Xeromammographic diagnosis of carcinoma of the breast in office practice.

Over the two year period from 1983 to 1984, 382 histologically proved carcinomas of the breast were diagnosed roentgenographically in an office referral practice in a population of 12,317 patients who had xeromammography as the routine technique. The patients examined were a mixed population comprising approximately 55 per cent symptomatic and 45 per cent screening patients. The over-all detection rate for cancer was 33.0 per 1,000 for all cancers and 7.6 per 1,000 for clinically occult cancers. For the 93 patients with clinically occult lesions, the yield ratio for biopsy for cancer was 36 per cent. The cost in Canadian dollars per diagnosis for occult carcinoma of the breast was $10,657. These results demonstrate the efficacy of xeromammographic examination of the breast in accomplishing early diagnosis of carcinoma of the breast. Xeromammography is an accurate and sensitive tool both for screening and assessment of symptomatic patients and is ideal for use in a private office setting.

Experience with fine-wire localization breast biopsies for nonpalpable breast lesions detected mammographically.

There is evidence to suggest that the early diagnosis and treatment of breast cancer may be associated with a better prognosis. Technical advances such as mammography can detect nonpalpable breast lesions and changes associated with early carcinoma. With fine-wire localization under mammographic control, the surgeon can reliably remove nonpalpable lesions while sparing normal breast tissue. The authors describe the technique for fine-wire localization and removal of lesions and report their experience over 3 years with 262 women who underwent 269 biopsies for nonpalpable lesions. Four subgroups were identified: screened women who had no indication for mammography other than age, women who were referred for mammography by community physicians, a group referred to the Cancer Control Agency of British Columbia and a group referred to the agency for localization biopsy after mammography performed outside the Vancouver area had suggested a malignant lesion. The yield of cancers from biopsies was 10%, 38%, 43% and 26% respectively. The yield was significantly (p less than 0.05) lower for the screened group. Age over 60 years, previous breast cancer and mammographic technique were identified as possible predictors of a positive biopsy. The authors have found fine-wire localization biopsy a safe and reliable method of removing nonpalpable breast lesions.

Observer variation in the classification of mammographic parenchymal patterns.

Wolfe has described different cancer risks associated with a classification of four patterns of the breast parenchyma on mammography, but there is however little information available on the ability of radiologists to agree on the classification of the different patterns. We have assessed inter-rater agreement on the assignment of films to one of the four mammographic patterns described by Wolfe. One hundred xeromammograms were selected, copied and distributed to 10 radiologists who were experts in mammography. Films were classified according to the presence or absence of several radiological signs, according to diagnosis and recommendation, and according to mammographic pattern. Agreement was assessed after correction for agreement expected by chance, using the Kappa statistic. In general, high levels of agreement were found for the classification of mammographic pattern. Agreement on the classification of mammographic pattern was substantially greater than agreement for any other feature of mammographic interpretation, including diagnosis and recommendation.

Observer variation in the interpretation of xeromammograms.

We have examined variation in the interpretation of xeromammograms among radiologists designated to take part in a Canadian multicenter randomized controlled trial of screening for breast cancer. Radiologists read 100 xeromammograms comprising 10 histologically proved cancers, 40 benign abnormalities, and 50 normal films. Radiologists' opinions differed widely on the frequency of suspected or identified cancer. The diagnostic category "suspicion of cancer" or "cancer" was selected by radiologists for 10-55% of the films, and biopsy or aspiration was recommended for 21 to 53% of patients whose films were examined. Agreement on specific diagnostic categories was greatest for the diagnosis of cancer; agreement was least for the diagnosis of benign abnormalities and intermediate for the diagnosis of normality. Known cancers were in general correctly identified. These results indicate a need for development of methods to reduce observer variation in a interpretation of xeromammograms while preserving diagnostic sensitivity and validity. Results also emphasize the importance of developing strategies to ensure quality control in multicenter trials.