Clinical significance of HER2 status in T1bN0 breast cancer: a nationwide study from the Korean Breast Cancer Society.

PURPOSE: The prognosis of patients with node-negative T1b tumors according to human epidermal growth factor receptor 2 (HER2) status is not known. This group of patients has not been studied in the available randomized trials. The objective of this study was to evaluate the survival of patients in a monoethnic group diagnosed with T1b lymph node-negative breast cancer depending on HER2 status. METHODS: We analyzed 3110 patients with T1bN0M0 breast cancer whose data were deposited into the Korean Breast Cancer Society Registry database between 2000 and 2009. Overall survival (OS) and breast cancer-specific survival (BCSS) were compared according to HER2 status. RESULTS: Among all patients, 494 (15.9%) had HER2-positive breast cancer. At a mean follow-up of 93 months, 108 deaths and 86 breast cancer-specific deaths were noted among all patients. There was no significant difference in OS between the HER2-negative and HER2-positive groups (p = 0.103). The same result was observed for BCSS. However, in the subgroup of estrogen receptor (ER)-positive women, HER2-negative patients had a better BCSS prognosis than HER2-positive patients (p = 0.025). Multivariate analysis also indicated a significant difference in BCSS in the ER-positive subgroup (HR 2.60; 95% CI 1.15-5.87; p = 0.021). CONCLUSION: This study analyzed a large nationwide and monoethnic cohort and found a significant difference only in BCSS in the ER-positive subgroup according to HER2 status. Anti-HER2 therapy may be considered in HER2-positive and ER-positive patients with small, node-negative breast cancer.

Impact of the COVID-19 Pandemic on the Diagnosis and Surgery of Breast Cancer: A Multi-Institutional Study.

PURPOSE: The coronavirus disease 2019 (COVID-19) pandemic has significantly impacted the rates of screening, case identification, and referral for cancer diagnosis. We investigated the diagnosis and surgery status of breast cancer before and after the COVID-19 pandemic at a multi-institutional level. METHODS: We collected breast cancer data from the clinical data warehouse which contained the medical records of patients from six academic institutions in South Korea. Patients were divided into two groups: February to April (period A) and May to July (period B). The data from the two groups were then compared against the same periods in 2019 and 2020. The primary objective was to investigate the differences in breast cancer stages before and after the COVID-19 pandemic. RESULTS: Among 3,038 patients, there was a 9.9% reduction in the number of diagnoses in 2020. This decrease was more significant during period A than period B. The breast cancer stage was not statistically different in period A (p = 0.115), but it was in period B (p = 0.001). In the subset analysis according to age, there was a statistical difference between 2019 and 2020 in period B for patients under the age of 65 years (p = 0.002), but no difference was observed in the other groups. CONCLUSION: The number of breast cancer cases declined during the pandemic, and the staging distribution has changed after the pandemic peak.