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Actor and director Chadwick Boseman, who played Black Panther in theaters, died last Friday night of colon cancer. He had been battling the disease for four years.
Bowel or colorectal cancer includes tumors that begin in the part of the large intestine called the colon and in the rectum (end of the intestine and beginning of the anus) and anus. Globally, this is the third most common type of cancer and accounts for 10% of all new cases of the disease overall.
One of the peculiarities of this type of tumor is that it is more frequent in more developed regions, such as North America, Europe and Oceania. Even in Brazil, the highest incidence rates are found in the south and southeast.
The condition is strongly related to eating habits, making it a preventable type of cancer. The colonoscopy examination itself, indicated for diagnosis and screening, is also preventive in nature: when polyps are found, they can be removed before they progress to a malignant tumor. In addition, the disease usually progresses slowly, which favors the treatment of cancer.
Symptoms
In most cases, colorectal cancer is asymptomatic at first. As it progresses, manifestations such as:
Presence of blood or mucus in the stool.
? Dark or ribbon-shaped stools
? Anemia
? Abdominal cramps
? Pain or bleeding when you have a bowel movement
? Change in bowel habit (the person begins to have diarrhea or constipation that does not go away and has no apparent cause)
? Feeling that the intestine has not emptied after a bowel movement.
? Packing sensation
? Unexplained weight loss
? Constant tiredness and fatigue
Remember that these symptoms can also be related to other conditions.
Where does the disease manifest itself?
The vast majority of bowel cancers are adenocarcinomas, that is, they begin in the mucosa that lines the inside of the intestine. Most tumors start with small benign lesions called polyps, wart species that appear on the mucosa. The colon and rectum are the parts that make up the large intestine.
Most of the nutrients are absorbed before reaching it, in the small intestine, a region where the appearance of cancer is more rare. “In the large intestine, the content passes more slowly, so the risk is greater”, justifies Samuel Aguiar Junior, specialist in cancer surgery at the AC Camargo * Oncology Center.
Other types of cancer in the intestine: carcinoid tumors (which begin in the hormone-producing cells of the intestine), gastrointestinal stromal tumors (or Gist, which begin in the interstitial cells of Cajal, in the intestinal wall), lymphomas (which appear in lymphatic cells) and sarcomas (in blood vessels, muscle or connective tissue).
Modifiable risk factors
? Excessive intake of red meat, especially processed meat: the mechanism of action would be carcinogenic compounds generated during processing (to turn sausage, bacon, ham, etc.) or when the meat is subjected to high temperatures (such as grilling, frying or grilling). The barbecue would be even worse as it includes compounds from burning charcoal. Excess is understood to be more than five times a week, or an average of more than 100 grams per day.
? Diets low in fruits and vegetables: Vegetables are rich in antioxidants and fiber, which have a protective role against obesity and cancer. That is why the recommendation is to eat five daily servings of these foods.
? Abdominal obesity: the condition involves hormonal and inflammatory reactions that increase the risk of cancer.
? Sedentary lifestyle: regular exercise fights obesity and improves hormonal profile.
? Smoking: Smoking has also been linked to colorectal cancer.
? Excessive alcohol consumption: Men who drink more than 14 drinks per week, as well as women who drink more than seven drinks per week, have a higher risk of having this and other types of cancer.
Non-modifiable risk factors
? Age: most patients with the disease are over 50 years old.
? Inflammatory bowel diseases: Patients with ulcerative colitis or Crohn’s disease are more prone to colorectal cancer.
? Family inheritance: some families have a history of this type of cancer, and in these cases it is common to appear before the age of 50. There are also syndromes associated with the disease, such as hereditary nonpolyposis colorectal cancer (HNPCC or Lynch syndrome) and familial adenomatous polyposis (FAP).
? Personal history of cancer or polyps: Anyone who has had adenomatous polyps or has had colorectal, ovarian, uterine or breast cancer is also more likely.
? Ethnicity: Studies indicate that Jews of Eastern European origin are more likely to have this type of cancer, as well as black people, although the causes are not clear.
? Type 2 diabetes: According to the American Cancer Association, patients with the disease are at higher risk even after discounting factors such as abdominal obesity and physical inactivity.
How was the diagnosis made?
The main test to detect colorectal cancer is a colonoscopy. In addition to being requested when there are symptoms, or after a positive result in the fecal occult blood test (PSOF), it is used for colorectal cancer screening from the age of 50, or from the age of 40 in patients with a family history.
Although in Brazil most diagnoses occur after the age of 55, cases of colorectal cancer in patients aged 40 or 45 have increased, according to doctors.
How is the treatment?
The treatment can be carried out using various therapies and is recommended according to the situation of each patient. They can be:
Surgery
Only some early-stage tumors can be removed by colonoscopy. Surgery to remove tumors from the colon is called a colectomy. It can be opened (with an incision in the abdomen) or done laparoscopically. Nearby lymph nodes can also be removed in the same procedure. In cases of intestinal obstruction, a stent may be inserted before the procedure.
The main risks of surgery are infections, bleeding, blood clots, and adhesions (when one tissue sticks to the other, which may require additional surgery).
In relation to rectal cancer, chemotherapy or radiation therapy may often be indicated to shrink the tumor before the surgical procedure. Because the rectum is inside the pelvic cavity, the surgeon’s work is hampered. There are minimally invasive techniques capable of removing localized tumors without incisions.
Chemotherapy
After surgery, the clinical oncologist evaluates the need for preventive chemotherapy based on the results of the pathology examination. In certain cases, such as when the tumor is in the rectum, chemotherapy may be done before the surgical procedure to shrink the cancer and facilitate resection. The main side effects of chemotherapy are nausea, vomiting, infections, hair loss, and fatigue, among others.
Radiotherapy
It may also be indicated before surgery, to shrink the tumor, or afterwards, to prevent recurrences, or to control metastases and relieve symptoms. The most common side effects are irritation, bowel incontinence, and fatigue.
Target therapies
They are drugs or other substances that are used to identify and attack cancer cells without harming the healthy ones that surround them, so they cause fewer side effects than chemotherapy. There are already some approved target therapies for some types of colorectal cancer. According to Diogo Bugano, these drugs have significantly increased the survival of patients with incurable metastatic disease in recent years.
Immunotherapy
Treatment considered promising for some cancers helps the immune system recognize cancer cells and destroy them more effectively. Only a small part of colorectal cancer patients can benefit from immunotherapy, but since this use is not yet foreseen in any leaflet in Brazil, families must pay for the treatment, which is expensive.
* With information from an article published on 10/02/2018.
