Table 1 Numbers and reasons for the excluded articles after full-text review

Patients treated with other than IMRT

3

[9,10,11]

HRs of CNN for DMFS was not performed or unable to calculate

7

[12,13,14,15,16,17,18]

Survival analysis was not performed for CNN

2

[32, 33]

CNN + necrotic primary tumour as one variable was assessed

1

[34]

Studies conducted by the same institution with overlapping patient recruitment periods and analysis performed for the same CNN pattern

5

[35,36,37,38,39]