Diseases of the intestines are some of the most common conditions found in the population. Due to its direct connection to the outside world (through the oral cavity), the human intestines are exposed to constant contact with many harmful environmental agents that are responsible for the development of diseases such as viral or bacterial diarrhoea, for example. On the other hand, susceptible to damage or toxic agents, the intestines sometimes succumb to neoplastic processes, which in turn can lead to the development of the extremely dangerous colorectal cancer.
Hereditary non-polyposis colorectal cancer (Lynch syndrome) - this form of cancer accounts for approximately 5% of all colorectal cancers. Depending on whether the cancer affects only the bowel or other organs, we distinguish between Lynch syndrome I (only colorectal cancer is present) and Lynch syndrome II (in addition to colorectal cancer, patients suffer from malignancies such as cancer of the uterus, ovary, stomach, skin or urinary tract). As in the case of familial polyposis, patients with suspected Lynch syndrome or related patients require genetic testing and colonoscopy every 2 years, starting at 25 years of age. In addition, all women are required to have a gynaecological assessment including a thorough Medical US examination of the reproductive organs and regular cytological examination. Occasionally, the gynaecologist may decide that a biopsy of the endometrium is necessary to exclude endometrial cancer.
In addition to the aforementioned genetic syndromes, the most common form of colorectal cancer, so-called sporadic colorectal cancer, also arises as a result of genetic mutations. The difference, however, is that in this case the genetic changes are not inherited, but arise spontaneously, for example as a response to cell damage by toxic substances (food, bacteria, etc.). 85% of sporadic cancers develop as a result of these acquired, superimposed mutations of suppressor genes (APC, DCC, p53) leading to proliferation of the glandular epithelium and formation of an adenoma, followed by its malignant transformation as a result of oncogene activation.
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Risk factors - environmental
Apart from the obvious influence of genetic disorders on the incidence of colorectal cancer, in populations of developed countries (including Poland) lifestyle and environmental conditions play a key role in the pathogenesis of this cancer. We are primarily referring to diet. Colorectal cancer is primarily associated with the consumption of highly processed foods, rich in saturated fatty acids. The effect of such substances on the mucosa is not fully understood, but statistical studies clearly indicate an increase in the detection of bowel cancer, for example among patients who frequently consume fast-food products.
Nevertheless, limiting the amount of fibre consumed is an important factor. Dietary fibre (especially insoluble fibre) helps to ensure continuous intestinal transit without backlogging of faecal contents. This in turn reduces the risk of damage to the intestinal mucosa. In addition, backlogged faeces themselves probably play a significant role in the formation of malignant forms of intestinal cancer. It should also be remembered that a diet poor in fruit and vegetables reduces the supply of vitamins. These substances, which act as antioxidants, prevent the formation of oxygen free radicals (which are also likely to contribute to the development of cancer). At the same time, it should be borne in mind that vitamins A, C, E and beta-carotene have no proven anticancer effect in relation to the large intestine, so the use of dietary supplements as a form of colorectal cancer prevention is not justified.
