Preliminary experience with mammography. Reliability of mammography in patients with a palpable tumour of the breast.

Radiologists with very limited practical experience in mammography initially achieved a low PVpos (0.50) and a high PVneg (0.95) in blind mammography of 80 patients with 85 excised and histologically examined breast tumours. After having read films from approximately 2500 patients the initial films were blindly reevaluated. PVneg was unchanged, whereas PVpos was elevated significantly (0.80). The intraobserver variation was 11.5 per cent. The actual interobserver variation was 3.2 per cent. These findings indicate that the reliability of blind mammography in patients with palpable tumours of the breast is considerable, also in case of only limited mammographic experience.

The predictive value of three diagnostic procedures in the evaluation of palpable breast tumours.

In a prospective study of 200 palpable breast tumours of 200 women, the diagnostic specificity and sensitivity of clinical examination, mammography, and fine needle aspiration were compared, alone and in combinations. All tumours were excised and examined histologically, and 38 were malignant. The diagnostic sensitivity of clinical examination was high, 98% (91-99), whereas the specificity was rather low, 48% (36-60). No statistically significant differences were found between the sensitivities or the specificities of the three examinations. When the methods were combined the sensitivity was 100% (96-100) and the specificity was 37% (27-46). Statistically, no improvement of the diagnostic value could be shown. It is concluded that the possibility of distinguishing between malignant and benign palpable breast tumours is not increased by adding mammography and/or fine needle aspiration, but the discovery of two non-palpable malignant tumours by mammography underscores the importance of this method in disclosing subclinical malignant lesions. The study disclosed a statistical possibility of overlooking a few malignant tumours when using these three procedures. Therefore, we advise that all palpable breast tumours should be excised.