Since the tumor is rare, certain knowledge about the right treatment is hard to generate. Therefore, a working group of the International Society of Pediatric Oncology (SIOP) has in 1999 designed a tumor cell registration and treatment study, which was opened in 2000. In 2008 the data from this study as well as continued literature reviews have shown that (1) surgical resection is important (2) radiation treatment is effective, at least in children old enough that it can be given, (3) chemotherapy can shrink the tumors. But there is significant uncertainty which chemotherapeutic agents should be used and how they should be combined. Learning more about this is the purpose of this study.

    Two types of irradiation are used in medical treatment: photon irradiation and proton radiation. Photon radiation is somewhat similar to diagnostic x-rays. An invisible beam travels through the body, delivering energy to biological structures. Certain molecules including oxygen are altered, thereby making the molecules more reactive. The genetic material (DNA) of proliferating cells is susceptible to alterations in this process. There is some repair of those alterations in living cells, but when the alterations become too many, the cell will die. Proton beam differs from photon by the radiation particle. Protons are hydrogen atoms stripped of their electrons. They also travel through tissue and deliver energy which destroys tumor cells. The two most important difference to photon beam are, (1) that the proton beam will not travel all through the body, but the beam will stop several cm away form the skin, and (2) that proton beams are quite novel and the medical experience is much less than with photon beams.

    In principle, irradiation harms both tumor and normal cells, but the tumor cells are generally more susceptible for two reasons. On the one hand, tumor cells proliferate faster, but on the other, the repair mechanisms in normal cells are more effective than in cancer cells. Therefore, in an ideal situation, just enough radiotherapy will be given to kill the tumor cells, but allow the normal cells to recover. In practice, radiotherapy will start with an explanation by the radiation oncologist (doctor for irradiation) to patients and their families about the treatment details and side effects. Subsequently, the irradiation is planned. One important element of this is the irradiation field. The field will be chosen so that the least amount of normal tissue will be within the irradiation beam. It is crucial that the body position is exactly the same for each treatment session so that the preplanned field does not miss the tumor and does not include more normal tissue than necessary. Especially with children, many precautions need to be taken to make sure the body position is identical in each session. The actual treatment is a short period of a few minutes given once per day, five days per week, over a period of approximately 6 weeks. Most of the patients do not need to stay in the hospital during this time, as continuous infusion is not required.

    Irradiation side effects reflect the harm of the normal tissue in the irradiation beam. The different tissue types vary in their susceptibility for irradiation harm. The skin frequently becomes red towards the end of the treatment, similar to a sunburn. The hair within the irradiation field will fall out and might not come back. On the lower border of the middle of the brain is a hormone producing gland, which is called the “pituitary gland”. If this gland is in the irradiation field, various hormone deficiencies are likely to occur. Most frequently, the growth hormone will be missing. This is important in children, as they slow down in growth compared to their age mates. Growth hormones can be replaced if it is missing. This replacement treatment can be considered after the tumor treatment has been completed. It is not a major problem during the first year of tumor treatment. When the brain is in the irradiation field, brain function such as intelligence can be reduced after irradiation. This side effect is largely dependent on the developmental stage of the brain. It is much worse when the maturing brain of infants is treated with radiotherapy than when older children or adults receive the same treatment. In general, irradiation of infant’s brains is therefore avoided in treatment plans, except when the radiation field includes only small parts of the brain wich is only possible with very advanced radaition techniques. It is hard to decide at which age exactly the benefit of radiotherapy exceeds the harm it can potentially do. The limit is also dependent on the tumor type. For metastatic choroid plexus carcinoma, the international study committee has decided to adapt the most frequently used limit of the 3rd birthday and irradiate not before, since the radiation field needed for this tumor treatment includes all of the brain and the spinal cord. For other tumors, the radiation field can be much smaller, and radiation is recommended for younger children. The indication for radiation also depends on teh success of chemotherapy. The more successful teh first chemotherapy is, the less improtant is it to start radiation early. The CPT-SIOP-2009 protocol has a very detailled receommendation when to start which type of radiation.

    Chemotherapy of cancer is a generic term, describing a large variety of treatments which include agents/drugs given to the patient in order to kill tumor cells. It is most frequently given systemically, which means to the whole body, and most of the treatments share some mechanisms of action and some side effects. Most of the agents included in chemotherapy are derived from plants (such as vincristine and etoposide). Some are chemically engineered (such as carboplatin and cyclophosphamide). Most chemotherapeutic agents are given directly into the blood. They reach the tumor cells with the blood supply inside the tumors. Chemotherapy kills growing cells, which can include both tumor cells and normal cells, and side effects arise from the harm to normal tissue.

    One can categorize chemotherapy side effects into two groups: A) non specific, mostly temporary side effects, which may occur with any type of chemotherapy. Those side effects are considered acceptable up to a certain level. B) The other category includes permanent harm to certain organs which may or may not occur and which should be avoided if possible. The most frequent types of side effects in the first category, the temporary side effects, include nausea/vomiting, hair loss, and low blood counts.

    Nausea and vomiting occur predominantly during and shortly after the chemotherapy is given. These side effects diminish the day after the chemotherapy. Hair loss begins several days or a few weeks after the chemotherapy protocol has started, and does not get better before the whole protocol is finished. Low blood cell counts occur one to two weeks after each chemotherapeutic block. The blood counts must recover before the next chemotherapy is given. Low blood cell counts affect three distinct types of blood cells: red blood cells (erythrocytes), white blood cells (leukocytes), and blood platelets (thrombocytes). The function of red blood cells is to transport oxygen from the lung to the other tissues such as brain or muscle. If the red blood cell count is low, the person will be pale and will feel weak. This can be treated by giving the patient someone else’s red blood cells (transfusion). The white blood cells are part of the immune system which fights infections. If the white blood cell count is low, it might not be physically noticeable, but if an infection occurs at this time, the infection can be much more dangerous than in a person with normal white blood cell counts. Therefore, in the case of fever after chemotherapy, patients and their families should immediately consult the treating physician. Often antibiotic treatment will be necessary to support the immune system in fighting the infection. The normal function of platelets is to stop bleeding. A low number of platelets in blood can cause nose bleeds or formation of tiny red spots in the skin which indicate small hemorrhages. None of these two signs are very dangerous, but hemorrhages can occur in other places as well. Of most concern, is development of a hemorrhage inside of the brain if a brain tumor patient bumps his head. To prevent this, if the platelet count in blood reaches a dangerously low level, platelets from a different person can be given. As a standard part of chemotherapy treatment, blood counts are frequently checked to ensure that they are not too low, or if they are declining, to treat the problem early enough. This is a well-established standardized way to deliver chemotherapy which is quite safe, as it is based on experience of treating many thousands of patients in similar ways.

    The second group of side effects are mostly specific for the drug, and every single drug comes with a long list of more or less frequent side effects, some of which can be permanenent. It goes beyond this website to describe all of them in detail. One has to keep in mind, however, that any chemotherapeutic agent can potentially harm any organ, and a complete list of side effects regardless of frequency would be quite long. Please ask your doctor for teh specific list of side effects for each drug. One should also keep in mind, that none of the described side effects necessarily need to happen. Many patients go through chemotherapy experiencing only hair loss, nausea, and low blood counts, but none of the other side effects. In fact, frequent criticisms from former cancer patients are that physicians over-emphasized possible side effects at the beginning of the treatment, which scared them more than necessary.