Impact of mammographic interval on stage and survival after the diagnosis of contralateral breast cancer

Background: Following treatment for primary breast cancer, annual mammograp hy and regular clinical breast examination is advised. The aim of this stud y was to investigate whether annual mammography resulted in an improvement in stage of contralateral breast cancers compared with mammography performe d at a longer interval. Methods: This was a retrospective analysis of patients treated for breast c ancer, who developed a contralateral breast cancer between 1977 and 1998. P atients were stratified into two groups according to mammographic interval. Results: Data were available for 275 patients who developed contralateral b reast cancer during follow-up. Annual mammography was performed in 51 per c ent; these patients were a mean of 5 years younger at diagnosis. Patients w ho had annual or biennial mammography had comparable rates of impalpable co ntralateral breast cancer, 30 and 27 per cent respectively. The tumours wer e of favourable stages in 60 and 58 per cent respectively. Five-year diseas e-free survival following diagnosis of contralateral breast cancer was 75 p er cent in bath groups. When the contralateral lesion was detected by mammo graphy, disease-free survival was better, irrespective of the stage of the ipsilateral breast cancer. Conclusion: No difference was found between the two groups in stage distrib ution and disease-free survival after the diagnosis of contralateral breast cancer. Survival was better in patients in whom the contralateral breast c ancer was first detected by mammography.