Ependymoma
  • 1.8% of all adult brain tumors

Pathology

  • Rosette formation is —> hallmark of ependymoma on pathological examination
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Anaplastic Ependymoma

  • Increased cellularity
  • Cytologic atypia
  • Microvascular proliferation

Behaviour

  • May expand locally
  • May extend along ependymal spaces
  • Occasionally disseminate through the CSF
  • Predominant pattern of relapse is local
    • Even with anaplasia

Treatment

  • Maximal surgical resection
    • second surgery if necessary
  • Surgery alone may be sufficient in selected patients
    • based on the results of pediatric series
  • Standard of care for most adults is postoperative irradiation.
  • Appears to be a radiation dose response with improved tumor control with doses >50 Gy
    • Doses of 54 to 59.4 Gy are typically prescribed

Volumes for RT in Posterior fossa tumors:

  • Historically entire posterior fossa has been irradiated
  • Paulino —> has shown that the pattern of failure to be local ( within the tumor bed itself )
    • In 9 patients who received RT to the tumor bed + 2 cm margin
      • Two failures in this group —> still within the tumor bed ( no failures within the posterior fossa outside the tumor bed)
      • ==> No more craniospinal…

Standard treatment:

  • For most patients, a more usual volume now consists of the tumor bed and any residual disease (GTV) plus an anatomically defined margin of 1 to 1.5 cm to create a CTV.
  • Larger margins may be required in areas of infiltration, and special attention must be paid to areas of spread along the cervical spine since 10% to 30% of fourth ventricular tumors extend down through the foramen magnum to the upper cervical spine
  • LP test:
    • if CSF is negative ==> Limited field RT
    • if CSF is positive for neuraxis spread ==> CSI—> 40 to 45 Gy with boosts to the areas of gross disease and to the primary tumor to total doses of 50 to 54 Gy
  • Chemotherapy has not been proven useful in ependymoma.
  • Cisplatin-based chemotherapy has shown some activity in recurrent ependymoma in adults
  • Pre-RT cyclophosphamide, vincristine, cisplatin, and etoposide : more promising than agents and regimens used in the past

Results of Treatment

  • Nondisseminated disease 5-year survival is on the order of 70%

Factors associated with survival:

  • post-op RT ( in retrospective series )
  • Hemispheric tumours better than 3rd ventricle tumours
    • 5yr survival
      • 100% vs 73%

Evidence-Based Treatment Summary

  • Maximal surgical resection should be performed when feasible.
  • Postoperative radiotherapy is considered the standard, but no prospective trials have validated its role.
  • Craniospinal irradiation is used only in patients with disseminated disease.
  • The role of chemotherapy remains to be defined.