Outcome after PSMA-PET/CT-based salvage radiotherapy for nodal recurrence after radical prostatectomy

Dose Recommendations for Prostrate-specific Membrane Antigen Positron Emission Tomography (PSMA PET) Guided Boost Irradiation to Lymphatic Tissue in Prostate Adenocarcinoma

AIMS

Prostrate-specific membrane antigen positron emission tomography (PSMA-PET) imaging has led to an increase in identifiable small volume metastatic disease in prostate adenocarcinoma. There is clinical equipoise in how to treat these using radiotherapy regimens. The aim of this study is to determine an adequate dosing regimen for small volume lymphatic metastases in prostate adenocarcinoma.

MATERIALS AND METHODS

The authors first estimated the cell count of small volume metastases in prostate adenocarcinoma and then used a Poisson distribution-based estimation of the tumour control probability distribution, the required doses for 95% and 99% probabilities of tumour sterilisation were calculated using the linear quadratic formula.

RESULTS

Lymph node metastases of 3, 5, and 10 mm diameter were estimated to harbour 1.4, 6.5, and 52.3 million clonogens, respectively. When attempting for a 95% tumour control probability, estimated BEDs of 116.5, 127.0, and 141.1Gy were required. This translated to doses of 26.0, 27.3, and 29.0Gy in 5 fraction regimens. When attempting for a 99% tumour control probability, estimated biological effective doses (BEDs) of 127.6, 138.1, and 152.2 Gy were required. This translated to doses of 27.4, 28.6, and 30.2 Gy in 5 fraction regimens.

CONCLUSION

In prostate cancers with small-volume metastatic disease, doses can be adjusted according to tumour size without likely to compromise tumour control. This would have positive implications on radiotherapy planning and possibly lead to decreased risks of toxicity in scenarios where planning difficulty is encountered. Clinical evaluation of efficacy and safety for these dose regimens is warranted.

A machine learning model incorporating 18F-prostate-specific membrane antigen-1007 positron emission tomography/computed tomography and multiparametric magnetic resonance imaging for predicting prostate-specific antigen persistence in patients with prostate cancer after radical prostatectomy

Background

Although 18F-prostate-specific membrane antigen-1007 (18F-PSMA-1007) positron emission tomography/computed tomography (PET/CT) and multiparametric magnetic resonance imaging (mpMRI) are good predictors of prostate cancer (PCa) prognosis, their combined ability to predict prostate-specific antigen (PSA) persistence has not been thoroughly evaluated. In this study, we assessed whether clinical, mpMRI, and 18F-PSMA-1007 PET/CT characteristics could predict PSA persistence in patients with PCa treated with radical prostatectomy (RP).

Methods

This retrospective study involved consecutive patients diagnosed with PCa who underwent both preoperative mpMRI and PSMA PET/CT scans between April 2019 and June 2022. Scatter plots and heat maps were employed to determine the correlation of mpMRI and PSMA PET/CT features with preoperative PSA. Univariate logistic regression analyses were used assess the correlation between age, maximum Prostate Imaging-Reporting and Data System (PI-RADS) score, prostate-specific antigen density (PSAD), extracapsular extension (EPE), seminal vesicle invasion (SVI), total lesion PSMA (PSMA-TL), and PSA persistence. Multivariate logistic regression analyses were used to develop a predictive model for PSA persistence, while decision tree analysis was used to classify patients into different risk groups for easy interpretation and visualization. We divided the patient cohort into training and validation sets in an 8:2 ratio. To ensure the reliability of the model, we performed five-fold cross-validation of the validation results.

Results

Ultimately, this study included 190 patients with PCa. The median age of the patients was 69 years [interquartile range (IQR) 64-73 years]. Among the patients, 35 (18%) experienced PSA persistence following RP. Additionally, SVI was identified in 31 (16%) patients. The median values for SUVmax and PSMA-TL were 11.83 (IQR 7.44-20.89) and 41.92 (IQR 21.25-113.83), respectively. Spearman correlation analysis indicated that the preoperative PSA levels in patients with PCa were slightly correlated with the maximum standardized uptake value (SUVmax) (r=0.41; P<0.001), significantly correlated with PSMA-TL (r=0.58, P<0.001), and strongly correlated with PSAD (r=0.865, P<0.001). Multivariate logistic regression analysis showed that the independent predictors of PSA persistence were SVI on mpMRI [area under the curve (AUC)=0.63; 95% confidence interval (CI): 0.516-0.739] and PSMA-TL (AUC =0.80; 95% CI: 0.723-0.877) on PSMA PET/CT (all P values <0.05). Patients with SVI and PSMA-TL >63.38 cm3 were more likely to have PSA persistence. Decision tree analysis stratified patients into low-risk (5%), intermediate-risk (36%), and high-risk (48%) categories for PSA persistence. The model exhibited good discriminatory capability in internal validation (AUC 0.93, 95% CI: 0.850-0.930).

Conclusions

18F-PSMA-1007 PET/CT and mpMRI parameters were proved effective in predicting PSA persistence in postoperative patients with PCa. The decision tree classification model could help clinicians to assess patients with individualized risk stratification. Patients with PSMA-TL levels below the threshold are highly likely not to have PSA persistence.

Salvage lymphadenectomy or radiation therapy in prostate cancer patients with biochemical recurrence and PET positive lymph nodes after radical prostatectomy: A systematic review and pooled analysis

OBJECTIVE

To analyze the oncologic outcomes of biochemical recurrence (BCR) patients who received salvage treatment of lymph node dissection (LND) or radiation therapy (RT) for positron emission tomography (PET)-positive lymph node recurrences following radical prostatectomy (RP).

METHODS

Research using the MEDLINE, Cochrane, and Web of Science databases was conducted until June 2023. Inclusion criteria were BCR patients that received salvage LND or RT for PET-positive lymph node recurrence following primary RP for prostate cancer. Studies with a follow-up period of less than 12 months were excluded.

RESULTS

This study included 2476 patients (995 LND, 1481 RT) from 19 publications. The pooled incidences were 51.1 % and 74.3 % in PSA response, 69.8 % and 26.9 % in PSA progression, 41.5 % and 26.9 % in image progression, 41.5 % and 32.0 % in systemic progression, 0.9 % and 0.5 % in overall mortality, and 6.5 % and 1.3 % in cancer-specific mortality in LND and RT, respectively. Limitations include high heterogeneity.

CONCLUSION

Although heterogeneity is high across all studies, the pooled rates of PSA, image, and systemic progressions are higher in LND than in RT concerning BCR patients with PET-positive lymph nodes. For future trial designs in BCR, assessing the optimal timing of PSMA PET scans, concurrent systemic therapy, and salvage therapy type is imperative.

Whole pelvis vs. hemi pelvis elective nodal radiotherapy in patients with PSMA-positive nodal recurrence after radical prostatectomy - a retrospective multi-institutional propensity score analysis

PURPOSE

Despite growing evidence for bilateral pelvic radiotherapy (whole pelvis RT, WPRT) there is almost no data on unilateral RT (hemi pelvis RT, HPRT) in patients with nodal recurrent prostate cancer after prostatectomy. Nevertheless, in clinical practice HPRT is sometimes used with the intention to reduce side effects compared to WPRT. Prostate-specific membrane antigen positron emission tomography / computed tomography (PSMA-PET/CT) is currently the best imaging modality in this clinical situation. This analysis compares PSMA-PET/CT based WPRT and HPRT.

METHODS

A propensity score matching was performed in a multi-institutional retrospective dataset of 273 patients treated with pelvic RT due to nodal recurrence (214 WPRT, 59 HPRT). In total, 102 patients (51 in each group) were included in the final analysis. Biochemical recurrence-free survival (BRFS) defined as prostate specific antigen (PSA) < post-RT nadir + 0.2ng/ml, metastasis-free survival (MFS) and nodal recurrence-free survival (NRFS) were calculated using the Kaplan-Meier method and compared using the log rank test.

RESULTS

Median follow-up was 29 months. After propensity matching, both groups were mostly well balanced. However, in the WPRT group there were still significantly more patients with additional local recurrences and biochemical persistence after prostatectomy. There were no significant differences between both groups in BRFS (p = .97), MFS (p = .43) and NRFS (p = .43). After two years, BRFS, MFS and NRFS were 61%, 86% and 88% in the WPRT group and 57%, 90% and 82% in the HPRT group, respectively. Application of a boost to lymph node metastases, a higher RT dose to the lymphatic pathways (> 50 Gy EQD2α/β=1.5 Gy) and concomitant androgen deprivation therapy (ADT) were significantly associated with longer BRFS in uni- and multivariate analysis.

CONCLUSIONS

Overall, this analysis presents the outcome of HPRT in nodal recurrent prostate cancer patients and shows that it can result in a similar oncologic outcome compared to WPRT. Nevertheless, patients in the WPRT may have been at a higher risk for progression due to some persistent imbalances between the groups. Therefore, further research should prospectively evaluate which subgroups of patients are suitable for HPRT and if HPRT leads to a clinically significant reduction in toxicity.

Prostate-specific membrane antigen-radioguided surgery salvage lymph node dissection: experience with fifty oligorecurrent prostate cancer patients

PURPOSE

The higher detection efficacy of PSMA PET for oligometastatic recurrence of prostate cancer has promoted new loco-regional treatment options. PSMA-targeted radioguided surgery (PSMA-RGS) was introduced to facilitate salvage surgery of small tumor deposits. The objectives of this retrospective analysis are to describe an independent single-center consecutive cohort of patients undergoing PSMA-RGS and to evaluate its clinical and oncological outcomes.

METHOD

Between 2018 and 2022, 53 patients were treated with PSMA-RGS and 50 patients were available for final analyses. All patients were initially treated with radical prostatectomy (RP) and presented with biochemical recurrence (BCR) with at least one positive lesion on PSMA-PET imaging. After preparation of 99mTc-PSMA-I&S and intravenous injection, surgery was performed by using a gamma-probe intraoperatively.

RESULTS

Median age was 70 years (IQR 65-73) and the median PSA at salvage surgery was 1.2 ng/mL (IQR 0.6-3.0). In all patients pathologically positive lesions could be removed during PSMA-RGS. 29 (58%) patients had one pathologically positive lesion, 14 (28%) had two and 7 (14%) had three or more, respectively. The overall complication rate was 26% with 4 (8%), 1 (2%), and 8 (16%) having Clavien-Dindo (CD) type I, II, and IIIb complications, respectively. During the follow-up period 31 (62%) patients experienced BCR and 29 (58%) received further therapy.

CONCLUSIONS

PSMA-RGS is a promising treatment option to enhance salvage surgery in early biochemical recurrence. However, only 42% of the patients treated with PSMA RGS remain without a biochemical recurrence. Further research is mandatory to identify patients, who profit from PSMA-RGS.

Comparative analysis of robot-assisted and open approach for PSMA-radioguided surgery in recurrent prostate cancer

PURPOSE

To compare the oncological and surgical outcomes of patients with recurrent prostate cancer (PCa) who underwent either open or newly established robot-assisted salvage prostate-specific membrane antigen-radioguided surgery (PSMA-RGS).

MATERIALS AND METHODS

Patients who consecutively underwent PSMA-RGS for PCa recurrence between January 2021 and December 2022 were identified. The rate of complete biochemical response, biochemical recurrence-free survival [BFS], and the rate of salvage therapy were evaluated. Univariable and multivariable regression models tested the association between the surgical approach and surgical outcomes.

RESULTS

Overall, 85 patients were selected, with 61 patients (72%) undergoing open PSMA-RGS and 24 patients (28%) receiving a robot-assisted approach. The oncological outcomes of the two groups were comparable (12-month BFS: 41% (Confidence interval (CI): 29-58%) vs. 39% (CI: 19-79%), p = 0.9, respectively). According to multivariable regression models, the robotic approach did not significantly influence estimated blood loss (EBL) (β = -40, 95% CI: -103, 22; p = 0.2) and significantly increased operative time (OT) (β = 28, 95% CI: 10, 46; p = 0.002). No Clavien-Dindo III-V complications were reported in the robotic group.

CONCLUSION

Both, the open as well as the robot-assisted approach for PSMA-RGS had comparable oncological outcomes. No safety concerns arose for the robotic-assisted approach offering a potentially improved quality of life for patients.

Prostate cancer and elective nodal radiation therapy for cN0 and pN0-a never ending story? : Recommendations from the prostate cancer expert panel of the German Society of Radiation Oncology (DEGRO)

For prostate cancer, the role of elective nodal irradiation (ENI) for cN0 or pN0 patients has been under discussion for years. Considering the recent publications of randomized controlled trials, the prostate cancer expert panel of the German Society of Radiation Oncology (DEGRO) aimed to discuss and summarize the current literature. Modern trials have been recently published for both treatment-naïve patients (POP-RT trial) and patients after surgery (SPPORT trial). Although there are more reliable data to date, we identified several limitations currently complicating the definitions of general recommendations. For patients with cN0 (conventional or PSMA-PET staging) undergoing definitive radiotherapy, only men with high-risk factors for nodal involvement (e.g., cT3a, GS ≥ 8, PSA ≥ 20 ng/ml) seem to benefit from ENI. For biochemical relapse in the postoperative situation (pN0) and no PSMA imaging, ENI may be added to patients with risk factors according to the SPPORT trial (e.g., GS ≥ 8; PSA > 0.7 ng/ml). If PSMA-PET/CT is negative, ENI may be offered for selected men with high-risk factors as an individual treatment approach.

Peering through the PSMA PET Lens: The Role of the European Association of Urology Biochemical Recurrence Risk Groups after Radical Prostatectomy

(1) Background: The European Association of Urology (EAU) biochemical recurrence (BCR) risk grouping relies on data from historical cohorts that used conventional imaging techniques. In the era of PSMA PET/CT, we compared the patterns of positivity in the two risk groups and provided insight into positivity predictive factors. (2) Methods: Data from 1185 patients who underwent ⁶⁸Ga-PSMA-11PET/CT for BCR was analyzed, out of which 435 patients treated initially treated by radical prostatectomy were included in the final analysis. (3) Results: A significantly higher rate of positivity in the BCR high-risk group was observed (59% vs. 36%, p < 0.001). BCR low-risk group demonstrated more local (26% vs. 6%, p < 0.001) and oligometastatic (100% vs. 81%, p < 0.001) recurrences. The BCR risk group and PSA level at the time of PSMA PET/CT were independent predictive factors of positivity. (4) Conclusions: This study confirms that the EAU BCR risk groups have different rates of PSMA PET/CT positivity. Even with a lower rate in the BCR low-risk group, oligometastatic disease was 100% in those with distant metastases. Given the presence of discordant positivity and risk classification, integrating PSMA PET/CT positivity predictors into risk calculators for BCR might improve patient classification for subsequent treatment options. Future prospective studies are still needed to validate the above findings and assumptions.

Impact of 18 F-Fluciclovine PET/CT Findings on Failure-Free Survival in Biochemical Recurrence of Prostate Cancer Following Salvage Radiation Therapy

PURPOSE

We aimed to evaluate the impact of 18 F-fluciclovine PET/CT imaging on failure-free survival (FFS) post-salvage radiotherapy (SRT) for prostate cancer (PCa) recurrence.

METHODS

Seventy-nine patients were recruited in a phase 2/3 clinical trial to undergo 18 F-fluciclovine PET/CT before SRT for PCa. Four patients with extrapelvic disease were excluded. All patients were followed up at regular intervals up to 48 months. Treatment failure was defined as a serum prostate-specific antigen level of ≥0.2 ng/mL above the nadir after SRT, confirmed with an additional measurement, requiring systemic treatment or clinical progression. Failure-free survival was computed and compared between patients grouped according to 18 F-fluciclovine PET/CT imaging findings.

RESULTS

Eighty percent (60/75) of patients had a positive finding on 18 F-fluciclovine PET/CT, of which 56.7% (34/60) had prostate bed-only uptake, whereas 43.3% (26/60) had pelvic nodal ± bed uptake. Following SRT, disease failure was detected in 36% (27/75) of patients. There was a significant difference in FFS between patients who had a positive versus negative scan (62.3% vs 92.9% [ P < 0.001] at 36 months and 59.4% vs 92.9% [ P < 0.001] at 48 months). Similarly, there was a significant difference in FFS between patients with uptake in pelvic nodes ± bed versus prostate bed only at 36 months (49.8% vs 70.7%; P = 0.003) and at 48 months (49.8% vs 65.6%; P = 0.040). Failure-free survival was also significantly higher in patients with either negative PET/CT or prostate bed-only disease versus those with pelvic nodal ± prostate bed disease at 36 (78% vs 49.8%, P < 0.001) and 48 months (74.4% vs 49.8%, P < 0.001).

CONCLUSIONS

Findings on pre-SRT 18 F-fluciclovine PET/CT imaging, even when acted upon to optimize the treatment decisions and treatment planning, are predictive of post-SRT FFS in men who experience PCa recurrence after radical prostatectomy. A negative 18 F-fluciclovine PET/CT is most predictive of a lower risk of failure, whereas the presence of pelvic nodal recurrence portends a higher risk of SRT failure.

Outcome of patients with biochemical recurrence of prostate cancer after PSMA PET/CT-directed radiotherapy or surgery without systemic therapy

BACKGROUND

Radiotherapy (RT) and surgery are potential treatment options in patients with biochemical recurrence (BCR) following primary prostate cancer treatment. This study examines the value of prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT)-informed surgery and RT in patients with BCR treated without systemic therapy.

METHODS

This is a post-hoc subgroup analysis of a prospective clinical trial. Inclusion criteria were: histologically proven prostate cancer at initial curative-intent treatment, BCR after primary treatment with curative intent, having five or fewer lesions identified on [¹⁸F]DCFPyL PET/CT, and treatment with either PET/CT-directed RT or surgery without systemic therapy. The biochemical progression-free survival after PSMA ligand PET/CT-directed RT and surgery was determined. Uni- and multivariate Cox regression analyses were performed for the association of patients' characteristics, tumor-specific variables, and PSMA PET/CT imaging results with biochemical progression at the last follow-up.

RESULTS

Fifty-eight patients (30 in surgery and 28 in radiotherapy groups) met the inclusion criteria. A total of 87 PSMA-positive lesions were detected: 16 local recurrences (18.4%), 54 regional lymph nodes (62.1%), 6 distant lymph nodes (6,8%), and 11 osseous lesions (12.7%). A total of 85.7% (24 of 28) and 70.0% (21 of 30) of patients showed a ≥ 50% decrease in prostate-specific antigen (PSA) levels after RT and surgery, respectively. At a median follow-up time of 21 months (range, 6-32 months), the median biochemical progression-free survival was 19 months (range, 4 to 23 months) in the radiotherapy group, as compared with 16.5 months (range, 4 to 28 months) in the surgery group. On multivariate Cox regression analysis, the number of PSMA positive lesions (2-5 lesions compared to one lesion), and the anatomic location of the detected lesions (distant metastasis vs. local relapse and pelvic nodal relapse) significantly correlated with biochemical progression at the last follow-up, whereas other clinical, tumor-specific, and imaging parameters did not.

CONCLUSIONS

This study suggests that RT or surgery based on [¹⁸F]DCFPyL PET/CT are associated with high PSA response rates. The number and site of lesions detected on the PSMA PET/CT were predictive of biochemical progression on follow-up. Further studies are needed to assess the impact of targeting these sites on patient relevant outcomes.

TRIAL REGISTRATION

Registered September 14, 2016; NCT02899312; https://clinicaltrials.gov/ct2/show/NCT02899312.

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).

Necessity of Pelvic Lymph Node Irradiation in Patients with Recurrent Prostate Cancer after Radical Prostatectomy in the PSMA PET/CT Era: A Narrative Review

The main prostate cancer (PCa) treatments include surgery or radiotherapy (with or without ADT). However, none of the suggested treatments eliminates the risk of lymph node metastases. Conventional imaging methods, including MRI and CT scanning, are not sensitive enough for the diagnosis of lymph node metastases; however, the novel imaging method, PSMA PET/CT scanning, has provided valuable information about the pelvic LN involvement in patients with recurrent PCa (RPCa) after radical prostatectomy. The high sensitivity and negative predictive value enable accurate N staging in PCa patients. In this narrative review, we summarize the evidence on the treatment and extent of radiation in prostate-only or whole-pelvis radiation in patients with positive and negative LN involvement on PSMA PET/CT scans.

PSMA PET-CT in the Diagnosis and Staging of Prostate Cancer

Prostate cancer is the most common cancer and the second leading cause of cancer death in men. The imaging assessment and treatment of prostate cancer has vastly improved over the past decade. The introduction of PSMA PET-CT has improved the detection of loco-regional and metastatic disease. PSMA PET-CT also has a role in the primary diagnosis and staging, in detecting biochemical recurrence after curative treatment and in metastasis-directed therapy. In this paper we review the role of PSMA PET-CT in prostate cancer.

Evaluation of [68 Ga]Ga-PSMA-I&T PET/CT with additional late scans of the pelvis in prostate-specific antigen recurrence using the PROMISE criteria

Background

PSMA PET/CT is the recommended imaging test in cases with prostate-specific antigen (PSA) recurrence after primary therapy of prostate cancer (PCa). However, imaging protocols remain a topic of active research. The aim of the presented study was to examine the impact of additional late scans of the pelvis in [⁶⁸ Ga]Ga-PSMA-I&T PET/CT of patients with rising PSA after prostatectomy.

Methods

A total of 297 patients (median PSA 0.35 ng/ml, interquartile range (IQR) 0.2–0.8) who underwent early whole-body [⁶⁸ Ga]Ga-PSMA-I&T PET/CT (median dose 141 MBq, IQR 120–163; median 86 min, IQR 56–107) and additional late scans of the pelvis (median 180 min, IQR 170–191) were investigated retrospectively. Early and late images were staged separately according to the PROMISE criteria and compared with a final consensus of both. Standardized uptake values were analyzed for early and late scans.

Results

One hundred and thirty-four (45.1%) [⁶⁸ Ga]Ga-PSMA-I&T PET/CT showed evidence of recurrent PCa (114/38.4% early, 131/44.1% late). Of 195 lesions, 144 (73.8%) were identified correctly on early scans. 191 (97.9%) lesions were detected on late imaging. The lesion SUVmax (median 3.4, IQR 0.4–6.5 vs. median 3.9, IQR 2.6–8.2) as well as the SUVmax to background ratio (median 9.4, IQR 1.7–19.1 vs. median 15.5, IQR 9.6–34.1) increased significantly between the imaging time points (p < 0.01, respectively). Compared to the final consensus, the miTNM-staging of early scans changed in 58 (19.5%) cases. Of these, 31 patients (10.4%) with negative early scans (T0 N0 M0) were upstaged. Twenty-seven (9.1%) patients with PCa characteristic lesions on early imaging (> T0 N0 M0) were up- and/or downstaged. In 4 (1.3%) cases, PCa-related lesions were only detectable on early PET/CT leading to upstagings of late imaging.

Conclusions

Additional late scans of the pelvis in [⁶⁸ Ga]Ga-PSMA-I&T PET/CT detected more lesions and an increasing contrast compared to early imaging. This influenced the final miTNM-staging substantially.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13550-022-00938-3.

Salvage Nodal Radiotherapy as Metastasis-Directed Therapy for Oligorecurrent Prostate Cancer Detected by Positron Emission Tomography Shows Favorable Outcome in Long-Term Follow-Up

Simple Summary

Patients, who suffer from oligorecurrent prostate cancer with limited nodal involvement, may be offered positron emission tomography (PET)-directed salvage nodal radiotherapy to delay disease progression. This current analysis aimed to access salvage radiotherapy for nodal oligorecurrent prostate cancer with simultaneous integrated boost to PET-involved lymph nodes as metastasis-directed therapy. A long-term oncological outcome was favorable after salvage nodal radiotherapy and severe toxicity rates were low. Androgen deprivation therapy plays a major role in recurrent prostate cancer management and demonstrates a positive influence on the rate of biochemical progression in patients receiving salvage nodal radiotherapy. The present long-term analysis may help clinicians identify patients who would benefit from salvage nodal radiotherapy and androgen deprivation therapy, as a multimodal treatment strategy for oligorecurrent prostate cancer.

Abstract

Background: The study aimed to access the long-term outcome of salvage nodal radiotherapy (SNRT) in oligorecurrent prostate cancer. Methods: A total of 95 consecutive patients received SNRT for pelvic and/or extrapelvic nodal recurrence after prostate-specific membrane antigen (PSMA) or choline PET from 2010 to 2021. SNRT was applied as external beam radiotherapy with simultaneous integrated boost up to a median total dose of 62.9 Gy (EQD2_1.5Gy) to the recurrent lymph node metastases. The outcome was analyzed by cumulative incidence functions with death as the competing risk. Fine–Gray regression analyses were performed to estimate the relative hazards of the outcome parameters. Genitourinary (GU)/gastrointestinal (GI) toxicity evaluation utilized Common Toxicity Criteria for Adverse Events (v5.0). The results are as follows: the median follow-up was 47.1 months. The five-year biochemical progression rate (95% CI) was 50.1% (35.7–62.9%). Concomitant androgen deprivation therapy (ADT) was adminstered in 60.0% of the patients. The five-year biochemical progression rate was 75.0% (42.0–90.9%) without ADT versus 35.3% (19.6–51.4%) with ADT (p = 0.003). The cumulative five-year late grade 3 GU toxicity rate was 2.1%. No late grade 3 GI toxicity occured. Conclusions: Metastasis-directed therapy through SNRT for PET-staged oligorecurrent prostate cancer demonstrated a favorable long-term oncologic outcome. Omittance of ADT led to an increased biochemical progression.

Differences in Distribution and Detection Rate of the [68Ga]Ga-PSMA Ligands PSMA-617, -I&T and -11-Inter-Individual Comparison in Patients with Biochemical Relapse of Prostate Cancer

The biochemical relapse of prostate cancer is diagnostically challenging but of high clinical impact for subsequent patient treatment. PET/CT with radiolabeled PSMA ligands outperforms conventional diagnostic methods in the detection of tumor recurrence. Several radiopharmaceuticals were and are available for use. The aim of this study was to investigate whether the routinely applied [⁶⁸Ga]Ga-PSMA ligands PSMA-617, -I&T and -11 (HBED-CC) differ in physiological and pathological distribution, or in tumor detection rate. A retrospective evaluation of 190 patients (39 patients received PSMA-617, 68 patients PSMA-I&T and 83 patients PSMA-11) showed significant differences in tracer accumulation within all organs examined. The low retention within the compartments blood pool, bone and muscle tissue is a theoretical advantage of PSMA-11. Evaluation of tumor lesion uptake and detection rate did not reveal superiority of one of the three radiopharmaceuticals, neither in the whole population, nor in particularly challenging subgroups like patients with very low PSA levels. We conclude that all three [⁶⁸Ga]Ga-PSMA ligands are equally feasible in this clinically important scenario, and may replace each other in case of unavailability or production restrictions.