The objective of surgery is to completely remove the cancer and a margin of tumor-free tissue; or, if the tumor cannot be totally removed or a clear margin achieved, to eliminate as much of it as possible, so that subsequent measures such as chemotherapy and/or radiation therapy might be more effective.
External-beam radiation therapy destroys tumor cells using a narrow beam of high-energy X rays from a special machine.
The word chemotherapy literally means “drug therapy,” but it has become synonymous with cancer treatment. Surgery and radiation therapy treat cancer locally; chemotherapy is usually a systemic therapy. Ingested orally or injected, the chemicals hunt down vagrant tumor cells anywhere in the body and stop them from proliferating. Your youngster may be prescribed a single medication, but more likely she’ll receive combination chemotherapy of two, three, perhaps more drugs. One regimen used for advanced lymphoblastic lymphoma consists of no fewer than ten drugs.
Anti-cancer agents owe their effectiveness to the fact that they zero in on rapidly dividing cells. While malignant cells sustain the most damage, normal cells in the lining of the digestive tract, the white blood cells and the hair also happen to be highly active, and they too incur the wrath of the chemo agents. Consequently, symptoms such as nausea, lowered resistance against infection, mouth sores, diarrhea and hair loss may accompany treatments. Radiation also targets rapidly dividing cells, but the adverse effects tend to be confined to the treatment area, or field.
If defined loosely, chemotherapy can be said to include hormonal drugs and immunologic agents. This latter group, long regarded in some quarters as the future of cancer treatment, has been slow in fulfilling its promise. The principle behind immunotherapy is to beef up the body’s immune system against the intruders, or to direct antibodies (with or without a drug attached) to the surface of cancer cells. For the time being, immunologics have yet to assume their place as front-line treatments.
Bone-marrow transplantation (BMT)
Bone-marrow transplantation has two roles in cancer treatment. In leukemia, it may be curative therapy, replacing the diseased marrow with new marrow withdrawn from the hip bone of a family member or a matched unrelated donor, then infused into the patient’s bloodstream.
In other pediatric cancers, BMT makes it possible for youngsters to receive higher-than-normal doses of chemotherapy and/or radiation therapy. The increased amounts of drugs wipe out more cancer cells but also destroy the bone marrow, which then must be replenished with healthy marrow cells—often the patient’s own. You may hear this procedure referred to as high-dose chemotherapy with stem-cell support. Stem cells are the undeveloped cells in the marrow that mature into blood cells. They are also found, in lesser numbers, in the bloodstream. Half the transplants performed in the United States now use peripheral-blood stem cells (PBSCs) in place of bone marrow.
There are two main types of bone-marrow transplants: allogeneic and autologous. In an allogeneic transplant, the stem cells are harvested from another person with genetically compatible cells. A perfect match improves the chances that the body will accept the transplanted marrow, or graft, and that the graft will take to its new home. The most-likely matched donor is a brother or sister, followed by a parent. However, two in three BMT candidates do not have an immediate family member with matching cells. In that event, the patient’s doctor might arrange for him to be registered with the National Marrow Donor Program, which attempts to match patients with volunteer donors from its ever-expanding data base.
In autologous stem-cell transplantation, the patient’s own marrow is aspirated through a needle during a period of remission, frozen, then given back to him later. (If the person never enters remission, the marrow can be treated with chemotherapy in the laboratory until it tests negative for cancer cells.) This technique, which has been used in relapsed Hodgkin’s disease and non-Hodgkin’s lymphomas, and experimentally for several other resistant pediatric cancers, is less dangerous and less costly. It is now the front-line treatment for neuroblastoma. Since the patient is receiving his own stem cells, there is no chance of the body rejecting the graft and avoids the chance that the graft will mistake its old haunt for a foreign invader and go on the attack. Graft-versus-host disease (GVHD), as this is called, is a common and potentially serious side effect of allogeneic BMT and is a particularly severe problem when unrelated donors are used.
Side Effects of Cancer Treatment
If your child should require chemotherapy, radiation therapy and/or bone-marrow transplantation, and so on, her oncologist will undoubtedly discuss with you the possible side effects that may occur during treatment. While it is important to be aware of the possibilities, don’t jump to conclusions that your child is going to be racked with nausea and diarrhea and lose all of her hair. There is no way to predict how a patient’s body will respond to the drugs or the radioactive rays. Some youngsters sail through their treatments, barely missing a day of school.
It is hoped that will be your son’s or daughter’s story too. But it’s wise to be aware of potential problems. One of the first questions to ask the doctor in the wake of a cancer diagnosis is, “What steps can be taken to relieve any symptoms and side effects?” You and your child will probably be heartened by his answer, for some of the most striking progress in cancer care has come in the area of symptom management. For instance, we now have such effective antinausea drugs that many chemotherapy patients never spend a day feeling sick to their stomachs. The key to success is to have the doctor prescribe them prophylactically, to be taken just prior to treatments. This is a point to take up with the pediatric oncologist.