Colon cancer

Colon cancer

Cancer remains a major cause of death inspite of substantial progress in understanding its molecular basis and the development of an array of powerful treatments. Colon cancer is the second to third most frequent type of common malignant neoplasm in the world. The incidence of colon cancer is higher in developed countries, with approximately half of the western population developing adenoma by the age of 70.

Colon cancer rate in India is lower than the western countries, but is increasing with increasing migration of rural population to the cities, increase in life expectancy and changes in life style. Western type-high fat, high protein, low carbohydrate and low fiber diet is thought to be an important factor for the increase in colon cancer incidence in India. The peak incidence of the disease is on the seventh decade of life, and it is fairly equally distributed between men and women. Incidence rates vary around the world; the developed countries (Europe, Japan, Australia, New Zealand and North America) account for almost 65% of the total global incidence. Central and South America, Asia and Africa are areas of low risk, but the incidence is now increasing in these regions. Colorectal cancer is one of the leading cause of cancer related deaths in western countries and is becoming increasingly common in Asia.

Despite the development of new screening strategies, aggressive surgical and adjuvant therapy, and intensive research effects, little progress has been made in the successful management of this disease. The cure rate for this cancer has remained at 50% for several decades. The etiology of colorectal cancer is complex and may be attributable to the combined actions of inherited and environmental factors. Colon carcinogenesis is a multi-step process involving three distinct stages, initiation that alters the molecular message of a normal cell, followed by promotion and progression that ultimately ends up with a phenotypically altered ‘‘transformed cell’’. Epidemiological and experimental studies suggest that colon cancer is strongly influenced by nutritional factors, including the amount and composition of dietary fat. Pathological significance of persistent oxidative stress leads to DNA damage and mutations in cancer-related genes. Epidemiological studies have indicated that colorectal cancer is strongly associated with diet and thus it may be possible to prevent the occurrence of this cancer by dietary modification.

Many dietary components have been examined in relation to colorectal cancer. Food-derived products exist universally and are expected to be safe, and are highly interesting for the development as chemopreventive agents. While minimizing exposure to carcinogens and changes in lifestyle reduce cancer incidence, chemoprevention offers an alternative approach with potential for more immediate results. In recent years, attention has been focused on whether naturally occurring compounds can modify the mutagenic and carcinogenic effects of some contaminants