Table 3

Studies reporting the prevalence of venous tumour invasion for stage II colorectal carcinoma

Group	Year of publication	Case number	Prevalence (%)
Dukes et al^*	1941	574	8.7
Krasna et al^*	1988	30	20
Talbot et al^†	1981	264	36
Merkel et al^†	2001	305	10.2
Peterson et al	2002	268	34
Dirschmid et al^†	1996	31	52

↵* No separation between intra-and extramural venous invasion.
↵† Only extramural venous invasion.