Medulloblastoma (MB) is the most common central nervous system (CNS) malignant tumor in children and reaches its peak in the first decade of life. In adults, MB is very rare, comprising less the 1% of total CNS tumors. Although molecular subtypes are well defined, the impact of other prognostic variables, such as postoperative residual tumor (PRT) and the presence of neuroaxis dissemination (NAD) are controversial.
We performed a retrospective analysis in consecutive adult patients with MB treated at Instituto do Câncer do Estado de São Paulo from 2008 to 2016. Patients data on tumor histology, ECOG-PS at diagnosis, low/high-risk clinical classification (according to tumor size, metastasis, NAD and PRT) and adjuvant radiotherapy (RT) or chemotherapy (CT) were reviewed through medical records.
Thirty-eight patients were included. Median age was 28,8 years-old (18,3 to 40,8) and patients were followed-up for a median of 5,28 years. Five patients died during follow-up, all cancer related, and 8 had progression events. All patients were submitted to surgical resection; 15 were considered high-risk patients; 34 were submitted to RT and 23 to CT in addition to RT. The most common RT regimen was 36Gy on neuroaxis and 18Gy boost on the posterior fossa (67%) and the most common CT protocol was a combination of lomustine, vincristine and cisplatin (39%). The two most common histological subtypes were classical (19), followed by desmoplastic (14). Fifteen patients were considered high-risk. On univariate analysis, the presence of PRT (p < 0,0001) and NAD (p = 0,008) had a negative impact on survival. Cox proportional-hazards regression for multivariate analysis confirmed the detrimental impact of PRT, while NAD had a marginal effect.
Medulloblastoma seems to bear a general favorable prognosis among adults. The presence of postoperative residual tumor, and perhaps neuroaxis dissemination, seem to impact negatively survival.
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