highly significantp < 0.0001
The association with pN-category was highly significant ( p < 0.0001); the percentage of cases with ECG doubled from category pN1 to pN2 and tripled from pN1 to pN3 (pN1: n = 89, ECG 19%; pN2: n = 59, ECG = 41%; pN3: n = 51, ECG = 63%).