Overview:
- It is abnormal cells multiply in an uncontrollable way at colon wall cells, which bulging inside lumen of colon causing obstructive symptoms and may extend to outside of colon wall giving pressure symptoms over another organs.
cancer cells may give distant metastasis (mainly liver metastasis)
- Colon cancer does not cause any symptoms in early stages (due to large size of colon lumen), it requires a long time until becomes big enough that leads to obstructive or compressive symptoms
so, it is necessary to screen early for colon and rectal cancer.
Etiology:
- Cancer cells are normal cells in origin, but have undergone changes or mutations in their DNA
- The changes caused an imbalance in how they grow and divide and a disorder in their functions
Symptoms:
- Abdominal pain
- Abdominal distension
- Change in bowel frequency: constipation , diarrhea
- Rectal bleeding
- Bloody stools
- Thin stools
- Feeling of a lump in the rectum
- general systemic symptoms of cancer (weight loss, fatigue, weakness, pallor, fever and night sweating).
Causes:
risk factors include:
- Unbalanced diet: fatty, red meat, processed meat, poor in fiber.
- Poor physical activity
- Age: over fifty
- African origin
- Smoking
- Inflammatory bowel disease: (Crohn’s, ulcerative colitis)
- Obesity
- Diabetes mellitus
- Radiation therapy
- Family history of colorectal cancer
- Family history of familial polyposis
- Excessive alcohol intake
- genetic syndromes:
- Lynch syndrome: hereditary nonpolyposis colorectal cancer
- Familial adenomatous polyposis (FAP): where there are thousands of polyps and are predisposed to cancer
Diagnosis:
- clinical examination
- Laboratory test to assess anemia, liver function and screening for tumor marker CEA
- colonoscopy with biopsy for cancer diagnosis
- CT and MRI of abdomen, pelvis and chest to determine tumor stage.
Treatment:
- Do not forget regular colonoscopy after fifty to detect any colon tumor in its early stages
- colonoscopy should be performed less than fifty in case of a risky family history
- A very early tumor in colon mucosa can be treated with endoscopic removal with close monitoring
- malignancy at tip of polyp can be treated with a polypectomy during colonoscopy
- Other options include:
- Laparoscopic partial colectomy: Colon tumor is removed with mesenteric lymph nodes, and reconnection of colon edges
- Laparoscopic lower anterior resection: in upper rectum tumor, rectum is resected with mesenteric lymph nodes and reconnect colon to anus.
- Abdominal perineal amputation: in low rectal tumors, rectum and anus are excised with its mesenteric lymph nodes and permanent colostomy is performed
- emergency surgery in colon tumors: it is to treat bowel obstruction, perforation or bleeding
usually, colon tumor is removed and temporary colostomy is performed
colostomy closure can be done after a few weeks
- Chemotherapy:
- Pre surgery: to decrease tumor size
- Post-surgery: as a supportive adjuvant therapy to kill any remaining cancer cells
- palliative treatment when unable to perform surgery
- Radiotherapy:
- Pre surgery: to decrease tumor size
- Post-surgery: as a supportive adjuvant therapy to kill any remaining cancer cells
- palliative treatment when unable to perform surgery
- Radiotherapy and chemotherapy are often both involved in colorectal cancer.