Purpose: While the benefit of neoadjuvant chemotherapy (NAC) has been established in human epidermal growth factor receptor 2 (HER2)-positive and triple-negative breast cancers, its effectiveness in achieving pathological complete response (pCR) and optimal patient selection in estrogen receptor (ER)-positive, HER2-negative breast cancers remain less clearly defined. This study aimed to identify immunohistochemistry (IHC)-based predictors of pCR and to develop a scoring model for ER-strong positive/HER2-negative breast cancer. Methods: Data from a prospective cohort were retrospectively analyzed. We included 522 patients with ER-strong positive/HER2-negative tumors who received NAC and surgery between 2008 and 2021. IHC markers including progesterone receptor (PR), Ki-67, epidermal growth factor receptor (EGFR), cytokeratin 5/6 (CK5/6), and p53 were evaluated to identify predictors of pCR. Independent predictors of pCR from multivariate logistic regression were used to develop a weighted 4-point model. Model performance was assessed using receiver operating characteristic analysis. The prognostic impact of pCR was evaluated using KaplanMeier and Cox regression analyses. Results: Independent predictors of pCR included PR-negative status, positivity for basallike markers (EGFR or CK5/6), and Ki-67 ≥ 50%. The scoring model demonstrated good discrimination for pCR (area under the curve = 0.754). pCR rates increased stepwise, with scores of 4.9% (low), 10.7% (intermediate), and 36.2% (high). In the high-score group, pCR was significantly associated with improved disease-free survival (hazard ratio [HR], 0.09; p = 0.023) and distant metastasis-free survival (HR, 0.11; p = 0.035), whereas no significant survival differences according to pCR status were observed in the low and intermediate score groups. Conclusion This IHC-based model predicts pCR and helps identify subgroups in which pCR is associated with meaningful survival benefit following NAC in ER-positive/HER2-negative breast cancers. High-scoring patients may benefit from NAC, while patients with low- or intermediatescores may be better managed with surgery and endocrine therapy. This model may support personalized treatment decisions regarding NAC.

Purpose: Lobular carcinoma In Situ (LCIS) is a noninvasive lesion associated with an increased risk of invasive cancer. Since its removal from the tumor, node, metastasis classification in the 8th edition of the American Joint Committee on Cancer (AJCC) guidelines, the clinical management of LCIS has shifted from surgery to surveillance. However, studies focusing on the risk and associated factors for invasive cancer development in pure LCIS without ductal carcinoma In Situ (DCIS) or invasive cancer remain limited. Methods: We retrospectively analyzed 106 patients diagnosed with pure LCIS between 2008 and 2018. This study evaluated the effect of tamoxifen use and histologic type on the development of invasive cancer. Results: All 106 patients underwent surgery, and nine (8.5%) developed invasive cancer over a median follow-up of 67.5 months. The incidence of invasive cancer was lower in the tamoxifen group (6.3%, n = 4) than in the non-tamoxifen group (11.9%, n = 5), although this difference was not statistically significant (p = 0.266). Pleomorphic LCIS had a significantly higher incidence of invasive cancer (30.0%, n = 3) than classic LCIS (6.3%, n = 6) (p = 0.045).Multivariable Cox regression analysis showed no significant difference in the risk of invasive cancer according to tamoxifen use (hazard ratio [HR], 2.031; 95% confidence interval [CI], 0.544–7.579; p = 0.292). However, pleomorphic LCIS showed a trend toward an increased risk of invasive cancer compared to classic LCIS (HR, 3.856; 95% CI, 0.922–16.126; p = 0.064). Conclusion Postoperative tamoxifen did not significantly lower invasive cancer development in patients with pure LCIS. Pleomorphic LCIS may carry a higher risk than classic LCIS. These findings require tailored follow-up and treatment strategies based on the histologic subtype of LCIS.

Purpose: Surveillance guidelines following breast cancer surgery recommend mammography as the sole imaging modality. However, the accuracy of mammography is low in younger women and in those with dense breast tissue. Additional imaging modalities, such as ultrasonography and magnetic resonance imaging (MRI), may offer diagnostic benefits.This prospective, multicenter study (KBCSG-27) aims to compare the diagnostic performances of mammography, ultrasonography, and MRI for detecting second breast cancer (SBC) in women with a personal history of breast cancer (PHBC) and dense breasts. Methods This study will recruit approximately 1,756 women, aged 20–75 years, who were treated for stage 0–III breast cancer and have dense breast tissue on mammography.Participants will undergo two annual breast screenings, each consisting of mammography, ultrasonography, and MRI. MRI will be performed using either abbreviated magnetic resonance imaging (AB-MRI) or full-protocol magnetic resonance imaging (FP-MRI), which will be randomly assigned such that each participant receives both protocols alternately.Radiologists will independently interpret all images. A combination of pathology results and 12-month follow-up will serve as the reference standard. A patient-reported outcome (PRO) tool will be used to assess patients’ experiences and preferences between AB-MRI and FPMRI. The primary objective is to compare the cancer detection rates of ultrasonography versus AB-MRI and ultrasonography versus FP-MRI. Secondary outcomes include comparisons of the invasive cancer detection rates, abnormal interpretation rates, sensitivity, specificity, positive and negative predictive values, accuracy, and interval cancer rates. Subgroup analyses will be conducted based on age, menopausal status, mammographic breast density, and molecular subtype. Additionally, PRO results of AB-MRI and FP-MRI will be compared.Discussion: This ongoing, prospective, multicenter study aims to evaluate the performance of ultrasonography, AB-MRI, and FP-MRI in SBC surveillance in women with PHBC and dense breasts. Enrollment is expected to be completed by 2025, with results anticipated after 2028.

Purpose: This study aimed to evaluate the clinical outcomes and prognostic implications of regional nodal irradiation (RNI) after neoadjuvant chemotherapy (NAC) in patients with residual triple-negative breast cancer (TNBC). Materials and Methods: We analyzed 152 patients with residual TNBC who underwent breast-conserving surgery after NAC between December 2008 and December 2017. Most patients (n = 133; 87.5%) received taxane-based chemotherapy. Adjuvant radiotherapy (RT) was administered at a total dose of 45–65 Gy in 15–30 fractions to the whole breast, with some patients also receiving RT to regional nodes. Survival was calculated using the Kaplan–Meier method, and prognostic factors influencing survival were analyzed using the Cox proportional-hazards model. Results: During a median follow-up of 66 months (range, 9 to 179 months), the 5-year disease-free survival (DFS) rate was 68.0%. The 5-year locoregional recurrence-free survival, distant metastasis-free survival, and overall survival rates were 83.6%, 72.6%, and 78.7%, respectively. In the univariate analysis, the cN stage, ypT stage, ypN stage, axillary operation type, and RT field were associated with DFS. Multivariate analysis revealed that higher ypT stage (hazard ratio [HR] = 2.0; 95% confidence interval [CI] 1.00–3.82; p = 0.049) and ypN stage (HR = 4.7; 95% CI 1.57–14.24; p = 0.006) were associated with inferior DFS. Among clinically node-positive patients, those who received RT to the breast only had a 5-year DFS of 73.7%, whereas those who received RNI achieved a DFS of 59.6% (p = 0.164). There were no differences between the DFS and RNI. Conclusion In patients with residual TNBC, higher ypT and ypN stages were associated with poorer outcomes after NAC. RNI did not appear to improve DFS. More intensive treatments incorporating systemic therapy and RT should be considered for these patients.

Purpose: This study aimed to evaluate the clinical outcomes and prognostic implications of regional nodal irradiation (RNI) after neoadjuvant chemotherapy (NAC) in patients with residual triple-negative breast cancer (TNBC). Materials and Methods: We analyzed 152 patients with residual TNBC who underwent breast-conserving surgery after NAC between December 2008 and December 2017. Most patients (n = 133; 87.5%) received taxane-based chemotherapy. Adjuvant radiotherapy (RT) was administered at a total dose of 45–65 Gy in 15–30 fractions to the whole breast, with some patients also receiving RT to regional nodes. Survival was calculated using the Kaplan–Meier method, and prognostic factors influencing survival were analyzed using the Cox proportional-hazards model. Results: During a median follow-up of 66 months (range, 9 to 179 months), the 5-year disease-free survival (DFS) rate was 68.0%. The 5-year locoregional recurrence-free survival, distant metastasis-free survival, and overall survival rates were 83.6%, 72.6%, and 78.7%, respectively. In the univariate analysis, the cN stage, ypT stage, ypN stage, axillary operation type, and RT field were associated with DFS. Multivariate analysis revealed that higher ypT stage (hazard ratio [HR] = 2.0; 95% confidence interval [CI] 1.00–3.82; p = 0.049) and ypN stage (HR = 4.7; 95% CI 1.57–14.24; p = 0.006) were associated with inferior DFS. Among clinically node-positive patients, those who received RT to the breast only had a 5-year DFS of 73.7%, whereas those who received RNI achieved a DFS of 59.6% (p = 0.164). There were no differences between the DFS and RNI. Conclusion In patients with residual TNBC, higher ypT and ypN stages were associated with poorer outcomes after NAC. RNI did not appear to improve DFS. More intensive treatments incorporating systemic therapy and RT should be considered for these patients.

Purpose: We evaluated the association between changes in social support after cancer treatment and recurrence-free survival (RFS) in such patients using a prospective cohort study. Materials and Methods: Data were obtained from a prospective cohort study (NCT03131089) conducted at Samsung Medical Center (2013-2021). The primary outcome measure was RFS. Social support was measured using the social and family well-being (SFWB) domain of the Functional Assessment of Cancer Therapy-General. We calculated the changes in SFWB scores before and during treatment and the hazard ratio for RFS by comparing such changes. Results: The mean±standard deviation (SD) age of the patients was 35±3.9 years, and 71.5% and 64.8% of the patients were married and had children, respectively. The mean±SD SFWB score at baseline was 20.5±5.0 out of 26. After cancer treatment, 35.9%, 10.3%, and 53.8% of the participants had increasing, unchanged, and decreasing SFWB scores, respectively. The decreasing SFWB score group had a higher risk of mortality or recurrence than the increasing group. Risk factors for the decreasing score were the presence of children during diagnosis. Conclusion In this cohort, changes in social support after treatment were associated with RFS in young patients with breast cancer. Health professionals should develop family interventions to help them receive proper social support.

Purpose: This study aimed to evaluate the clinical outcomes and prognostic implications of regional nodal irradiation (RNI) after neoadjuvant chemotherapy (NAC) in patients with residual triple-negative breast cancer (TNBC). Materials and Methods: We analyzed 152 patients with residual TNBC who underwent breast-conserving surgery after NAC between December 2008 and December 2017. Most patients (n = 133; 87.5%) received taxane-based chemotherapy. Adjuvant radiotherapy (RT) was administered at a total dose of 45–65 Gy in 15–30 fractions to the whole breast, with some patients also receiving RT to regional nodes. Survival was calculated using the Kaplan–Meier method, and prognostic factors influencing survival were analyzed using the Cox proportional-hazards model. Results: During a median follow-up of 66 months (range, 9 to 179 months), the 5-year disease-free survival (DFS) rate was 68.0%. The 5-year locoregional recurrence-free survival, distant metastasis-free survival, and overall survival rates were 83.6%, 72.6%, and 78.7%, respectively. In the univariate analysis, the cN stage, ypT stage, ypN stage, axillary operation type, and RT field were associated with DFS. Multivariate analysis revealed that higher ypT stage (hazard ratio [HR] = 2.0; 95% confidence interval [CI] 1.00–3.82; p = 0.049) and ypN stage (HR = 4.7; 95% CI 1.57–14.24; p = 0.006) were associated with inferior DFS. Among clinically node-positive patients, those who received RT to the breast only had a 5-year DFS of 73.7%, whereas those who received RNI achieved a DFS of 59.6% (p = 0.164). There were no differences between the DFS and RNI. Conclusion In patients with residual TNBC, higher ypT and ypN stages were associated with poorer outcomes after NAC. RNI did not appear to improve DFS. More intensive treatments incorporating systemic therapy and RT should be considered for these patients.

Purpose: This study aimed to evaluate the clinical outcomes and prognostic implications of regional nodal irradiation (RNI) after neoadjuvant chemotherapy (NAC) in patients with residual triple-negative breast cancer (TNBC). Materials and Methods: We analyzed 152 patients with residual TNBC who underwent breast-conserving surgery after NAC between December 2008 and December 2017. Most patients (n = 133; 87.5%) received taxane-based chemotherapy. Adjuvant radiotherapy (RT) was administered at a total dose of 45–65 Gy in 15–30 fractions to the whole breast, with some patients also receiving RT to regional nodes. Survival was calculated using the Kaplan–Meier method, and prognostic factors influencing survival were analyzed using the Cox proportional-hazards model. Results: During a median follow-up of 66 months (range, 9 to 179 months), the 5-year disease-free survival (DFS) rate was 68.0%. The 5-year locoregional recurrence-free survival, distant metastasis-free survival, and overall survival rates were 83.6%, 72.6%, and 78.7%, respectively. In the univariate analysis, the cN stage, ypT stage, ypN stage, axillary operation type, and RT field were associated with DFS. Multivariate analysis revealed that higher ypT stage (hazard ratio [HR] = 2.0; 95% confidence interval [CI] 1.00–3.82; p = 0.049) and ypN stage (HR = 4.7; 95% CI 1.57–14.24; p = 0.006) were associated with inferior DFS. Among clinically node-positive patients, those who received RT to the breast only had a 5-year DFS of 73.7%, whereas those who received RNI achieved a DFS of 59.6% (p = 0.164). There were no differences between the DFS and RNI. Conclusion In patients with residual TNBC, higher ypT and ypN stages were associated with poorer outcomes after NAC. RNI did not appear to improve DFS. More intensive treatments incorporating systemic therapy and RT should be considered for these patients.

Purpose: This study aimed to evaluate the clinical outcomes and prognostic implications of regional nodal irradiation (RNI) after neoadjuvant chemotherapy (NAC) in patients with residual triple-negative breast cancer (TNBC). Materials and Methods: We analyzed 152 patients with residual TNBC who underwent breast-conserving surgery after NAC between December 2008 and December 2017. Most patients (n = 133; 87.5%) received taxane-based chemotherapy. Adjuvant radiotherapy (RT) was administered at a total dose of 45–65 Gy in 15–30 fractions to the whole breast, with some patients also receiving RT to regional nodes. Survival was calculated using the Kaplan–Meier method, and prognostic factors influencing survival were analyzed using the Cox proportional-hazards model. Results: During a median follow-up of 66 months (range, 9 to 179 months), the 5-year disease-free survival (DFS) rate was 68.0%. The 5-year locoregional recurrence-free survival, distant metastasis-free survival, and overall survival rates were 83.6%, 72.6%, and 78.7%, respectively. In the univariate analysis, the cN stage, ypT stage, ypN stage, axillary operation type, and RT field were associated with DFS. Multivariate analysis revealed that higher ypT stage (hazard ratio [HR] = 2.0; 95% confidence interval [CI] 1.00–3.82; p = 0.049) and ypN stage (HR = 4.7; 95% CI 1.57–14.24; p = 0.006) were associated with inferior DFS. Among clinically node-positive patients, those who received RT to the breast only had a 5-year DFS of 73.7%, whereas those who received RNI achieved a DFS of 59.6% (p = 0.164). There were no differences between the DFS and RNI. Conclusion In patients with residual TNBC, higher ypT and ypN stages were associated with poorer outcomes after NAC. RNI did not appear to improve DFS. More intensive treatments incorporating systemic therapy and RT should be considered for these patients.

Purpose: Data on subsequent arm lymphedema (SAL) after salvage treatment for locoregional recurrence (LRR) of breast cancer are limited. We conducted a study to evaluate the risk of SAL in patients with LRR. Methods: We reviewed the data of patients with breast cancer who had LRR and were initially diagnosed between January 2003 and December 2017. Among the 214 patients who received curative salvage treatment, most had local (n = 125, 57.9%), followed by regional (n = 73, 34.1%), and locoregional (n = 16, 7.9%) recurrences. A competing risk analysis considering the factors of death and a second LRR were performed to exclude potential malignant lymphedema. We used the Fine-Gray subdistribution hazards model to estimate the hazard ratio (HR) for comparing the risk of SAL. Results: With a median follow-up duration of 41.4 months (interquartile range, 25.6–65.1), 51 patients (23.8%) experienced SAL with a median interval of 9.9 months after treatment.The two-year cumulative incidence of SAL was 12.7%. Among the 18 patients with initial lymphedema, nine (50.0%) developed SAL. Multivariate analysis revealed that a history of lymphedema (HR, 4.61; p < 0.001) and taxane-based salvage chemotherapy (HR, 2.38; p = 0.009) were significantly associated with SAL development. Conclusion Salvage treatment for LRR-induced SAL was performed in 24% of the patients.A history of initial lymphedema and salvage taxane-based chemotherapy increases the risk of developing SAL. Therefore, close surveillance for the incidence of SAL is required in patients opting for salvage treatment for LRR.