Cengiz Karacin, Berna Oksuzoglu, Ayşe Demirci, Merve Keskinkılıç, Naziyet Köse Baytemür, Funda Yılmaz, Oğuzhan Selvi, Dilek Erdem, Esin Avşar, Nail Paksoy, Necla Demir, Sema Sezgin Göksu, Sema Türker, Ertuğrul Bayram, Abdüssamet Çelebi, Hatice Yılmaz, Ömer Faruk Kuzu, Seda Kahraman, İvo Gökmen, Abdullah Sakin, Ali Alkan, Erdinç Nayır, Muzaffer Uğraklı, Ömer Acar, İsmail Ertürk, Hacer Demir, Ferit Aslan, Özlem Sönmez, Taner Korkmaz, Özde Melisa Celayir, İbrahim Karadağ, Erkan Kayıkçıoğlu, Teoman Şakalar, İlker Nihat Öktem, Tülay Eren, Enes Erul, Eda Eylemer Mocan, Ziya Kalkan, Nilgün Yıldırım, Yakup Ergün, Baran Akagündüz, Serdar Karakaya, Engin Kut, Fatih Teker, Burçin Çakan Demirel, Kubilay Karaboyun, Elvina Almuradova, Olçun Ümit Ünal, Abdilkerim Oyman, Deniz Işık, Kerem Okutur, Buğra Öztosun, Burcu Belen Gülbağcı, Mehmet Emin Kalender, Elif Şahin, Mustafa Seyyar, Özlem Özdemir, Fatih Selçukbiricik, Metin Kanıtez, İsa Dede, Mahmut Gümüş, Erhan Gökmen, Arzu Yaren, Serkan Menekşe, Senar Ebinç, Sercan Aksoy, Gökşen İnanç İmamoğlu, Mustafa Altınbaş, Bülent Çetin, Başak Oyan Uluç, Özlem Er, Nuri Karadurmuş, Atike Pınar Erdoğan, Mehmet Artaç, Özgür Tanrıverdi, İrfan Çiçin, Mehmet Ali Nahit Şendur, Esin Oktay, İbrahim Vedat Bayoğlu, Semra Paydaş, Adnan Aydıner, Derya Kıvrak Salim, Çağlayan Geredeli, Tuğba Yavuzşen, Mutlu Doğan, İlhan Hacıbekiroğlu, MÜ, Tıp Fakültesi, Dahili Tıp Bilimleri Bölümü, Alkan, Ali, Karacin C., Oksuzoglu B., Demirci A., KESKİNKILIÇ M., Baytemür N. K., Yılmaz F., Selvi O., Erdem D., Avşar E., Paksoy N., et al., and Demir, Hacer
Background There is no standard treatment recommended at category 1 level in international guidelines for subsequent therapy after cyclin-dependent kinase 4/6 inhibitor (CDK4/6) based therapy. We aimed to evaluate which subsequent treatment oncologists prefer in patients with disease progression under CDKi. In addition, we aimed to show the effectiveness of systemic treatments after CDKi and whether there is a survival difference between hormonal treatments (monotherapy vs. mTOR-based). Methods A total of 609 patients from 53 centers were included in the study. Progression-free-survivals (PFS) of subsequent treatments (chemotherapy (CT, n:434) or endocrine therapy (ET, n:175)) after CDKi were calculated. Patients were evaluated in three groups as those who received CDKi in first-line (group A, n:202), second-line (group B, n: 153) and ≥ 3rd-line (group C, n: 254). PFS was compared according to the use of ET and CT. In addition, ET was compared as monotherapy versus everolimus-based combination therapy. Results The median duration of CDKi in the ET arms of Group A, B, and C was 17.0, 11.0, and 8.5 months in respectively; it was 9.0, 7.0, and 5.0 months in the CT arm. Median PFS after CDKi was 9.5 (5.0–14.0) months in the ET arm of group A, and 5.3 (3.9–6.8) months in the CT arm (p = 0.073). It was 6.7 (5.8–7.7) months in the ET arm of group B, and 5.7 (4.6–6.7) months in the CT arm (p = 0.311). It was 5.3 (2.5–8.0) months in the ET arm of group C and 4.0 (3.5–4.6) months in the CT arm (p = 0.434). Patients who received ET after CDKi were compared as those who received everolimus-based combination therapy versus those who received monotherapy ET: the median PFS in group A, B, and C was 11.0 vs. 5.9 (p = 0.047), 6.7 vs. 5.0 (p = 0.164), 6.7 vs. 3.9 (p = 0.763) months. Conclusion Physicians preferred CT rather than ET in patients with early progression under CDKi. It has been shown that subsequent ET after CDKi can be as effective as CT. It was also observed that better PFS could be achieved with the subsequent everolimus-based treatments after first-line CDKi compared to monotherapy ET.