The treatment of pediatric leukemia is a special battle waged at the "starting point of life." Unlike adults, children's bodies are like saplings in the process of growth, with both immature development and extreme vulnerability. Therefore, during treatment, while eradicating cancer cells, we must also safeguard the hope of children's growth. Every decision in pediatric leukemia treatment conceals a unique "pediatric code."
More Concentrated Disease Distribution: Approximately 75 - 85% of newly diagnosed children have acute lymphoblastic leukemia (ALL) (according to the WHO 2022 classification criteria). These cancer cells are sensitive to chemotherapy and are as likely to "melt" as snow and ice exposed to sunlight.
Priority Given to Growth and Development: Children's bone marrow and immune systems are still developing, so treatment cannot be one - size - fits - all. For example, for children with ALL, a 1 - year - old infant may need to have their medication dosage adjusted to avoid affecting bone growth, while adolescents with ALL need to have potential damage to their reproductive systems monitored during chemotherapy.
Higher Cure Rate: Under standardized chemotherapy, the cure rate for low - risk ALL children exceeds 90%, and that for medium - risk children is also over 80%, which is much higher than that for adults. This means that most children can win the battle against leukemia through chemotherapy without the need for a "desperate" transplant.
Every child is unique. The first step in leukemia treatment is to create a "customized battle map" for them:
Gene tests (such as the BCR - ABL fusion gene test) and chromosomal analysis can accurately determine the risk level. Children carrying high - risk genes may need to receive CAR - T therapy or transplantation earlier, while low - risk children can "go into battle lightly" with a shortened chemotherapy cycle.
Case: After a 5 - year - old child named Xiaoyu was diagnosed with ALL, gene testing showed that he had a low - risk type. The doctor decisively adopted a simplified chemotherapy plan. After 2 years of treatment, he stopped taking medicine smoothly and now attends primary school as normal.
After every 1 - 2 chemotherapy courses, minimal residual disease (MRD) in the bone marrow is detected to assess the "remaining strength" of cancer cells at any time. If the MRD remains negative, it indicates that chemotherapy is effective, and the treatment can proceed as originally planned. If it is positive, "upgrades" are needed, such as adding CAR - T therapy to clear the remaining cancer cells or preparing for transplantation in advance.
Data: A study shows that the relapse rate of children whose treatment is adjusted dynamically is 15% lower than that of those on a fixed - treatment plan.
Children's liver and kidney functions are not yet mature, and the metabolism rate of chemotherapy drugs in children is different from that in adults. During treatment, blood routine and liver and kidney function tests need to be performed weekly, and the drug dosage needs to be adjusted carefully. For example, when calculating the dosage of methotrexate based on body surface area, due to the immature CYP450 enzyme system in infants, the drug clearance rate may be reduced by about 20 - 40%, so more frequent "detoxification" measures (such as alkalinizing urine and hydration therapy) are required.
For low - and medium - risk ALL, standardized chemotherapy (such as the VDLP regimen) is the first choice. Through 4 - 6 courses of "combination therapy," most cancer cells can be eradicated. The cost is approximately 200,000 - 300,000 yuan. With the popularization of domestic chemotherapy drugs, the financial threshold has been significantly reduced.
Key Reminder: The standardization of the first - round treatment is of great importance. Chemotherapy must strictly follow the guidelines. Arbitrarily increasing or decreasing the number of treatment courses may lead to drug resistance and even exacerbate the disease into a more severe form. For example, a primary - level hospital once reduced the dosage of anthracycline drugs for a medium - risk child due to concerns about side effects, and the child relapsed 1 year later.
CAR - T therapy "comes to the rescue" only when chemotherapy fails or the disease relapses. Its advantages include:
Targeted Killing: CD19 - CAR - T for B - cell leukemia can identify cancer cells like a "GPS navigator," causing less harm to normal cells.
Bridging Transplantation: For children in remission after chemotherapy but with remaining cancer cells, CAR - T can first "clean the battlefield," increasing the transplantation success rate from 50% to 70%.
Note: CAR - T is not a "panacea," and serious complications may occur. When used in children, cytokine release syndrome (CRS) needs to be closely monitored. Approximately 25 - 40% of children may develop CRS, with a 10 - 15% incidence of grade 3 - 4 reactions. The entire treatment process must be closely monitored in the ICU.
According to the disease condition, only about 20% of children need transplantation, and the following conditions must be met:
Chemotherapy resistance or relapse, along with high - risk genes (such as KMT2A rearrangement).
For newly diagnosed AML children, except for those with APL (acute promyelocytic leukemia), children in the medium - and high - risk groups need to consider allogeneic hematopoietic stem cell transplantation (referring to the NCCN 2023 guidelines).
Risk Comparison: The long - term survival rate of children after the first transplantation is approximately 60% - 70% (one - year survival rate), but the transplantation - related mortality rate is 20% - 30% (mainly due to infection and rejection). In contrast, the cure rate for low - risk ALL children through chemotherapy can exceed 90% (data from the Chinese Children's Oncology Group (CNCL) in 2023 shows that the 5 - year event - free survival rate for low - risk ALL is 92.3%). This means that for children who can be cured by chemotherapy, blind transplantation may be "more of a loss than a gain."
Don't blindly believe that "CAR - T is the latest technology and must be better than chemotherapy." For low - risk children, chemotherapy is the optimal solution. For high - risk children with relapsed leukemia, CAR - T may be the "key to survival." Pediatricians will provide personalized treatment plans, and the most suitable one is the best.
Pediatric leukemia has its own characteristics, and treatment requires multi - disciplinary collaboration (such as pediatric hematology, cardiology, surgery, and neurology). For example, supplementing with L - carnitine during chemotherapy can reduce cardiotoxicity, and regular psychological counseling can reduce the risk of "treatment - related post - traumatic stress disorder" in children.
After being cured, 90% of low - risk children can grow and develop normally and have a normal married life and children in the future. Medium - risk children need to have their endocrine functions (such as thyroid function and growth hormone) monitored regularly, and some may require growth hormone replacement therapy.
Precision Targeting with Gene Editing: New - generation CAR - T (such as CD22 - CAR - T) is used for refractory leukemia. The complete remission rate of CD19 CAR - T in relapsed/refractory B - ALL can reach 70 - 90% (a multi - center study by CARSI in 2022).
Exploration of "Chemotherapy - Free" Treatments: For some low - risk infant leukemia cases, targeted drugs (such as imatinib) are being tried as a substitute for chemotherapy to reduce developmental toxicity.
Early Warning through Dynamic Monitoring: By monitoring circulating tumor DNA (ctDNA) in the blood, signs of relapse can be detected 3 months in advance, shifting the treatment window from "after relapse" to the "minimal residual disease stage."
The treatment of pediatric leukemia, especially the first - round treatment opportunity, is extremely precious. It is not a "gamble - and - see" adventure but a scientific process of "tailoring clothes to fit the body." When our doctors, holding your child's gene report and MRD (minimal residual disease, referring to the remaining lesions detected by flow cytometry (with a sensitivity of 10^ - 4) or PCR (with a sensitivity of 10^ - 5) after morphological remission) results, earnestly discuss and adjust the treatment plan with you, it is precisely modern pediatric medicine fulfilling its commitment of "putting children first and focusing on the future." We are not aiming to "eradicate all cancer cells" but to enable children to embrace a complete life after being cured.
Remember: On the battlefield of pediatric leukemia, "precision" is more important than "aggressiveness," and "suitability" is more precious than "novelty." Cherishing the first - round treatment opportunity is of utmost importance. Every little life deserves to be tenderly and wisely protected, and every little life can have a wonderful future.
Liu Zhouyang
Beijing Jingdu Children's Hospital
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