Clinicopathologic characteristics of 143 patients with synchronous bilateral invasive breast carcinomas treated in a single institution.
BACKGROUND
Synchronous bilateral invasive breast carcinoma (SBIBC) ranged in incidence from 0.3% to as high as 12%.


METHODS
Between April 1997 and February 2003, 143 consecutive patients with SBIBC were treated at the European Institute of Oncology (Milan, Italy). Their information was collected prospectively in a database. The bilateral tumors were divded into left and right tumors. Tumor size, histology, grade, lymph node status, estrogen (ER) and progesterone receptor (PgR) status, HER-2 expression, peritumoral vascular invasion (PVI), Ki-67 expression, extensive in situ component (EIC), and multifocality between the two groups were analyzed. During the same time period, 6218 patients with unilateral invasive breast carcinoma (UIBC) were analyzed in the same manner for comparison with the patients with SBIBC.


RESULTS
There were no significant differences between left and right tumors, and the observed histopathologic agreement within the same patient was significantly superior than statistically expected for all characteristics except size, lymph node status, and multifocality. When compared with patients with UIBC, patients with SBIBC were more likely to present with smaller tumors and showed a higher frequency of invasive lobular carcinoma, lower histologic grade, higher rate of ER and PgR positivity, and lower PVI and Ki-67 expression.


CONCLUSIONS
The high concordance of histopathologic characteristics between SBIBC within the same patient could reflect a particular hormonal environment that influenced either the initiation and development of these lesions simultaneously and independently from the single or multi-clonal origin, either a less aggressive biological behavior compared with UIBC. In particular, the strong agreement of the observed EIC in SBIBC within the same patient seemed to definitively exclude the metastatic origin of these tumors.
Intra
Mattia
M
Division of Breast Surgery, European Institute of Oncology, Milan, Italy. mattia.intra@ieo.it
Rotmensz
Nicole
N
Viale
Giuseppe
G
Mariani
Luigi
L
Bonanni
Bernardo
B
Mastropasqua
Mauro G
MG
Galimberti
Viviana
V
Gennari
Roberto
R
Veronesi
Paolo
P
Colleoni
Marco
M
Tousimis
Eleni
E
Galli
Arianna
A
Goldhirsch
Aron
A
Veronesi
Umberto
U
D002288:Adenocarcinoma, Mucinous / Q000473:pathology*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis; D001943:Breast Neoplasms / Q000473:pathology*; D018270:Carcinoma, Ductal, Breast / Q000473:pathology*; D018275:Carcinoma, Lobular / Q000473:pathology*; D005260:Female; D006801:Humans; D015994:Incidence; D019394:Ki-67 Antigen / Q000378:metabolism; D008198:Lymph Nodes / Q000473:pathology; D008875:Middle Aged; D009361:Neoplasm Invasiveness / Q000473:pathology*; D009367:Neoplasm Staging; D011379:Prognosis; D011446:Prospective Studies; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism; D012680:Sensitivity and Specificity
D014408:Biomarkers, Tumor; D019394:Ki-67 Antigen; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone