BE often leads to esophageal adenocarcinoma but some studies contradict this statement
Genetics: ESCC is known to be associated with numerous genetic alterations. Both somatic and germline mutations play a vital role in causing ESCC.
In summary, its very important to have a healthy lifestyle with good dietary habits to avoid risk of such dreadful disease that has high morbidity rate particularly in our state.
(The author is Scientist, Centre for Advanced Research, University of Kashmir)
Dr Ruchi Shah