Introduction: mass screening, health technology assessment, and health policy in some European countries.

Objective: The series of papers in this issue was developed to examine the use of health technology assessment in policies toward prevention-specifically toward mass screening-in European countries. The papers actually examined three screening strategies: mammography screening for breast cancer, prostate-specific antigen screening for prostate cancer, and routine ultrasound in normal pregnancy.

Methods: Papers were sought from the member states of the European Union, plus Switzerland. Ultimately, nine acceptable papers were received, and were reviewed, revised, and edited.

Results: Screening is an accepted strategy in many countries for reducing the burden of disease through early detection and intervention. In part, this is because of successful screening programs that have been evaluated and implemented in many countries. At the same time, unevaluated and even useless and harmful screening programs-unjustified medically or economically-are widespread. Health technology assessment could help assure that only effective and cost-effective screening programs are implemented.

Conclusion: The main conclusion is that screening is an important preventive strategy. Any screening program, however, should be carefully assessed before implementation.