Table 3 Grade ≥ 3 toxicities and fluoropyrimidine chemotherapy dose modifications by DPYD genotype

Grade ≥ 3 gastrointestinal

2 (6.3)

29 (8.6)

0.68 (0.17–2.73)

1

Grade ≥ 3 haematological

1 (3.1)

46 (13.6)

0.22 (0.03–1.53)

0.0998

Grade ≥ 3 dermatological

0 (0)

4 (1.2)

0 (0-N/A)

1

Any grade cardiac

0 (0)

11 (3.3)

0 (0-N/A)

0.609

Grade ≥ 3 other

1 (3.1)

15 (4.4)

0.64 (0.08–4.69)

1

Overall grade ≥ 3

4 (12.1)

89 (26.4)

0.46 (0.18–1.16)

0.0913

Deaths due to fluoropyrimidine toxicity

0 (0)

2 (0.6)

0.16 (0.02–1.13)

1

Dose modifications

 Dose reduction

1 (3.0)

62 (18.3)

0.16 (0.02–1.13)

0.0261

 Dose escalations

10 (30.3)

7 (2.1)

12.80 (5.22–31.40)

 < 0.00001

 Cessation within first two cycles

2 (6.1)

11 (3.3)

1.70 (0.40–7.38)

0.3245

 Dose reduction with first two cycles

2 (6.1)

36 (10.7)

0.55 (0.14–2.20)

0.2282

Patients requiring admission

4 (12.1)

46 (13.6)

0.87 (0.33–2.27)

1