Experience with S-1 in older Caucasian patients with metastatic colorectal cancer (mCRC): Findings from an observational chart review

Figures & data

Table 1. Characteristics for 71 older patients receiving S-1 for mCRC. SOx was received as primary first-line therapy, S-1 was received as first-line therapy and IRIS was received as primary second-line therapy.

Characteristic	SOx	S-1	IRIS
Number	44	9	18
Median age, years (range)	75 (67–83)	82 (78–87)	73 (67–82)
Gender, n (%)
Male	26 (59)	5 (56)	11 (61)
Female	18 (41)	4 (44)	7 (39)
WHO PS, n (%)
0	14 (32)	2 (29)	7 (39)
1	23 (52)	7 (71)	10 (55)
2	7 (16)	0 (0)	1 (6)
No. of patients starting with capecitabine	11	0	0
Number of cycles, median (range)	6 (1–9)	8 (1–9)	6 (3–9)
Patients starting full dose chemotherapy, n (%)	27 (61)	9 (100)	15 (83)
S-1 dose intensity, % (IQR)	88 (76–99)	100*	87 (40–103)
Oxaliplatin/irinotecan dose intensity, % (IQR)	82 (76–97)	–	97 (75–100)
Median oxaliplatin cumulative dose, mg (IQR)	629 (446–771)	–	–
Reason for S-1 discontinuation n (%)
Completed at least 6 cycles	32 (73)	6 (67)	10 (56)
Poor PS, clinical PD	5 (11)	1 (11)	1 (6)
PD	3 (7)	0	5 (27)
Toxicity or patients’ wish	4 (9)	2 (22)	2 (11)
First-line therapy, n (%)	37 (84)	9 (100)	0
Prior adjuvant therapy, n (%)	6 (14)	0	4 (22)

*All nine very old patients started and continued with S-1 25 mg/m² twice daily.

IQR, interquartile range.

Table 2. Outcome data for 71 older patients receiving S-1 for mCRC.

	SOx	S-1	IRIS
Number of patients	44	9	18
First-line therapy, n (%)	37 (84)	9 (100)	0
Complete response (CR)	0	0	0
Partial response (PR), n (%)	18 (41)	2 (22)	5 (28)
Stable disease (NC), n (%)	20 (45)	6 (67)	9 (50)
Progression (PD), n (%)	3 (7)	1 (11)	4 (22)
Not evaluable, n (%)	3 (7)	0	0
Median PFS, months (95% CI)	8.5 (7.4–9.6)	6.4 (4.0–9.2)	7.8 (4.0–9.6)
Median OS, months (95% CI)	18.5 (12.3–38.6)	15.8 (6.8–NR)	16.5 (13.3–NR)

Table 3. Toxicity in 71 older patients receiving S-1 regimens for non-resectable mCRC.

Therapy	SOx		S-1		IRIS
No. of patients	44		9		18
Toxicity, n (%)	Grade
Non-hematological	Any	3-4	Any	3-4	Any	3-4
Diarrhea	21 (48)	5 (11)	3 (33)	0	10 (56)	2 (11)
Nausea	15 (34)	0	3 (33)	0	8 (44)	0
Vomiting	9 (20)	0	1 (11)	0	3 (17)	0
Fatigue	35 (80)	6 (14)	2 (22)	0	16 (89)	0
HFS	3 (7)	0	0	0	1 (6)	0
Neuropathy	31 (70)	3 (7)	0	0	–	–
Infection/fever	2 (5)	2 (5)	1 (11)	1 (11)	1 (6)	1 (6)
Mucositis	5 (16)	2 (6)	0	0	3 (17)	0
Hematological
Neutropenia	5 (14)	3 (7)	0	0	4 (28)	3 (17)
Thrombocytopenia	5 (14)	1 (2)	5 (56)	2 (22)	2 (11)	1 (6)
Febrile neutropenia	2 (5)	2 (5)	0	0	1 (6)	1 (6)

In addition three cases of grade 3 AE (heart failure, syncope, dehydration) were noticed in patients receiving S-1 monotherapy.