Does active smoking induce hematogenous metastatic spread in colon cancer?

No consensus exists on the influence of active smoking on the baseline staging of colon cancer patients.

A cohort of colon cancer patients treated surgically at Massachusetts General Hospital (2004 to 2011) was reviewed.

Of 1,071 patients, 563 reported ever smoking, among which 128 (12%) patients were current smokers. Ex-smokers and never smokers had similar rates of nodal (relative risk [RR] .9, P = .19) and metastatic disease (RR .96, P = .72), leading to comparable colon cancer-related mortality (RR 1.01, P = .95). Current smokers had similar rates of lymph node disease (RR 1.01, P = .88), but had significantly higher stage-adjusted odds of metastatic disease at presentation (odds ratio 2.57, 95% confidence interval 1.36 to 4.98, P = .005), in addition to higher stage-adjusted all-cause mortality (hazard ratio 1.44, P = .017).

Active smoking was a stage-independent risk factor for baseline hematogenous metastasis and mortality. As this link was not present in former smokers, a potential healthcare benefit may be achieved in terms of baseline colon cancer presentation and outcomes through smoking cessation.