Results showed that progression free survival (PFS) was significantly improved in CTC- patients, while no significant impact of AR, PSA and PSMA expression was detected both in terms of PSA-drop or PFS. Interestingly, patients included in this trial were the object of a previous publication showing that CTCs detection was correlated to shorter time to castrate resistance occurrence, suggesting that CTCs may have a prognostic role throughout the clinical history of metastatic disease since hormone sensitive to castrate resistance status.1 Furthermore, a significant percentage of patients included in PRIMERA trial were at the same time included in another trial from our institution, the ARTO trial (NCT03449719). ARTO trial is a phase II trial including patients affected by oligometastatic mCRPC, randomized to receive standard of care (GnRH agonist or antagonist plus abiraterone acetate 1000 mg and oral prednisone 10 mg daily) with or without Stereotactic Body Radiotherapy on all metastatic sites of disease.
A previous report of the ARTO trial was presented at ASCO Genitourinary cancer symposium in 2021, showing that CTCs detection in this selected cohort of oligo-mCRPC patients was lower compared to unselected population of PRIMERA trial.2 (NCT04188275) Thus, CTCs may be useful to identify a cohort of good prognosis patients affected by oligometastatic disease, potentially amenable to local treatment intensification with metastasis directed therapy associated with standard I line treatment.
Currently, the ARTO trial completed the enrollment, and results are awaited for 2023. Hopefully, insights about the role of CTCs analysis within an homogeneous population of mCRPC patients with oligometastatic disease will help to improve selection criteria in this scenario. Moreover, a panel of selected micro RNA involved in CRPC development and androgen-independent growth was assessed in patients enrolled in PRIMERA and ARTO trials, and further information from these analyses are awaited to refine treatment tailoring of mCRPC patients.
Written by: Giulio Francolini, Mauro Loi, Lucia Pia Ciccone, Beatrice Detti, Vanessa Di Cataldo, Pamela Pinzani, Francesca Salvianti, Giulia Salvatore, Mariangela Sottili, Costanza Santini, Giulio Frosini, Luca Visani, Luca Burchini, Chiara Mattioli, Andrea Gaetano Allegra, Marianna Valzano, Cecilia Cerbai, Michele Aquilano, Viola Salvestrini, Isacco Desideri, Monica Mangoni, Icro Meattini, Lorenzo Livi
Radiation Oncology Unit, Azienda Ospedaliero-Universitaria Careggi, Viale Morgagni 85, Florence, Italy., Radiation Oncology Unit, Azienda Ospedaliero-Universitaria Careggi, Viale Morgagni 85, Florence, Italy., Department of Biomedical, Experimental, and Clinical Sciences "Mario Serio", University of Florence, Florence, Italy.
References:
- Francolini G, Loi M, Salvestrini V, Mangoni M, Detti B, Di Cataldo V, Aquilano M, Pinzani P, Salvianti F, Desideri I, Mariotti M, Garlatti P, Stocchi G, Ciccone LP, Lucidi S, Salvatore G, Sottili M, Meattini I, Livi L. Prospective assessment of AR splice variant and PSMA detection on circulating tumor cells of mCRPC patients: preliminary analysis of patients enrolled in PRIMERA trial (NCT04188275). Clin Exp Metastasis. 2021 Oct;38(5):451-458.
- Francolini G, Garlatti P, Loi M, Detti B, Aquilano M, Allegra A, Guerrieri B, Salvestrini V, Pinzani P, Bellini C, Salvianti F, Stocchi G, Ciccone L, Salvatore G, Sottili M, Di Cataldo V, Desideri I, Mangoni M, Meattini I, Livi L. ARTO trial (NCT03449719), a randomized phase II trial enrolling oligometastatic castration-resistant prostate cancer patients treated with frst-line abiraterone acetate with or without stereotactic body radiation therapy: preliminary results comprehensive of biochemical outcomes and circulating tumor cells analysis. J Clin Oncol. 2021;39(6_suppl):118–118.