Elvire Pons-Tostivint1, Youlia Kirova2, Amélie Lusque3, Mario Campone4, Julien Geffrelot5, Sofia Rivera6, Audrey Mailliez7, David Pasquier8, Nicolas Madranges9, Nelly Firmin10, Agathe Crouzet11, Anthony Gonçalves12, Clémentine Jankowski13, Thibault De La Motte Rouge14, Nicolas Pouget15, Brigitte De La Lande16, Delphine Mouttet-Boizat17, Jean-Marc Ferrero18, Lionel Uwer19, Jean-Christophe Eymard20, Marie-Ange Mouret-Reynier21, Thierry Petit22, Coralie Courtinard23, Thomas Filleron3, Mathieu Robain24, Florence Dalenc25. 1. Medical Oncology Department, Claudius Regaud Institute, IUCT-Oncopole, Toulouse, France. Electronic address: elvire.pons-tostivint@inserm.fr. 2. Radiation Oncology Department, Curie Institute, Paris, France. 3. Biostatistics Department, Claudius Regaud Institute, IUCT-Oncopole, Toulouse, France. 4. Medical Oncology Department, René Gauducheau Center, Institute de Cancérologie de l'Ouest (ICO), Saint-Herblain, France. 5. Radiation Oncology Department, François Baclesse Center, Caen, France. 6. Radiation Oncology Department, Gustave Roussy Institute, Villejuif, France. 7. Medical Oncology Department, Oscar Lambret Center, Lille, France. 8. Radiation Oncology Department, Oscar Lambret Center, Lille, France. 9. Medical Oncology Department, Bergonié Institute, Bordeaux, France. 10. Medical Oncology Department, Cancer Institute, Montpellier, France. 11. Surgery Department, Henri Becquerel Center, Rouen, France. 12. Medical Oncology Department, Paoli-Calmettes Institute, Marseille, France. 13. Surgery Department, Georges-François Leclerc Center, Dijon, France. 14. Medical Oncology Department, Eugène Marquis Center, Rennes, France. 15. Surgery Department, René Huguenin Center, Curie Institute, Saint Cloud, France. 16. Radiation Oncology Department, René Huguenin Center, Curie Institute, Saint-Cloud, France. 17. Surgery Department, Curie Institute, Paris, France. 18. Medical Oncology Department, Antoine Lacassagne Cancer Center, Nice, France. 19. Medical Oncology Department, Lorraine Cancer Institute, Vandoeuvre-lès-Nancy, France. 20. Medical Oncology Department, Jean Godinot Institute, Reims, France. 21. Medical Oncology Department, Jean Perrin Center, Clermont-Ferrand, France. 22. Medical Oncology Department, Paul Strauss Center, Strasbourg, France. 23. Biostatistics Unit, Curie Institute, PSL Research University, Paris, France. 24. Biostatistics Unit, Curie Institute, PSL Research University, Paris, France; Department of Research and Development, R&D Unicancer, Paris, France. 25. Medical Oncology Department, Claudius Regaud Institute, IUCT-Oncopole, Toulouse, France.
Abstract
BACKGROUND: The impact of locoregional treatment (LRT) on overall survival (OS) in de novo metastatic breast cancer (dnMBC) is still under debate, with very few data available regarding exclusive radiotherapy (ERT) as a therapeutic modality. METHODS: We evaluated the impact of ERT, exclusive surgery, or a combination of surgery plus radiotherapy (bimodality therapy, BMT) on survival outcomes in a national real-life dnMBC cohort. The primary and secondary end points were OS and progression free survival (PFS) according to LRT (ERT, exclusive surgery, BMT) and no LRT. Sensitivity analyses were performed using propensity score matched analyses. RESULTS: From 2008 to 2014, 4507 dnMBC patients were identified. Only patients alive and free from progression under systemic therapy at least 1 year after diagnosis were included (n = 1965). Forty-five percent of patients (891/1965) underwent LRT: 41.1% (n = 366) ERT, 13.7% (n = 122) exclusive surgery, and 45.2% (n = 403) BMT. OS adjusted for major prognostic factors was significantly longer in the ERT and BMT group compared with no-LRT group, but not exclusive surgery (hazard ratio (HR) = 0.63, 95% confidence interval (CI) [0.49, 0.80], p < 0.001, HR = 0.61, 95%CI [0.47, 0.78], p < 0.001 and HR = 0.87, 95%CI [0.61, 1.26], p = 0.466 respectively). Results were similar after matching on a propensity score. ERT, surgery and BMT were all associated with a significantly better PFS in multivariable analysis. CONCLUSION: ERT was significantly associated with better OS in dnMBC, in the same magnitude as BMT, compared with no-LRT. However, even with statistical models adjusted for known prognostic factors and propensity score analysis, selection biases cannot be eliminated from observational studies.
BACKGROUND: The impact of locoregional treatment (LRT) on overall survival (OS) in de novo metastatic breast cancer (dnMBC) is still under debate, with very few data available regarding exclusive radiotherapy (ERT) as a therapeutic modality. METHODS: We evaluated the impact of ERT, exclusive surgery, or a combination of surgery plus radiotherapy (bimodality therapy, BMT) on survival outcomes in a national real-life dnMBC cohort. The primary and secondary end points were OS and progression free survival (PFS) according to LRT (ERT, exclusive surgery, BMT) and no LRT. Sensitivity analyses were performed using propensity score matched analyses. RESULTS: From 2008 to 2014, 4507 dnMBC patients were identified. Only patients alive and free from progression under systemic therapy at least 1 year after diagnosis were included (n = 1965). Forty-five percent of patients (891/1965) underwent LRT: 41.1% (n = 366) ERT, 13.7% (n = 122) exclusive surgery, and 45.2% (n = 403) BMT. OS adjusted for major prognostic factors was significantly longer in the ERT and BMT group compared with no-LRT group, but not exclusive surgery (hazard ratio (HR) = 0.63, 95% confidence interval (CI) [0.49, 0.80], p < 0.001, HR = 0.61, 95%CI [0.47, 0.78], p < 0.001 and HR = 0.87, 95%CI [0.61, 1.26], p = 0.466 respectively). Results were similar after matching on a propensity score. ERT, surgery and BMT were all associated with a significantly better PFS in multivariable analysis. CONCLUSION: ERT was significantly associated with better OS in dnMBC, in the same magnitude as BMT, compared with no-LRT. However, even with statistical models adjusted for known prognostic factors and propensity score analysis, selection biases cannot be eliminated from observational studies.