Professor Lianxin/Zhang Fuquan: Should Glioblastoma Be Treated with Radiation or Chemotherapy First? Is a Higher Dose of Radiation Better?

Professor Lianxin/Zhang Fuquan: Should Glioblastoma Be Treated with Radiation or Chemotherapy First? Is a Higher Dose of Radiation Better?

Source: Sunflower Children  

Author: Lianxin  

Editor: Zhengty  

Date: December 20, 2024  

1. Postoperative Radiation and Chemotherapy: How to Choose the Order?

Whether to conduct radiation therapy or chemotherapy after surgery for pediatric glioblastoma depends on multiple factors, including the pathological type, the extent of surgical resection, the child's age, and overall health. Generally speaking, if a child's low-grade glioma is completely resected, postoperative radiation and chemotherapy may not be necessary, and only follow-up observation is required. 

If the tumor is not completely removed, considering the long-term effects of radiation on younger children, it is recommended to prioritize postoperative chemotherapy and delay radiation therapy, especially for children under three years old. However, for high-grade gliomas, due to their aggressive nature and rapid progression, it is advised to begin radiation therapy as soon as possible after surgery. 

Research indicates that the survival time of high-grade glioblastoma patients is closely related to the timing of radiation therapy; early postoperative radiation can effectively prolong the survival of these patients. Therefore, it is strongly recommended to start radiation therapy early (2 to 6 weeks post-surgery). The conventional age to begin radiation therapy is considered to be three years, but for high-grade glioma patients, age restrictions can be relaxed. Additionally, for diffuse midline gliomas and diffuse pontine gliomas, radiation therapy is currently the only relatively effective treatment method, and it should commence as soon as the diagnosis is confirmed.

2. Is Higher Radiation Dose Always Better?

The radiation dose is not always better at higher levels. The choice of radiation dose needs to balance tumor control and potential damage to normal brain tissue. Since children's brain tissue is more sensitive to radiation, excessively high doses can harm the child's brain, affecting intelligence and growth development. Therefore, when treating tumors, efforts should be made to minimize the exposure of normal brain tissue to high doses of radiation.

Currently, widely used intensity-modulated radiation therapy (IMRT) can optimize the distribution of radiation doses, making high-dose areas more closely aligned with the tumor while reducing the volume and dose of surrounding normal brain tissue exposed to radiation. Proton beam therapy, compared to conventional X-rays, offers better physical properties and superior protection for normal organs. Therefore, proton therapy should also be considered for pediatric glioblastoma patients.

3. How Long After Radiation Should MRI Follow-Up Be Done?

Children who have undergone radiation therapy for glioblastoma require regular follow-up with cranial CT scans and enhanced MRIs. It is recommended that low-grade glioma patients have follow-ups every 3 to 6 months for the first five years post-radiation, and then annually thereafter. For high-grade gliomas, a follow-up MRI should be performed 2 to 6 weeks after the last radiation treatment, with subsequent follow-ups every 2 to 4 months for the first three years, and every 6 months thereafter. If any central nervous system-related symptoms arise, timely MRI follow-up is essential.

4. Is There a High Risk of Secondary Malignant Tumors After Radiation?

The likelihood of developing secondary tumors after radiation therapy in children is a complex issue influenced by various factors, including the dose of radiation, the area of exposure, the site of irradiation, the child’s age, and genetic background. Thus, it is challenging to provide an exact probability. Generally, the higher the radiation dose, the broader the exposure, and the younger the patient, the greater the risk of developing secondary tumors. However, with advancements in radiation therapy technology, modern techniques can more precisely target tumors, reducing damage to normal tissue and thereby lowering the risk of secondary tumors.

Consequently, when formulating a radiation therapy plan, doctors will consider all these factors and strive to use low-dose, high-precision techniques. Additionally, regular follow-up and monitoring after radiation therapy are critical for timely detection and management of any potential abnormalities. Although there are certain risks associated with radiation therapy, it remains one of the essential treatment methods for many pediatric cancer patients. Therefore, parents and doctors need to weigh the risks and benefits thoroughly to develop the most appropriate treatment plan for the child.

Formatting: Wu Jun  

Proofreading: He Fei