It is not clear whether screening for breast cancer works as public health policy and whether early indicators of effect predict an ultimate reduction in mortality.
The malignant potentials of 248 breast cancers detected by the screening service in Finland were compared with those of 490 control cancers diagnosed before the screening service was established.
Aggressiveness was assessed by DNA flow cytometry and clinical status by cancer size and node involvement.
After the first screening round, the results of DNA flow cytometry were the same in cancers diagnosed by screening and in controls ; these findings are consistent with the hypothesis that the biological aggressiveness of breast cancer remains constant as the cancer progresses.
The proportion of patients with node-negative and small T1 cancers after the first screening was higher among the screened population than among controls, indicating earliness of diagnosis among those screened.
Cancers diagnosed in the first round had a low malignant potential, as indicated by the DNA flow-cytometry and by clinical stage.
Lower aggressiveness of cancers found by screening than of control cancers would indicate overdiagnosis or lengthbiased sampling, but not earliness of diagnosis.
Screening with mammography is practised as a publichealth policy in Finland.
The results predict that the mortality reduction found in randomised trials can be repeated with a screening service.
Mots-clés Pascal : Glande mammaire pathologie, Tumeur maligne, Glande mammaire, Dépistage, Technique, Homme, Femelle, Etude statistique, Exploration ultrason, Echographie, Evaluation performance
Mots-clés Pascal anglais : Mammary gland diseases, Malignant tumor, Mammary gland, Medical screening, Technique, Human, Female, Statistical study, Sonography, Echography, Performance evaluation
Notice produite par :
Inist-CNRS - Institut de l'Information Scientifique et Technique
Cote : 95-0191365
Code Inist : 002B20E02. Création : 09/06/1995.