Surgery and radiotherapy deal with cancers directly at the site of the tumor ; chemotherapy differs in that it is a generalized treatment that affects the whole body. By the nature of the disease, cancer almost invariably spreads to other organs unless the rogue cells are destroyed, so it is necessary where possible to kill any cancer cells before they develop elsewhere into secondary cancers. Chemotherapy can also be used where the cancer has already spread to other sites in the body as chemotherapy drugs reach all the areas involved.
Chemotherapy is offered to combat a range of cancers although it is not an effective treatment in all cancers. In particular, it is used in the treatment of acute leukaemia, lymphomas, childhood and adult cancers. The therapy may be given in combination with surgery and/or radiotherapy; the exact program will be aimed at achieving the best results.
The name chemotherapy means ‘treatment with chemicals’ – drugs that actively destroy body cells. In cancer treatment, the term applies to drugs that are capable of damaging cancer cells. Strictly speaking, all drug treatments are drug therapies, but in medical language the term ‘chemotherapy’ refers only to the special cytotoxic drugs used for cancer treatment. Cytotoxic drugs work by damaging all cells – cancerous and normal. They are given in such a way that the damage to the cancer cells is maximized and the damage to normal cells is minimized. The treatment is tailored to reduce, as far as possible, the side effects caused by the drugs and the damage to normal tissue.
Which drugs are used in chemotherapy ?
There are several types of cytotoxic drugs in use, often given in combination, according to the type of cancer. The information given below lists a few examples only, there are a number of different drugs in each category.
- The alkylating agents work by attacking DNA (the blueprint information for the cell) thus interfering with cell reproduction; examples of drugs include mustine and ifosfamide.
- The cytotoxic antibiotics used primarily in the treatment of acute leukaemia and lymphomas include doxorubicin and bleomycin.
- The antimetabolites combine with vital enzyme systems of the cell to prevent normal cell division. An enzyme is a chemical produced naturally by the body to trigger an important body process. Drugs used are fluorouracil and methotrexate.
- The vinca alkaloid group of drugs include vinchristine and vinblastine, often used to treat lymphomas and leukaemias.
The source of the drugs
Scientists are working continually to develop new drug treatments and improve existing drugs. The raw materials from which the drugs are derived come mainly from natural substances collected all over the world; for example, plants and fungus from the rain forests, algae from water and metal derivatives. Some drugs have been found because of a direct search by pharmaceutical companies for likely substances; others are discovered more by chance when researchers come across a promising candidate whilst doing other experiments. The drug doxorubicin was discovered in Northern Italy from a fungus taken from the ruins of a medieval tower. This drug is now widely used in the treatment of non-Hodgkin’s lymphoma.
Adjusting to the treatment
Patients who attend cancer centers soon get into the routine and some people manage to fit attendance at the out-patient clinic around their normal daily life. How well or poorly a person feels depends largely on their age and what combination of drugs they are being given, and, to a small degree, their personal approach to the treatment. There are some publicized cases of well-known people undergoing cancer treatment whilst still continuing to work. Patients receiving small doses of drugs in tablet form (for example, for low-grade non-Hodgkin’s lymphomas) may respond well to such treatment.
But for most people having chemotherapy and continuing to lead a busy life will simply not be an option; getting themselves through the chemotherapy treatment period will be about as much as they can manage. This is not the time for heroics. Special care for cancer patients are highly advisable. Further, it is likely that your relative will need considerable physical and emotional support whilst receiving chemotherapy.