Answer
Cancers may be treated by surgery, radiation, or chemotherapy alone. But often the use of a single modality is not adequate to remove the observed cancerous cells completely, deal with metastases, and protect against recurrences. Experience has shown that a judicious combination of two or all three modalities may be the best long-term option for the patient. Sometimes immune cancer therapy procedures are used to enhance the efficacy of the treatment.
Work Step by Step
Surgery. Surgery is used to remove, damage or kill cancer cells in reachable regions of the body. The advancements in surgical techniques means that most areas of the body can be operated on surgically. But the risks of surgery are so high in certain circumstances as to be prohibitive. In such cases, radiation is often employed to destroy cancerous cells, especially cells in metastases which cannot be easily observed visually or even instrumentally.
Chemotherapy is used to to shrink tissue before surgery ( neoadjuvant) or after surgery or to kill remaining cells ( adjutant use). Chemotherapy is especially useful in treating advanced metastatic cancers of the digestive system. It is sometimes given as a single treatment but may involve several treatments over weeks or months
Unfortunately, there is a phenomenon called drug resistance, and this displays in cancer therapy also. For this and other reasons mentioned above, a combined surgical, plus radiation, plus "chemo" treatment regimen gives the patient the best chance of a cure and long term survival (>10 years).
