Colon and rectal cancer (CRC)
Colon and rectal cancers mainly develop from polyps found in these organs. One million people throughout the world contract colon and rectal cancer each year.
What is it?
The other name given to large intestine or colon and rectal cancer (CRC) is colorectal cancer. About 1 million people worldwide contract CRC every year, with 30,000 new cases each year in Turkey. Men are slightly more likely than women to contract CRC during their lifetime, with a rate of 4.5% for men and 3.2% for women. CRC mainly develops from adenomas (polyps). These benign tumors, originating from the colon or rectum mucosa, are not generally recognized, as they may lie dormant for many years. The rate of incidence of adenomas increases with age. However, although the adenoma related cancer development process has recently been brought to light, external factors triggering the process are still under debate.
What are the methods of diagnosis?
Imaging methods are indispensable examinations in CRC evaluation and in the determination of the phase of the disease are imaging methods. Lung X-rays, computed tomography (CT) of the resonance imaging (MRI), endorectal ultrasonography (ERUS) and positron emission tomography (PET) may all be required depending on the patient and on the characteristics of the tumor. The phase of the disorder is determined and treatment is planned at the end of the evaluation process.
Which tests are carried out?
The patients must consult a physician and must undergo a very reliable and thorough physical examination. Subsequently, thefollowing tests are carried out,respectively:
• Examination of blood in the feces
• Radiological workups
• Laboratory workups
• Endoscopic workups
How is it treated?
There are various methods for treating colon and rectal cancers. Surgery, chemotherapy (medicated therapy) and radiotherapy are the most frequently used methods of treatment. It is important here to obtain information on the patient’s general status and the extent of the disorder before determining the treatment. Therefore, the phase of the CRC must be known in advance.
In how many phases is CRC classified ?
CRC is classified in 4 phases:
Phase I: This is the earliest phase of the disease. Cancerous cells affect the inner and middle layers of the colon. The lymph nodes and distant organs are not yet affected.
Phase II: Cancerous cells affect all layers of the colon, reach the outmost layer and may spread to adjacent organ(s). Lymph nodes and distant organs are not yet affected.
Phase III: Regardless of the level of involvement in the colon walls is, the tumor spreads to lymph nodes that are adjacent to the colon.
Phase IV: This is the disease’s latest phase. Independent of the extent of h ow far the tumor has spread in the colon walls or lymph nodes, there is metastasis in such organs as the liver, the lungs, the peritoneum, the bonesand the brain.
How is surgical treatment applied?
In all phases, the primary treatment method for CRC is surgery. However, the form of surgical treatment may vary depending on the location of the tumor in the colon and rectum, as well as its size, phase and emergency conditions under which patient comes to the hospital with tumor complications (atresia, perforation, bleeding, etc.). Today, laparoscopic applications gradually become widespread in the surgical treatment of CRC.
Primary techniques used are the following:
• In some small rectal tumors, local excision is the term used for cutting and removing only the part with the tumor through the anus.
• Resection is the term used for cutting and removing a part of the large intestine (or the whole) and a part of the rectum (or the whole) depending on the location of the tumors. In this surgical technique, lymph nodes adjacent to the intestine are removed along with the intestine. If the tumor has spread to adjacent organs, these organs must also be removed with radical surgery. The remaining healthy parts of the removed intestine are matched up and joined (anastomosis).
• A non-anatomic anus is constructed (ileostomy or colostomy) by connecting it to the small intestine or colon abdominal wall for various reasons after the colon or rectal resections. The contents of the intestine are discharged into a plastic bag which is connected to the abdominal wall through this non-anatomic anus. This situation may be permanent for some patients. However, since it is not medically required in some patients, the non-anatomic anus is closed and patients are allowed to defecate normally.
• A certain number of liver and lung metastases at certain size may be removed via surgical technique (metastasectomy).
• Palliative surgical interventions (such as opening colostomy) that would improve the quality of life of the patient are carried out for colon and rectal cancers in later stages, which radical surgical treatment will not be beneficial to.
• Chemotherapy and/or radiotherapy is included in the treatment plan before and/or after surgery at patients in phase III and IV.