Colorectal carcinoma is the most frequent cancer of the digestive tract. In Spain, its incidence ranges between 12 and 23 cases per 100,000 inhabitants, and increases every year. Worldwide, it is the third most common malignant disease in men and the fourth in women.
In Spain, 9% of deaths from malignant tumors are attributable to colorectal tumors, a figure that represents 40% of deaths if only digestive tract tumors are taken into account.
Diagnosis of colorectal cancer
The average age at diagnosis of colorectal disease is 71 years for colon tumors and 69 years for rectal tumors.
Between 5% and 10% of tumors are considered hereditary. For this reason it is essential to follow up and screen this population group, as well as carriers of polyps larger than 1 cm (due to their high risk of malignization).
Symptoms of colorectal cancer
In 41% of cases, the first clinical symptom is the presence of blood in the gastrointestinal tract, followed by a change in the stool rhythm (alternating constipation-diarrhea) and abdominal pain.
Between 6% and 25% of tumors debut (first clinical symptom) as complications in the form of occlusion or perforation. These situations are accompanied by a worse long-term prognosis and high perioperative morbidity and mortality.
There is no specific tumor marker (CEA, Ca 19.9…) to diagnose them with a simple analysis. However, the elevation of their numbers could indicate the existence of a tumor.
To confirm the diagnosis, the procedures of choice are CT and, above all, colonoscopy with direct vision and biopsy.
Treatment of colorectal cancer
In recent years cytogenetic analysis (K-ras, p53, c-myc…) has made it possible to identify patients at high risk of colorectal cancer, and is also very useful in the selection of adjuvant treatment and, consequently, in improving long-term results.
Once diagnosed, the treatment of choice is surgical with curative intent.
The surgical technique varies depending on the location of the tumor. Rectal tumors often require the practice of abdominoperineal amputation (removal of the anus and colostomy), performed by a specialist in General Surgery.
As a backup to surgical treatment, almost half of the patients will need chemotherapy or radiotherapy (sometimes prior to surgical treatment in the case of rectal tumors).
Currently 60% of patients survive more than 10 years after treatment, provided it is diagnosed early.