The impact of the definition of biochemical recurrence following salvage radiotherapy on outcomes and prognostication in patients with recurrent prostate cancer after radical prostatectomy: a comparative study of three definitions

Can 68 Ga-PSMA positron emission tomography and multiparametric MRI guide treatment for biochemical recurrence after radical prostatectomy?

OBJECTIVE

To evaluate the role of multiparametric magnetic resonance imaging (mpMRI) and Gallium-68 (68 Ga)-prostate-specific membrane antigen (PSMA) positron emission tomography (PET)/computed tomography (CT) in guiding salvage therapy for patients with biochemical recurrence (BCR) post-radical prostatectomy.

PATIENTS AND METHODS

Patients were evaluated with paired mpMRI and 68 Ga-PSMA PET/CT scans for BCR (prostate-specific antigen [PSA] >0.2 ng/mL). Patient, tumour, PSA and imaging characteristics were analysed with descriptive statistics.

RESULTS

A total of 117 patients underwent paired scans to investigate BCR, of whom 53.0% (62/117) had detectable lesions on initial scans and 47.0% (55/117) did not. Of those without detectable lesions, 8/55 patients proceeded to immediate salvage radiotherapy (sRT) and 47/55 were observed. Of patients with negative imaging who were initially observed, 46.8% (22/47) did not reach threshold for repeat imaging, while 53.2% were rescanned due to rising PSA levels. Of these rescanned patients, 31.9% (15/47) were spared sRT due to proven distant disease, or due to absence of disease on repeat imaging. Of the original 117 patients, 53 (45.3%) were spared early sRT due to absence of disease on imaging or presence of distant disease, while those undergoing delayed sRT still maintained good PSA responses. Of note, patients with high-risk features who underwent sRT despite negative imaging demonstrated satisfactory PSA responses to sRT. Study limitations include the observational design and absence of cause-specific or overall survival data.

CONCLUSION

Our findings support the use of mpMRI and 68 Ga-PSMA PET/CT in guiding timing and necessity of salvage therapy tailored to detected lesions, with potential to reduce unnecessary sRT-related morbidity. Larger or randomized trials are warranted to validate this.

Efficacy and safety of salvage radiotherapy combined with endocrine therapy in patients with biochemical recurrence after radical prostatectomy: A systematic review and meta-analysis of randomized controlled trials

Background

The addition of endocrine therapy to salvage radiotherapy (SRT) is expected to further improve the prognosis of patients with biochemical recurrence of prostate cancer after radical prostatectomy (RP). The quantitative synthesis of clinical outcomes of SRT combined with endocrine therapy is limited. Whether salvage radiotherapy plus endocrine therapy remains inconclusive. We performed a systematic review and meta-analysis of existing randomized controlled trials to evaluate the efficacy and safety of salvage radiotherapy combined with endocrine therapy in patients with biochemical recurrence after radical prostatectomy.

Methods

A systematic search of PubMed, EMBASE, and the Cochrane library was performed for articles published between January 1, 2012 and October 10, 2022. Data were analyzed using Review Manager 5.4.1 (Cochrane Collaboration Software). Main outcome and measures included biochemical progression-free survival (bPFS), metastasis free survival (MFS), overall survival (OS), and Grade 3 or higher adverse events (3+AEs), including acute and late adverse events.

Results

In this systematic review and meta-analysis, 4 randomized controlled studies enrolling 2731 male (1374 of whom received SRT combined with endocrine therapy and 1357 controls) met the inclusion criteria. SRT combined with endocrine therapy were related to significantly improve bPFS (HR=0.52; 95% CI: 0.46 0.59; p<0.00001) and MFS (HR=0.75; 95% CI: 0.64 0.88; p<0.001). Compared with SRT alone, the combination therapy tended to be associated with prolong OS (HR=0.83; 95% CI: 0.69-1.01; p=0.06), but not statistically significant. At early follow-up, the risk of acute AEs was comparable in the two groups (RR=1.04; 95% CI: 0.22-4.85). However, the risk of late AEs was higher in the combination group at later follow-up (RR=1.33; 95% CI: 1.09-1.62).

Conclusions

This systematic review and meta-analysis found superior efficacy associated with adding endocrine therapy to SRT compared with SRT alone in patients with biochemical recurrence after RP. Additional endocrine therapy is safe and feasible for patients with biochemical recurrence after RP.

Systematic review registration

https://www.crd.york.ac.uk/prospero, identifier (CRD42022365432).

5-Aminolevulinic acid overcomes hypoxia-induced radiation resistance by enhancing mitochondrial reactive oxygen species production in prostate cancer cells

Background

The naturally occurring amino acid 5-aminolevulinic acid (5-ALA) is a precursor of protoporphyrin IX (PpIX) biosynthesised in the mitochondria. When accumulated PpIX is excited by light (wavelength of 625–635 nm), reactive oxygen species (ROS) are generated. Here, we investigated whether 5-ALA may increase the sensitisation of prostate cancer (PCA) cells to radiotherapy through the generation of ROS via its metabolite, PpIX.

Methods

Effect of 5-ALA on PC-3 and DU-145 PCA cell lines treated with ionising radiation (IR) was examined in vitro and in vivo with assessment by clonogenic assay, mitochondrial function and ROS production under normoxia or hypoxia condition.

Results

5-ALA enhanced intra-mitochondrial ROS production immediately after exposure to IR and decreased mitochondrial membrane potential via increase of intra-cellular PpIX. IR with 5-ALA induced mitochondrial dysfunction and increased ATP production, switching energy metabolism to the quiescence. Under hypoxic condition, ROS burst and mitochondrial dysfunction were induced by IR with 5-ALA resulting reducing cancer stemness and radiation resistance.

Conclusion

These results suggest that combined therapy with 5-ALA and radiation therapy is a novel strategy to improve the anti-cancer effects of radiation therapy for PCA.

Imaging and its Impact on Defining the Oligometastatic State

Successful treatment of oligometastatic disease (OMD) is facilitated through timely detection and localization of disease, both at the time of initial diagnosis (synchronous OMD) and following the initial therapy (metachronous OMD). Hence, imaging plays an indispensable role in management of patients with OMD. However, the challenges and complexities of OMD management are also reflected in the imaging of this entity. While innovations and advances in imaging technology have made a tremendous impact in disease detection and management, there remain substantial and unaddressed challenges for earlier and more accurate establishment of OMD state. This review will provide an overview of the available imaging modalities and their inherent strengths and weaknesses, with a focus on their role and potential in detection and evaluation of OMD in different organ systems. Furthermore, we will review the role of imaging in evaluation of OMD for malignancies of various primary organs, such as the lung, prostate, colon/rectum, breast, kidney, as well as neuroendocrine tumors and gynecologic malignancies. We aim to provide a practical overview about the utilization of imaging for clinicians who play a role in the care of those with, or at risk for OMD.

Adaptive sequential plan-on-plan optimization during prostate-specific antigen response guided radiotherapy of recurrent prostate cancer

Background

Treatment adaptation based on tumour biomarker response during radiotherapy of prostate cancer, could be used for both escalation and de-escalation of radiation doses and volumes. To execute an adaptation involving extension of treatment volumes during radiation can however be restricted by the doses already delivered. The aim of this work was to develop a treatment planning method that addresses this challenge.

Material and methods

A volumetric-modulated-arc-therapy (VMAT) planning method with sequential plan-on-plan optimization was developed for a prospective phase II trial including 100 patients on salvage radiotherapy (SRT) for prostate cancer recurrence. A treatment adaptation was performed after five weeks of SRT based on prostate-specific antigen response during this phase of the treatment. This involved extension of treatment volumes for non-responders (n = 64) to include pelvic lymph nodes and boost to ⁶⁸Gallium-Prostate-Specific-Membrane-Antigen-Positron-Emission-Tomography positive lesions. This method was evolved by introducing an EQD2 (equivalent dose in 2.0 Gy fractions) correction of the base plan for improved dose coverage.

Results

All dose-volume criteria for target coverage were met for the non-responders when based on physical dose. An EQD2 correction of the base plan for non-responders, implemented for the final 29 patients, led to a statistically significant improvement in dose coverage as compared to the 35 patients treated without EQD2 correction.

Conclusions

This is to our knowledge the only study presented on biomarker-guided sequential VMAT radiotherapy using a plan-on-plan technique in the pelvis. By using a biologically adapted technique an improved target coverage was achieved without compromising doses to organs at risk.

A valuable MRI examination method for prostate cancer screening

To investigate the value of the 1.5T magnetic resonance imaging (MRI) apparent diffusion coefficient (ADC) and the prostate imaging reporting and data system (PI-RADS) score in prostate cancer (PCa) screening.Forty PCa patients diagnosed by pathology from December 2014 to September 2018 were recruited as the PCa group; 60 patients with benign prostatic hyperplasia (BPH) were recruited as the benign group. Patients from both groups underwent 1.5T MRI scanning. The prostate ADC values, exponential apparent diffusion coefficient (eADC) values, and PI-RADS scores of patients from the 2 groups were compared. The different methods for PCa diagnosis were compared.The ADC values of patients in the PCa group were significantly lower than those in the benign group, whereas the eADC values of patients were significantly higher than those in the benign group, with statistically significant differences (P < .05). The differences in the PI-RADS scores of patients from the 2 groups were statistically significant (P < .05). Receiver Operating Characteristic (ROC) curve results showed that the ADC value combined with the PI-RADS score was superior to the ADC value or the PI-RADS score alone in sensitivity, specificity, and Youden index for PCa diagnosis. By comparing the area under the curve (AUC) of each ROC curve from the different diagnostic methods, the combination of ADC value and PI-RADS score showed the largest area.The ADC value from 1.5T MRI combined with the PI-RADS score could be used as the standard for PCa screening, which would effectively improve screening for PCa and be valuable for clinical applications.

The effects of PSA kinetics on the outcome of hypofractionated salvage radiotherapy for biochemical recurrence of prostate cancer after prostatectomy

The feasibility and efficacy of hypofractionated salvage radiotherapy (HS-RT) for prostate cancer (PC) with biochemical recurrence (BR) after prostatectomy, and the usefulness of prostate-specific antigen (PSA) kinetics as a predictor of BR, were evaluated in 38 patients who received HS-RT without androgen deprivation therapy between May 2009 and January 2017. Their median age, PSA level and PSA doubling time (PSA-DT) at the start of HS-RT were 68 (53-74) years, 0.28 (0.20-0.79) ng/ml and 7.7 (2.3-38.5) months, respectively. A total dose of 60 Gy in 20 fractions (three times a week) was three-dimensionally delivered to the prostate bed. After a median follow-up of 62 (30-100) months, 19 (50%) patients developed a second BR after HS-RT, but only 1 patient died before the last follow-up. The 5-year overall survival and BR-free survival rates were 97.1 and 47.4%, respectively. Late grade 2 gastrointestinal and genitourinary morbidities were observed in 0 and 5 (13%) patients, respectively. The PSA level as well as pathological T-stage and surgical margin status were regarded as significant predictive factors for a second BR by multivariate analysis. BR developed within 6 months after HS-RT in 11 (85%) of 13 patients with a PSA-DT < 10 months compared with 1 (17%) of 6 with a PSA-DT ≥ 10 months (median time to BR: 3 vs 14 months, P < 0.05). Despite the small number of patients, our HS-RT protocol seems feasible, and PSA kinetics may be useful for predicting the risk of BR and determining the appropriate follow-up schedule.

Prostate cancer trajectory-map: clinical decision support system for prognosis management of radical prostatectomy

Purpose

Prostate cancer has a low mortality rate and requires persistent treatment; however, treatment decisions are challenging. Because prostate cancer is complex, the outcomes warrant thorough follow-up evaluation for appropriate treatment. Electronic health records (EHRs) do not present intuitive information. This study aimed to develop a Clinical Decision Support System (CDSS) for prognosis management of radical prostatectomy.

Methods

We used data from 5,199 prostate cancer patients from three hospitals' EHRs in South Korea, comprising laboratory results, surgery, medication, and radiation therapy. We used open source R for data preprocessing and development of web-based visualization system. We also used R for automatic calculation functionalities of two factors to visualize the data, e.g., Prostate-Specific Antigen Doubling Time (PSADT), and four Biochemical Recurrence (BCR) definitions: American Society of Therapeutic Radiology and Oncology (ASTRO), Phoenix, consecutive PSA > 0.2 ng/mL, and PSA > 0.2 ng/mL.

Results

We developed the Prostate Cancer Trajectory Map (PCT-Map) as a CDSS for intuitive visualization of serial data of PSA, testosterone, surgery, medication, radiation therapy, BCR, and PSADT.

Conclusions

The PCT-Map comprises functionalities for BCR and PSADT and calculates and visualizes the newly added patient data automatically in a PCT-Map data format, thus optimizing the visualization of patient data and allowing clinicians to promptly access patient data to decide the appropriate treatment.

Ten-Year Outcomes of Moderately Hypofractionated Salvage Postprostatectomy Radiation Therapy and External Validation of a Contemporary Multivariable Nomogram for Biochemical Failure

PURPOSE

Although high-level evidence supports moderately hypofractionated radiation therapy for definitive prostate treatment, there is less evidence for its use in the postprostatectomy setting. We externally validated a contemporary nomogram predicting biochemical failure (BF) after salvage radiation therapy (SRT) and report long-term disease control outcomes for hypofractionated SRT to the prostate bed.

METHODS AND MATERIALS

A retrospective review was performed for 112 patients treated with hypofractionated SRT (52.5 Gy in 20 fractions using 3-dimensional conformal radiation therapy) for pT2-4R0-1N0/XM0 prostate adenocarcinoma, with postoperative prostate-specific antigen (PSA) greater than 0.1 ng/mL or rising. Freedom from BF (FFBF), distant metastasis, cancer-specific mortality, and overall survival were analyzed from commencement of radiation therapy. Cox regression was performed on FFBF to account for covariates. BF was defined as a PSA ≥0.4 ng/mL and rising after SRT. Early SRT was defined as SRT commencing at a pre-SRT PSA of ≤0.2 ng/mL.

RESULTS

Median follow-up was 10.0 years (interquartile range, 9.3-10.7 years), median pre-SRT PSA was 0.4 ng/mL, and androgen deprivation therapy was used in 14% of patients. The 5/10-year FFBF, distant metastasis, cancer-specific mortality, and overall survival were 68%/51%, 7%/16%, 5%/11%, and 90%/75%, respectively. FFBF for early SRT compared with late SRT was 81% versus 66% at 5 years and 68% versus 49% at 10 years. On multivariable analysis, pre-SRT PSA, International Society of Urologic Pathology grade group, seminal vesicle invasion, and androgen deprivation therapy use were associated with FFBF. The nomogram c-index was 0.67, and it overestimated FFBF by 10% and 15% at 5 and 10 years, respectively, with confidence intervals overlapping the line of unity.

CONCLUSIONS

Hypofractionated SRT provides long-term disease control outcomes comparable to conventionally fractionated radiation therapy. Early SRT provides improved disease control, with two-thirds of patients with pre-SRT PSA of ≤0.2 ng/mL free of BF at 10 years. We performed the first external validation of the Tendulkar salvage nomogram, which showed a robust model performance.

Prognostic significance of lymphovascular invasion in patients with prostate cancer treated with postoperative radiotherapy

Purpose

To determine prognostic significance of lymphovascular invasion (LVI) in prostate cancer patients who underwent adjuvant or salvage postoperative radiotherapy (PORT) after radical prostatectomy (RP)

Materials and Methods

A total of 168 patients with prostate cancer received PORT after RP, with a follow-up of ≥12 months. Biochemical failure after PORT was defined as prostate-specific antigen (PSA) ≥0.2 ng/mL after PORT or initiation of androgen deprivation therapy (ADT) for increasing PSA levels regardless of the value. We analyzed the clinical outcomes including survivals, failure patterns, and prognostic factors affecting the outcomes.

Results

In total, 120 patients (71.4%) received salvage PORT after PSA levels were >0.2 ng/mL or owing to clinical failure. The 5-year biochemical failure-free survival (BCFFS), clinical failure-free survival (CFFS), distant metastasis-free survival (DMFS), overall survival, and cause-specific survival rates were 78.3%, 94.3%, 95.0%, 95.8%, and 97.3%, respectively, during a follow-up range of 12–157 months (median: 64 months) after PORT. On multivariate analysis, PSA level of ≤1.0 ng/mL at the time of receiving PORT predicted favorable BCFFS, CFFS, and DMFS. LVI predicted worse CFFS (p = 0.004) and DMFS (p = 0.015). Concurrent and/or adjuvant ADT resulted in favorable prognosis for BCFFS (p < 0.001) and CFFS (p = 0.017).

Conclusion

For patients with adverse pathologic findings, PORT should be initiated as early as possible after continence recovery after RP. Even after administering PORT, LVI was an unfavorable predictive factor, and further intensive adjuvant therapy should be considered for these patients.

Low-dose-rate brachytherapy for prostate cancer: A 15-year experience in Japan

The history of prostate brachytherapy has passed one century. In 1983, modern low-dose-rate prostate brachytherapy using a transrectal ultrasound-guided procedure was introduced. In the early 1990s, low-dose-rate brachytherapy was introduced and rapidly spread across the USA due to its excellent oncological control, cost-effectiveness and technically easy procedure. Since low-dose-rate brachytherapy was introduced in Japan (2003), over 15 years have passed. More than 43 000 patients have undergone low-dose-rate brachytherapy. Japanese urologists and radiation oncologists are on course with leading brachytherapists in the USA. A nationwide prospective cohort study, J-POPS, was initiated in 2005. The J-POPS group also provides educational programs including an annual novel training course in low-dose-rate brachytherapy to familiarize urologists, radiation oncologists and pathologists with the procedure. Important information on Japanese patients has accumulated, especially by the J-POPS study group. The Japanese investigators reported excellent oncological outcomes of low-dose-rate brachytherapy, showing equivalent or superior efficacy to surgery in low- to intermediate-risk patients, and superior efficacy in high-risk patients using the surgery biochemical recurrence definition (prostate-specific antigen cut-off value of 0.2 ng/mL). Two randomized controlled studies (SHIP study: intermediate risk, and TRIP study: high risk) carried out by the J-POPS group are ongoing, and an additional follow-up study (J-POPS 2 study) has been started to evaluate survival outcomes over longer follow-up periods. Low-dose-rate brachytherapy is expected to provide a survival benefit, which must be confirmed by further studies with longer follow-up periods in the future.