Abstract
Introduction Breast cancer is the most common type of cancer in women worldwide, and early detection plays a key role in improving survival and treatment outcomes. National breast screening programs help identify both invasive and non-invasive cancers, such as ductal carcinoma in situ (DCIS). This study aimed to compare the one-year outcomes of screen-detected invasive breast cancer and DCIS in women diagnosed through a regional screening program. Methods A retrospective cohort study was conducted at our tertiary center in the UK. Patients diagnosed with screen-detected breast cancers from January 1, 2023, to December 31, 2024, were followed for one year post-surgery. A total of 216 patients were included: 108 with invasive breast cancer (Group A) and 108 with DCIS (Group B). Data on demographics, tumor characteristics, surgical procedures, postoperative complications, and oncological outcomes were collected using electronic records. Comparative statistical analyses were performed using SPSS version 26 (IBM Corp., Armonk, USA). Chi-square and independent t-tests were used for categorical and continuous variables, and odds ratios (ORs) with 95% confidence intervals were calculated to assess the strength of associations. Statistical significance was set at p < 0.05. Results The mean age was similar between groups (Group A: 57.6 ± 10.8 years; Group B: 58.1 ± 11.5 years). Estrogen and progesterone receptor (ER/PR) positivity was high in both groups (70.4% vs. 75%, p = 0.431). Human epidermal growth factor receptor 2 (HER2) positivity was more frequent in Group A (17.6% vs 11.1%, p = 0.173). Multifocality (24.1% vs 13%, p = 0.038), positive margins (17.6% vs 6.5%, p = 0.015), and nodal involvement (23.1% vs 0%, p < 0.001) were significantly more common in invasive cancers. Postoperative complications (hematoma, wound infection, seroma, flap necrosis) were similar in both groups. However, local recurrence was higher in Group A (9.3% vs 2.8%, p = 0.044), and one-year disease-free survival was lower (85.2% vs 97.2%, p = 0.002). Chemotherapy was given only to patients in Group A (59.3%). Conclusion In our study, we found that screen-detected in situ breast cancer had better short-term outcomes than invasive cancer, with fewer recurrences and higher one-year disease-free survival. Both groups were similar in demographics, but invasive cancer had more multifocality and required more aggressive surgery. Re-excision was more common in the in situ group. The results suggest avoiding overtreatment of DCIS and using risk tools to balance treatment with quality of life. Improving patient education, collaboration, and standardizing surgical decisions is important. The study highlights the need for evidence-based approaches in treatment planning.