Colorectal cancer (CRC) is the most frequent malignant tumor of the large intestine, which is formed by the colon and rectum. The estimate of new cases of CRC in Brazil for the year 2020, according to the National Cancer Institute (INCA), is 20,540 cases in men and 20,470 cases in women, thus being the second most common type of cancer between men and women.
Screening is defined with the investigation of asymptomatic people (without symptoms), in order to classify them as high or low probability of developing a disease. It appears that colorectal cancer is a disease eligible for screening because it has a high prevalence, can be detected in a pre-malignant phase and is capable of being cured. Survival rates can reach at least 90% when detected early.
The most performed and most complete procedure for CCR screening is colonoscopy, as it can investigate the entire extension of the large intestine (colon and rectum), in addition to providing at the same time the removal of polyps and other precursor lesions of the CCR, allowing reduction considerable number of deaths related to this type of cancer.
Populations at risk for colorectal cancer
The risk is determined by genetic factors and acquired throughout life. Strategically, individuals are divided into two populations: those of medium risk and high risk. The medium-risk population is composed of individuals without symptoms, of both sexes, aged 50 years or older, without other risk factors.
High-risk and high-risk populations are those who have a history of polyps and colorectal cancer; have a family history of colorectal cancer or polyps; personal history of long-lasting inflammatory bowel disease (Ulcerative Colitis and Crohn’s Disease), that is, with more than eight years and presence or suspicion of hereditary syndromes (Familial Adenomatous Polyposis and Hereditary Non-Polyposis Colorectal Cancer (HNPCC – also known as Lynch syndrome).
When to start screening for colorectal cancer?
In general, it is recommended that colonoscopy screening be started at age 50. However, individuals with a family history (1st degree relatives) of colorectal cancer, as a rule, should be screened at 40 or 10 years before the earliest case (the one diagnosed at the youngest age). In families considered to have Lynch Syndrome, screening should begin at around 22 years of age.
The most common symptoms are changes such as constipation or diarrhea, and blood in the stool. In tumors of the rectum, feces may also have a tapered appearance. Abdominal pain, unexplained weight loss or feeling of continued weakness may be present in more advanced cases. Anyone with these symptoms should see a specialist for early diagnosis and treatment.
RAC diagnosis and evaluation
Commonly performed through colonoscopy. Once diagnosed, imaging exams (usually tomography) complement the preoperative staging of the disease with information about the presence or absence of a disease beyond the large intestine (metastases).
When it comes to cancer of the rectum, magnetic resonance imaging is unquestionable nowadays, as it determines whether the tumor should be treated with radiotherapy and chemotherapy before surgery.
However, definitive staging – which decides on the need for some postoperative treatment (chemotherapy) and provides a prognostic analysis of the disease – is performed only after surgical treatment that allows the detailed audit of the tumor with its lymph nodes by the pathologist.
In order to provide a cure, surgical treatment of RCC is almost always performed. CCR surgery removes the intestinal segment where the tumor is located together with its lymph nodes.
In the case of cancer of the rectum, its distance from the anus and its local behavior is what determines whether the initial treatment will be surgery or radiation therapy with chemotherapy followed by surgery.
The creation of a colostomy (placing the open intestine on the abdominal wall in a pouch) is a less common event and is usually performed in cases where the tumor is very close to the anus or when there is a need for reoperation due to postoperative complications.
Colorectal surgeons or coloproctologists are trained in minimally invasive or laparoscopic surgery and should offer this access route to patients whenever possible, as it reproduces the same oncological results as conventional open surgery, in addition to providing faster recovery of the patient in the postoperative period with early return to their daily activities.
Follow-up after treatment
Even when the cancer appears to have been completely treated and removed, there is a possibility of recurrence, which can be local or distant (metastases). This is because undetected malignant cells remain somewhere in the body after treatment. Therefore, the patient must be monitored at predetermined time intervals through assessments that include physical examination, imaging exams and colonoscopy, for a period of approximately five years.
* Dr. Esdras Camargo A. Zanoni, coloproctologist, digestive and colorectal cancer surgeon at Hospital VITA (Curitiba – PR); PhD in surgery from the Medical School of USP.
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