Abstract
BACKGROUND
Medulloblastoma is comprised of four distinct molecular subgroups (WNT, SHH, Group3,Group4) with unique clinical and prognostic implications. However, this relationship is rarely reported in the Middle East.
METHODS
We assembled an institutional cohort of children<18 years diagnosed with medulloblastoma and received radiotherapy at KHCC/Jordan between 2003–2015 and subgrouped tumours using limited gene expression analysis.
RESULTS
Eighty-one patients were identified (36% females) with median age 7.3years (2.9–17.6years). Twenty-six patients (32%) were M1-M3. Twenty-eight patients were treated as standard risk (SR, 47%) and 43 as high risk (HR, 53%). Subgrouping revealed 27 Group4 (33%), 20 SHH (25%), 20 Group3 (25%) and 14 Wnt (17%). The median time between craniotomy and radiotherapy was 45 days (17-155days). Median duration of radiotherapy was 44days (36-74days). Overall 5year EFS was 70.5 ± 6% and OS 68.8 ± 6.1%; statistically not significant between SR and HR (p=0.1). Absence of metastasis had survival advantage (OS 81.3 ± 6.9% for M0 and 43.6 ± 11% for M1-M3, p=0.001). SHH and Group4 tumors had very good OS (79.7 ± 10.7% and 81.5 ± 9.8% respectively). Metastatic Group4 did very well (OS 80 ± 17.9%) while metastatic Group3 had dismal OS (33.3 ± 13.5%). Unexpectedly, WNT patients had relatively poor OS (67.9 ± 15.9%).
CONCLUSIONS
SHH and Group4 medulloblastomas had an excellent survival comparable to developed countries despite treatment delays. Strikingly, we observed lower survival of WNT subgroup, suggesting possible background differences compared to other cohorts. This highlights the importance of validation of molecular stratification in the developing world, and suggests that background genetic differences may underlie differences in therapy response.