Comparison of chemoradiotherapy with radiotherapy alone for “biopsy only” anaplastic astrocytoma

BACKGROUND It has become increasingly common to incorporate adjuvant chemotherapy with radiotherapy in the treatment of resected anaplastic astrocytoma based on results from recent phase II/III randomized trials. However, whether or not combined chemoradiotherapy is associated with improved survival outcome in patients who undergo "biopsy only" is less clear. METHODS The US National Cancer Data Base was used to identify patients with histologically confirmed, biopsy-only anaplastic astrocytoma who received either radiotherapy alone or combined chemoradiotherapy from 2006 through 2014. RESULTS In total, 1896 patients with biopsy-only anaplastic astrocytoma were included, among whom 363 (19.1%) received radiotherapy alone and 1533 (80.9%) received combined chemoradiotherapy. The median age at diagnosis was 60 years. Combined chemoradiotherapy was associated with a significant survival benefit when compared with radiotherapy alone on univariable analysis (median, 13.2 versus 5.6 months; hazard ratio [HR], 0.57; 95% confidence interval [CI], 0.50-0.65; p < 0.001) and on multivariable analysis (HR, 0.62; 95% CI, 0.55-0.71; p < 0.001). A significant survival benefit for combined chemoradiotherapy persisted in a propensity score-matched analysis (HR, 0.67; 95% CI, 0.56-0.78; p<0.001). CONCLUSIONS Our results suggest that combined chemoradiotherapy may be associated with significantly improved survival over radiotherapy alone in patients with anaplastic astrocytoma who undergo biopsy only.