Colorectal cancer chemotherapy is of three types and depends on the stage of the cancer.

Primary chemotherapy: It is used for the treatment of advanced colorectal cancer that is spread to other parts of the body. In this case, surgery cannot remove the entire tumor and thus primary chemotherapy for colorectal cancer is used to reduce symptoms, shrink the tumor and prolong the survival of the patient.

Adjuvant chemotherapy: It is used after the tumor is removed surgically. This treatment kills the remaining cancer cells after the surgery. These remaining cancer cells could have spread to the liver or other organs.

Neoadjuvant chemotherapy: It is given before surgery to shrink the tumor. This makes the surgical removal of the tumor easy. This types of chemotherapy is also given along with radiation in some cases.

Invasive colorectal cancer can be cured to a great extent. Early detection through various diagnostic tests and screening programs is the most important factor for preventing colorectal cancer. In the last few years, very good advancements in systemic therapy for colorectal cancer have come up that have dramatically improved results for metastasized disease.

Chemotherapy Drugs Used for Colorectal Cancer

5-Fluorouracil (5-FU) is the most preferred chemotherapy drug for colorectal cancer since many years. It is used in combination with leucovorin a vitamin, which enhances the effect of 5-FU. This drug is given intravenously. Xeloda is a pill form of this drug. It is used for treatment for colorectal cancer, which has metastasized. It is used as a neoadjuvant therapy with radiation in rectal cancers to enhance the effect of radiation.

Many new chemotherapy drugs are used for the treatment of colorectal cancer that has metastasized. These are Camptosar, Eloxatin, Avastin, Erbitux, and Vectibix. Camptosar, Eloxatin, and Avastin are used in combination with 5-FU for metastatic colorectal cancer. Erbitux is administered intravenously either alone or with Camptosar. Vectibix is used in combination with 5-FU and leucovorin.

Side effects of these drugs are diarrhea, mouth irritation, low white blood cell count and hair loss.

Colorectal cancer with liver metastasis is treated with floxuridine that is administered intra-arterially. The side effects of this drug are nausea, vomiting, diarrhea, and inflammation of the intestine or enteritis.

Blocking agents like cetuximab are used along with chemotherapy drugs to treat metastatic colorectal cancer. These drugs prevent cancer cell receptors from receiving epidermal growth factor that stimulates cell growth, cell division and further metastasis. Blocking agents target specific cells hence, the side effects are reduced. Some of the side effects are allergic reactions like rash, breathlessness and low blood pressure.

Bevacizumab is also used to treat advanced colorectal cancer. This drug prevents formation of new blood vessels and hence prevents tumor growth. It does not affect the normal tissues. The side effects include blood clots and high blood pressure. These are controlled with medication.

Panitumumab is a complete human monoclonal antibody used to treat metastatic colorectal cancer after first chemotherapy. This drug is administered intravenously once in two weeks.

Colorectal cancer chemotherapy is effective for certain stages of cancer and also prolonging survival in advanced stages. Although surgery is the preferred option in this condition, especially in early stages as the tumor can be removed totally there are clinical trials going on for newer and better drugs to cure colorectal cancer with reduced side effects.