A study found that proton beam therapy is as safe as conventional radiotherapy for the treatment of children with cancer, particularly brain cancer medulloblastoma. Proton beam therapy is a more accurate method of radiotherapy but less toxic to surrounding tissues and other parts of the body.
The researchers found that proton beam therapy appears not as toxic to the rest of the body compared to the conventional one. Massachusetts General Hospital's Dr. Torunn Yock led the research team.
Medulloblastoma progresses at the back of the brain, near the skull's bottom. It is the most prevalent form of childhood brain cancer. The tumors, which are called medulloblastomas, grow quickly and spread to various areas along the brain's surface and spinal cord through the cerebrospinal fluid.
Chemotherapy and photon radiotherapy are commonly used to remove the tumors but patients often suffer grave side effects such as hearing loss, which can affect the language development and learning. Conventional treatments also affected hormone function and cognition.
Moreover, radiation exposure is toxic to the reproductive system, vertebra, lungs, thyroid and heart. Normally, the level of long-term effects are worse when the patient is younger at the time of therapy.
On the other hand, proton beam therapy is used to treat "hard-to-reach cancers" because of its accuracy. The more targeted treatment also comes with lower side effects and lower risk of surrounding tissue damage.
The study analyzed 59 patients, wherein 55 had their tumors partially or fully removed via surgery. The patients were between the ages of 3 to 21 years old. All of the participants received chemotherapy and proton beam therapy and were monitored for up to seven years.
In the three-year mark, 12 percent of the child patients experienced severe hearing loss. In the five-year mark, the rate surged to 16 percent. The patients also had trouble processing speed and verbal understanding. The team noted that there were no problems with working memory and perceptual reasoning.
In the five-year mark, 55 percent of the patients experienced neuroendocrine system problems in which the growth hormone was most affected. Patients who had photon radiotherapy normally suffers pulmonary, cardiac or gastrointestinal problems. The researchers found none of these problems in the participants.
After three years, progression-free survival was given the rating of 83 percent. After five years, the rate went down to 80 percent.
"Our findings suggest that proton radiotherapy seems to result in an acceptable degree of toxicity and had similar survival outcomes to those achieved with photon-based radiotherapy," said the authors.
The findings were published in the journal The Lancet Oncology on Jan. 29.