What is Chemotherapy for colon cancer
Colon cancer refers to malignant growths in the colon, rectum, and the appendix. Commonly, cancers that arise from these areas of the body are referred to as colorectal cancer. However, let us individually discuss how chemotherapy plays a role in both colon and rectal cancer.
Chemotherapy for colon cancer is used to reduce the likelihood of cancer cells from spreading, shrink tumor size, or slow growth of tumors. Application of chemotherapy may be applied after surgery (adjuvant), before surgery (neo-adjuvant), or as primary therapy (palliative). The drugs used in chemotherapy are often called anticancer drugs. Chemotherapy for colon cancer is given intravenously, by injection or by mouth. It can be used as a standalone treatment or may be combined with radiation therapy or surgery.
Chemotherapy for colon cancer is often coupled with repulsive side effects like nausea, vomiting, hair loss, and mouth sores. Leveraging new delivery protocols assist in the reduction of side effects and allow chemotherapy treatment more bearable for patients. For instance, administration of total dose of chemotherapy divided in smaller doses over a longer period of time helps reduce nausea and vomiting.
Chemotherapy for colon cancer applied after surgery is usually only done when the cancer has reached stage III wherein cancer has spread to the lymph nodes. It may prolong survival for patients whose metastases have spread to adjacent lymph nodes.
As for rectal cancer, treatment and prognosis, similar to all cancer forms, depend on the cancer stage. Oncologists first determine tumor invasion extent, if the lymph nodes have cancer in them, or if the rectal cancer has spread to other body parts most commonly the liver and the lungs. Stage I rectal cancer involves only the first or second layer of the rectal wall and no lymph nodes are involved. Stage II is when the tumor has penetrated the mesorectum, but no lymph nodes are involved. Stage III is when the lymph nodes are affected. Stage IV is when evidence of cancer existence in other body parts outside the rectal area is found. Localized rectal cancer stages are from Stages I to III. Metastatic cancer is stage IV
After removal of a tumor, it may be possible that cancer cells may have penetrated the mesorectum (stage II) or that the lymph nodes have been invaded by cancer cells (stage III). In such circumstances, chemotherapy is offered after recovery from the surgery to lessen chances for cancer to come back. Chemotherapy after surgery is then adjuvant therapy as mentioned earlier.
Patients initially diagnosed with stage II or II rectal cancer, chemotherapy may be given before surgery and is called neoadjuvant therapy. It is done to shrink the tumor to make it easier to remove it through surgery. A patient is more likely to tolerate the side effects of chemotherapy combined with radiation therapy before surgery than when it is administered after surgery. After recovery from surgery, patients who undergo neoadjuvant therapy should discuss with the oncologist on the number of sessions needed for additional chemotherapy application.
For metastatic rectal cancer, surgery and radiation therapy would only be performed if the patient suffers from persistent bleeding or bowel obstruction. Otherwise, chemotherapy alone is the treatment best suitable for metastatic rectal cancer wherein the rectal cancer is not curable. The introduction of new medications, however, has allowed longer prognosis for patients with metastatic rectal cancer.
