Contrasting Circulating Tumor Cells and Free Circulating DNA Responses in Men Treated for Prostate Cancer after Primary Versus Salvage Radiotherapy

Author Info

Adrian L. Breto Adrian Ishkanian Alan Dal Pra Alan Pollack Anthony Williams Jorge Torres-Munoz Kavitha Ramachandran Matthew C. Abramowitz Mausam Patel Merce Jorda Radka Stoyanova Rakesh Singal Ram Datar Richard Cote Sakhi Abraham Teresa M. Giret Thirupandiyur S. Udayakumar Youssef H. Zeidan Zheng Ao

Corresponding Author

Radka Stoyanova
Department of Radiation Oncology, University of Miami Miller School of Medicine, Miami, Florida, USA

A B S T R A C T

Purpose: To investigate the relationships between circulating tumor cells (CTCs), free circulating DNA (fcDNA) and biochemical response in prostate cancer patients treated primarily versus salvage radiotherapy (RT). Methods and Materials: Blood was collected prospectively from patients, enrolled in two institutional Phase II trials for primary and salvage RT. Three blood samples were collected at: (i) prior to treatment [RT or androgen deprivation therapy (ADT)], (ii) last week of RT, and (iii) three months post-RT. CTCs were quantified in 31 samples from 12 primary patients and 30 samples from 12 salvage patients; fcDNA were analyzed in 11 primary (28 samples) and 5 (9 samples) salvage patients. CTCs were visualized by immunofluorescence after microfilter capture and fcDNA was quantified using real-time Polymerase chain reaction (PCR). CTCs and fcDNA were correlated with early biochemical response by subdividing patients into early favorable and unfavorable response at 3 months after RT. Results: For those treated primarily, there was a direct correlation with CTC counts and prostate specific antigen (PSA) pre-RT that changed to a reciprocal relationship 3 months post-RT. CTCs increased significantly (p=0.03) at 3 months after primary RT in the biochemical favorable patients, while no significant association was observed for fcDNA. Correspondingly, post-RT fcDNA levels were inversely related to CTC counts. In salvage patients, the number of CTCs was related to pre-RT PSA, but it was not correlated to RT response. In post-RT series, a significant direct correlation was observed between CTCs and PSA. Conclusion: Our preliminary studies suggest that RT affects CTC counts, which are thus associated with prostate cancer biochemical response. A larger cohort with longer follow-up will be needed to establish the association with more recognized treatment endpoints.

Article Info

Article Type

Research Article

Publication history

Received: Tue 03, Dec 2019
Accepted: Mon 23, Dec 2019
Published: Fri 10, Jan 2020

Copyright

© 2023 Radka Stoyanova. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Hosting by Science Repository.
DOI: 10.31487/j.COR.2019.06.13