Led by Mackay Memorial Hospital’s Department for Pediatric Hematology-Oncology, Taiwan has used intrathecal chemotherapy as the treatment of choice for childhood acute lymphoblastic leukemia (ALL) since 2009, and the treatment can decrease the rate of central nervous system relapses and avoid the long-term pathological conditions caused by prophylactic cranial irradiation, the hospital said yesterday.
ALL is the most common cancer among children, affecting one in every four children who have cancer.
Traditionally, the disease had been treated by administering cranial irradiation and intrathecal chemotherapy injections, department director Liu His-che (劉希哲) said.
However, the Mackay Memorial Hospital dropped the use of prophylactic irradiation in 1999 to avoid the serious complications and chronic conditions that it could cause, such as brain tumors, neurocognitive deficits, endocrinopathy — a hormone imblance — and short stature.
Liang Der-cherng (梁德成), an attending physician at the department, who has headed the establishment of a national treatment protocol for childhood ALL since 1993, said that the lumbar puncture required by intrathecal chemotherapy, which was usually done at the time of diagnosis, has also been delayed in the new procedure.
Performing the lumbar puncture before circulating cancer cells are first eliminated by chemotherapeutic drugs can result in cancer cells in the blood being taken to the brain, Liang said, adding that this could inadvertently complicate the disease.
“Mackay has treated 152 children with ALL since 1999 with treatment that omitted prophylactic cranial irradiation and nearly 90 percent of them were cured, with no cases of isolated central nervous system relapses and a combined central nervous system relapse rate of just 1.4 percent,” Liu said.
Another strategy that has furthered the success of treating ALL is measuring the level of minimal residual leukaemic cells to accurately predict the risk of relapse, and determine and adjust the intensity of therapy, Liu said.
“It’s better to have a minimal residual leukemia level lower than 0.01 percent, which is one leukemic cell among 10,000 normal cells,” Liu said.
The hospital said that in January, the measurement was integrated into the latest national treatment procedure for ALL.
However, the measurement is not covered by National Health Insurance.
Each patient needs multiple minimal residual leukemia measurements, and each test costs more than NT$20,000, which can be a huge financial burden especially for low-income families, said the two doctors, who also called on the society to support the new treatment by way of donations.