Colonic cancer diagnostics
The unity of origin and diagnostics made it possible to combine rectal and colonic cancer differing in treatment approach and prognosis in the single term «colorectal cancer» (CRC).
For the initial detection of a rectal tumor, a digital examination is sufficient, after which instrumental proctoscopy is performed. All the higher sections of the intestine one and a half meter long are accessible only to the endoscopic equipment in the course of a colonoscopy.
Sometimes, an ultrasound examination of the abdominal cavity and small pelvis can reveal a tumor formation originating from the large intestine, but the intestine itself cannot be seen with ultrasound imaging. On the other hand, colonoscopy combined with ultrasound enables visualization of the entire thickness of the intestinal wall and parietal arrangements in the abdominal cavity outside the intestine.
In some cases, tumor of the sigmoid colon is detected during proctoscopy, however, in all cases of CRC, a total colonoscopy is indicated with a biopsy, where a piece of pathological tissue is obtained for examination under a microscope. Currently, the resolution of endoscopic research is increased by the possibility of local magnification, spectral analysis and special staining techniques.
What specifying diagnostics will be required?
A positive result of the histological study of a piece of the tumor taken at endoscopic examination of the intestine is sufficient to establish a diagnosis of cancer.
Further clarification of the malignant process advancement will be needed, for which irrigoscopy is used, that is, fluoroscopy with intestinal filling with a contrast agent. X-ray images show the degree of narrowing of the intestinal tube lumen, the tumor spreading in the intestinal wall, and the relationship with the tissues of the abdominal cavity adjacent to the intestine.
Irrigoscopy is required when it is impossible to perform a total endoscopic examination of the intestine.
Laboratory diagnostics of colonic cancer
Laboratory methods of diagnostics include the examination of feces for concealed blood to detect bleeding, and determining the level of tumor markers CEA and CA 19.9. These markers do not increase in 100% of cases, but in the future, changes of their level allow monitoring the course of the process and evaluate the effectiveness of treatment.
In a piece of tumor tissue, mutations of the KRAS and NRAS genes are determined, which makes it possible to plan targeted drug therapy.
In all cases, blood tests are made repeatedly.
Identification of metastases
With an established colonic cancer, abdominal and retroperitoneal ultrasound examination is a method of searching for metastases, although it is inferior to CT in sensitivity and accuracy, supplemented by intravenous administration of a contrast agent for better results.
The liver is the favorite organ for the development of metastases, so a CT scan of the liver is more than relevant for CRC. Liver MRI is necessary to develop the tactics for treating metastatic liver damage.
Chest radiography can be replaced by chest CT scan showing even smaller changes, which is not at all superfluous given that colonic cancer often gives pulmonary metastases.
Laparoscopy may be required if the spread of tumor seedings in the peritoneum is suspected.
Diagnostics should be sufficient but not excessive, as each examination is associated with anxiety, of which a cancer patient has too much as it is. The experts of the Clinic Medicine 24/7 are careful with patients and are united with them with one goal, to make the life of each of them as long and as comfortable as possible. Sign up for a consultation: +7 (495) 151-14-47
Colonic cancer is a malignant neoplasm localized in the blind, transverse and sigmoid colon. The rectum also belongs to the colonic intestine, but its cancer has specific features of the course and therapy, therefore it is considered a separate condition.
Like a century ago, colonic cancer can only be cured by surgery, though modern oncology has introduced fine endosopic excisions of the tissues affected by cancer to the group of radical interventions.
Surgery is now applied for the condition much more often, while the adherence to chemotherapy somewhat diminished with the increase in the role of targeted drugs. The condition has remained aloof from the success of radiation therapy, as not a single method of irradiation has been found that would allow at least minimal control over the process.
Symptoms of colonic cancer
The large intestine is composed of the transverse colon and sigmoid colon, the rectum also being a part of the large intestine. Rectal cancer has specific features of its course and some differences in the therapeutic strategy, therefore it is singled out as a separate disease. The clinical course of a malignant neoplasm of the segmented intestine, even with signs of high aggressiveness, is much better than morphologically equivalent lesion of the rectum.
It has been noticed that malignant processes of the upper parts of the large intestine proceed with less aggressiveness than of the lower ones, especially the rectum. Often the tumor process is detected after it has significantly advanced, when a person lands on the operating table for complete intestinal obstruction.
The late detection of cancer is due to the high extensibility of the intestinal tube and the lack of condition-specific clinical signs. The lack of clinical signs of a tumor lesion, which allows the condition to proceed covertly, is not so bad for the patient. The fact is that a process initially characterized by clinical symptoms has a worse prognosis than an asymptomatic neoplasm of the same size in a patient with similar anthropometric and age characteristics. Symptoms are usually associated with a decrease in the intestinal tube lumen and a blood loss due to vessels destruction by the tumor.
Tumor markers allow tracking the course of cancer and the effectiveness of treatment, but are useless to detect it, for example, during clinical examination, because they increase with any intestinal condition and other benign gastrointestinal processes. The only method for diagnosing cancer is colonoscopy.