From improving outcomes in children with brain cancer to reduce the risk of damage to the brainstem in children with tumors of the central nervous system. These are the benefits of proton therapy or pronoterapia that, according to two new studies , summing up the evidence on this therapeutic option has not grown.
The first study, published in "Pediatric Blood and Cancer", found that very young children who received therapy for protons for medulloblastoma -the most common type of brain tumor in children - had rates of overall survival and recurrence-free survival more elavadas that of the patients who received intense chemotherapy without radiation therapy.associate Professor of Radiation Oncology
The second paper, published in "Acta Oncologica", shows that children with central nervous system tumors who received proton therapy with a newer technique, called scanning with the beam pen , experienced a significantly lower rate of damage of the brainstem, patients treated with the techniques of proton oldest.
Both studies were led by Christine Hill-Kayser , associate professor of Radiation Oncology at the Faculty of Medicine Perelman University of Pennsylvania , member of Cancer Center Abramson Penn and oncology pediatric in the Cancer Center of Children's Hospital of Philadelphia (CHOP) .
proton therapy presents key differences with radiation of photons traditional. The radiation of photons generally uses multiple beams of X-rays to attack a target tumor, but, inevitably, deposited radiation on the normal tissue that surrounds your target, damaging, potentially those tissues when the beam comes out of the body.
proton therapy is a treatment that targets protons positively charged to the tumor, where they deposit most of the radiation dose, with a minimum residual radiation delivered beyond the target, which potentially reduces side effects and damage to surrounding tissue. Is less detrimental than the conventional radiotherapy, the pronoterapia is specifically designed to treat sick children and areas that are very sensitive because the proton radiation works with total precision on the tumor, without damaging healthy tissue.
In the world there are less than 30 units. Spain will soon with two, located in two centres, private health - Chiron Health and Clinic of the University of Navarra - both in Madrid.proton therapy has minimal residual radiation delivered beyond the target, potentially reducing the side effects
The pediatric tumors and mainly localized in the nervous system and nearby tissues and delicate organs such as the eyes, the head, the spinal cord, the heart and the lungs, are the main candidates to receive this treatment.
The first study focused on children with medulloblastoma with newly diagnosed, a cancer of the base of the skull. Older children, between 4 and 18 years of age, with the disease usually receive radiation to the whole brain and spine; however, this treatment can be very toxic to the developing brains of very young children , of four years or less.
therefore, the smaller usually receive chemotherapy regimens intense in place of radiation, but can often relapse, and previous studies have shown that the increased risk of relapse is related to an area called the posterior fossa, the part of the base of the skull where it is located mainly in the tumor .
The researchers looked at 14 young children who received proton therapy after surgery and chemotherapy. And they found that the overall survival rate at five years was 84%, while the rate of recurrence-free survival was 70 %. The historical data show that both of these rates are usually between 30 and 60 % in very young patients who do not receive radiation therapy.
"Our study, although small, shows promising results when we use the proton therapy directed only to the area of surgery in these cases, instead of radiating the whole brain and the areas of the spine," says the lead author of the study, Amardeep Grewal.Second test
The second trial was conducted with a new technique of proton call scanning with beam pen , more effective in preserving the healthy tissue that the techniques of proton oldest, such as the scanning dual-sparse or uniform.Jennifer Hyatt Vogel. - File
In this case, is analyzed to 166 patients with pediatric tumors of the central nervous system and he discovered that, 24 months, the rate of patients who experience harm in the tissue of the brainstem by this therapy is 0.7 percent , a figure much lower that the rates of serious toxicity of the brain stem reported historically in the literature after treatment with proton therapy with double dispersion.
"The effect of proton therapy brainstem has been the subject of much debate, but our data show that proton therapy with scanning beam pen does not increase the risk in comparison with the conventional techniques of photon," says lead author of the study, Jennifer Hyatt Vogel.it Is estimated that, in Spain, could be candidates for this treatment, 2% of patients with cancer
The authors say that these data justify future studies, especially in high-risk patients and patients who have received prior radiation therapy . "Regardless of the technique, the experience in the planning of the proton therapy and the strict fulfilment of the security restrictions are essential, particularly in the treatment of tumors near the brainstem," adds Hill-Kayser.Updated Date: 12 September 2019, 18:00