[Cancer and prevention].

INTRODUCTION

The aim of the study was to estimate the preventable potential of various types of cancer in Denmark on the basis of present knowledge.

MATERIAL AND METHODS

The well-documented factors in lifestyle and environment causing cancer in Denmark were identified from the IARC Monograph series. The population attributable risk per cent (PAR%) and the annual number of preventable cancers were calculated for each aetiology and cancer type around the year 2000.

RESULTS

A large proportion of the cancers occurring in the lungs, larynx, upper digestive tract, skin, lower urinary tract, and the uterine cervix is potentially avoidable, whereas only a small proportion of breast and colorectal cancers is preventable on the given knowledge. The main causative factors include active and passive smoking, alcohol intake, exposure to asbestos and other occupational carcinogens, solar and ionising radiation, obesity, human papillomavirus infection in the female genital tract, and infection with Helicobacter pylori. More than 5000 cancers in men and almost 3500 in women annually in Denmark could have been avoided by eliminating exposure to these known carcinogens. This is equivalent to 39% and 23% of all cancers occurring respectively in men and women, around the year 2000. Smoking habits account for more than half of these avoidable cases.

DISCUSSION

The incidence of cancer could be greatly reduced through primary prevention, especially of tobacco smoking, which is the major single factor. A large proportion of the cancers occurring in the lungs, larynx, upper digestive tract, skin, lower urinary tract, and the uterine cervix are potentially avoidable. More research in the field of aetiological factors causing female breast cancer and colorectal cancer is much needed in order to be able to prevent these types of cancer.