Hypofractionated short-course radiotherapy in elderly patients with glioblastoma multiforme: an analysis of the National Cancer Database

For elderly patients with glioblastoma multiforme (GBM), randomized trials have shown similar survival with hypofractionated short-course radiotherapy (SCRT) compared to conventionally fractionated long-course radiotherapy (LCRT). We evaluated the adoption of SCRT along with associated factors and survival in a national patient registry. Using the National Cancer Data Base (NCDB), we identified patients aged ≥70 years with GBM, diagnosed between 1998 and 2011, who received SCRT (34-42 Gy in 2.5-3.4 Gy fractions), or LCRT (58-63 Gy in 1.8-2.0 Gy fractions). Crude and adjusted hazard ratios (HR) were calculated using Cox regression modeling. 4598 patients were identified, 304 (6.6%) in the SCRT group and 4294 (93.4%) in the LCRT group. Median follow-up was 8.4 months. Median age was 78 versus 75 years, respectively (P < 0.0001). Patients who received SCRT had higher Charlson-Deyo comorbidity scores versus LCRT (score of ≥2: 16.9% vs. 10.8%, respectively; P = 0.006), and were more likely to be female (53.0% vs. 44.6%, P = 0.005). Patients who received SCRT were less likely to undergo chemotherapy (42.8% vs. 79.3%, P < 0.0001), more likely to undergo biopsy only (34.5% vs. 19.5%, P < 0.0001), and more likely to receive treatment at academic/research programs (49.2% vs. 37.2%, P = 0.0001). Median survival was 4.9 months versus 8.9 months, respectively (P < 0.0001). The survival detriment with SCRT persisted on multivariable analysis [HR 1.51 (95% CI: 1.33-1.73, P < 0.0001)], adjusting for age, gender, race, comorbidities, diagnosis year, facility type, surgery, and chemotherapy. In conclusion, hypofractionated SCRT was associated with worse survival compared to conventionally fractionated LCRT for elderly patients with GBM. Patients who received SCRT were older with worse comorbidities, and were less likely to undergo chemotherapy or resection.