Document Type: Research Articles
Department of Surgery, Haeundae Paik Hospital, College of Medicine, Inje University, Busan, Korea.
Department of Surgery, Korea Cancer Center Hospital, Korea Institute of Radiological and Medical Sciences, Seoul, Korea.
Department of Surgery, College of Medicine, Dong- A University, Busan, Korea.
Department of Surgery, Seoul National University College of Medicine, Seoul, Korea.
Department of Surgery, Chonnam National University Hwasun Hospital, Chonnam, Korea.
Department of Surgery, Gangnam Severance Hospital, Yonsei University Medical College, Seoul, Korea.
Department of Surgery, Breast Cancer Center, Gachon University Gill Medical Center, Incheon, Korea.
Department of Pharmacology, Inje University College of medicine, Clinical Trial Center, Inje University Busan Paik Hospital, Busan, Korea.
Department of Surgery, Dongnam Institution of Radiological and Medical Science, Busan, Korea.
Objective: Interval breast cancer (IC) is a limitation of breast cancer screening. We investigated data from a
large scaled breast cancer dataset of patients with breast cancer who underwent breast cancer screening in order to
recapitulate the overall survival (OS) of patients with ICs compared to those with non-ICs. Methods: A total of 27,141
patients in the Korean breast cancer registry with breast cancer who had ever participated in biannual national breast
cancer screening programs between 2009 and 2013 were enrolled. We compared the social, pregnancy-associated, and
pathologic characteristics between the IC and non-IC groups and identified the significant prognostic factors for OS.
Results: The proportion of ICs was 1.3% (370/27,141) in this study population. ICs were correlated with age 45-55
years at diagnosis, higher levels of education, early menopause (provinces (Kangwon, Kyungnam, Jeju, and Dae-jeon), and family history of breast cancer. Low-to-intermediate nuclear
grade, early stage (stage 0-I), and low Ki-67 level were also correlated with IC proportion. Non-ICs were associated
with an increased risk of five-year mortality (hazard ratio [HR] 7.4; 95% confidence interval [CI]:1.85-29.66; p = 0.005)
compared to ICs. Lymph node metastasis, residence (Kyung-nam province), low education status, high histologic grade,
and asymptomatic cancers increased the HR of five-year OS. Conclusion: ICs occurred unequally in specific province
and relatively high-educated women in Korea. They were also diagnosed with early-stage breast cancer with a favorable
recurrence risk, and their outcome was better than those of patients with other breast cancers in breast cancer screening.