The relationship between Wolfe's classification of mammograms, accepted breast cancer risk factors, and the incidence of breast cancer.

Data collected between 1973 and 1984 on 696 incident cases of breast cancer and 1,376 matched controls from four Breast Cancer Detection Demonstration Project clinics in the United States were used to assess the role of mammographic parenchymal pattern as a risk factor and its relationship with other, accepted, risk factors. The data confirm previous reports of the influence of benign breast biopsy, age at first live birth, family history of breast cancer, and duration of menstruation on the incidence of breast cancer. Height is also found to be an influential factor.

Wolfe mammographic parenchymal patterns. A study of the masking hypothesis of Egan and Mosteller.

Wolfe defined four different classes of breast parenchymal patterns and claimed that they were associated with different risks for the subsequent development of breast cancer. Egan and Mosteller suggested that these patterns did not constitute a true risk factor, rather the effect was caused by the greater difficulty of detecting breast cancers in the dense (P2, DY) patterns compared with the fatty (N1, P1) patterns. Similarly, Mendell believed that a bias was introduced into Wolfe's work by requiring a negative mammogram before a patient entered the study.

Breast cancer prediction and the Wolfe classification of mammograms.

Mammographic parenchymal patterns have been proposed as a method of determining women at high risk of developing breast cancer. Wolfe's original report of relative risks as high as 37:1 for "dysplastic" breasts (DY) as compared with adipose breasts (N1), with intermediate values of P1 and P2, were not uniformly confirmed by others. (Relative risks are used here as the equivalent of odds ratios.

Outpatient lumbar myelography with metrizamide.

A prospective study of 70 adult patients was undertaken to determine whether lumbar metrizamide myelography can be performed as an outpatient procedure without an increased incidence of side effects and without undue risk. In selected patients and with a specific protocol, the incidence of common sequelae was similar to that in previous studies of inpatients either in bed with the head elevated or ambulatory after lumbar metrizamide myelography. No patient in this series experienced seizures or other severe complications.

Caveats in the sonographic determination of fetal femur length for estimation of gestational age.

Alterations from the standard conditions under which measurements of fetal femurs are made may alter the estimate of gestational age by up to four weeks. We describe and quantify the errors induced by variations in depth, gain settings, and angle of the femur relative to the US beam. We describe a simple phantom that may be used to help eliminate these sources of possible error.