Clinical quality assurance in breast cancer screening and diagnosis: a warning regarding mammographic positioning

Abstract

Objective: This study aimed to evaluate the clinical image quality of mammograms performed in users of the Brazilian Unified Health System (SUS) referred to a tertiary hospital. Methods: A prospective study assessed mammograms from women referred to a specialist breast center in Goiânia, Goiás, Brazil, between May and October 2017. Scans performed in the preceding 6 months, either screening or diagnostic, were included in the study. Clinical quality was determined from 40 variables related to patient identification, technical performance, the equipment, radiological findings, reporting of results, and breast positioning. Scans performed in the public and private healthcare networks were compared regarding mammographic positioning. Results: Overall, 4,560 variables associated with the clinical quality of the images were evaluated in scans from 114 women with a mean age of 50.6 years. A total of 660 (14.47%) inadequacies were found, 443 (67.12%) of which were related to breast positioning. The most common errors were as follows: pectoral muscle could not be seen in 86.8% of scans in the craniocaudal view and inframammary angle could not be seen in 79.8% of scans in the mediolateral oblique view. Considering the breast-positioning criteria evaluated in the mediolateral oblique view, there was a greater risk of the breast not being centrally positioned with the nipple in profile (RR 4.66; 95%CI 1.05−20.62; p=0.02) and of nonvisualization of the retro-areolar area (RR 4.14; 95%CI 0.92−18.66; p=0.04) in the exams performed in the private compared to the public network. Conclusion: The clinical quality of the scans analyzed was found to be inadequate, with most of the nonconformities being related to breast positioning.