Table 3.

Multivariate analysis of prognostic factors for PFS (a) and OS (b)

Factor	Subgroup	HR	95 % CI	p value
(a)
Age	>40	1.00
	≤40	1.802	1.1875–2.7347	0.005
Resection of residual disease during imatinib therapy	Yes	1.00
	No	0.3539	0.2420–0.5175	<0.001
Primary tumor site	Duodenum	1.00
	Small bowel	0.7208	0.4097–1.2682	0.256
	Large bowel/rectum	0.3959	0.1793–0.8741	0.022
	Stomach	0.4711	0.2576–0.8613	0.014
	Other or intraperitoneally with unknown primary origin	1.315	0.6809–2.5401	0.415
Tumor genotype	Wild type	1.00
	Exon 11 KIT	0.5897	0.3458–1.0055	0.052
	Exon 9 KIT	1.2	0.6183–2.3292	0.589
	Exon 18 PDGFRA D842V	4.102	1.6520–10.1851	0.002
	Other	0.9746	0.2781–3.4154	0.968
Baseline neutrophils count	Normal	1.00
	High	1.72	1.1724–2.5248	0.006
Baseline hemoglobin level	Normal	1.00
	Low	1.592	1.0396–2.4385	0.032
Performance status (WHO score)	Good <2	1.00
	Poor ≥2	2.79	1.8647–4.1755	<0.001
(b)
Resection of residual disease during imatinib therapy	Yes	1.00
	No	0.3179	0.20001–0.5052	<0.001
Primary tumor site	Duodenum	1.00
	Small bowel	1.2	0.59257–2.4317	0.612
	Large bowel/rectum	0.9214	0.36381–2.3337	0.863
	Stomach	0.8693	0.41325–1.8285	0.712
	Other or intraperitoneally with unknown primary origin	2.437	1.08447–5.4745	0.031
Presence of liver metastases at imatinib start	Yes	1.00
	No	1.387	1.01151–1.9029	0.042
The maximal diameter of the largest tumor (mm)	≤50	1.00
	>50–100	1.04	0.60162–1.7980	0.888
	>100	1.636	0.97002–2.7583	0.065
Tumor genotype	Wild type	1.00
	Exon 11 KIT	0.4466	0.24163–0.8254	0.01
	Exon 9 KIT	0.6156	0.28451–1.3318	0.218
	Exon 18 PDGFRA D842V	3.049	1.142–8.1414	0.026
	Other	0.4076	0.09017–1.8429	0.244
Baseline albumin level	Normal	1.00
	Low	2.415	1.48174–3.9363	0.0004
Baseline hemoglobin level	Normal	1.00
	Low	1.007	0.60318–1.6801	0.979
Performance status (WHO score)	Good <2	1.00
	Poor ≥2	2.427	1.53092–3.8491	0.0002

HR hazard ratio, CI confidence interval