Impact of relative dose intensity on bone marrow suppression induced by S-1: retrospective observational study

Table 2 Univariate Cox proportional hazard model of bone marrow suppression induced by S-1

Variables	HR	95% CI	p value
Male gender	1.11	0.77–1.64	0.58
Age (years)	0.99	0.97–1.01	0.27
Height (cm)	1.01	0.99–1.03	0.57
Body weight (kg)	1.01	0.99–1.02	0.41
BMI (kg/m²)	1.02	0.97–1.07	0.50
BSA (m²)	1.50	0.53–4.19	0.44
Grade ≥ 2 leukopenia^a	0.78	0.24–1.86	0.61
Grade ≥ 2 neutropenia^a	0.66	0.20–1.61	0.39
Grade ≥ 2 lymphocytopenia^a	3.79	1.31–8.78	< 0.05
Grade ≥ 2 anemia^a	0.71	0.30–1.41	0.35
AST (IU/L)	1.00	0.99–1.01	0.91
ALT (IU/L)	1.00	0.99–1.01	0.76
Total bilirubin (mg/dL)	0.65	0.40–0.99	< 0.05
Serum albumin (g/dL)	0.78	0.50–1.24	0.29
eGFR^b (mL/min/1.73 m²)	1.00	0.99–1.01	0.98
Gastrointestinal cancer	1.09	0.71–1.64	0.68
Clinical cancer stage ≥III	0.99	0.64–1.60	0.97
RDI^c > 70%	1.54	0.99–2.48	< 0.05
RDI^c > 75%	1.52	1.05–2.21	< 0.05
RDI^c > 80%	1.39	0.97–1.99	0.07
Presence of combination chemotherapy	1.46	0.99–2.13	0.06
Prior history of cytotoxic chemotherapy	1.21	0.82–1.74	0.34

HR hazard ratio, 95% CI 95% confidence interval, BMI body mass index, BSA body surface area, AST aspartate transaminase, ALT alanine aminotransferase, eGFR estimated glomerular filtration rate, RDI relative dose intensity
^aGrade ≥ 2 leukopenia, neutropenia, lymphocytopenia, anemia, and thrombocytopenia at the initiation of S-1 treatment were assessed using Common Terminology Criteria for Adverse Events (CTCAE) version 4.0. No patient had Grade ≥ 3 thrombocytopenia.
^beGFR was calculated using a prediction equation.
^cRDI is the ratio of the actual dose intensity administered and the planned dose intensity.

ISSN: 2055-0294