According to statistics, colon cancer is in 4th place in terms of incidence and in 2nd place in terms of mortality from malignant tumors. What you should know about such a pathology and how it differs from benign intestinal formations, aif.ru told MD, Corresponding Member of the Russian Academy of Sciences, Head of the Cancer Center Mikhail Davydov.
The term «colon cancer» is quite broad. “Speaking of colorectal cancer, they mean malignant tumors of the colon and rectum. Most often, they are represented by mucus-forming cells (adenomas), which, after transformation, become malignant (adenocarcinomas). But often there are also tumors that develop from other cells — neuroendocrine (from cells similar to cells of the nervous system and endocrine at the same time), stromal (in the submucosal layer) tumors, ”explains Mikhail Davydov.
They can be found in different parts of the colon. Most often, the oncologist Davydov emphasizes, tumors of the sigmoid and rectum are noted. It can also be affected:
- ascending and descending colon
- as well as the transverse colon.
The risks of such tumors
The danger lies in the risks of tumor germination or its metastasis (the process of spreading malignant cells throughout the body). “The tumor, going beyond the intestinal wall, while growing several layers, can grow into any neighboring structures: fatty tissue, large vessels, walls of the abdominal cavity or small pelvis, as well as organs, depending on the location of the tumor itself,” says Mikhail Davydov.
Favorite target organs for metastasis are:
- liver (more often);
- lymph nodes along large vessels;
- brain (less common).
The prognosis for these types of cancer depends on the stage of the disease — it is determined by the presence of affected lymph nodes and distant metastasis.
Survival depends on treatment. If the patient was operated on at an early stage, then the survival rate is 90%. In the third stage, the prognosis worsens to 70%, and then with a combination of surgery with additional therapy, such as radiation. Patients with stage 4, with all the treatment performed, live longer than 5 years in 10% of cases.
Why does bowel cancer develop?
Colorectal cancer is triggered by risk factors or hereditary predisposition, says oncologist Davydov. Risk factors include:
- Benign tumors, such as polyps.
- Chronic inflammation of the intestine — Crohn’s disease, ulcerative colitis.
Special attention should be paid to nutrition, as it plays an important role, the oncologist notes. Reduce the risk of developing cancer vegetables and fruits, dairy and seafood. But the use of red and thermally processed meat increases this risk by 10%.
Attention should be paid to bad habits. “With constant smoking and regular alcohol consumption, the risk increases. After quitting smoking, the risk of developing bowel cancer decreases by about 4% every 10 years,” says Mikhail Davydov.
Are benign formations dangerous?
Not always education in the intestine is cancer. There are also benign defects. These, lists Mikhail Davydov, include:
- lipomas (fatty tumor),
- leiomyomas (smooth muscle tumors) and some others.
Their main danger is that over time they degenerate into cancer, Mikhail Davydov warns. At the same time, the size of the formation matters: for example, if the polyp is less than 10 mm, the risk of cancer is not more than 10%, but if it is more than 20 mm, then the risk is already more than 50%. On average, about 3-5 years pass from the moment an adenoma forms to its transformation into cancer, Mikhail Davydov notes.
How are they treated?
The choice of tactics depends on the stage of the disease at the time of its detection, as well as on its localization. “For example, if we talk about the early stages of colon cancer, then the choice will be surgical treatment. If we are dealing with a tumor with distant metastases, then treatment should begin with chemotherapy or immunotherapy. With their successful ending, they will think about the operation, ”says Mikhail Davydov. In any case, surgical methods are considered the main ones in the treatment of bowel cancer.
Special attention should be paid to diet. Before and during treatment, a diet with a high protein content is offered. In addition, the menu should be designed so that there is a normal chair — eliminate coarse fiber and add the use of laxatives. After the operation, there are some nuances, but after a couple of months after therapy, the diet ceases to differ from the usual one.
Prevention in oncology is of particular importance. “There is a colorectal cancer screening program that helps prevent or detect the disease at an early stage. Now it is offered to all people over 40,” says Mikhail Davydov.
Screening is carried out in 2 stages:
1. Examination of feces for occult blood: in people aged 40-64 years — every two years, aged 65 to 75 years — annually.
2. This stage for those whose first one gave a positive result is a colonoscopy.
Start screening earlier than recommended for those who have a hereditary risk factor. Moreover, one should focus on the age at which cancer was diagnosed in a relative and start research 5-10 years earlier. In addition, under special control should be people with inflammatory bowel diseases.