Missed colorectal cancers in a fecal immunochemical test-based screening program: Molecular profiling of interval carcinomas

Table 1 Clinicopathological characteristics of all selected persons with fecal immunochemical test-interval and screen-detected colorectal cancers

Characteristics	FIT-interval CRC	SD-CRC	P value
Patients, n	27	54
Age at diagnosis, mean (min-max)	65.9 yr (53-76)	65.2 yr (50-75)	NS
Male sex, n (%)	16 (59.3)	33 (61.1)	NS
Socio-economic status, n (%)			NS
Low	2 (7.4)	10 (18.5)
Normal	21 (77.8)	33 (61.1)
High	4 (14.8)	11 (20.4)
Tumor location, n (%)
Proximal	10 (37)	17 (31.5)	NS
Tumor stage, n (%)
Stage I	8 (29.6)	25 (46.3)	NS
Stage II	6 (22.2)	8 (14.8)
Stage III	9 (33.3)	20 (37.0)
Stage IV	4 (14.8)	1 (1.9)
Time interval between FIT and CRC
Mean	1.4 yr
Min-max	0.4-2.3 yr
IQR	0.9-2.0 yr
Mean Hb concentration last FIT in μg Hb/g feces, mean ± SD	2.7 ± 3.4a	167.8 ± 168.7	< 0.001

^a3 cases missing.

All values expressed as number and % with respect to fecal immunochemical test-interval and screen-detected colorectal cancers. FIT: Fecal immunochemical test; CRC: Colorectal cancer; SD-CRC: Screen-detected colorectal cancer; IQR: Interquartile range; Hb: Hemoglobin; NS: Not significant.

Table 2 Microsatellite instability analysis and CpG island methylator phenotype analysis

	FIT-interval CRC	SD-CRC	P value
MSI analysisa
MSI	4 (19%)	5 (12%)	0.469
MSS	17 (81%)	36 (88%)
CIMP analysisb
Methylated, positive	7 (33%)	8 (21%)	0.274
Unmethylated, negative	14 (66%)	31 (79%)

^an = 62.

^bn = 60.

All values expressed as number and % with respect to fecal immunochemical test-interval and screen-detected colorectal cancers. FIT: Fecal immunochemical test; CRC: Colorectal cancer; SD-CRC: Screen-detected colorectal cancer; MSI: Microsatellite instability; MSS: Microsatellite stable; CIMP: CpG island methylator phenotype.

Table 3 Copy number alterations

CGH-testa	Chr	Type	Band	Length basepairs	Group comparison	P valueb
2.50%	8	Gain	p11.22-q24.3	106890001	Less in FIT-interval CRCs	0.009
2.50%	20	Gain	p13-p12.1	14520001	More in FIT-interval CRCs	0.039

^aPercentage of information loss accepted at CGH-comparison test.

^bFrequency of altered region in FIT-interval CRCs compared to screen-detected CRCs.

CGH: Comparative genomic hybridization; FIT: Fecal immunochemical test; CRC: Colorectal cancer.