COLON CANCER TREATMENT
Colon cancer takes many years to develop and early detection may help in effective colon cancer treatment. Early diagnosis and cancer staging provide greater chances of a cure. Staging is performed to evaluate the penetration of a particular cancer and its extent of spread which helps determine the best mode of treatment.
The primary colon cancer treatment is surgery. Surgeries maybe categorized into curative, palliative, bypass, fecal diversion, or open and close.
Curative surgery
- Is done when the tumor is localized. During colonoscopy (screening test) when early cancer is discovered, which develops within a polyp, it can be removed by a procedure termed polypectomy.
- When the cancer is more advanced, surgical removal of the section of the colon with the tumor with sufficient margins is required. Radical en bloc resection of the mesentery and lymph nodes is also included to minimize the chances of recurrence. This is termed as colectomy. The remaining parts of the colon are anastomosed if possible to create a functioning colon or an artificial orifice / stoma is created.
- When the rectum is involved with the colon cancer, surgery involves total mesorectal incision or abdominoperineal excision.
Palliative surgery
This is done when there are multiple metastases and to reduce further morbidity, the primary tumor is resected. Surgical removal of isolated liver metastases may also be done.
Bypass surgery
Done when the tumor has invaded adjacent structures and excision is difficult. The tumor is bypassed (ileotransverse bypass) or a proximal fecal diversion is created through a stoma.
Open and close surgery
When the tumor is found to be unresectable and the small bowel is also involved, surgery is not proceeded with, as it may do more harm to the patient. But this is not a common occurrence these days as there is better radiological imaging and laparoscopy, which reduces the size of the incisions and reduces post operative pain.
Chemotherapy
Chemotherapy involves the use of drugs to reduce tumor size, enhance slow growth of the tumor or to reduce the chances of metastases. This can be done after or before surgery or as the primary mode of treatment. Chemotherapy after surgery is usually done only if the cancer has spread to the lymph nodes.
Drugs commonly used in chemotherapy for colon cancer involve 5-fluorouracil, leucovorin, and oxaliplatin.
Radiation therapy
Radiation is not usually done in colon cancer as it is difficult to target specific portions of the colon and it can also lead to radiation enteritis. It is more commonly done in rectal cancer. However, it may be done in colon cancer for pain relief and palliation when they are targeted at metastatic deposits if they compress vital structures and cause pain.
Other options: immunotherapy and cancer vaccines are being investigated for colon cancer.
Treatment of liver metastases
Studies have shown that over 20% of the patients who have been diagnosed present with metastatic colorectal cancer and 25% of them have resectable liver metastases which have to be done to increase their survival outcome.
When colorectal cancer is diagnosed at early stages, it can be curable; at later stages when metastases are present, a cure is less likely.