344MO - Experience of GEINO (Spanish cooperative group for research in neuro-oncology) oncologists in the management of adult medulloblastoma

Background

Medulloblastoma (MB) is extremely rare in adults (1% of CNS tumors). Comparative studies show important biological differences between adult and pediatric patients with implications in clinical behaviour and patient outcomes. Although MB is potentially curable with a multidisciplinary approach comprising a combination of maximal safe resection, craniospinal irradiation (CSI), and chemotherapy (CT), the lack of specific studies in the adult subpopulation forces oncologist to adapt treatment regimens.

Methods

GEINO Neuro-oncologists were asked to register MB patients in the GEINO-GETHI National CNS tumor register (pts alive at the time of inclusion gave informed consent).

Results

Between 1996 and 2021, 71pts either diagnosed as adults (median age 32y range 18-71) or referred to adult units (7pts), were identified. 42% were female, common symptoms included headache (69%) and ataxia (31%). Of 14 pts with molecular classification, 10 were SHH+(1 pt p53 mutated) and the others non-WNT non-SHH+ and of 23 patients with histological subtype 19 were desmoplasic-nodular. 70,6% underwent complete resection, 23,5 partial and 5,9 biopsy. 95% received radiotherapy, most commonly to the tumor (61%) with a median dose of 55Gy and to the neuroaxis (48%) with a median dose of 36 Gy. Diverse treatment strategies were used: sequential chemotherapy 42.9% (of wich 29% Vincristine-lomustine-platin), 19% concomitant and sequential (80%concomitant vincristine followed in 50% by Vincristine-lomustine-platin), 14% only concomitant CT (66% with vincristine) 7.9% only neoadjuvant(80% carboplatin-VP16, followed in 40% by the same schema) and 7.9% only CT(66% with a platin-VP16 triplet). Median survival was 14,37y and 70.1% remain relapse free.

Conclusions

Significant heterogeneity is present in the management of adult MB in Spain. Although treatment in MB should be individualized and treatment outcomes are in line with published series, differences in treatment schemas and availability of molecular diagnostic tools highlight the importance of collaborative groups to standardize management.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

GEINO-GETHI.

Funding

GEINO, GETHI.

Disclosure

All authors have declared no conflicts of interest.