Analysis of prognostic factors in localized high-risk prostate cancer patients treated with HDR brachytherapy, hypofractionated 3D-CRT and neoadjuvant/adjuvant androgen deprivation therapy (trimodality therapy)

Patients with PSA below 0.2 ng/mL at 8 years post high-dose-rate brachytherapy have an extremely low risk of subsequent recurrence

OBJECTIVES

We have analyzed the long-term follow-up data of patients with prostate cancer (PCa) who underwent high-dose-rate brachytherapy (HDR-BT) and external beam radiotherapy (EBRT) combined with long-term androgen deprivation therapy (ADT). The objective was to determine the optimal time for cessation of PSA monitoring after HDR-BT.

METHODS

We included 309 patients with clinical stage T1c-T4 N0-1 M0 PCa who received HDR-BT and EBRT combined with long-term ADT between 2005 and 2018. We stratified the patients based on their prostate-specific antigen (PSA) levels and identified the factors associated with biochemical recurrence (BCR) and clinical progression (CP).

RESULTS

The median follow-up duration was 98 months (range: 31-207 months). Among the 306 patients, 76 developed BCR and 47 developed CP subsequently. We found that the PSA levels at 3, 5, and 8 years significantly correlated with the oncological outcomes of brachytherapy. No patient with a PSA level ≤ 0.2 ng/mL at 8 years later developed BCR or CP.

CONCLUSION

Our long-term data suggest that in the presence of a PSA level ≤ 0.2 ng/mL at 8 years later, PSA monitoring may be safely discontinued due to the extremely low risk of subsequent oncological events. The data presented in this study will assist clinicians in determining the optimal management strategy for patients with PCa following HDR-BT and EBRT combined with long-term ADT.

Trimodal therapy with high-dose-rate brachytherapy and hypofractionated external beam radiation combined with long-term androgen deprivation for unfavorable-risk prostate cancer

Purpose

To assess the outcomes of high-dose-rate (HDR) brachytherapy and hypofractionated external beam radiation therapy (EBRT) combined with long-term androgen deprivation therapy (ADT) in very-high-risk (VHR) versus high-risk (HR) prostate cancer (PCa), as defined in the National Comprehensive Cancer Network (NCCN) criteria.

Methods

Data from 338 consecutive HR or VHR PCa patients who had undergone this tri-modal therapy between 2005 and 2018 were retrospectively analyzed. Biochemical recurrence (BCR)-free, progression-free, overall, and cancer-specific survival (BCRFS/PFS/OS/CSS) rates were analyzed using the Kaplan–Meier method and Wilcoxon test. Cox regression models were used to evaluate candidate prognostic factors for survival. C‑indexes were used to assess model discrimination.

Results

Within a median follow-up of 84 months, 68 patients experienced BCR, 58 had disease progression including only 3 with local progression, 27 died of any cause, and 2 died from PCa. The 5‑year BCRFS, PFS, OS, and CSS rates were 82.2% (HR 86.5%; VHR 70.0%), 90.0% (HR 94.3%; VHR 77.6%), 95.7% (HR, 97.1%; VHR, 91.8%), and 99.6% (HR, 100%; VHR, 98.0%), respectively. In multivariable analyses that adjusted for standard clinicopathologic features, the risk subclassification was associated both PFS and OS (p = 0.0003 and 0.001, respectively). Adding the risk subclassification improved the accuracy of models in predicting BCRFS, PFS, and OS.

Conclusion

While the outcome of this trimodal approach appears favorable, VHR PCa patients had significantly worse oncological outcomes than those with HR PCa. The NCCN risk subclassification should be integrated into prognostic tools to guide risk stratification, treatment, and follow-up for unfavorable PCa patients receiving this trimodal therapy.

Supplementary Information

The online version of this article (10.1007/s00066-021-01784-3) contains supplementary material, which is available to authorized users.

Cancer-specific mortality of high-risk prostate cancer after carbon-ion radiotherapy plus long-term androgen deprivation therapy

The treatment outcomes of patients with high‐risk localized prostate cancer (PC) after carbon‐ion radiotherapy (CIRT) combined with long‐term androgen deprivation therapy (LTADT) were analyzed, and compared with those of other treatment modalities, focusing on PC‐specific mortality (PCSM). A total of 1247 patients were enrolled in three phase II clinical trials of fixed‐dose CIRT between 2000 and 2013. Excluding patients with T4 disease, 608 patients with high‐risk or very‐high‐risk PC, according to the National Comprehensive Cancer Network classification system, who received CIRT with LTADT were evaluated. The median follow‐up time was 88.4 months, and the 5‐/10‐year PCSM rates were 1.5%/4.3%, respectively. T3b disease, Gleason score of 9–10 and percentage of positive biopsy cores >75% were associated with significantly higher PCSM on univariate and multivariate analyses. The 10‐year PCSM rates of patients having all three (n = 16), two (n = 74) or one of these risk factors (n = 217) were 27.1, 11.6 and 5.7%, respectively. Of the 301 patients with none of these factors, only 1 PCSM occurred over the 10‐year follow‐up (10‐year PCSM rate, 0.3%), and significant differences were observed among the four stratified groups (P <0.001). CIRT combined with LTADT yielded relatively favorable treatment outcomes in patients with high‐risk PC and very favorable results in patients without any of the three abovementioned factors for PCSM. Because a significant difference in PCSM among the high‐risk PC patient groups was observed, new categorization and treatment intensity adjustment may be required for high‐risk PC patients treated with CIRT.

Perioperative Search for Circulating Tumor Cells in Patients Undergoing Prostate Brachytherapy for Clinically Nonmetastatic Prostate Cancer

Despite the absence of local prostate cancer recurrence, some patients develop distant metastases after prostate brachytherapy. We evaluate whether prostate brachytherapy procedures have a potential risk for hematogenous spillage of prostate cancer cells. Fifty-nine patients who were undergoing high-dose-rate (HDR) or low-dose-rate (LDR) brachytherapy participated in this prospective study. Thirty patients with high-risk or locally advanced cancer were treated with HDR brachytherapy after neoadjuvant androgen deprivation therapy (ADT). Twenty-nine patients with clinically localized cancer were treated with LDR brachytherapy without neoadjuvant ADT. Samples of peripheral blood were drawn in the operating room before insertion of needles (preoperative) and again immediately after the surgical manipulation (intraoperative). Blood samples of 7.5 mL were analyzed for circulating tumor cells (CTCs) using the CellSearch System. While no preoperative samples showed CTCs (0%), they were detected in intraoperative samples in 7 of the 59 patients (11.8%; preoperative vs. intraoperative, p = 0.012). Positive CTC status did not correlate with perioperative variables, including prostate-specific antigen (PSA) at diagnosis, use of neoadjuvant ADT, type of brachytherapy, Gleason score, and biopsy positive core rate. We detected CTCs from samples immediately after the surgical manipulation. Further study is needed to evaluate whether those CTCs actually can survive and proliferate at distant sites.

Two-fraction high-dose-rate brachytherapy within a single day combined with external beam radiotherapy for prostate cancer: single institution experience and outcomes

We investigated the outcomes of treatment for patients with localized prostate cancer (PCa) treated with 3D conformal radiation therapy (3D-CRT) followed by two-fraction high-dose-rate brachytherapy within a single day (2-fr.-HDR-BT/day) at a single institution. A total of 156 consecutive Asian males (median age, 67 years) were enrolled. To compare our findings with those of other studies, we analyzed our results using the D'Amico classification, assigning the patients to low- ( N =: 5; 3.2%), intermediate- ( N =: 36; 23.1%) and high-risk ( N =: 115; 73.7%) groups (Stage T3 PCa patients were classified as high-risk). One patient in the D'Amico low-risk group (20%), 13 intermediate-risk patients (36.1%) and 99 high-risk patients (86.1%) underwent androgen deprivation therapy. We administered a prescription dose of 39 Gy in 13 fractions of 3D-CRT combined with 18 Gy of HDR-BT in two 9-Gy fractions delivered within a single day. We did not distinguish between risk groups in determining the prescription dose. The median follow-up period was 38 months. Of the 156 patients, one died from primary disease and five died from other diseases. The 3-year overall survival (OS) rates were 100%, 100% and 93.7%, and the 3-year 'biochemical no evidence of disease (bNED)' rates were 100%, 100% and 96.9% for the D'Amico low-, intermediate- and high-risk groups, respectively. No patient developed ≥ Grade 3 early toxicity. The Grade 3 late genitourinary toxicity rate was 2.6%, and no ≥ Grade 3 late gastrointestinal toxicity occurred. The efficacy and safety of this study were satisfactory, and longer-term follow-up is necessary.