Cancer in Children In 2005, the American Cancer Society estimated 9,510 cases of childhood cancer would be diagnosed in the U.S. The most common type of cancer in children is leukemia (accounting for 30 percent of all cancers in kids). Brain and nervous system cancers are the second most common cancers, accounting for 21 percent of cases.

Researchers have made significant strides in finding effective treatments for many childhood cancers. Today, overall five-year survival rates are higher than 70 percent. However, cancer is still the leading cause of death by disease in American children. Last year, 1,585 children were expected to die from cancer.

Chemotherapy for Childhood Cancer: Side Effects on Hearing Chemotherapy is the use of anticancer drugs to stop cancer cells from growing or multiplying. The treatment may be given to cure the patient, control the cancer or relieve symptoms caused by the cancer (like pain). Sometimes more than one drug is given to enhance the effects of treatment.

One common group of medications used to treat some childhood cancers are platinum-based drugs (like cisplatin and carboplatin). The medications are given to slow or prevent cancer cells from reproducing. However, research has shown that when given to children, the drugs also damage the tiny hair cells in the inner ear, which are needed to transmit sound waves to the brain. The damage begins with the outer hair cells and is progressive, cumulative and permanent.

In a study at Oregon Health & Science University (OHSU), investigators found 61 percent of children receiving platinum-based chemotherapy experienced hearing loss. Younger children (under 5) were at significantly higher risk for developing hearing loss after chemotherapy.

Chemotherapy-induced hearing loss can have devastating consequences for children. The problem often affects higher frequencies of hearing - in the range of human speech. For many children, hearing loss comes at a time when they should be acquiring critical language skills. Delayed development of speech and language can cause academic problems at school and difficulties with social relationships.

Protecting Hearing Investigators at OHSU are studying a treatment that may help protect children getting platinum-based chemotherapy from hearing loss. During chemotherapy, doctors open the protective blood-brain barrier with a concentrated sugar solution. The treatment shrinks the cells that normally prevent the passage of agents into the brain, creating a window for chemotherapy drugs to reach the brain. Thus, higher doses of the drugs can reach the tumor.

Several hours after chemotherapy, doctors give an intravenous solution of the drug, sodium thiosulfate (STS). Studies suggest STS binds to the platinum and prevents the chemotherapy drug from injuring the outer hair cells, hopefully preventing damage and hearing loss.

OHSU researchers want to soon test another drug to protect hearing loss from chemotherapy, called N-acetylcysteine, or NAC. This drug is sometimes used to treat patients who have experienced acetaminophen poisoning.

For information about the OHSU study: http://www.ohsu.edu/ohsuedu/newspub/releases/120805hearing.cfm

For information on chemotherapy or other cancer treatments: American Cancer Society, http://www.cancer.org, or contact your local chapter National Cancer Institute, http://www.nci.nih.gov