Adult gliosarcoma: epidemiology, natural history, and factors associated with outcome

Abstract

The epidemiology and natural history of adult gliosarcomas (GSMs), as well as patient and treatment factors associated with outcome, are ill defined. Patients over 20 years of age with GSM diagnosed from 1988 to 2004 were identified in the Surveillance, Epidemiology, and End Results (SEER) database. Kaplan-Meier survival analysis and Cox models were used to examine outcomes. Similar analyses were conducted for patients diagnosed with glioblastoma (GBM) over the same time period. GSM represented 2.2% of the 16,388 patients identified with either GSM or GBM. No significant differences between GSM and GBM were identified with respect to age, gender, race, tumor size, or use of adjuvant radiation therapy (RT). Patients with GSM were more likely to have temporal lobe involvement and undergo some form of tumor resection. The most important analyzed factors influencing GSM overall survival were age, extent of resection, and use of adjuvant RT. After adjusting for factors impacting overall survival, the prognosis for GSM appears slightly worse than for GBM (HR = 1.17, 95% CI, 1.05-1.31). GSM is a rare malignancy that presents very similarly to GBM with a slightly greater propensity for temporal lobe involvement. Optimal treatment remains to be defined. However, these retrospective findings suggest tumor excision, as opposed to biopsy only, and adjuvant RT may improve outcome. Despite therapy, prognosis remains dismal and outcomes may be inferior to those seen in GBM patients.

Fig. 1

Kaplan-Meier overall survival curves for GSM (solid line) and GBM (dashed line) patients.

Fig. 2

Kaplan-Meier overall survival curves for GSM and GBM patients by age. (A) GSM patients. (B) GBM patients. (A, B) Thick solid line: ≤ 40 years; thick dashed line: 40–49 years; thin solid line: 50–59 years; thin dashed line: 60–69 years; broken medium line: >70 years. (C) GSM patients. (D) GBM patients. (C, D) Dashed line: <50 years of age; solid line ≥50 years of age.

Fig. 3

Kaplan-Meier overall survival curves for GSM and GBM patients segregated by extent of tumor resection. (A) GSM patients. (B) GBM patients. (A, B) Thick solid line: no cancer-directed surgery; thick dashed line: subtotal tumor excision; thin solid line: gross total tumor excision; thin dashed line: partial excision of primary site; medium broken line: total excision of primary site. (C) GSM patients. (D) GBM patients. (C, D) Solid line: no cancer-directed surgery; dashed line: other.

Fig. 4

Kaplan-Meier overall survival curves for (A) GSM and (B) GBM patients who received (solid line) and who did not receive (dashed line) adjuvant radiation therapy. Comparable Kaplan-Meier overall survival curves for (C) GSM and (D) GBM patients who received (solid line) and who did not receive (dashed line) adjuvant radiation therapy with the exclusion of patients who did not survive a minimum of 2 months following diagnosis.