TY - JOUR
T1 - Early and multiple PSA bounces can occur following high-dose prostate stereotactic body radiation therapy
T2 - Subset analysis of a phase 1/2 trial
AU - Kim, D. Nathan
AU - Straka, Christopher
AU - Cho, L. Chinsoo
AU - Lotan, Yair
AU - Yan, Jingsheng
AU - Kavanagh, Brian
AU - Raben, David
AU - Cooley, Susan
AU - Brindle, Jeffrey
AU - Xie, Xian Jin
AU - Pistenmaa, David
AU - Timmerman, Robert
PY - 2017/1/1
Y1 - 2017/1/1
N2 - Purpose We hypothesized that high-dose stereotactic body radiation therapy (SBRT) would lead to faster time to nadir and lower nadir values compared with conventional radiation therapy experiences. We now report prostate-specific antigen (PSA) kinetics following high-dose SBRT in patients treated with radiation alone. Methods and materials Ninety-one patients were enrolled on the phase 1/2 dose escalation study of SBRT for localized prostate cancer. All patients with at least 36 months of follow-up and without hormone therapy were included in this analysis (n = 47). Treatment response parameters evaluated include time to nadir, nadir value, occurrence of PSA bounces (rise of ≥0.2 ng/mL followed by a subsequent fall), magnitude of bounces, duration of bounces, and correlation of bounces with clinical outcomes. Results Median follow-up was 42 months (range, 36-78 months). Treatment dose levels were 45 Gy (n = 10), 47.5 Gy (n = 8), and 50 Gy (n = 29) in 5 fractions. Biochemical control rate was 98%. Median PSA at follow-up was 0.10 ± 0.20 ng/mL. Median time to nadir was 36 ± 11 months. A total of 24/47 (51.1%) patients had ≥1 PSA bounce. Median magnitude of PSA rise during bounce was 0.50 ± 1.2 ng/mL. Median time to first bounce was 9 ± 7.0 months. Median bounce duration was 3 ± 2.3 months for the first bounce and 6 ± 5.2 months for subsequent bounces. Prostate volumes <30 mL were associated with a decreased likelihood of bounce (P =.0202), and increasing prostate volume correlated with increasingly likelihood of having ≥2 bounces (P =.027). Patients reaching PSA nadir of ≤0.1 ng/mL were less likely to experience any bounce (P =.0044). Conclusions Compared with other SBRT experiences, our study demonstrated a higher PSA bounce rate, a similar or shorter median time to bounce, and a very low nadir. Prostate volume appears correlated with bounce.
AB - Purpose We hypothesized that high-dose stereotactic body radiation therapy (SBRT) would lead to faster time to nadir and lower nadir values compared with conventional radiation therapy experiences. We now report prostate-specific antigen (PSA) kinetics following high-dose SBRT in patients treated with radiation alone. Methods and materials Ninety-one patients were enrolled on the phase 1/2 dose escalation study of SBRT for localized prostate cancer. All patients with at least 36 months of follow-up and without hormone therapy were included in this analysis (n = 47). Treatment response parameters evaluated include time to nadir, nadir value, occurrence of PSA bounces (rise of ≥0.2 ng/mL followed by a subsequent fall), magnitude of bounces, duration of bounces, and correlation of bounces with clinical outcomes. Results Median follow-up was 42 months (range, 36-78 months). Treatment dose levels were 45 Gy (n = 10), 47.5 Gy (n = 8), and 50 Gy (n = 29) in 5 fractions. Biochemical control rate was 98%. Median PSA at follow-up was 0.10 ± 0.20 ng/mL. Median time to nadir was 36 ± 11 months. A total of 24/47 (51.1%) patients had ≥1 PSA bounce. Median magnitude of PSA rise during bounce was 0.50 ± 1.2 ng/mL. Median time to first bounce was 9 ± 7.0 months. Median bounce duration was 3 ± 2.3 months for the first bounce and 6 ± 5.2 months for subsequent bounces. Prostate volumes <30 mL were associated with a decreased likelihood of bounce (P =.0202), and increasing prostate volume correlated with increasingly likelihood of having ≥2 bounces (P =.027). Patients reaching PSA nadir of ≤0.1 ng/mL were less likely to experience any bounce (P =.0044). Conclusions Compared with other SBRT experiences, our study demonstrated a higher PSA bounce rate, a similar or shorter median time to bounce, and a very low nadir. Prostate volume appears correlated with bounce.
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U2 - 10.1016/j.prro.2016.06.010
DO - 10.1016/j.prro.2016.06.010
M3 - Article
C2 - 27637137
AN - SCOPUS:84994876942
SN - 1879-8500
VL - 7
SP - e43-e49
JO - Practical Radiation Oncology
JF - Practical Radiation Oncology
IS - 1
ER -