Poor Prognosis of Lower Inner Quadrant in Lymph Node-negative Breast Cancer Patients Who Received No Chemotherapy: A Study Based on Nationwide Korean Breast Cancer Registry Database.
We aimed to investigate the prognostic influence of primary tumor site on the survival of patients with breast cancer.



Data of 63,388 patients with primary breast cancer from the Korean Breast Cancer Registry were analyzed. Primary tumor sites were classified into 5 groups: upper outer quadrant, lower outer quadrant, upper inner quadrant, lower inner quadrant (LIQ), and central portion. We analyzed overall survival (OS) and breast cancer-specific survival (BCSS) according to primary tumor site.



Central portion and LIQ showed lower survival rates regarding both OS and BCSS compared with the other 3 quadrants (all P < .05) and hazard ratios were 1.267 (95% CI, 1.180-1.360, P < .001) and 1.215 (95% CI, 1.097-1.345, P < .001), respectively. Although central portion showed more unfavorable clinicopathologic features, LIQ showed more favorable features than the other 3 quadrants. Primary tumor site was a significant factor in univariate and multivariate analyses for OS and BCSS (all P < .001). For lymph node-negative patients, LIQ showed a worse OS than the other primary tumor sites in the subgroup with no chemotherapy (P < .001), but that effect disappeared in the subgroup with chemotherapy (P = .058).



LIQ showed a worse prognosis despite having more favorable clinicopathologic features than other tumor locations and it was more prominent for lymph node-negative patients who received no chemotherapy. The hypothesis of possible hidden internal mammary node metastasis could be suggested to play a key role in LIQ lesions.
Department of Surgery, Seoul National University Boramae Medical Center, Seoul, Republic of Korea. Electronic address: kiterius@snu.ac.kr.
Ki-Tae
KT
Hwang
Department of Surgery, Seoul National University Boramae Medical Center, Seoul, Republic of Korea.
Jongjin
J
Kim
Department of Surgery, Seoul National University Bundang Hospital, Seongnam, Republic of Korea.
Eun-Kyu
EK
Kim
Department of Surgery, Chonbuk National University Medical School, Jeonju, Republic of Korea.
Sung Hoo
SH
Jung
Department of Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
Guiyun
G
Sohn
Department of Surgery, Yonsei University College of Medicine, Seoul, Republic of Korea.
Seung Il
SI
Kim
Department of Surgery, Gangnam Severance Hospital, Yonsei University, Seoul, Republic of Korea.
Joon
J
Jeong
Saegyaero Hospital, Busan, Republic of Korea.
Hyouk Jin
HJ
Lee
Department of Internal Medicine, Seoul National University Boramae Medical Center, Seoul, Republic of Korea.
Jin Hyun
JH
Park
Department of Biostatistics, Seoul National University Boramae Medical Center, Seoul, Republic of Korea.
Sohee
S
Oh
D014408:Biomarkers, Tumor / Q000378:metabolism*; D001943:Breast Neoplasms / Q000378:metabolism / Q000401:mortality* / Q000473:pathology* / Q000628:therapy; D003131:Combined Modality Therapy; D016208:Databases, Factual; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology*; D008875:Middle Aged; D011379:Prognosis; D011446:Prospective Studies; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism; D012042:Registries / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D015996:Survival Rate
D014408:Biomarkers, Tumor; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; C508053:ERBB2 protein, human
Primary tumor site; Prognosis; Survival analysis; Tumor location