Mammographic densities as a criterion for entry to a clinical trial of breast cancer prevention.

The most convincing evidence that a factor such as dietary fat is causally related to breast cancer would be obtained from a randomised controlled trial in which exposure to dietary fat intake was systematically varied. A limitation of randomised controlled trials of breast cancer prevention, however, is the large sample size required to detect plausible reductions in risk resulting from the intervention. We describe here experience over a period of 9 years with the use of one risk factor for breast cancer as a criterion for entry to a clinical trial of breast cancer prevention.

Sensitivity and specificity of first screen mammography in the Canadian National Breast Screening Study: a preliminary report from five centers.

Sensitivity and specificity of first screen mammography in a randomized screening trial at five centers are reported. A total of 23,101 women underwent mammography; in 139, breast cancer was detected at first screening; in 20, less than 12 months after first screening; and in 47, at second screening. All 206 cancer cases were histologically confirmed, and 174 were defined as being detectable at first screening.

Needle-guided breast biopsy for mammographic abnormalities in 561 patients.

Between 1977 and 1983, 561 consecutive patients underwent 595 surgical biopsies for suspicious mammographic lesions with negative clinical correlation. The procedure consisted of preoperative needle localization, with or without immediate radiologic examination of the biopsy specimen, depending on the presence or absence of microcalcifications in the mammographic lesion. Eighty-four carcinomas were found.

Mammographic patterns and breast cancer risk: methodologic standards and contradictory results.

The claim that classification of the pattern of the breast parenchyma upon mammography can distinguish groups at different risks for breast cancer has been examined by 17 other studies published in the English language literature with contradictory results; this controversy was assessed by us in examination of these studies for their adherence to commonly accepted methodologic standards for the investigation of causal relationships. The nine standards for the examination of the studies included a description of the way the study population had been assembled and followed up and descriptions of the methods of mammographic pattern classification and breast cancer risk analysis. A strong association was found between the standards adopted by a study and the obtained results.

Mammographic patterns and bias in breast cancer detection.

Wolfe's finding that some mammographic patterns (P2 and DY) are associated with an increased risk of breast cancer has been challenged by some authors who suggest that this is due to denser patterns concealing cancers present on the first examination: these cancers, it is argued, are diagnosed in later years, creating the spurious impression of increased cancer incidence. The authors examined this hypothesis in a series of patients with breast cancer but failed to find any evidence that the diagnosis was subject to systematic delay in patients with the P2 or DY pattern. Moreover, studies of a hypothetical model showed that bias in the detection of breast cancer was unlikely to account for more than a small increase in apparent cancer incidence.

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.

Mammographic signs as risk factors for breast cancer.

We have carried out a case-control study to examine the relationship between mammographic signs and breast cancer. The mammographic signs assessed were prominent ducts and dysplasia. The cases were a group of 183 women with histologically verified unilateral breast cancer.

Bias and the association of mammographic parenchymal patterns with breast cancer.

We have carried out a case-control study to evaluate the association between Wolfe's mammographic patterns and the risk of breast cancer, and to examine the influence of control selection and the radiologist who read the films upon the results obtained. Mammograms of the non-cancerous breast of 183 women with unilateral breast cancer were compared with mammograms from two age-matched control groups: a group of asymptomatic women attending a screening centre, and a group of symptomatic women referred for the diagnostic evaluation of suspected breast disease. Films were arranged in random sequence and independently classified by 3 radiologists.

Sophisticated radiology in otolaryngology. II. Diagnostic imaging: non-roentgenographic (non x-ray) modalities (ultrasound, nuclear medicine, thermography).

Newer forms of radiologic diagnostic imaging now include non-roentgenographic modalities such as ultrasound, nuclear medicin, and thermography, all of which can be applied to otolaryngology. It is the purpose of this presentation to demonstrate these modalities, and indicate their clinical application, yet in its earliest stages, to otolaryngology.

Sophisticated radiology in otolaryngology. I. Diagnostic imaging: roentgenographic (x-ray) modalities.

Conventional radiography is now complemented by a large range of newer radiologic diagnostic techniques, involving both roentgenographic and non-roentgenographic modalities. It is the purpose of this presentation to present these new roentgenographic modalities in graphic form, and demonstrate their application to otolaryngic diagnosis. The major roentgenographic modalities which will be stressed are: xeroradiography, angiography, and computerized tomographic scanning.