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Journal of Cancer Research and Therapeutics, Vol. 7, No. 1, January-March, 2011, pp. 15-18 Original Article A survey of risk factors in carcinoma esophagus in the valley of Kashmir, Northern India NA Khan1, M Ashraf Teli1, M Mohib-ul Haq2, GM Bhat3, Mohd. M Lone1, F Afroz1 1 Department of Radiation Oncology, SKIMS, Srinagar, India Correspondence Address: N A Khan, Department of Radiation Oncology, Sher-i-Kashmir Institute of Medical Sciences (SKIMS), Srinagar, Jammu & Kashmir - 190011, India, drnazirkhan@rediffmail.com Code Number: cr11004 PMID: 21546736 DOI: 10.4103/0973-1482.80431 Abstract Background/Objective: Esophageal cancer has a peculiar geographical distribution and shows marked differences in incidence within a particular geographical region. Presently, as there seems little prospect of early detection of this cancer, an understanding of the etiological factors may suggest opportunities for its primary prevention. In this paper, we have tried to determine the role of diet and other life-style related factors in the etiology of cancer of esophagus.Material and Methods: A total of 100 confirmed squamous cell carcinoma of esophagus patients were enrolled for the study (Group A). 100 healthy subjects were included as controls (Group B). A predesigned questionnaire dealing with the basic patient data, dietary and smoking habits etc. was distributed among the cases in both groups. The data was thoroughly analyzed to define an association with the development of cancer of esophagus. Results: Group A patients included 71 males and 29 females in the age range of 40-70 years. Majority 37% were farmers, 29% house wives. Of the 72% smokers, 66% smoked hookah. 29% had positive family history. More than 90% took salt-tea at breakfast. Meat consumption was low, 44% took it weekly and 42% on monthly basis. 69% took fish yearly. Group B included 75 males and 25 females of which 35.7% were hookah smokers. Conclusion: Poor socio-economic status resulting in fewer intakes of fresh fruits, vegetables and fish in addition to heavy hookah smoking are suspected to be the major risk factors for the development of esophageal cancer. Keywords: Esophageal cancer, Risk factors, Hookah, Diet Introduction Cancer is a major concern in all nations of the world. About 10 million people are diagnosed with cancer and more than 60% die of this disease every year. [1] Cancer is emerging as one of the leading causes of death in India. Despite recent advances in cancer therapy, esophageal cancer remains one of the least treatment- responsive malignancies. Even in developed countries, more than 85% of patients die within two years of diagnosis making it the sixth most common cause of cancer-related deaths in the world. [2] High incidence of cancer of esophagus has been reported from Caspian littoral of Iran, central and East Asia and certain areas of china. [2],[3] In India, esophageal cancer is the most common malignancy involving the gastrointestinal tract in Karnataka, Tamil Nadu, Kerala and Assam. [4] In Kashmir, esophageal cancer is ranking at number one. There is scarcity of epidemiological studies in this malignancy. [5] Since, the prognosis in esophageal carcinoma is extremely poor and as there seems to be little prospect for early detection or treatment, a better understanding of the etiology/risk factors may suggest opportunity for its primary prevention. With this idea, we have conducted a prospective study to identify the risk factors that may have a role in the development of this cancer in our region. Material and Methods Between January and December 2008, a prospective study including 100 patients of esophageal cancer (Group A) was carried out in a tertiary care institution in Northern India. One hundred healthy subjects were included as control (Group B). In both Group A and Group B, equal number of cases was selected from rural, urban and semi-urban areas. Group A patients had histopathologically confirmed squamous cell carcinoma of esophagus. Patients with histopathology of adenocarcinoma and with lesions of gastro-esophageal junction were excluded. A predesigned questionnaire covering personal, occupational, dietary and family history was distributed amongst all the cases who consented to answer the same. All the variables of the questionnaire were analyzed and conclusions were drawn accordingly. Results During the year 2008, 2405 patients of various malignancies were registered in the Department. Among these, 409 cases (17.03%) had esophageal cancer. One hundred cases with mid esophageal involvement and histopathology of squamous cell carcinoma were included in the study group comprising 71 male and 29 female cases with a male: female ratio of 2.4:1. Mean age was 54.3 ± 7.6 years (range 40-70 years). An equal number of healthy subjects in Group B comprising 75 male and 25 female cases with a male: female ratio of 3:1 and mean age of 58.1 ± 8.3 years (range 38-76 years). In Group A, majority of patients were farmers and house wives, 37 and 29% respectively. In Group B, majority were non-gazetted government employees and middle class businessmen, 44 and 24% respectively [Table - 1]. Patients in Group A mostly belonged to low socio-economic status with 20% literacy level of high class and above. In Group B, literacy level of high class and above was seen in 70% cases. Over 80% of patients belonged to rural areas in both the groups. In Group A, 29% cases had positive family history of esophageal carcinoma with one/more members′ death related with esophageal carcinoma. In Group B, 25% cases had family history of cancer related death [not necessarily due to esophageal cancer] [Table - 1]. In Group A, there were 72 smokers with hookah smoking being the major mode of smoking in 91.7% cases while as in the control group there were 42 smokers of which 35.7% were hookah smokers. In Group A, 78.8% patients smoked more than 20 g of tobacco/day while as none of the cases in Group-B smoked more than 20 g of tobacco/day. [Table - 1] Salted tea (noon chai) and homemade or backed bread was the breakfast for both the groups. Seventy six (76) and 90 cases consumed less than five cups /day in Group A and Group B respectively. More than five cups/day were consumed by 24 and 10% in Group A and Group B respectively [Table - 2]. In addition to salty tea, 20% also took black tea; three-five cups/day in both the groups. Luke warm tea was consumed by 72 and 77% cases in Group A and Group B respectively. Rice was the staple diet in both the groups. Fresh green vegetables were consumed by all our cases in both the groups; however, over 90% cases in both the groups used to take a leafy green vegetable of brassica family popularly known as "Haakh" daily in addition to other vegetables. Sun dried vegetables were consumed by 20 and 30% cases during the winter season only (that too occasionally) in Group A and Group B respectively. Forty-five percent of our patients in Group A consumed fruits monthly; 40% took these on weekly basis and none used to take these on daily basis while 45% used to take fruits weekly and 7% on daily basis in Group B. Meat was consumed by 44 , 42 and 14% patients on weekly, monthly and six monthly basis in Group A and 69%,15% cases consumed meat on weekly and daily basis respectively in Group B. Fried fish (not the smoked fish) was consumed by 69 and 31% twice or thrice a year in Group A and Group B respectively [Table - 2]. None of the cases in either group took fish on daily basis and none of our cases consumed alcohol or chewed tobacco in both the groups. Discussion Esophageal cancer is emerging as a common cancer in India. [6] In Kashmir Valley, it is ranking number one in both men and women, [3],[5] Squamous cell carcinoma of the esophagus is the third leading cancer in men and forth leading cancer in women in India, [7],[8],[9] Several risk factors have been studied as possible etiological factors for esophageal squamous cell carcinoma but very few have been shown to have an association with this cancer, [2] Incidence of esophageal cancer is higher in males and rises steadily with an advancing age, [10],[11] In the present survey, we observed a male preponderance with a male to female ratio of 2.4:1 with 89% cases in the age group of 40-70 years [Table - 1]. There is dearth of data regarding the occupational exposure being the risk factor in esophageal cancer. We observed 37% of our cases belonging to farmer category in Group A in contrast to 18% in Group B. It seems that the farmers may be exposed to a variety of hazardous chemicals and biological agents that are known or suspected carcinogens such as pesticides, solvents, fusel oils, zoonotic viruses and fungi. In addition, Hookah smoking is quite popular in our region particularity among farmers. There were 72 smokers and out of these 91% were hookah smokers in Group A in comparison to Group B where out of 42 smokers 35.7% were hookah smokers. Seventy eight (78%) patients in Group A had smoked more than 20 g of tobacco/day while as none of the cases in Group B had smoked more than 20 g of tobacco/day. The difference in smoking habit pattern of our patients in the two groups is statistically significant [Table - 1]. Smoking is an established risk factor for esophageal cancer, [4],[10],[12],[13],[14] In the present study, cancer of esophagus was found common in females as well although smoking is not so prevalent among female population in this region but they are exposed to passive smoking as they work neck to neck in fields with their male partners.Twenty-nine (29%) of our female cases in Group A were house wives versus 9% in Group B and were exposed to kitchen smoke and fumes as they use cow-dung, wood, coal etc. as fuels for cooking, [15] Several studies have shown association of alcohol with esophageal cancer, [3],[4],[10],[13] Our results in this regard are totally contradicting as none of our cases had consumed alcohol at any time in past. Similarly, bedi smoking, pan/tobacco chewing and use of smoke powder (naswar), though shown to have an association with this disease, [16],[17],[18],[19] had negligible importance in our region. The higher incidence of esophageal cancer in this geographical region may probably be due to interplay of various environmental; likely dietary factors with underlying poor nutritional status. The staple diet of our cases include cooked rice, green leafy vegetable of brassica family-called Haakh, and salted tea which is consumed twice a day. Several case control studies have shown protective effect of fresh raw vegetables and fruits. [2],[4],[10] We observed limited intake of different varieties of vegetables other than the Haakh and very low intake of fresh fruits being consumed by 45 and 40% on monthly and weekly basis in Group A patients in contrast to 45 and 7% cases on weekly and daily basis in Group B which is statistically significant [Table - 2] and consistent with other reports [2],[16] Consumption of sun dried and pickled vegetables, red chilies, spice cake (wur) and smoked fish have been suspected to be major risk factors in this region, [3],[4],[20],[21] We observed a decline in consumption of these food stuffs and these were used by 20% of our cases very infrequently and during three-four winter months only. Consumption of hot salted tea has been incriminated in causation of this malignancy, [3],[22] However, we observed a decline in this practice with 72% cases consuming warm tea and only 28% taking it hot at a rate of less than five cups/day in 76% cases in Group A [Table - 2]. Consumption of fried fish, -not a common practice in this region, was observed in 69 % cases who took it three-foure times /year in Group A in comparison to 34% case in Group B while as 8% vs 23% consumed fish on monthly basis in Group A and Group B respectively. Likewise, meat consumption was very low in our patient population. None of our patients consumed meat on a daily basis. Forty-four percent of our cases took meat once a week in Group A in contrast to Group B cases where 15% consumed meat on a daily basis and 69% on a weekly basis; the difference in meat consumption of the two groups being statistically significant [Table - 2]. There is very little data suggesting a genetic predisposition in esophageal cancer, [2],[23] We observed a positive family history in 29% of our cases which may reflect a hitherto unexplored genetic link or interplay of common shared environmental/dietary factors. Several and potentially critical genetic variations within the P13K/PTEN/ANK/mTOR pathways have been identified as important prognostic indicators in this disease. [24] These observations need to be explored fully in cross-sectional studies. Over 90% of our patients belonged to a low socio-economic and low education class which is consistent with other studies. [2],[4],[21] Conclusion Our observations in this geographical region of high incidence suggest and strongly suspect poor socio-economic status to be a major risk factor for the development of esophageal cancer as this population has limited access to different varieties of fresh fruits and vegetables. Occupational exposure and smoking, particularly the hookah smoking, are the contributory factors. The most feasible method to reduce this cancer burden is to identify and target etiological factors, improve socio-economic status, screen the high risk group of people (positive family history), and finally to develop strategies for prevention. An association of less consumption of meat and fish observed in our cohort of patients needs further evaluation. References
Copyright 2011 - Journal of Cancer Research and Therapeutics The following images related to this document are available:Photo images[cr11004t2.jpg] [cr11004t1.jpg] |
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