Education Level Is a Strong Prognosticator in the Subgroup Aged More Than 50 Years Regardless of the Molecular Subtype of Breast Cancer: A Study Based on the Nationwide Korean Breast Cancer Registry Database.
OBJECTIVE
This study investigated the role of the education level (EL) as a prognostic factor for breast cancer and analyzed the relationship between the EL and various confounding factors.


METHODS
The data for 64,129 primary breast cancer patients from the Korean Breast Cancer Registry were analyzed. The EL was classified into two groups according to the education period; the high EL group (≥ 12 years) and low EL group (< 12 years). Survival analyses were performed with respect to the overall survival between the two groups.


RESULTS
A high EL conferred a superior prognosis compared to a low EL in the subgroup aged > 50 years (hazard ratio, 0.626; 95% confidence interval [CI], 0.577 to 0.678) but not in the subgroup aged ≤ 50 years (hazard ratio, 0.941; 95% CI, 0.865 to 1.024). The EL was a significant independent factor in the subgroup aged > 50 years according to multivariate analyses. The high EL group showed more favorable clinicopathologic features and a higher proportion of patients in this group received lumpectomy, radiation therapy, and endocrine therapy. In the high EL group, a higher proportion of patients received chemotherapy in the subgroups with unfavorable clinicopathologic features. The EL was a significant prognosticator across all molecular subtypes of breast cancer.


CONCLUSIONS
The EL is a strong independent prognostic factor for breast cancer in the subgroup aged > 50 years regardless of the molecular subtype, but not in the subgroup aged ≤ 50 years. Favorable clinicopathologic features and active treatments can explain the main causality of the superior prognosis in the high EL group.
Department of Surgery, SMG-SNU Boramae Medical Center, Seoul, Korea.
Ki-Tae
KT
Hwang
Department of Surgery, Korea Cancer Center Hospital, Seoul, Korea.
Woochul
W
Noh
Department of Surgery, Dong-A University Medical Center, Busan, Korea.
Se-Heon
SH
Cho
Department of Surgery, Samsung Medical Center, Seoul, Korea.
Jonghan
J
Yu
Department of Surgery, Chonnam National University Medical School, Gwangju, Korea.
Min Ho
MH
Park
Department of Surgery, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
Joon
J
Jeong
Saegyaero Hospital, Busan, Korea.
Hyouk Jin
HJ
Lee
Department of Surgery, SMG-SNU Boramae Medical Center, Seoul, Korea.
Jongjin
J
Kim
Department of Biostatistics, SMG-SNU Boramae Medical Center, Seoul, Korea.
Sohee
S
Oh
Department of Pathology, SMG-SNU Boramae Medical Center, Seoul, Korea.
Young A
YA
Kim
D000328:Adult; D000367:Age Factors; D001943:Breast Neoplasms / Q000175:diagnosis / Q000453:epidemiology* / Q000401:mortality / Q000628:therapy; D003131:Combined Modality Therapy; D016208:Databases, Factual; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging; D011159:Population Surveillance; D011379:Prognosis; D012042:Registries; D056910:Republic of Korea / Q000453:epidemiology; D012307:Risk Factors; D016019:Survival Analysis; D047368:Tumor Burden
Breast neoplasms; Education; Educational status; Prognosis; Survival analysis