Upfront radiotherapy may improve event-free survival (EFS) in pediatric patients with sonic hedgehog medulloblastoma and Li-Fraumeni syndrome (LFS SHH-MB), according to a retrospective study presented at the 20th International Symposium on Pediatric Neuro-Oncology (ISPNO).
The study also suggests that high-dose chemotherapy does not provide a benefit over maintenance-type chemotherapy in this patient population.
Researchers conducted a multicenter study of 31 patients with LFS SHH-MB. This is the largest retrospective cohort of pediatric LFS SHH-MB patients to date, according to the researchers.
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Patients had large-cell anaplastic MB (43.8%), classic MB (15.6%), large-cell anaplastic/ desmoplastic MB (9.4%), MB not otherwise specified (6.2%), MB with extensive nodularity (3.1%), desmoplastic MB (3.1%), or no information on disease subtype (18.8%).
Most patients (69%) had undergone gross resection, and 81.2% had M0 disease (81.2%). The researchers noted that 72% of constitutional TP53 variants were missense variants, and all but 2 truncating variants were located within the DNA-binding domain.
Most patients (73.3%) experienced disease recurrence. The 2-year EFS rate was 26%, and the 5-year EFS rate was 8.8%. The 2-year overall survival (OS) rate was 40%, and the 5-year OS rate was 12%.
Patients who received post-operative radiotherapy followed by chemotherapy had a significantly higher 2-year EFS rate than patients who received chemotherapy before radiotherapy — 43% and 30%, respectively (P <.05).
On the other hand, the 2-year EFS and OS rates were similar for patients who received high-dose chemotherapy and those who received maintenance-type chemotherapy. The 2-year EFS rate was 22% with high-dose chemotherapy and 31% with maintenance-type chemotherapy. The 2-year OS rates were 44% and 45%, respectively.
Secondary malignancies occurred in 12.5% of patients, and all proved fatal.
Taking these findings together, the researchers concluded that patients with LFS SHH-MB have a “dismal” prognosis. The team noted that prospective data collection and treatment guidelines are needed for this patient population.
Reference
Kolodziejczak A, Guerrini-Rousseau L, Masliah Planchon J, et al. Clinical outcome of pediatric medulloblastoma patients with Li-Fraumeni syndrome. Presented at ISPNO 2022; June 12-15, 2022. Abstract MEDB-14.
