The Value of Radiological Examinations for Non-invasive Breast Cancer Before and After Neoadjuvant Treatment

Introduction In 2022, 2,3 million new cases of breast cancer was diagnosed globally, with DCIS detected in 33%–53% of invasive cases. Despite the rise in breast-conserving surgery, large DCIS with invasive cancer often results in mastectomy, even after neoadjuvant chemotherapy (ChT). Accurate lesion assessment is crucial, as invasive cancer appears as mass-like changes, while DCIS shows microcalcifications on mammography (MG) and non-mass enhancement on MRI. Ultrasound is less effective for DCIS detection and is not included in this study. It's believed that DCIS has a poor response to ChT. This study aims to analyze how ChT affects DCIS and its appearance on MG and MRI. Aim To assess the diagnostic value of mammography and MRI in determining the DCIS after ChT. Methods Data from a retrospective study of 74 breast cancer patients with a non-invasive component identified after biopsy or surgery, and ChT was given from 2023 to June 2024, were analyzed using SPSS version 29. Patient age, radiological data (mass, non-mass changes, calcifications in MG, mass, non-mass changes in MRI, extent of lesions) before and post treatment, histological data (tumor type, hormone receptor status, HER2 status, DCIS nuclear grade), type of surgery were collected. Patients were grouped by MG (calcifications vs. no calcifications) and MRI (nonmass enhancement vs. no nonmass enhancement). Radiological data and histological data were compared. Descriptive statistics, chi-square, and t-tests were used, with a p-value <0.05 considered significant. Results Patients' age ranged from 26 to 84 years; with a mean of 56 years. MG was performed before and after ChT in 67 patients (90%), showing suspicious calcifications in 30 before and 26 after, with 4 cases of disappearance. The mean size of malignant calcifications decreased from 39 mm before treatment to 33 mm post treatment, but this reduction was not significant. MRI was performed in 56 patients (76%), showing a significant reduction in tumor size. DCIS was suspected in 31 patients before and in 29 after ChT. Post-treatment, mass-like tumors shrank from 24 mm to 12 mm, and nonmass changes from 53 mm to 26 mm. Post-ChT. Surgery types were mastectomy (35%) and lumpectomy (65%). Patients without post-treatment DCIS on MRI were more likely to have lumpectomy (60% vs 24%), while those with DCIS were more likely to undergo mastectomy (76% vs 40%) (p<0.05). There was no significant difference between surgery type and malignant calcifications. Resection margins were clear in 96% of cases. Conclusions The study suggests that ChT significantly reduces DCIS lesion size on MRI. Breast-conserving surgery was more often chosen than mastectomy if there was no evidence of DCIS on MRI. Nearly all patients had clear resection margins, highlighting MRI's value in assessing tumor response and guiding surgery. The reduction in the size of malignant calcifications on MG was not significant and did not impact surgery type.