The invasive lobular carcinoma as a prototype luminal A breast cancer: a retrospective cohort study.
BACKGROUND
Although the invasive lobular carcinoma (ILC) is the second most frequent histologic subtype in Western countries, its incidence is much lower in Asia, and its characteristics are less well known.


METHODS
We assessed the clinical characteristics and outcomes of 83 Korean patients (2.8%) with ILC for comparison with 2,833 (97.2%) with the invasive ductal carcinoma (IDC), including 1,088 (37.3%) with the luminal A subtype (LA-IDC).


RESULTS
The mean age of all patients was 48.2 years, with no significant differences among the groups. Compared to IDC, ILC showed a larger tumor size (≥ T2, 59.8% vs. 38.8%, P = 0.001), a lower histologic grade (HG 1/2, 90.4% vs. 64.4%, P < 0.001), more frequent estrogen receptor positive (90.4% vs. 64.4%, P < 0.001), progesterone receptor positive (71.1% vs. 50.1%, P < 0.001) and HER2 negative (97.5% vs. 74.6%, P < 0.001) status, and lower Ki-67 expression (10.3% ± 10.6% vs. 20.6% ± 19.8%, P < 0.001), as well as being more likely to be of the luminal A subtype (91.4% vs. 51.2%, P < 0.001). Six (7.2%) ILC and 359 (12.7%) IDC patients developed disease recurrence, with a median follow-up of 56.4 (range 4.9-136.6) months. The outcome of ILC was close to LA-IDC (HR 0.77 for recurrence, 95% CI 0.31-1.90, P = 0.57; HR 0.75 for death, 95% CI 0.18-3.09, P = 0.70) and significantly better than for the non-LA-IDC (HR 1.69 for recurrence, 95% CI 1.23-2.33, P = 0.001; HR 1.50 for death, 95% CI 0.97-2.33, P = 0.07).


CONCLUSIONS
ILC, a rare histologic type of breast cancer in Korea, has distinctive clinicopathological characteristics similar to those of LA-IDC.
Center for Breast Cancer, National Cancer Center, Goyang-si, Korea. jungsro@ncc.re.kr
So-Youn
SY
Jung
Junsoo
J
Jeong
Seung-Ho
SH
Shin
Youngmee
Y
Kwon
Eun-A
EA
Kim
Kyoung Lan
KL
Ko
Kyung Hwan
KH
Shin
Keun Seok
KS
Lee
In Hae
IH
Park
Seeyoun
S
Lee
Seok Won
SW
Kim
Han-Sung
HS
Kang
Jungsil
J
Ro
D000328:Adult; D044466:Asian People; D014408:Biomarkers, Tumor / Q000032:analysis; D001943:Breast Neoplasms / Q000145:classification / Q000208:ethnology / Q000401:mortality / Q000473:pathology* / Q000628:therapy; D018270:Carcinoma, Ductal, Breast / Q000145:classification / Q000208:ethnology / Q000401:mortality / Q000473:pathology* / Q000628:therapy; D018275:Carcinoma, Lobular / Q000145:classification / Q000208:ethnology / Q000401:mortality / Q000473:pathology* / Q000628:therapy; D016009:Chi-Square Distribution; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D019394:Ki-67 Antigen / Q000032:analysis; D007723:Korea / Q000453:epidemiology; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local; D009367:Neoplasm Staging; D016016:Proportional Hazards Models; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis; D011960:Receptors, Estrogen / Q000032:analysis; D011980:Receptors, Progesterone / Q000032:analysis*; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D015996:Survival Rate; D009626:Terminology as Topic; D013997:Time Factors; D016896:Treatment Outcome
D014408:Biomarkers, Tumor; D019394:Ki-67 Antigen; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; C508053:ERBB2 protein, human