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Keywords:

  • medulloblastoma;
  • primitive neuroectodermal tumor;
  • relative survival;
  • covariate-by-follow-up interaction;
  • regression;
  • follow-up;
  • survival modeling

Abstract

BACKGROUND:

Medulloblastomas are 1 of the most common brain tumors in children but can affect individuals of all ages. For this report, the author investigated the impact of medulloblastomas/primitive neuroectodermal tumors (PNETs) on the US population with a focus on age differences.

METHODS:

Data from the Surveillance, Epidemiology, and End Results (SEER) database were used to describe cumulative relative survival (CRS) using crude, period, and longitudinal period approaches for patients diagnosed with all medulloblastoma subtypes and PNETs. CRS estimates were obtained using SEER expected mortality data and the Ederer II method for expected survival estimation. These data were applied to the construction of rational follow-up scheduling protocols.

RESULTS:

The 5-year period CRS for all patients who were followed between 2001 and 2006 was 69%. Adults had a worse overall prognosis, but this difference in excess hazard rates appeared only after 4 years of follow-up. Furthermore, the 5-year and 10-year CRS has improved a minimum of 11% in children, adolescents, and adults over the past 25 years.

CONCLUSIONS:

The survival difference between children, adolescents, and adults with medulloblastomas and PNETs depended on the length of follow-up, which was described in this report as an age-by-follow-up interaction and observed as a “fork” on Kaplan-Meier curves. Differences in survival between children and adults emerged only 4 years after diagnosis, and adults fared worse. There has been significant improvement in survival from medulloblastomas/PNETs since the late 1970s and early 1980s. Cancer 2012;. © 2011 American Cancer Society.