Prostate-specific antigen nadir after high-dose-rate brachytherapy predicts long-term survival outcomes in high-risk prostate cancer

Abstract

PurposeTo evaluate the prognostic value of prostate-specific antigen nadir (nPSA) after high-dose-rate (HDR) brachytherapy in clinically non-metastatic high-risk prostate cancer patients.Material and methodsData from 216 patients with high-risk or locally advanced prostate cancer who underwent HDR brachytherapy and external beam radiation therapy with long-term androgen deprivation therapy (ADT) between 2003 and 2008 were analyzed. The median prostate-specific antigen (PSA) level at diagnosis was 24 ng/ml (range: 3-338 ng/ml). The clinical stage was T1c-2a in 55 cases (26%), T2b-2c in 48 (22%), T3a in 75 (35%), and T3b-4 in 38 (17%). The mean dose to 90% of the planning target volume was 6.3 Gy/fraction of HDR brachytherapy. After 5 fractions, external beam radiation therapy with 10 fractions of 3 Gy was administered. All patients initially underwent neoadjuvant ADT for at least 6 months, and adjuvant ADT was continued for 36 months. The median follow-up was 7 years from the start of radiotherapy.ResultsThe 7-year PSA relapse-free rate among patients with a post-radiotherapy nPSA level of ≤ 0.02 ng/ml was 94%, compared with 23% for patients with higher nPSA values (HR = 28.57; 95% CI: 12.04-66.66; p < 0.001). Multivariate analysis revealed that the nPSA value after radiotherapy was a significant independent predictor of biochemical failure, whereas pretreatment predictive values for worse biochemical control including higher level of initial PSA, Gleason score ≥ 8, positive biopsy core rate ≥ 67%, and T3b-T4, failed to reach independent predictor status. The 7-year cancer-specific survival rate among patients with a post-radiotherapy nPSA level of ≤ 0.02 ng/ml was 99%, compared with 82% for patients with higher nPSA values (HR = 32.25; 95% CI: 3.401-333.3; p = 0.002).ConclusionsA post-radiotherapy nPSA value of ≤ 0.02 ng/ml was associated with better long-term biochemical tumor control even if patients had pretreatment predictive values for worse control.

Long‐term outcomes of combining prostate brachytherapy and metastasis‐directed radiotherapy in newly diagnosed oligometastatic prostate cancer: A retrospective cohort study

“…Previous studies suggested that the PSA nadir after radiotherapy is well correlated with prognostic values . In the present study, the proportion of patients who reached a PSA level of less than 0.02 ng/mL after radiotherapy was significantly higher in patients with MDRT than those without MDRT.…”

“…Previous studies suggested that the PSA nadir after radiotherapy is well correlated with prognostic values. 15,16 In the present study, the proportion of patients who reached a PSA level of less than 0.02 ng/mL after radiotherapy was significantly higher in patients with MDRT than those without MDRT. These results may reflect that ablative radiotherapy to all metastatic sites, in addition to definitive prostate radiotherapy, could achieve lower PSA nadir values and consequently improve CRPC-free survival in newly diagnosed oligometastatic prostate cancer patients.…”

Impact of five‐tiered Gleason grade groups on prognostic prediction in clinical stage T3 prostate cancer undergoing high‐dose‐rate brachytherapy

“…Our treatment protocol for HDR‐BT, EBRT, and hormone therapy in high‐risk prostate cancer was previously reported and is shown in Figure . All patients initially underwent at least 6 months of neoadjuvant ADT, and adjuvant ADT was continued for 36 months after completion of radiotherapy.…”

Long-term oncologic outcomes of radiotherapy combined with maximal androgen blockade for localized, high-risk prostate cancer

“…Although no further long-term survival data were reported for these two radiation modalities in localized, high-risk patients, LDR-BT is generally administered as a monotherapy in early diagnosed cases, while HDR-BT is usually applied along with EBRT in cases of prostate cancer in unspecified stages [ 28 ]. In addition, some clinical trials found that a PSA nadir of less than 0.02 ng/mL within 12 months of radiotherapy is associated with significantly improved biochemical tumor control and cause-specific survival in cases of locally advanced and non-metastatic high-risk prostate cancer co-administered HDR-BT, EBRT, and long-term ADT [ 29 ]. Thorsten et al reported a discrepant conclusion regarding the predictive value of PSA for the biochemical control rate in 79 cases with high-risk PCa administered HDR-BT following EBRT, with an average follow-up of 21 months; the authors described PSA as a negative predictive biomarker for local recurrence during follow-up, indicating that prolonged follow-up is required for reassessing long-term outcomes [ 30 ].…”