{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,23]],"date-time":"2026-09-23T17:33:43Z","timestamp":1790184823867,"version":"4.1.0"},"reference-count":57,"publisher":"Oxford University Press (OUP)","issue":"5","license":[{"start":{"date-parts":[[2025,8,12]],"date-time":"2025-08-12T00:00:00Z","timestamp":1754956800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100004587","name":"Instituto de Salud Carlos III","doi-asserted-by":"publisher","award":["ISCIII, JR24\/00024"],"award-info":[{"award-number":["ISCIII, JR24\/00024"]}],"id":[{"id":"10.13039\/501100004587","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2025,9,1]]},"abstract":"<jats:title>Abstract<\/jats:title>\n               <jats:sec>\n                  <jats:title>Background<\/jats:title>\n                  <jats:p>Cyclin-dependent kinase 4\/6 inhibitors (CDK4\/6i) combined with endocrine therapy are the standard-of-care for hormone receptor-positive (HR+)\/HER2-negative (HER2\u2212) metastatic breast cancer (MBC). Palbociclib, the first approved CDK4\/6i, significantly improved progression-free survival (PFS) in randomized controlled trials (RCTs). However, real-world (RW) outcomes may differ due to broader patient populations. This meta-analysis evaluates the applicability of pivotal RCT findings to RW settings.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Methods<\/jats:title>\n                  <jats:p>We conducted a systematic review and meta-analysis of RW studies on HR+\/HER2\u2212 MBC treated with palbociclib+aromatase inhibitors (AI) or fulvestrant, reporting median PFS (mPFS) and\/or overall survival (mOS). Pooled mPFS\/OS was estimated using the median of medians (MM) and weighted MM (WM). RW estimates were deemed comparable to RCTs if MMPFS\/OS or WMPFS\/OS fell within RCTs\u2019 95% confidence intervals (CIs). Similar criteria applied to pooled hazard ratios (HRs) of PFS\/OS for palbociclib+AI vs AI in visceral\/nonvisceral subgroups.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Results<\/jats:title>\n                  <jats:p>Twelve RW studies were analyzed. First-line palbociclib+AI MMPFS (22.5\u2009months, 95% CI = 19.5 to 31.8) aligned with PALOMA-1\/2 pooled mPFS (23.9, 95% CI = 20.2 to 27.6). First-line palbociclib+fulvestrant MMPFS (13.5, 95% CI = 11.6 to 28.5) exceeded PALOMA-3 (11.2, 95% CI = 9.5 to 12.9). Second-line palbociclib+fulvestrant MMPFS (11.5\u2009months, 95% CI = 6.3 to 15.3) was consistent with PALOMA-3. RW first-line mOS (51.2\u2009months, 95% CI = 49.1 to 53.3) surpassed PALOMA-1\/2 pooled mOS (45.7, 95% CI = 37.5 to 53.8). WMOS (49.1\u2009months, 95% CI = 49.1 to 53.3) was slightly lower than RCTs (53.7, 95% CI = 37.5 to 53.8). Palbociclib+AI outperformed AI in RW visceral disease, aligning with RCTs, and showed heterogeneous but favorable benefit in nonvisceral disease.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Conclusions<\/jats:title>\n                  <jats:p>RW data confirm palbociclib+endocrine therapy effectiveness, reinforcing its applicability to broader patient populations.<\/jats:p>\n               <\/jats:sec>","DOI":"10.1093\/jncics\/pkaf083","type":"journal-article","created":{"date-parts":[[2025,8,13]],"date-time":"2025-08-13T00:51:34Z","timestamp":1755046294000},"source":"Crossref","is-referenced-by-count":2,"title":["Comparative efficacy between real-world and randomized studies of palbociclib+endocrine therapy in HR-positive\/HER2-negative metastatic breast cancer: systematic review and meta-analysis"],"prefix":"10.1093","volume":"9","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-6561-1919","authenticated-orcid":false,"given":"Francesco","family":"Schettini","sequence":"first","affiliation":[{"name":"Translational Genomics and Targeted Therapies in Solid Tumors Group, August Pi i Sunyer Biomedical Research Institute (IDIBAPS) , Barcelona,","place":["Spain"]},{"name":"Department of Medical Oncology, Clinic Barcelona Comprehensive Cancer Center , Barcelona,","place":["Spain"]},{"name":"Faculty of Medicine and Health Sciences, University of Barcelona , Barcelona,","place":["Spain"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0004-7092-1785","authenticated-orcid":false,"given":"Sabrina","family":"Nucera","sequence":"additional","affiliation":[{"name":"Translational Genomics and Targeted Therapies in Solid Tumors Group, August Pi i Sunyer Biomedical Research Institute (IDIBAPS) , Barcelona,","place":["Spain"]},{"name":"Department of Clinical and Experimental Medicine, University of Catania , Catania,","place":["Italy"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0001-6147-9655","authenticated-orcid":false,"given":"Giuseppe","family":"Di Grazia","sequence":"additional","affiliation":[{"name":"Translational Genomics and Targeted Therapies in Solid Tumors Group, August Pi i Sunyer Biomedical Research Institute (IDIBAPS) , Barcelona,","place":["Spain"]},{"name":"Department of Human Pathology \u201cG. Barresi\u201d, University of Messina , Messina,","place":["Italy"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4160-3479","authenticated-orcid":false,"given":"Fabiola","family":"Giudici","sequence":"additional","affiliation":[{"name":"Cancer Epidemiology Unit, Centro di Riferimento Oncologico di Aviano (CRO) IRCCS , Aviano,","place":["Italy"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Carla","family":"Strina","sequence":"additional","affiliation":[{"name":"Multidisciplinary Unit of Breast Pathology and Translational Research, Cremona Hospital , Cremona,","place":["Italy"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Manuela","family":"Milani","sequence":"additional","affiliation":[{"name":"Multidisciplinary Unit of Breast Pathology and Translational Research, Cremona Hospital , Cremona,","place":["Italy"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Richard","family":"Tancredi","sequence":"additional","affiliation":[{"name":"Multidisciplinary Unit of Breast Pathology and Translational Research, Cremona Hospital , Cremona,","place":["Italy"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4720-2497","authenticated-orcid":false,"given":"Benedetta","family":"Conte","sequence":"additional","affiliation":[{"name":"Translational Genomics and Targeted Therapies in Solid Tumors Group, August Pi i Sunyer Biomedical Research Institute (IDIBAPS) , Barcelona,","place":["Spain"]},{"name":"Department of Translational Medicine, University of Piemonte Orientale , Novara,","place":["Italy"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9064-0113","authenticated-orcid":false,"given":"Carmen","family":"Criscitiello","sequence":"additional","affiliation":[{"name":"Department of Oncology and Hemato-Oncology, University of Milano , Milan,","place":["Italy"]},{"name":"Division of Experimental Therapeutics, European Institute of Oncology, IRCCS , Milan,","place":["Italy"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0835-3153","authenticated-orcid":false,"given":"Mario","family":"Giuliano","sequence":"additional","affiliation":[{"name":"Department of Clinical Medicine and Surgery, University Federico II , Naples,","place":["Italy"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1797-5296","authenticated-orcid":false,"given":"Matteo","family":"Lambertini","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine and Medical Specialties (DiMI), School of Medicine, University of Genova , Genova,","place":["Italy"]},{"name":"Department of Medical Oncology, UOC Clinica di Oncologia Medica, IRCCS Ospedale Policlinico San Martino , Genova,","place":["Italy"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5255-6620","authenticated-orcid":false,"given":"Rodrigo","family":"S\u00e1nchez-Bayona","sequence":"additional","affiliation":[{"name":"Department of Medical Oncology, Hospital Universitario , Madrid,","place":["Spain"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8431-3183","authenticated-orcid":false,"given":"Tom\u00e1s","family":"Pascual","sequence":"additional","affiliation":[{"name":"Translational Genomics and Targeted Therapies in Solid Tumors Group, August Pi i Sunyer Biomedical Research Institute (IDIBAPS) , Barcelona,","place":["Spain"]},{"name":"Department of Medical Oncology, Clinic Barcelona Comprehensive Cancer Center , Barcelona,","place":["Spain"]},{"name":"Faculty of Medicine and Health Sciences, University of Barcelona , Barcelona,","place":["Spain"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4074-2530","authenticated-orcid":false,"given":"Grazia","family":"Arpino","sequence":"additional","affiliation":[{"name":"Department of Clinical Medicine and Surgery, University Federico II , Naples,","place":["Italy"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9546-5841","authenticated-orcid":false,"given":"Lucia","family":"Del Mastro","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine and Medical Specialties (DiMI), School of Medicine, University of Genova , Genova,","place":["Italy"]},{"name":"Department of Medical Oncology, UOC Clinica di Oncologia Medica, IRCCS Ospedale Policlinico San Martino , Genova,","place":["Italy"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5943-6066","authenticated-orcid":false,"given":"Paolo","family":"Vigneri","sequence":"additional","affiliation":[{"name":"Department of Clinical and Experimental Medicine, University of Catania , Catania,","place":["Italy"]},{"name":"Medical Oncology Unit, Istituto Clinico Humanitas, Misterbianco , Catania,","place":["Italy"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4194-7175","authenticated-orcid":false,"given":"Massimo","family":"Cristofanilli","sequence":"additional","affiliation":[{"name":"Department of Medicine, Division of Hematology-Oncology, Weill Cornell Medicine , New York, NY,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6710-4814","authenticated-orcid":false,"given":"Hope S","family":"Rugo","sequence":"additional","affiliation":[{"name":"Department of Medicine (Hematology\/Oncology), University of California San Francisco Helen Diller Family Comprehensive Cancer Center , San Francisco, CA,","place":["United 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