What are the risk factors of the colorectal cancer?
Etiology of the colorectal cancer is not completely understood. It is not possible to definitely clarify why some people catch the disease and why others do not. What we do know is colorectal cancer is not contagious. This disease is not transmitted from one person to the other.
Age: Risk of being caught by the colorectal cancer increases by aging. Ninety percent of people with final diagnosis of colorectal cancer are older than 50 years. Mean age at diagnosis is around 60 years.
Colorectal polyp: Polyps outgrow on interior wall of the colon. They are common in people older than 50. Polyps are mostly benign in nature or they do not transform into cancer. However, some polyps (i.e. adenomas) may progress into cancer. Diagnosis and excision of polyps substantially reduce the risk of colorectal cancer.
Familial history of colorectal cancer: Colorectal cancer is more likely for people who have a family member (parents, siblings or children) with personal history of colorectal cancer. The risk is higher especially if colorectal cancer is diagnosed at younger age. The likelihood increases, if there is more than one family member with history of colorectal cancer.
Genetic alterations: Alterations in some genes increase the risk of colorectal cancer. Hereditary non-polyposis colorectal cancer syndrome (HNPCC) is the most common one of hereditary (genetically transmitted) colorectal cancers. It accounts for up to 2% of all colorectal cancer cases. An altered HNPCC is observed in patients with this type of the cancer. Every 3 of 4 people with altered HNPCC gene develop colorectal cancer. The HNPCC gene-associated colorectal cancer is diagnosed at earlier ages (around 40s).
Familial Adenomatous Polyposis (FAP): Hundreds of polyps exist in colon and rectum of patients with this rare familial condition. An alteration in a special gene, also known as APC, leads to the polyp formation. FAP transforms into the colorectal cancer at the age of 40s, if it is left untreated. It is not a common disease and accounts for less than 1% of all colorectal cancers.
Genetic analysis is required for all persons, who have family members with HNPCC or FAP, in order to identify changes specific to this disease early. If genetic alterations are identified, means to reduce the risk of colorectal cancer are searched and presence of the disease is investigated using various diagnostic methods. Adult patients with familial colorectal polyposis can be recommended surgical removal of whole or a part of colon.
Personal history of colorectal cancer: If a person has been previously diagnosed with colorectal cancer and started on treatment, this type of cancer can recur. The risk of colorectal cancer increases in persons who have personal history of ovarian, endometrial or breast cancer.
Ulcerative Colitis and Crohn’s Disease: If colonic inflammatory conditions, such as Ulcerative colitis and Crohn’s disease, persist for many years, the risk of colorectal cancer increases.
Nutrition: Scientific studies show that the risk of colorectal cancer increases in people who eat foods rich in fat (especially animal fat) and consume low amount of calcium and folic acid and low-fiber foods. Again, scientific studies demonstrate that the risk of colorectal cancer increases in people who have a diet poor in fruits and vegetables. However, more scientific studies are need for better understanding of how eating affects the risk of colorectal cancer.
Smoking: Smoking increases formation of colonic polyps and the risk of colorectal cancer.
If you think that you are at risk, you should inform your doctor about your concerns. Your doctor will inform you about risk-minimization means and recommend you an appropriate check-up plan.
Screening and Diagnosis Methods for Colorectal Cancer
For early diagnosis of polyps or the colorectal cancer;
- Every person aged at or above 50 should be assessed.
- Persons with moderate to high risk of colorectal cancer should visit a doctor,
Even they are younger than 50 years of age, they should be started on screening programs and necessary tests should be compared in the light of benefits and risks of each test and frequency of the screening program.
Following screening tests are used to determine colorectal polyps and cancers or abnormal conditions of colon and rectum:
- Fecal occult blood
- Double contrast barium enema radiography
- Digital rectal examination
What are the symptoms of the colorectal cancer?
Symptoms of the colorectal cancer are as follows:
- A change in bowel habits,
- Diarrhea, constipation or feeling of incomplete emptying of bowel
- Blood in stool,
- Stool getting thinner
- Abdominal discomfort (frequently relapsing gas pain, abdominal distension or cramps),
- Idiopathic weight loss,
- Persistent tiredness,
- Nausea and vomiting.
However, those symptoms can very frequently be linked to non-cancerous health problems. Despite this fact, seeking medical attention immediately in the presence of those symptoms is very important for early diagnosis and treatment.
Diagnosis of the Colorectal Cancer
If symptoms and signs of the colorectal cancer are identified, advanced diagnostic methods should be employed to verify or rule out the cancer.
- Blood tests
- Endorectal ultrasound
- Computed tomography
- Chest X-ray
Treatment Methods for the Colorectal Cancer
Surgery, chemotherapy and radiotherapy are frequently used in combination for the treatment of the colorectal cancer.
Surgery is the most common treatment modality used for the colorectal cancer. The tumor located in colon or rectum and peri-tumoral region are surgically removed. Surgery can be combined with radiotherapy and/or chemotherapy depending on the location and the stage of the cancer.
Chemotherapy can be preoperatively used to reduce size of the tumor (debulking). Again, chemotherapy is a therapeutic option to destroy postoperative tumor residues or to prevent the recurrence.
External radiotherapy: Radiation beams are extracorporeally delivered by radiotherapy devices.
Internal radiotherapy (implant irradiation): Fine tubes are inserted into or nearby the tumor and radioactive substance is delivered by this intra-corporeal radiation source.