Abstract P6-08-10: Impact of age at diagnosis of metastatic breast cancer on overall survival in the real-life "ESME" cohort

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 (<40, 40 to 60 and >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 <40y, 40y to 60y and older than 60y respectively. Median follow-up was 54.8 months.

Pts <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 <0.0001).

MBC characteristics according to age groups Age at MBC diagnosis (years)p-value <4040-60>60 Tumor subtype   <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(%)   <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(%)   <0.0001< 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 <40, 40-60 and >60, respectively (p=0.2).

Tumor subtype and age showed a significant interaction on OS (p<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<4040-60>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)<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 <40, 40-60 and >60, respectively (p<0.0001).

Conclusion

At onset of MBC, young age was associated with more aggressive presentations, however with no global impact on OS. Pts <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.

Paclitaxel plus bevacizumab or paclitaxel as first-line treatment for HER2-negative metastatic breast cancer in a multicenter national observational study

BACKGROUND

Bevacizumab combined with paclitaxel as first-line chemotherapy for patients with HER2-negative metastatic breast cancer (MBC) has led to mixed results in randomized trials, with an improvement in progression-free survival (PFS) but no statistically significant overall survival (OS) benefit. Real-life data could help in assessing the value of this combination.

PATIENTS AND METHODS

This study aimed to describe the outcome following first-line paclitaxel with or without bevacizumab in the French Epidemiological Strategy and Medical Economics (ESME) database of MBC patients, established in 2014 by Unicancer. The primary and secondary end points were OS and PFS, respectively.

RESULTS

From 2008 to 2013, 14 014 MBC patient files were identified, including 10 605 patients with a HER2-negative status. Of these, 3426 received paclitaxel and bevacizumab (2127) or paclitaxel (1299) as first-line chemotherapy. OS adjusted for major prognostic factors was significantly longer in the paclitaxel and bevacizumab group compared with paclitaxel [hazard ratio (HR) 0.672, 95% confidence interval (CI) 0.601-0.752; median survival time 27.7 versus 19.8 months]. Results were consistent in all supportive analyses (using a propensity score for adjustment and as a matching factor for nested case-control analyses) and sensitivity analyses. Similar results were observed for the adjusted PFS, favoring the combination (HR 0.739, 95% CI 0.672-0.813; 8.1 versus 6.4 months).

CONCLUSIONS

In this large-scale, real-life setting, patients with HER2-negative MBC who received paclitaxel plus bevacizumab as first-line chemotherapy had a significantly better OS and PFS than those receiving paclitaxel. Despite robust methodology, real-life data are exposed to important potential biases, and therefore, results need to be treated with caution. Our data cannot therefore support extension of current use of bevacizumab in MBC.