Optimal use of staging data in international comparisons of colorectal cancer survival

Figures & data

Table I. Origin of stage variable for patients included in survival analyses of the ICBP study: Colon and rectal cancer patients diagnosed during 2000–2007.

	Valid Dukes’ stage (%)^a	of which	Dukes’ stage value derived from T, N, M (%)	of which	Origin of ‘T’ code			Origin of ‘N’ code			Origin of ‘M’ code
					Pathological	Clinical	Unknown	Pathological	Clinical	Unknown	Pathological	Clinical	Unknown
COLON
Canada^b	93.7		99.9		85.6	7.1	0.0	82.5	11.9	0.0	11.4	88.6	0.0
Denmark^b	80.0		100.0		0.0	0.0	91.8	0.0	0.0	89.1	0.0	0.0	100.0
Sweden	96.6		30.1		0.0	0.0	92.8	0.0	0.0	91.1	0.0	0.0	100.0
UK	72.2		17.2		28.3	15.4	27.8	30.4	16.2	26.9	32.7	35.1	32.2
RECTUM
Canada^b	74.5		99.4		74.7	20.9	0.0	72.4	22.9	0.0	24.3	75.7	0.0
Denmark^b	76.7		100.0		0.0	0.0	94.5	0.0	0.0	89.8	0.0	0.0	100.0
Norway^c	70.0		0.0		–	–	–	–	–	–	–	–	–
Sweden	90.2		33.9		0.0	0.0	92.2	0.0	0.0	90.2	0.0	0.0	100.0
UK	69.4		18.8		31.1	13.0	29.3	32.2	14.5	28.7	31.1	34.1	34.8

^aFinal proportions of all patients for whom a valid stage category could be obtained from the raw data. ^bPatients diagnosed in 2004–2007. ^cFinal stage defined solely from Dukes’ stage information: no component T, N and M codes available.

Table II. Comparisons of stage distribution (%) in the UK, by source.

				Dukes’ stage
			Number	A	B	C	D
Eden et al.	Colon and rectum combined	“ICBP-like”	2 406	22	37	39	2
		Integrated	2 406	21	33	32	14
Maringe et al.a	Colon	Final	102 555	9.4	38.6	35.1	16.9
		T, N and Mb	17 650	4.4	20.4	18.1	57.2
		Dukes^c	84 905	10.5	42.4	38.7	8.5
	Rectum	Final	46 769	20.7	28.6	33.8	16.9
		T, N and Mb	8 808	11.7	17.8	22.1	48.4
		Dukes^c	37 961	22.8	31.1	36.5	9.6

^aObserved stage distributions; imputation of missing stage values did not alter the distribution much. ^bRestriction to patients whose final stage was derived from the component T, N and M values. ^cRestriction to patients whose final stage was derived from the raw Dukes’ stage variable.