A systematic review of cancer risk among users of smokeless tobacco (Swedish snus) exclusively, compared with no use of tobacco

Abstract

The main objective of this systematic review was to assess cancer risk, and mor-tality after cancer diagnosis, for exclusive users of Swedish snus, compared withnon-users of tobacco. We followed international standards for systematic reviewsand graded our confidence in the risk estimates using the GRADE approach. Oursearch gave 2450 articles, of which 67 were assessed in full text against ourinclusion criteria. Of these, 14 cohort-studies and one case-control study wereincluded in the review. The studies investigated risk of cancer in the oral cavityor oropharynx (3 studies), esophagus (1 study), stomach (1 study), pancreas (2studies), colorectum (2 studies), anus (1 study) and lung (1 study), as well asmalignant lymphoma (1 study), leukemia and multiple myeloma (1 study), mela-noma (1 study), any cancer (1 study) and mortality after cancer diagnosis (4 stud-ies). Cancer risk could only be evaluated in men as there was a general lack ofdata for women. All included studies were evaluated to have a moderate risk ofbias, mostly related to validity of exposure information. An increased risk of can-cer of the esophagus, pancreas, stomach and rectum as well as an associationbetween use of snus and increased mortality after a cancer diagnosis wasreported. Our confidence in the various risk estimates varied from moderatethrough low to very low.

A systematic review of cancer risk among users of smokeless tobacco (Swedish snus) exclusively, compared with no use of tobacco