{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,6]],"date-time":"2026-10-06T13:57:36Z","timestamp":1791295056943,"version":"4.1.0"},"reference-count":0,"publisher":"Oxford University Press (OUP)","license":[{"start":{"date-parts":[[2026,10,6]],"date-time":"2026-10-06T00:00:00Z","timestamp":1791244800000},"content-version":"am","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>Prognostic biomarkers for risk stratification remain limited in de novo metastatic hormone-sensitive prostate cancer (mHSPC) treated with androgen receptor pathway inhibitors (ARPIs). We evaluated baseline serum 25-hydroxyvitamin D [25(OH)D] and developed and externally validated a progression-free survival (PFS) model.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>This multicenter retrospective study included 273 patients initiating ARPI-based therapy between January 2021 and April 2026. Etlik City Hospital formed the training cohort (n\u2009=\u2009192; 85 PFS events), and Gazi University and K\u00fctahya City Hospital formed the external validation cohort (n\u2009=\u200981; 27 PFS events). LASSO-penalized Cox regression retained age, ISUP grade group, CHAARTED disease volume, log-transformed PSA, and hemoglobin. Model B added continuous 25(OH)D. Internal validation used 1,000 bootstrap resamples. Performance was assessed by Harrell C-index, time-dependent AUC, and calibration at 1 and 2 years. PFS was the primary endpoint; overall survival analyses were exploratory. The study was not prospectively registered.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>Higher baseline 25(OH)D was associated with longer PFS in Model B (HR per 10-ng\/mL increase, 0.64; 95% CI, 0.49\u20130.83; p&amp;lt;.001). Adding 25(OH)D improved model fit (likelihood-ratio \u03c7\u00b2=12.71; p&amp;lt;.001) and increased apparent C-index from 0.712 to 0.740. In external validation, C-indices were 0.71 (95% CI, 0.64\u20130.78) and 0.76 (95% CI, 0.69\u20130.83), respectively (\u0394\u2009=\u20090.05; 95% CI, 0.01\u20130.10).<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>Baseline 25(OH)D added modest prognostic information beyond clinical factors, with supportive external validation. These findings do not establish treatment-predictive utility or benefit from vitamin D supplementation. Prospective validation is needed before clinical implementation.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1093\/oncolo\/oyag396","type":"journal-article","created":{"date-parts":[[2026,10,5]],"date-time":"2026-10-05T11:21:20Z","timestamp":1791199280000},"source":"Crossref","is-referenced-by-count":0,"title":["Baseline 25-Hydroxyvitamin D and Progression-Free Survival in de novo mHSPC: Prognostic Model Development and External Validation"],"prefix":"10.1093","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-0698-777X","authenticated-orcid":false,"given":"Galip Can","family":"Uyar","sequence":"first","affiliation":[{"name":"Etlik City Hospital Department of Medical Oncology, , Ankara,","place":["Turkey"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6091-730X","authenticated-orcid":false,"given":"Kadriye","family":"Ba\u015fkurt","sequence":"additional","affiliation":[{"name":"Etlik City Hospital Department of Medical Oncology, , Ankara,","place":["Turkey"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0212-1191","authenticated-orcid":false,"given":"Orhun","family":"Akdo\u011fan","sequence":"additional","affiliation":[{"name":"Gazi University Department of Medical Oncology, Faculty of Medicine, , Ankara,","place":["Turkey"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0947-702X","authenticated-orcid":false,"given":"Enes","family":"Ye\u015filba\u015f","sequence":"additional","affiliation":[{"name":"Etlik City Hospital Department of Medical Oncology, , Ankara,","place":["Turkey"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9035-4846","authenticated-orcid":false,"given":"Mustafa","family":"Ersoy","sequence":"additional","affiliation":[{"name":"K\u00fctahya City Hospital Department of Medical Oncology, , K\u00fctahya,","place":["Turkey"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7750-814X","authenticated-orcid":false,"given":"Tuba","family":"U\u011fur Tuzcu","sequence":"additional","affiliation":[{"name":"Gazi University Department of Medical Oncology, Faculty of Medicine, , Ankara,","place":["Turkey"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4745-1605","authenticated-orcid":false,"given":"Kadriye","family":"Bir Y\u00fccel","sequence":"additional","affiliation":[{"name":"Etlik City Hospital Department of Medical Oncology, , Ankara,","place":["Turkey"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8024-2362","authenticated-orcid":false,"given":"Mustafa","family":"Alt\u0131nba\u015f","sequence":"additional","affiliation":[{"name":"Etlik City Hospital Department of Medical Oncology, , Ankara,","place":["Turkey"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2756-8646","authenticated-orcid":false,"given":"\u00d6m\u00fcr Berna","family":"\u00c7akmak \u00d6ks\u00fczo\u011flu","sequence":"additional","affiliation":[{"name":"Etlik City Hospital Department of Medical Oncology, , Ankara,","place":["Turkey"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0356-0727","authenticated-orcid":false,"given":"G\u00f6k\u015fen \u0130nan\u00e7","family":"\u0130mamo\u011flu","sequence":"additional","affiliation":[{"name":"Etlik City Hospital Department of Medical Oncology, , Ankara,","place":["Turkey"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3835-2741","authenticated-orcid":false,"given":"Osman","family":"S\u00fctc\u00fco\u011flu","sequence":"additional","affiliation":[{"name":"Gazi University Department of Medical Oncology, Faculty of Medicine, , Ankara,","place":["Turkey"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"286","published-online":{"date-parts":[[2026,10,6]]},"container-title":["The Oncologist"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/academic.oup.com\/oncolo\/advance-article-pdf\/doi\/10.1093\/oncolo\/oyag396\/71627067\/oyag396.pdf","content-type":"application\/pdf","content-version":"am","intended-application":"syndication"},{"URL":"https:\/\/academic.oup.com\/oncolo\/advance-article-pdf\/doi\/10.1093\/oncolo\/oyag396\/71627067\/oyag396.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,10,6]],"date-time":"2026-10-06T13:13:27Z","timestamp":1791292407000},"score":1,"resource":{"primary":{"URL":"https:\/\/academic.oup.com\/oncolo\/advance-article\/doi\/10.1093\/oncolo\/oyag396\/8868966"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,10,6]]},"references-count":0,"URL":"https:\/\/doi.org\/10.1093\/oncolo\/oyag396","relation":{},"ISSN":["1083-7159","1549-490X"],"issn-type":[{"value":"1083-7159","type":"print"},{"value":"1549-490X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,10,6]]},"article-number":"oyag396"}}