Abstract P6-08-10: Impact of age at diagnosis of metastatic breast cancer on overall survival in the real-life "ESME" cohort
Authors: Frank S , Tchokothe C , Carton M , Mouret-Fourme E , Dubot C , Campone M , Pistilli B , Dalenc F , Mailliez A , Levy C , D'Hondt V , Debled M , Leheurteur M , Coudert B , Perrin C , Gonçalves A , Uwer L , Ferrero J-M , Eymard J-C , Petit T , Mouret-Reynier M-A , Guesmia T , Bachelot T , Robain M , Cottu P 
Published: February 2018

Abstract
Background
Young age is a known poor prognosis factor in early stage breast cancer (BC). Its value is less documented for metastatic BC (MBC). Guidelines state that age should not guide the treatment strategy. We used the ESME database to evaluate the impact of age at MBC diagnosis on overall survival (OS).
Patients and Methods
ESME is a unique national cohort, collecting retrospective data using clinical trial-like methodology. It included all consecutive MBC patients (pts) who initiated at least 1 treatment in one of the 18 participating French cancer centers between 01/01/2008 and 12/31/2014. The database was locked on 12/8/2016. Primary objective were the comparisons of MBC characteristics between age groups (&lt;40, 40 to 60 and &gt;60 years (y)) and the evaluation of the impact of age at MBC diagnosis on OS.
Interaction between age and tumor subtype was tested using a Cox regression model.
ResultsAmong 16 703 included pts, 1539 had no information on tumor receptors (ER/PR/HER2) and 682 had an exclusion criteria (unknown age, men or other cancer in the last 5y), leaving 14 482 for analysis. At the onset of MBC, 902 pts (6.2%), 6269 (43.3%) and 7311 (50.5%) were &lt;40y, 40y to 60y and older than 60y respectively. Median follow-up was 54.8 months.
Pts &lt;40 had significantly more aggressive presentations than other age groups: more HER2+ (26.5%), and triple negative (26.4%) subtypes, more visceral involvement (57.1%), and shorter time to metastasis (26.9% between 6 to 24 months) (all p-value vs other age groups &lt;0.0001).
MBC characteristics according to age groups Age at MBC diagnosis (years)p-value &lt;4040-60&gt;60 Tumor subtype &lt;0.0001HR+/HER2-425 (47.12)3816 (60.87)5262 (71.97) HR-/HER2-238 (26.39)1126 (17.96)884 (12.09) HER2+239 (26.5)1327 (21.17)1165 (15.93) Type of metastasis, N(%) &lt;0.0001Bone only219 (24.31)1832 (29.23)2367 (32.41) Non visceral168 (18.65)1046 (16.69)1314 (17.99) Visceral514 (57.05)3389 (54.08)3623 (49.6) Time to first metastasis (months), N(%) &lt;0.0001&lt; 6304 (33.74)1882 (30.1)2107 (28.9) [6-12[65 (7.21)241 (3.85)209 (2.9) [12-24[177 (19.64)760 (12.15)564 (7.7) ≥24355 (39.4)3370 (53.89)4416 (60.53) Number of metastatic sites, N(%) 0.51 site709(78.6)4948 (78.93)5805 (79.4) 2 sites163(18.07)1130 (18.03)1313(17.96) ≥3 sites30(3.33)191 (3.05)193 (2.64)
Overall, median OS was identical in the different age groups: 39.1, 41.1 and 39.8 months for pts &lt;40, 40-60 and &gt;60, respectively (p=0.2).
Tumor subtype and age showed a significant interaction on OS (p&lt;0.0001), especially among HER2+ MBC
Overall survival (months) according to tumor subtypes and age groups Age groups (years)p-value (log-rank)Tumor subtype&lt;4040-60&gt;60 HR+/HER2-46,4 (CI 95% 40.5-55.4)47,8 (CI 95% 46-50)44,2 (CI 95% 42.1-46.3)0.0023HER2+60,7 (CI 95% 45.6-76.4)50,4 (CI 95% 46.3-56.3)44 (CI 95% 38.8-48.9)&lt;0.0001Triple negative14 (CI 95% 11.5-16.5)14,7 (CI 95% 13.7-15.9)15,7 (CI 95% 14.6-17.1)0.01
. Anti-HER2 with first-line treatment was given preferentially to young pts: 86.6, 81.9 and 74.9%for pts &lt;40, 40-60 and &gt;60, respectively (p&lt;0.0001).
Conclusion
At onset of MBC, young age was associated with more aggressive presentations, however with no global impact on OS. Pts &lt;40 with HER2+ disease carried a better prognosis, maybe related to therapy.
Citation Format: Frank S, Tchokothe C, Carton M, Mouret-Fourme E, Dubot C, Campone M, Pistilli B, Dalenc F, Mailliez A, Levy C, D'Hondt V, Debled M, Leheurteur M, Coudert B, Perrin C, Gonçalves A, Uwer L, Ferrero J-M, Eymard J-C, Petit T, Mouret-Reynier M-A, Guesmia T, Bachelot T, Robain M, Cottu P. Impact of age at diagnosis of metastatic breast cancer on overall survival in the real-life "ESME" cohort [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P6-08-10.