The intestine is the organ responsible for absorbing the nutrients that come from food. It has the appearance of a hollow tube about 7 meters long (but can vary from 4 to 10 meters or even more) divided into the small intestine or small intestine (in turn divided into duodenum, jejunum, and ileum) and large intestine or large intestine.
The large intestine includes the right or ascending colon (with the blind and the appendix), the transverse colon, the left or descending colon, the sigmoid and the rectum.
Colon cancer is due to the uncontrolled proliferation of cells in the mucous membrane that lines this organ.They are generally distinguished in tumors of the colon proper and in tumors of the rectum, that is of the last tract of the intestine, in how much they can manifest in different modalities and frequencies: respectively 70 percent and 30 percent.
In addition, the precise location of the tumor along the colon and in the rectum can correspond to different molecular characteristics and can influence the choice of the type of surgery, sometimes radiotherapy and treatment offered to the patient.
The symptoms of colon cancer are numerous and nonspecific, usually, they appear after some time from the onset of the disease and will vary based on the location of the tumor.
In other words, colon cancer presents, after an initial asymptomatic phase, with a broad symptomatic picture, not very specific and dependent on its location along the large intestine.
The most common clinical manifestations of colon cancer are:
- Change in intestinal habits (eg: alternating diarrhea – constipation, changes in the consistency of stools, etc.);
- Rectal bleeding
- Blood in the stool ;
- Abdominal pain ;
- Abdominal cramps ;
- Abdominal swelling ;
- The sensation of incomplete emptying of the intestine, after defecation ;
- Anemia ;
- Weakness and ease of fatigue;
- Loss of weight for no reason;
Like most malignant tumors, colon cancer has an infiltrative power, which allows it, in an advanced stage of the disease, to invade the anatomically adjacent organs and lymph nodes and to contaminate (exploiting the passage of part of the cancer cells in blood vessels and lymphatic vessels ) anatomically distant organs and lymph nodes.
Readers are reminded that cancer cells disseminated elsewhere by an advanced malignancy are called metastases and that the dissemination process of metastases – the so-called metastasis – seriously compromises – and, almost always, without the possibility of recovery – the state of health of the victim.
In Which Organs Does Colon Cancer Dissemine Metastasis?
The most common target organ of colon cancer metastasis in the liver; contamination of the latter occurs through the numerous blood vessels that collect blood from the intestine. After the liver, the other organs most affected by colon cancer metastasis are, in order: the lungs, bones, and brain.
When to Seek Medical Attention?
According to experts, the problems that should induce an individual to immediately contact their doctor, for investigations, are the change in intestinal habits (alternation of diarrhea-constipation, production of abnormally shaped stools, etc.) and the presence of blood in the stool.
It is important to remember that colon cancer guidelines recommend screening tests from 50-55 years of age, for people without a history, a family history or an inheritance for cancer in question, and starting at 40 years, for people who instead have the aforementioned familiarity or inheritance.
How Widespread It Is?
In western countries, colorectal cancer represents the second malignancy by incidence after that of the breast in women and the third after that of the lung and prostate in men.
In recent years there has been an increase in colorectal cancer diagnoses, but also a decrease in mortality, mainly attributable to screening programs, to early diagnosis and improvement of therapies, increasingly targeted and personalized.
Who Is at Risk?
Colorectal cancer risk factors are related to diet, genes, and other non-hereditary causes. Since these are fairly common factors, everyone is at risk.
Many studies show that a diet high in fat and animal protein and low in fiber is associated with an increase in intestinal cancers. Conversely, high-fiber diets characterized by high consumption of fruit and vegetables seem to have a protective role. Obesity and sedentary life are additional risk factors.
It is possible to inherit the predisposition to get colorectal cancer if diseases such as hereditary adenomatous polyposis (including familial polyposis adenomatosis or FAP, Gardner’s and Turcot’s syndrome ) have occurred in the family of origin. carcinoma hereditary colorectal on a non-polyposis (also called HNPCC or Lynch syndrome ).
These are diseases transmitted by parents with specific genetic alterations and may even not give rise to any symptoms. The probability of transmitting the altered gene to offspring is 50 percent, regardless of gender.
Age is important (the incidence is 10 times higher among people aged between 60 and 64 than those aged 40-44), smoking, inflammatory bowel diseases (including rectocolitis) ulcerative and Crohn’s disease ), a past clinical history of colon polyps or previous colorectal cancer.
Polyps and carcinomas that are not included in the hereditary syndromes are called “sporadic”. The risk of developing colon cancer is estimated to increase two to three times in first degree relatives of a person suffering from cancer or polyps of the large intestine.
Most colorectal cancers derive from the transformation in the malignant sense of polyps, that is, of small growths due to the proliferation of cells of the intestinal mucosa. Polyps are considered precancerous forms, although they fall under benign pathologies.
The polyp can be defined, based on its characteristics, sessile (i.e. with a flat base) or pedunculate (i.e. attached to the intestinal wall by a small stem). Not all polyps, however, are at risk of malignancy.
There are in fact three different types: the so-called hyperplastic polyps (i.e. characterized by a rapidly proliferating mucosa), hamartomatous (also called juvenile polyps and Peutz-Jeghers polyps) and adenomatosis. Only the latter constitute precancerous lesions and only a small percentage of them turn into malignant neoplasm.
The probability of a colon polyp evolving into an invasive form of cancer depends on the size of the polyp itself: it is minimal (less than 2 percent) for sizes less than 1.5 cm, intermediate (2-10 percent) for sizes of 1.5-2.5 cm and significant (10 percent) for dimensions greater than 2.5 cm.
Once it has turned into cancerous tissue, the intestinal mucosa can present itself with different characteristics, distinguishable under the microscope: adenocarcinoma is the most common epithelial tumor, followed by mucinous adenocarcinoma, the ring cell adenocarcinoma with bezel, the squamous cell carcinoma and undifferentiated carcinoma.