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ASCO 2023: Does PSA Nadir After Radiotherapy Impact Outcomes in Localized Prostate Cancer?

By: Julia Fiederlein Cipriano
Posted: Thursday, June 22, 2023

Praful Ravi, MB, BChir, MRCP, of the Dana-Farber Cancer Institute, Boston, and colleagues conducted an analysis to determine the prognostic impact of having a prostate-specific antigen (PSA) nadir of at least 0.1 ng/mL within 6 months of completing radiotherapy for localized prostate cancer. Their findings, which were presented during the 2023 American Society for Clinical Oncology (ASCO) Annual Meeting (Abstract 5002), revealed the “strong” predictivity of these values for prostate cancer–specific, metastasis-free, and overall survival in those who also underwent androgen-deprivation therapy (ADT).

“This could be used as an early signal-seeking endpoint in trials evaluating novel systemic therapies with radiotherapy plus ADT and to help identify patients for therapy (de)escalation trials,” the investigators commented.

Using data from 16 trials in the ICECAP repository, the investigators identified patients who received radiotherapy alone (n = 2,629) or in combination with short-term (3–6 months; n = 6,033) or long-term (18–36 months; n = 1,753) ADT. A total of 98%, 84%, and 77% of patients, respectively, achieved a PSA nadir of at least 0.1 ng/mL within 6 months of completing radiotherapy. After adjustment, in both those who underwent short-term and long-term ADT, such levels seemed to be associated with poorer prostate cancer–specific, metastasis-free, and overall survival; weaker associations were reported in patients who received radiotherapy alone.

Compared with patients who achieved a PSA nadir of at least 0.1 ng/mL, those with a lower level exhibited higher 5-year metastasis-free survival rates both with radiotherapy alone (91% vs. 79%) and ADT (short-term: 83% vs. 76%; long-term: 87% vs. 74%); this appeared to hold true for 10-year prostate cancer–specific survival (radiotherapy alone: 92% vs. 84%; short-term ADT: 91% vs. 83%; long-term ADT: 88% vs. 83%). The 10-year overall survival rates were 52% and 58% with radiotherapy alone, 62% and 56% with short-term ADT, and 63% and 50% with long-term ADT, respectively.

Disclosure: Dr. Ravi reported no conflicts of interest. For full disclosures of the other study authors, visit

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