GSTM1 and anemia: Multivariate analysis showed that cetuximab plus RT was an independent predictor for post-RT anemia (OR 3.16, 95%, CI 1.49–7.05; p = 0.003) and low post-RT Hb level (Estimate 0.6, CI 1.13–0.06; p = 0.029) (Tables S3–5).