Radiographic features and molecular subtypes association of breast cancer in women younger than 40 years old

Abstract

Background: Breast cancer is the most commonly diagnosed cancer and the leading cause of cancer death among females, particularly in women under the age of 40 years. However, early detection of breast cancer in this population remains challenging and it tends to present at a later stage with poorer prognosis.Objective: To review mammographic and ultrasonographic findings, pathological features and molecular subtypes of breast cancer in younger than 40-year-old patients diagnosed in King Chulalongkorn Memorial Hospital and to determine which radiological characteristics are associated with molecular subtypes. Materials and Methods: The study included 278 patients aged under 40 years who were diagnosed with breast cancer and underwent mammographic and ultrasonographic studies between January 2009 and December 2019. A retrospective review of mammographic and ultrasonographic findings, histopathological reports as well as biological markers were made. The association of radiological characteristics and molecular subtypes was analyzed by SPSS. Results: In the 278 patients, the most common clinical presentation was palpable mass (268, 96.4%). The common mammographic findings were irregular shape mass (196, 77.8%) with hyperdensity (114, 45.2%) and an obscured margin (99, 39.3%). Presenting of microcalcification is not frequent (122, 48.4%). We found 27 patients with normal mammograms which were later detected in ultrasounds as 25 masses, 1 intraductal lesion and 1 focal duct change. The predominant ultrasonographic features were irregular shape mass (257, 91.5%), an angular margin (89, 31.7%), hypoechogenicity (198, 70.5%), no posterior feature (210, 74.7%) and internal vascularity (170, 60.5%). These radiological characteristics were classified as BI-RADS 5 in 194 lesions (69%). The most common histopathological type was mixed-type carcinoma (143, 50.9%), followed by invasive ductal carcinoma (114, 40.6%). Luminal B was the mostly found in this study (86, 30.6%). The patients frequently presented with stage IIA (91, 32.7%) while 15 patients were detected with an advanced stage at the first presentation. We found that triple negative, HER 2 overexpression and luminal B subtypes were associated with an obscured mass on mammography (p 0.048). Luminal B and HER 2 overexpression subtypes were also associated with the presence of fine pleomorphic microcalcification (p <0.001).        Conclusion: In this study, we found an association of the mass margin and suspicious calcification morphology on mammography with molecular subtypes. It would be helpful for further clinical management in young patients. The knowledge can be used for planning appropriate treatments according to molecular subtypes which are associated with these characteristics. However, the precision of cancer treatment is still based on the tissue diagnosis.