[299] Luminal A Breast Adenocarcinoma Has Similar Rate of Metastatic Progression as Luminal B but Greater Overall and Disease Free Survival.

Riyam Zreik, Cary Chisholm, Courtney Yao, Christopher Ruud, VO Speights. Scott & White Memorial Hospital, Temple, TX

Background: Breast cancer has been classified into subtypes based on type of differentiation (ductal, lobular, etc) and/or immunohistochemical and fluorescence in-situ hybridization characteristics (Luminal A, Luminal B, etc). We studied patients who were found to have metastases at the time of their initial breast cancer diagnosis to evaluate overall/disease free survival and sites of metastases based on their biochemical phenotype.
Design: 108 patients with metastatic breast carcinoma at presentation were identified from 1999-2007. These were sub-typed into Luminal A (ER+/Her2-, Ki-67 <14%), Luminal B (ER+/Her2-, Ki-67 >14%), ER+/Her2+, ER-/Her2+, and triple negative (ER-/PR-/Her2-). Data was compiled regarding the histological criteria of the primary tumor, the sites of metastasis, and overall/disease free survival.
Results:

Breast Cancer Results
VariableLuminal A (N=18)Luminal B (N=34)ER+/Her2+ (N=21)ER-/Her2+ (N=10)Triple Negative (N=25)
Histologic Type     
Ductal132618924
Lobular56310
Other02001
Histologic Grade     
141000
2823913
361012922
Survival     
Alive48622
Dead142615823
Overall (months)6750445232
Disease Free (months)5537363537
Initial Site of Metastasis     
Visceral62212714
Bone151713412
Brain00313
Other35526
Site of Metastasis Progression     
Visceral920759
Bone1212624
Brain01104
Other344128


Luminal A tumors was the second most infrequent sources of metastases. Luminal A had the longest overall and disease free survival. Luminal A most frequently metastasized to the bone at presentation (83%). ER-/Her+ tumors were the most frequent source of initial visceral metastasis (70%). Brain metastases were most commonly found at diagnosis of ER+/Her2+ (14%) and triple negative tumors (12%). Triple negative tumors most frequently spread to brain (16%).
Conclusions: Luminal A tumors, commonly thought to have a less aggressive clinical course, had more frequent bone metastases than their more aggressive counterparts. Metastatic progression involving the brain was most common among patients with triple negative tumors. Overall/disease free survival and histologic grade were the only major differences between Luminal A and Luminal B, with Luminal A having much improved survival and lower histologic grade. Rates of metastatic progression between Luminal A and Luminal B tumors were similar.
Category: Breast

Monday, February 28, 2011 1:00 PM

Poster Session II # 61, Monday Afternoon

 

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