A multi-institutional retrospective cohort of adult-onset medulloblastoma in the modern era

Abstract

Background: Adult onset medulloblastoma (aMB) is a rare tumor with limited available evidence. We present a large multi-institutional retrospective cohort of aMB patients treated in the modern era, with an emphasis on understanding the role of chemotherapy at initial diagnosis.

Methods: We included 267 consecutive patients with aMB treated at 7 different institutions from 2000-present, controlling for chemotherapy regimen and cycles received.

Results: Treatment factors were highly intercorrelated with one another and with treating institution. Concurrent chemotherapy was not associated with overall survival (OS). Adjuvant chemotherapy was associated with OS on univariable analyses (HR = 0.55, P = .029) and on multivariable analysis when adjusting for risk status (HR 0.55, P = .026) but not when also adjusting for treating institution. Proton craniospinal irradiation was associated with improved survival on univariable (HR = 0.50, P = .019) and multivariable analysis adjusting for risk status (HR = 0.51, P = .024) but not when treating institution was also considered. On subgroup analysis, adjuvant chemotherapy was associated with improved survival in M0 (HR = 0.55, P = .043) but not M1 disease, in patients with subtotal resection (HR = 0.43, P = .048) but not those with GTR. Similarly, progression-free survival was improved with chemotherapy in patients with M0 (HR = 0.57, P = .032) but not M1 disease, and in patients with subtotal (HR = 0.50, P = .054) but not gross total resection.

Conclusions: There was no benefit of concurrent chemotherapy. Adjuvant chemotherapy was associated with improved overall survival and this effect was driven by select subgroups, specifically those with M0 disease and those with residual tumor. We could not confirm that these associations are independent of the treating institution.

Keywords: adjuvant chemotherapy; adult medulloblastoma; concurrent chemotherapy; craniospinal radiation; proton.

Figure 1.

Population statistics. (A) Overall survival is depicted from diagnosis (OS-1) or from time of first progression (OS-2). (B) Progression-free survival from time of diagnosis.

Figure 2.

Subgroup analyses. Overall survival was improved with adjuvant chemotherapy in patients with M0 (A) but not M1-3 (B) disease. OS was improved in patients with residual tumor who received adjuvant chemotherapy (C) but unchanged in patients who underwent gross total resection (D). There was a trend towards improved survival in patients treated with standard dose craniospinal radiation (E), but the same analysis could not be performed for patients receiving low dose craniospinal radiation because almost all (91%) of these patients also got adjuvant chemotherapy (F). P values are calculated by log-rank test.