Professor Sun Xiaofei: Can Medulloblastoma Be Treated with Targeted Drugs and Immunotherapy? Is Bone Marrow Transplantation Useful?

Professor Sun Xiaofei: Can Medulloblastoma Be Treated with Targeted Drugs and Immunotherapy? Is Bone Marrow Transplantation Useful?

Author: Sunflower Children  

Date: December 6, 2023

The "Medulloblastoma Q&A" column invites experts in the field of pediatric brain tumors to answer questions related to every aspect of medulloblastoma. Today we bring you the 15th issue, and we welcome readers to leave your questions in the comments section!

1. Can medulloblastoma be treated with targeted drugs?

Targeted drugs are a concept in genomics, where genetic testing on tumors identifies key mutations that play a critical role in the tumor's development. Drugs designed to target these mutations are called targeted therapies. For pediatric medulloblastoma, according to the 2016 WHO classification of central nervous system tumors, medulloblastomas are divided into four subtypes based on differences in genetic mutations: WNT, SHH, Group 3, and Group 4.

Currently, targeted drugs specifically for medulloblastoma are still under research. For SHH-activated medulloblastoma, the inhibitor targeting the SHH PTCH1 pathway, vismodegib, may be effective. A clinical study in the United States on recurrent medulloblastoma showed that, among 12 children treated with vismodegib, 3 had radiographic responses; however, in two cases, the effectiveness lasted less than 2 months, while one lasted over 6 months. Furthermore, it was effective only in patients with upstream mutations in the SHH pathway at the PTCH1 or SMO levels. However, due to its effects on bone growth, vismodegib is only used for children with mature skeletons.

In summary, current targeted therapies for medulloblastoma are still in the clinical trial phase. The mainstay treatments for medulloblastoma remain traditional surgery, radiotherapy, and chemotherapy. The chemotherapy regimens used typically consist of well-established drug combinations, such as carboplatin, cisplatin, vincristine, lomustine, cyclophosphamide, and etoposide. Of course, chemotherapy protocols may vary by country based on individual patient conditions.

2. Can medulloblastoma be treated with immunotherapy?

Immunotherapy is one of the exploratory research avenues for difficult-to-treat or recurrent medulloblastoma. It mainly includes immune checkpoint inhibitors, PD-1, B7-H3, CAR-T, NK cells, and oncolytic viruses. However, most clinical trials involving immunotherapy are still in the early phases, and their effectiveness against medulloblastoma has yet to be confirmed. We look forward to more research creating hope for the future.

3. Can CAR-T be used for medulloblastoma?

CAR-T cell therapy for medulloblastoma is still in the early research stage, and its effectiveness against medulloblastoma has not yet been established.

4. Is bone marrow (hematopoietic stem cell) transplantation useful for medulloblastoma?

The primary treatment methods for medulloblastoma are surgery, radiotherapy, and chemotherapy. According to standard comprehensive treatments, the survival rate for standard-risk medulloblastoma exceeds 80%, and bone marrow transplantation is not required.

For high-risk medulloblastoma, the current standard of surgery, radiotherapy, and chemotherapy yields a survival rate of about 60%. Autologous hematopoietic stem cell transplantation supported by high-dose chemotherapy can be considered as one of the experimental treatment options.

For patients over the age of 3 with high-risk medulloblastoma, whether autologous hematopoietic stem cell transplantation is beneficial is still under investigation. Eligible patients may participate in relevant clinical trials. For high-risk medulloblastoma patients younger than 3 years, due to the significant side effects of radiotherapy, it is generally not recommended. High-risk patients who do not receive radiotherapy tend to have poorer outcomes, with survival rates around 30%-40%. Some studies have reported benefits from high-dose chemotherapy supported by autologous hematopoietic stem cell transplantation in young high-risk medulloblastoma patients who do not undergo radiotherapy.

5. Can transplantation replace radiotherapy and chemotherapy?

Transplantation cannot replace radiotherapy and chemotherapy. For medulloblastoma patients aged 3 and older, the main treatment methods are surgery, radiotherapy, and chemotherapy, all of which are essential. High-dose chemotherapy supported by hematopoietic stem cell transplantation is only one of the experimental treatment methods for high-risk medulloblastoma, and relevant research is ongoing.

6. What risks are associated with transplantation?

The primary risks associated with high-dose chemotherapy supported by autologous hematopoietic stem cell transplantation include complications from bone marrow suppression, such as infections, bleeding, anemia, organ function impairment, and immune dysfunction, as well as the risk of tumor recurrence after transplantation. Before transplantation, doctors will conduct a comprehensive evaluation of the patient. Only those who meet the criteria will be considered for transplantation. The benefits of transplantation are greater when performed after tumor remission.

7. Can patients take traditional Chinese medicine for medulloblastoma?

Traditional Chinese medicine is only an adjunct therapy and can be used as a method to help regulate the patient's body.

Layout | Ying Tao  

Proofreading | A Dou Dou