The "Europe against Cancer" programme has, from its inception, emphasised the key role which general practitioners must play in the actions necessary to achieve its aim of reducing the incidence and the mortality from cancer in the European Community. General practitioners, because of their day-to-day direct and continuing contact with patients, playa role not only in primary prevention and education of patients, but also in motivating their patients to accept secondary prevention and screening, some of it carried out by general practitioners themselves. These preventive activities are in addi tion to their traditional role in the care and management of patients with cancer at home, and increasingly, their role in active treatment. In view of the importance of the general practitioner in the "Europe against Cancer" programme, the European Commission, with a view to providing general practitioners with up-to-date useful information, has sponsored the production of this series of publi cations on organbased cancers, especially written for general practitioners. Regis Malbois Advisor in charge of the "Europe against Cancer" programme Commission of the European Communities Brussels Preface Colorectal cancer is the second most common cause of death from malignant disease with a high incidence in many European countries. This book is part of a series of pub lications on major cancer diseases designed for the European family doctor. It is pub lished by the Commission of the European Communities within the context of the Eu rope Against Cancer Programme.