Influence of subgroup, location, and tumor volume in medulloblastoma surgery and consideration for second look...

The goal of this study was to systematically analyze tumor subgroup, location, and volume in relationship to extent of resection (EOR) through a retrospective approach and examine the role for second-look surgery with a single-institution case series.

Retrospective data review of pathologically confirmed medulloblastoma patients under the age of 21 who underwent surgery at the Mayo Clinic Rochester.

There were 45 patients who met the inclusion criteria. All subgroups were represented, and those without subgroup data were classified as unknown with histopathologic confirmed grade IV medulloblastoma. The most common location of tumors was the fourth ventricle, though this varied by subgroup. The foramen of Lushka was the most invaded structure. Tumor size and volume were classified with respect to EOR and subgroup and there was no statistically signifcant difference noted. There were 5 non-WNT non-SHH subgroup patients who underwent second look surgery. EOR and the location of residual tumor varied, but GTR was achieved in all cases.

When indicated, second look surgery is safe and offers an opportunity to achieve GTR. The EOR and role of second look surgery remain controversial, and larger multicenter studies will be needed.