CancerLinkThere are four conventional primary methods to treat a cancer: surgery, radiation, chemotherapy, and immunotherapy. There are four goals of treatment: cure, prevention, prolongation of survival, and palliation. Palliation means that treatment is given to remedy a symptom of the cancer without being able to treat the cancer itself.
Surgery may be the initial step in diagnosis and treatment but not be curative itself. Other methods of treatment such as radiation or chemotherapy would be the primary treatment. Ovarian cancer is usually diagnosed surgically. The surgery is seldom sufficient as complete treatment and additional treatment with chemotherapy is then given.
The normal cells are also injured but are able to repair themselves better then the cancer cells. Thus the cancer cells are selectively killed more than are the normal cells. The amount of energy deposited in the cancer is called a RAD. This means Radiation Absorbed Dose. A typical radiation regimen may deliver 200 RADS per day, 5 days per week for 5 weeks. The dose would be 5,000 RADS. Recently the unit RAD has been changed to the Gray (Gy). One RAD is equal to one cGy (centigray); one hundred RADS are equal to one Gy.
Radiation therapy is also administered by radiation implants. Other terms for this are: intra-cavitary implant, interstitial implant, radium implant, cesium implant, high dose rate insertion, needle implant, and some that are named for the developer of that particular technique. The overall term is brachytherapy which means slow therapy. These implants are placed in the cancer itself or right next to it and are usually left in place for several hours or several days and then removed. The implant is loaded with a radioactive source that gives off radiation to the surrounding tissue while it is in place. Brachytherapy is a method for giving very high doses of radiation to the specific area implanted.
The amount of radiation administered is determined by the tolerance of the normal tissues that are also irradiated. Standard doses for specific areas of the body have been developed by past experience. A dose can be given that will kill all cancers but will probably also kill patients. A dose can be given for which there will be no side effects but which also probably will not cure anybody. There is always a trade off: the probability of cure vs the risk of complications. Radiation complications mainly depend on the normal tissue being irradiated. There are common side effects for each major area of the body being irradiated.
X-rays are not the only type of external irradiation. Electron beams are used in special circumstances. Other particle beams are being used mostly in the research setting.
All chemotherapeutic agents have side effects. Many have specific side effects characteristic of that drug. Some have major toxicity to the heart, some to the kidneys, and some to the nerves. Almost all are toxic to the bone marrow which is responsible for the production of the white and the red blood cells and the platelets. The white blood cells: granulocytes, monocytes and lymphocytes, are primarily responsible for fighting infections. The platelets are necessary to prevent bleeding. Those chemotherapeutic agents that are toxic to bone marrow cause a drop in the white cell count after each course of chemotherapy. The lowest count is called the nadir count. It is expected that the white cell count and the platelet count will go down and that they will return to normal so the next dose of chemo can be given.
Until recently there was nothing to do but wait for the bone marrow to recover. Now there are drugs that can be given to stimulate the bone marrow to produce more white cells. If the white cell count gets too low, then infections can occur which may be fatal. If the platelet count gets too low then spontaneous bleeding can occur from various parts of the body. The red cells are not affected as much. They are responsible for carrying oxygen. Over a period of time there may also be a drop in the red cell count which could cause symptoms of fatigue. Occasionally a blood transfusion may be necessary.
Nausea is a common side effect of chemotherapy but there are now several very effective drugs that can be given to prevent this. For most people it is no longer a major problem. The cells lining the mouth and digestive tract are actively dividing to replace those that are lost every day. Injury to the lining of the intestines and mouth can result in ulcerations that must heal before more chemotherapy can be given. Some drugs effect the skin, so sun exposure should be avoided.
Once chemotherapy is started it is usually repeated for a predetermined number of courses. It is continued as long as there is no evidence that it is not working, or until the predetermined number of courses has been given. Then a decision is made to either stop or continue with some sort of maintenance dosage. There are standard regimens that are used to treat each type of cancer. These regimens have been determined by studies comparing various treatments. The standard treatment represents the most effective treatment known at that time. When other regimens or new drugs are developed they are compared with the standard treatment and if found to be better become the new standard, or best known treatment.
The doctors who are specialists in chemotherapy are called medical oncologists. They go to meetings at least every three months where they are told about new and wondrous drugs or re-arrangements of old drugs so they are never at a loss as to what to recommend. The doctors who specialize in radiation therapy are called radiation oncologists. They go to meetings also and in the last twenty years have changed the unit of dose from RAD to Gray [Gy]. They are imperturbable and thoroughly predictable whereas the medical oncologists are an unruly and tempestuous lot.
The immune system primarily functions by recognizing what is self and what is not self and destroys that which is non-self. If a cancer cell were sufficiently different from a normal cell so as to be recognized as non-self then it would be destroyed. This is the rationale for the tremendous expenditure of research activity into immunotherapy as a cancer treatment.
Conventional treatment is the result of the scientific process. A problem or phenomenon is studied. An hypothesis is made and experiments done to confirm or reject the hypothesis. The human body and its workings are incompletely understood. There is more unknown than known about it. But, even with this lack of knowledge the scientific process has yielded huge benefits to us. There are no advocates of alternative electricity, electronics, aerodynamics, refrigeration, chemical engineering or physics. Everything you have that the caveman didn't have is the result of the scientific process.
The reason that there are unconventional therapies in medicine and none in any other field of applied science is that medicine is an inexact science. And, everybody is going to die of something sooner or later. There is no avoiding it. There is no scientific way to stop it. Excluding accidents and trauma, everybody is going to develop an illness which will be fatal. They may be able to avoid or cure one or several illnesses, but they will get another one sooner or later that will become untreatable or incurable. It will happen to everybody. Since there is no scientific way to avoid it and since nobody wants to die there is nothing else to do but to try anything. This assures a large, continually renewing population of desperate people.
Unconventional therapies can be useful in certain circumstances. They give hope where none is otherwise expected. They allow the patient to participate more and to take more control over their treatment. Unconventional therapy should not take the place of conventional therapy as long as there is scientific proof that the conventional treatment may be helpful. Unfortunately, there are many situations in which it has been scientifically proven that conventional treatment will not be helpful. In these situations the options are no treatment, investigational scientific studies, or unconventional treatment. At this point the decisions are philosophical not medical.
William M. Rich, MD
Last updated 2 July 1996