Is there a role for ¹¹C-choline PET/CT in the early detection of metastatic disease in surgically treated prostate cancer patients with a mild PSA increase <1.5 ng/ml?

Whole-body tumour burden on [18F]DCFPyL PET/CT in biochemical recurrence of prostate cancer: association with tumour biology and PSA kinetics

PURPOSE

The objective was to assess the association between molecular imaging (mi) variables on [18F]DCFPyL-PET/CT with clinical and disease characteristics and prostate specific antigen (PSA) related variables in patients with biochemical recurrence of prostate cancer (BRPC).

MATERIAL AND METHODS

We analysed patients with BRPC after radical treatment. We obtained clinical and PSA variables: International Society of Urology Pathology (ISUP) grade group, European Association of Urology (EAU) risk classification, PSA (PSA≤1ng/ml, 12), PSA doubling time (PSAdt) and PSA velocity (PSAvel). All PET/CT scans were reviewed with the assistance of automated Prostate Molecular Imaging Standardized Evaluation (aPROMISE) software and lesions' segmentation in positive scans was performed using this platform. Standardized uptake value (SUV) derived variables; tumour burden variables [whole-body tumour volume (wbTV), whole-body tumour lesion activity (wbTLA) and whole-body mi PSMA (wbPSMA)] and miTNM staging were obtained. Cut-off of PSA and kinetics able to predict PET/CT results were obtained. Associations between disease and mi variables were analysed using ANOVA, Kruskal-Wallis and Spearman's correlation tests. Multivariate analysis was also performed.

RESULTS

Two hundred and seventy-five patients were studied. [18F]DCFPyL-PET/CT were positive in 165/275 patients. In multivariate analysis, moment of biochemical recurrence, ISUP group, PSA level and PSAvel showed significant association with the detection rate. miTNM showed significant association with PSA level (p<0.001) and kinetics (p<0.001), being higher in patients with metastatic disease. Both PSA and PSAvel showed moderate correlation with wbTV, wbTLA and wbPSMA (p<0.001). A weak correlation with SUVs was found. Mean wbTV, wbTLA and wbPSMA values were significantly higher in PSA > 2ng/ml, PSAdt ≤ 6 months and PSAvel ≥ 0.2ng/ml/month groups. Also, wbTV (p=0.039) and wbPSMA (p=0.020) were significantly higher in patients with ISUP grade group 5. PSA and PSAvel cut-offs (1.15 ng/ml and 0.065 ng/ml/month) were significantly associated with a positive PET/CT.

CONCLUSION

Higher PSA values, unfavourable PSA kinetics and ISUP grade group 5 were robust predictive variables of larger tumour burden variables on [18F]DCFPyL PET/CT assessed by aPROMISE platform.

Addressing the need for more therapeutic options in neuroendocrine prostate cancer

INTRODUCTION

Neuroendocrine prostate cancer (NEPC) is an aggressive form of prostate cancer frequently seen after prolonged treatment of castration resistant prostate cancer (CRPC). NEPC has become increasingly prevalent over the last 20 years, with a poor prognosis caused by a late diagnosis and limited treatment options. Recent advances in PET/CT imaging and targeted radioimmunotherapy are promising, but more research into additional treatment options is needed.

AREAS COVERED

The aim of this review is to analyze the current imaging and treatment options for NEPC, and to highlight future potential treatment strategies. A Pubmed search for 'Neuroendocrine Prostate Cancer' was performed and relevant articles were reviewed.

EXPERT OPINION

The recent FDA approval and success of 177 PSMA Lutetium in CRPC is promising, as 177 Lutetium could potentially be paired with a NEPC specific biomarker for targeted therapy. Recent laboratory studies pairing DLL3, which is overexpressed in NEPC, with 177 Lutetium and new PET agents have showed good efficacy in identifying and treating NEPC. The success of future development of NEPC therapies may depend on the availability of 177 Lutetium, as current supplies are limited. Further research into additional imaging and treatment options for NEPC is warranted.

Comparing the diagnostic performance of radiotracers in prostate cancer biochemical recurrence: a systematic review and meta-analysis

OBJECTIVES

To systematically assess the early detection rate of biochemical prostate cancer recurrence using choline, fluciclovine, and PSMA.

METHODS

Under the guidance of the Preferred Reporting Items for Systematic reviews and Meta-Analysis Diagnostic Test Accuracy guidelines, literature that assessed the detection rates (DRs) of choline, fluciclovine, and PSMA in prostate cancer biochemical recurrence was searched in PubMed and EMBASE databases for our systematic review from 2012 to July 15, 2021. In addition, the PSA-stratified performance of detection positivity was obtained to assess the DRs for various methods, including fluciclovine, PSMA, or choline PET/CT, with respect to biochemical recurrence based on different PSA levels.

RESULTS

In total, 64 studies involving 11,173 patients met the inclusion criteria. Of the studies, 12, 7, and 48 focused on choline, fluciclovine, and PSMA, respectively. The pooled DRs were 24%, 37%, and 44%, respectively, for a PSA level less than 0.5 ng/mL (p < 0.001); 36%, 44%, and 60% for a PSA level of 0.5-0.99 ng/mL (p < 0.001); and 50%, 61%, and 80% for a PSA level of 1.0-1.99 ng/mL (p < 0.001). The DR with 18F-labeled PSMA was higher than that with 68Ga-labeled PSMA, and the DR was 58%, 72%, and 88% for PSA levels < 0.5 ng/mL, 0.5-0.9 ng/mL, and 1.0-1.99 ng/mL, respectively.

CONCLUSION

The DRs of PSMA-radiotracers were greater than those of choline-radiotracers and fluciclovine-radiotracers at the patient level. 18F-labeled PSMA achieved a higher DR than 68Ga-labeled PSMA.

KEY POINTS

• The DRs of PSMA-radiotracers were greater than those of choline-radiotracers and fluciclovine-radiotracers at the patient level. • 18F-labeled PSMA achieved a higher DR than 68Ga-labeled PSMA.

Detection Rate and Clinical Impact of PET/CT with 18F-FACBC in Patients with Biochemical Recurrence of Prostate Cancer: A Retrospective Bicentric Study

Our aim was to assess the detection rate (DR) of positron emission computed tomography (PET/CT) with anti-1-amino-3-[18F]-flurocyclobutane-1-carboxylic acid (18F-FACBC) in patients with biochemical recurrence (BCR) from prostate cancer (PC). As a secondary endpoint, we evaluated 18F-FACBC PET/CT’s impact on patients management. Clinical records of 81 patients submitted to 18F-FACBC PET/CT due to PC BCR in two Italian Nuclear Medicine Units were retrospectively assessed. DR was gauged in the whole cohort and stratifying patients by discrete intervals of PSA levels. PET/CT’s impact on clinical management was scored as (1) major if it entailed an intermodality change (e.g., from systemic to loco-regional therapy); (2) minor if it led to an intramodality change (e.g., modified radiotherapy field). PET/CT’s DR resulted in 76.9% in the whole cohort, with a positive predictive value of 96.7%. Stratified by PSA quartile intervals, PET/CT’s DR was 66.7%, 71.4%, 78.9% and 90% for PSA 0.2–0.57 ng/mL, 0.58–0.99 ng/mL, 1–1.5 ng/mL and >1.5 ng/mL without significant difference among groups (p = 0.81). The most common sites of relapse were prostate bed and pelvic lymph nodes (59.3%). PET/CT impacted on clinical management in 33/81 cases (40.7%), leading to a major change in 30 subjects (90.9%). 18F-FACBC PET/CT localized recurrence in patients with BCR, with meaningful DR also at low PSA levels and significantly impacted on clinical management.

Negative 11C-choline PET/computed tomography imaging in restaging of patients with prostate cancer with serum prostate-specific antigen values >20 ng/mL

OBJECTIVE

Several studies have reported about the performance of C-choline-PET/computed tomography (CT) (choline) in patients with biochemical recurrent (BCR) prostate cancer, but there is a lack of information regarding negative choline in the same clinical setting. Our aim was to retrospectively analyse negative choline in a cohort of BCR-patients with high prostate-specific antigen (PSA).

METHODS AND RESULTS

We retrospectively analysed all choline-scans performed at two high-volume imaging centres between 2005 and 2018, selecting those of interest according to the following inclusion criteria: (1) proven prostate cancer treated either with radical prostatectomy or primary external beam radiation therapy (EBRT), (2) BCR after radical prostatectomy or EBRT, (3) PSA serum values >20 ng/mL at the time of scan and (4) scan reported as negative for active disease. Overall, among 5792 scans performed for BCR-prostate cancer, 14 matched the inclusion criteria and were classified as follows: 5/14(36%) inaccurate reports, 3/14(21%) questionable underestimation of positive findings, originally described as unclear, 6/14(43%) negatives. Choline showed a high detection rate in BCR-prostate cancer patients with PSA >20 ng/mL.

CONCLUSIONS

Although negative reports can be found in this clinical setting, in our review various disease-relevant findings were identified in more than half of the cases originally reported as negative warranting a double reading in such cases to avoid false-negative reports.

10-Year Clinical Experience With 18F-Choline PET/CT: An Italian Multicenter Retrospective Assessment of 3343 Patients

PURPOSE

The primary aim of this multicenter retrospective analysis is to examine the role of F-choline PET/CT as a diagnostic tool for staging and restaging prostate cancer (PCa) in a large population in the light of 10 years of clinical experience. A secondary aim of the study is to produce data on the predictors of a positive F-choline PET/CT result in the setting of PCa primaries and biochemical recurrences.

MATERIALS AND METHODS

This multicenter retrospective cohort study is based on data collected by 9 Italian nuclear medicine departments. Between October 2008 and September 2019, 3343 men underwent F-choline PET/CT scans before receiving definitive treatments for a primary PCa or biochemical recurrence. Inclusion criteria were (1) histologically proven PCa (on surgical specimens or prostate biopsies from patients not treated surgically) and (2) availability of clinical and pathological data, including serum prostate specific antigen (PSA) level at the time of PET/CT scanning.

RESULTS

F-choline PET/CT was performed in 545 cases (16.4%) for cancer staging and in 2798 (83.6%) for restaging purposes, and the result was positive in 540 (99.1%) for the former and 1993 (71.2%) for the latter. A positive PET/CT result was always associated with a high Gleason score (>7) and high PSA levels (P < 0.01). The percentage of patients with a PSA threshold less than 1.0 ng/mL for performing PET/CT was higher in the years 2014 to 2019 (n = 341, 25% of cases) than during the previous period (n = 148, 16%; in 2008-2013). When used for staging purposes, receiver operating characteristic analysis showed that PSA levels of 9.2, 16.4, and 16.6 ng/mL were the optimal cutoffs for distinguishing between positive and negative PET/CT findings for local disease, lymph node involvement, and metastasis, respectively. In the restaging setting, a PSA level of 1.27 ng/mL was the optimal cutoff for distinguishing between a positive and negative PET/CT scan.

CONCLUSIONS

F-choline PET/CT can help identify early recurrences, even in the case of low PSA levels (<1 ng/mL). Our data suggest that important improvements have been made in the interpretation of F-choline images and in patient selection in the last 5 years.

Non-FDG PET/CT

The major applications for molecular imaging with PET in clinical practice concern cancer imaging. Undoubtedly, 18F-FDG represents the backbone of nuclear oncology as it remains so far the most widely employed positron emitter compound. The acquired knowledge on cancer features, however, allowed the recognition in the last decades of multiple metabolic or pathogenic pathways within the cancer cells, which stimulated the development of novel radiopharmaceuticals. An endless list of PET tracers, substantially covering all hallmarks of cancer, has entered clinical routine or is being investigated in diagnostic trials. Some of them guard significant clinical applications, whereas others mostly bear a huge potential. This chapter summarizes a selected list of non-FDG PET tracers, described based on their introduction into and impact on clinical practice.

Detection Rate of 18F-Fluorethylcholine-PET/CT in relation to PSA Value in PCA Patients Referred with Biochemical Relapse

Attempts to predict the likelihood of positive morphological imaging related with PSA value in patients referred with biochemical recurrence were the focus of many studies. Using nuclear medicine modalities, numerous studies likewise had been performed for the same purpose, however mostly using C-11-labeled choline. For this purpose, we selected 193 prostate cancer patients from our database between 2006 and 2010. They had been referred to our department to undergo ¹⁸F-fluorethylcholine (FECH)-PET/CT due to biochemical recurrence after potentially curative procedures. As a result, in 84 out of 193 patients, ¹⁸F-FECH-PET demonstrated positive findings with an overall detection rate of 44%. Statistically, there was a significant difference in PSA values in positive findings vs. negative findings (p < 0.001), and there was a linear correlation between the detection rate and PSA value (r = 0.91). Moreover, there was a relation between initial therapy and recurrence type. So, the local relapse was the most frequent recurrence (>70%) after radiation therapy alone. By contrast, patients after radical prostatectomy followed by salvage radiotherapy showed a low likelihood of local recurrence. In conclusion, PSA value was confirmed to have a determinant role in ¹⁸F-FECH-PET outcome. Moreover, there was a link between recurrence type and initial therapy, which—if prospectively confirmed—may play a guiding role in selecting the appropriate diagnostic methods.

Localization and restaging of carcinoma prostate by 68Gallium prostate-specific membrane antigen positron emission tomography computed tomography in patients with biochemical recurrence

INTRODUCTION

Radical prostatectomy (RP) and radical radiotherapy (RT) are well established primary curative options for localized prostate cancer. Despite technical improvements, prostate-specific antigen (PSA)-recurrence after RP and RT is a common clinical scenario. We aimed to assess the role of ⁶⁸Gallium (⁶⁸Ga) prostate-specific membrane antigen positron emission tomography computed tomography (PSMA PET/CT) in patients with biochemical recurrence of prostate cancer after RP or RT for the detection and localization recurrent and metastatic disease.

MATERIALS AND METHODS

We ambispectively (70 retrospective and 100 prospective) analyzed the data of men with biochemical recurrence post-RP and post-RT who were evaluated by ⁶⁸Ga PSMA PET/CT at our institute. We aimed to assess the relationship between serum PSA levels and the probability of having a positive scan in patients with recurrent prostate cancer.

RESULTS

The study included 170 men, all had adenocarcinoma of the prostate, 124/170 had previous RP and 46/170 had prior RT. The median serum PSA in the RP group was 1.8 ng/ml and 5.2 ng/ml in the RT group. In the post-RP cohort, the detection rate of ⁶⁸Ga PSMA PET/CT was 39.3% for PSA 0.2 to <0.5 ng/ml, 47.3% for PSA 0.5 to <1 ng/ml, 68.4% for PSA 1 to <2 ng/ml and 93.1% for PSA ≥2 ng/ml. In the post-RT group, the detection rate was 88.8% for PSA 2 to <4 ng/ml and 100% for PSA ≥4 ng/ml.

CONCLUSIONS

⁶⁸Ga PSMA PET/CT provides a novel imaging modality for the detection of prostate cancer recurrence and metastases at low posttreatment PSA levels, which may help in directing appropriate salvage treatments.

Positron emission tomography (PET) radiotracers for prostate cancer imaging

Imaging plays an increasing role in prostate cancer diagnosis and staging. Accurate staging of prostate cancer is required for optimal treatment planning. In detecting extraprostatic cancer and sites of early recurrence, traditional imaging methods (computed tomography, magnetic resonance imaging, radionuclide bone scan) have suboptimal performance. This leaves a gap between known disease recurrence as indicated by rising prostate-specific antigen and the ability to localize the recurrence on imaging. Novel positron emission tomography (PET) agents including radiolabeled choline, fluciclovine (¹⁸F-FACBC), and agents targeting prostate-specific membrane antigen are being developed and tested to increase diagnostic performance of non-invasive prostate cancer localization. When combined with CT or MRI, these tracers offer a combination of functional information and anatomic localization that is superior to conventional imaging methods. These PET radiotracers have varying mechanisms and excretion patterns affecting their pharmacokinetics and diagnostic performance, which will be reviewed in this article.

Value of 18F-Choline PET/MRI hybrid technique on the therapeutic approach for patients with prostate cancer treated with prostatectomy and rising prostate specific antigen levels below 1 ng/ml

OBJECTIVE

To assess the detection rate of ¹⁸F-Choline PET/MRI and subsequent changes in therapy approach for patients with prostate cancer treated by prostatectomy and with rising levels of PSA <1 ng/ml.

METHODS

Prospective study with our first 36 patients with prostatectomy for prostate cancer and rising levels of PSA, who were referred for an ¹⁸F-Choline PET/MRI study. A dual-phase study was acquired after intravenous administration of 185±10% MBq of ¹⁸F-Choline: 1) early imaging (immediately after tracer administration) of prostate area (emission PET/Multiparametric MRI). 2) whole-body imaging 1 h after tracer injection (emission PET/MRI: T1, T2, STIR, diffusion). The therapy approach for patients was decided upon the Oncology Committee consensus based on ¹⁸F-Choline PET/MRI findings.

RESULTS

Twenty out of 36 patients (55.6%) were positive for the ¹⁸F-Choline PET/MRI study: 8 (22.2%) within the prostatectomy bed, 7 (19.4%) with infradiaphragmatic lymph nodes, 4 (11.1%) with local recurrence and infradiaphragmatic lymph nodes, and 1 (2.8%) with bone metastasis. Sixteen out of the 36 patients (44.4%) were negative for the ¹⁸F-Choline PET/MRI study. ¹⁸F-Choline PET/MRI findings had an impact on the therapy approach to follow: 15 patients (41.6%) showed oligometastatic disease which was treated by imaging-guided radiotherapy, 5 (13.9%) with multiple metastatic disease were treated by androgen deprivation therapy, 16 (44.4%) negative were under active surveillance.

CONCLUSION

Hybrid ¹⁸F-Choline PET/MRI procedure showed a high detection rate for recurrence in prostate cancer patients treated with prostatectomy and rising PSA levels <1 ng/ml, and ¹⁸F-Choline PET/MRI findings resulted in a better tailored therapy approach delivered to our patients.

18F-rhPSMA-7 PET for the Detection of Biochemical Recurrence of Prostate Cancer After Radical Prostatectomy

¹⁸F-labeled prostate-specific membrane antigen (PSMA) PET tracers are increasingly used in preference to ⁶⁸Ga-PSMA-11 for restaging biochemical recurrence (BCR) of prostate cancer. They are associated with longer half-lives, larger-scale production, and lower positron range than their ⁶⁸Ga-labeled counterparts. Here, we describe the efficacy of an ¹⁸F-labeled radiohybrid PSMA, rhPSMA-7, a novel theranostic PSMA-targeting agent for imaging BCR of prostate cancer. Methods: Datasets from 261 consecutive patients with noncastrate BCR after radical prostatectomy who underwent ¹⁸F-rhPSMA-7 PET/CT at our institution between June 2017 and March 2018 were reviewed retrospectively. All lesions suspected of being recurrent prostate cancer were recorded. The detection rate for sites of presumed recurrence was correlated with patients' prostate-specific antigen (PSA) level, primary Gleason score, and prior therapy (androgen deprivation therapy and external-beam radiation therapy). Results: The 261 patients had a median PSA level of 0.96 ng/mL (range, 0.01-400 ng/mL). The median injected activity of ¹⁸F-rhPSMA-7 was 336 MBq, with a median uptake time of 76 min. In total, 211 patients (81%) showed pathologic findings on ¹⁸F-rhPSMA-7 PET/CT. The detection rates were 71% (42/59), 86% (44/51), 86% (42/49), and 95% (76/80) at PSA levels of 0.2 to <0.5 ng/mL, 0.5 to <1 ng/mL, 1 to <2 ng/mL, and ≥2 ng/mL, respectively. In 32% patients (7/22) with a PSA of less than 0.2 ng/mL, suggestive lesions were present. ¹⁸F-rhPSMA-7 PET/CT revealed local recurrence in 43% of patients (113). Lymph node metastases were present in the pelvis in 42% of patients (110), in the retroperitoneum in 17% (45), and in a supradiaphragmatic location in 8.0% (21). Bone and visceral metastases were detected in 21% (54) and 3.8% (10), respectively. Detection efficacy was not influenced by prior external-beam radiation therapy (79.1% vs. 82.1%, P = 0.55), androgen deprivation therapy within the 6 mo preceding imaging (80.6% vs. 80.9%, P = 0.54), or primary Gleason score (77.9% for ≤7 vs. 82.6% for ≥8, P = 0.38). Conclusion: ¹⁸F-rhPSMA-7 PET/CT offers high detection rates in early BCR after radical prostatectomy, especially among patients with low PSA values.

18F-Choline PET/CT Identifies High-Grade Prostate Cancer Lesions Expressing Bone Biomarkers

The main aim of this study was to investigate the possible association between ¹⁸F–choline uptake and histopathological features of prostate biopsies such as the Gleason Group and the expression of both epithelial to mesenchymal transition (vimentin) and bone mineralization (bone morphogenetics protein (BMP)-2, runt-related transcription factor 2 (RUNX2), receptor activator of nuclear factor-κB ligand (RANKL), vitamin D receptor (VDR), and pentraxin 3 (PTX3) in situ biomarkers. To this end, we enrolled 79 consecutive prostate cancer patients that underwent both the ¹⁸F–choline PET/CT analysis and the prostate bioptic procedure. The standardized uptake value (SUV) average values were collected from ¹⁸F–choline PET/CT analysis whereas Gleason Group and immunostaining data were collected from paraffin-embedded sections. Histological classification showed a heterogenous population including both low/intermediate and high-grade prostate cancers. A significant increase of ¹⁸F–choline uptake in high-grade prostate lesions (Gleason Score ≥8) was found. Also, linear regression analysis showed a significant correlation between ¹⁸F–choline uptake and the number of vimentin, RANKL, VDR, or PTX3 positive prostate cancer cells. Conversely, we observed no significant association between ¹⁸F–choline uptake and the expression of bone biomarkers involved in the early phases of osteoblast differentiation (BMP-2, RUNX2). In conclusion, results here reported can lay the foundation for the use of ¹⁸F–choline positron emission tomography (PET)/computed tomography (CT) as a diagnostic tool capable of identifying high-grade prostate cancer lesions expressing bone biomarkers.

Stroke detection with 3 different PET tracers

Stroke is a common cause of patient morbidity and mortality, being the fifth leading cause of death in the United States. Positron emission tomography (PET) is a proven tool for oncology patients, and may have utility in patients with stroke. We demonstrate findings of stroke incidentally detected on oncologic PET/CTs using ¹⁸F-FDG, ¹¹C-Choline, and ⁶⁸Ga-DOTATATE radiotracers. Specifically, focal ¹¹C-Choline or ⁶⁸Ga-DOTATATE uptakes localized in areas of MRI confirmed ischemia, and paradoxically increased ¹⁸F-FDG activity was visualized surrounding a region of hemorrhage, in different patients. These cases demonstrate that PET may have utility in evaluating patients with stroke based on flow dynamics, metabolic activity, and receptor expression.

Anatomical mapping of lymph nodes in patients receiving salvage lymphadenectomy based on a positive 11C-choline positron emission tomography/computed tomography scan

INTRODUCTION

This paper aims to assess the diagnostic accuracy of an 11C-choline positron emission tomography/computed tomography (PET/CT) scan in the detection of lymph node (LN) metastases in patients with biochemical recurrence after radically treated prostate cancer (PCa), as compared to histology. The secondary goal is to depict spreading patterns of metastatic LNs in recurrent PCa.

MATERIAL AND METHODS

A single center retrospective study comprising of 30 patients who underwent retroperitoneal and/or pelvic salvage lymph node dissection (LND) due to 11C-choline PET/CT-positive nodal recurrences after radical treatment (median Prostate Specific Antigen (PSA) 1.5 ng/ml, range 0.2-11.4). Positive nodes on the preoperative PET/CT scans were mapped and compared to post-operative pathology results.LNs were marked as true positive, false positive, true negative and false negative and a patient- and a region-based analysis was performed. Sensitivity, specificity and positive/negative predictive value (PPV/NPV) were calculated.

RESULTS

Sixty positive LNs were detected on PET/CT with a median number of two positive nodes per patient (range 1-6). In 29 patients, a super-extended pelvic LND (PLND) was performed combined with a retroperitoneal LND (RPLND) in 13 of those cases. One patient underwent an inguinal LND. One hundred thirty-seven of 644 resected LNs contained metastases. The 11C-choline PET/CT scan correctly predicted 31 positive nodes (55%) while 25 nodes were falsely positive (45%). One hundred and six histologically proven metastatic nodes were not detected on the 11C-choline PET/CT scan (77%). Sensitivity, specificity, PPV and NPV of the 11C-choline PET/CT were 23%, 95%, 55% and 82%, respectively.

CONCLUSIONS

11C-choline PET/CT has a relatively low detection rate and a moderate PPV for metastatic LNs in patients with biochemical recurrence after radically treated PCa.

The Evolving Role of Prostate-Specific Membrane Antigen-Based Diagnostics and Therapeutics in Prostate Cancer

Prostate-specific membrane antigen (PSMA)-based imaging seeks to fill some critical gaps in prostate cancer staging and response assessment, and may select patients for treatment with radiolabeled PSMA conjugates. In biochemical recurrence, at prostate-specific antigen (PSA) levels as low as 0.2 ng/dL, ⁶⁸Ga-PSMA imaging has demonstrated a 42% detection rate of occult metastatic disease, and detection has been greater than 95% when PSA levels are higher than 2 ng/dL. This may facilitate novel approaches, including salvage lymphadenectomy or metastasis-directed radiation therapy, in patients with oligometastatic disease. PSMA-based imaging has shown promise in evaluating treatment response in hormone-sensitive and castration-resistant disease; however, additional longitudinal assessment is needed given the heterogeneity in uptake changes after the initiation of androgen-deprivation therapy. Changes in uptake must be taken in context of RECIST measurements and other response parameters, given the potential for growth of PSMA-negative lesions and persistent uptake in treated bone lesions of uncertain significance. For selecting patients to receive PSMA-targeted radioconjugate therapy, standardized uptake value thresholds remain to be established. Nevertheless, preliminary data from ¹⁷⁷Lu-PSMA theranostic trials have yielded PSA responses in up to 57% of patients, as well as pain relief and improved quality of life. Thrombocytopenia was the most common grade 3 or greater toxicity; however, grade 1 xerostomia occurred frequently and was cited as the most common reason for treatment discontinuation.

11C-choline PET/CT predicts survival in prostate cancer patients with PSA < 1 NG/ml

PURPOSE

The main drawback of ¹¹C-choline PET/CT for restaging prostate cancer (PCa) patients with biochemical failure is the relatively low positive detection rate for prostate specific antigen (PSA) < 1 ng/ml. This study assessed whether ¹¹C-choline PET/CT predicts survival in PCa patients with PSA < 1 ng/ml.

METHODS

This retrospective study included 210 PCa patients treated with radical prostatectomy who underwent ¹¹C-choline PET/CT from December 1, 2004 to July 31, 2007 due to biochemical failure. PCa-specific survival was estimated using Kaplan-Meier curves. Cox regression analysis was used to evaluate the association between clinicopathologic variables and PCa-specific survival. PCa-specific survival was computed as the interval from radical prostatectomy to PCa-specific death.

RESULTS

Median follow-up after radical prostatectomy was 6.9 years (95% confidence interval, CI, 2.0-14.5 years). ¹¹C-choline PET/CT was positive in 20.5% of patients. Median PCa-specific survival was 13.4 years (95% CI, 9.9-16.8 years) in patients with positive ¹¹C-choline PET/CT, and it was not achieved in patients with negative ¹¹C-choline PET/CT (log-rank, chi-square = 15.0, P < 0.001). Ten-year survival probabilities for patients with negative ¹¹C-choline PET/CT and for patients with positive ¹¹C-choline PET/CT were 86.0% (95% CI: 80.7%-91.3%) and 63.6% (95% CI: 54.5-72.7%). At multivariate analysis, only ¹¹C-choline PET/CT significantly predicted PCa-specific survival (hazard ratio = 2.54, 95% CI, 1.05-6.13, P = 0.038). Patients with pathological ¹¹C-choline uptake in the prostatic bed or in pelvic lymph nodes had longer PCa-specific survival in comparison to patients with pathological tracer uptake in the skeleton (log-rank: chi-square = 27.4, P < 0.001).

CONCLUSION

Despite the relatively low positive detection rate for PSA < 1 ng/ml, positive ¹¹C-choline PET/CT predicts PCa-specific survival in this low PSA range. As long as more sensitive radiotracers, such as ⁶⁸Ga-PSMA-11, do not become more widely available, these results might support a broader use of radiolabeled choline in restaging PCa for PSA < 1 ng/ml.

Intraindividual comparison of 68Ga-DOTATATE PET / CT vs 11C-Choline PET / CT in patients with prostate cancer in biochemical relapse: in vivo evaluation of the expression of somatostatin receptors

BACKGROUND AND OBJECTIVES

To prospectively compare the detection rate of ⁶⁸Ga-DOTATATE versus ¹¹C-choline PET/CT in patients with prostate cancer in biochemical relapse, and to evaluate somatostatin receptor expression in vivo to plan targeted therapies (¹⁷⁷Lu-DOTATATE).

MATERIAL AND METHODS

We prospectively analysed 64 patients with biochemical relapse (median PSA: 4.25 ng/mL). A PET/CT was performed with ¹¹C-choline, and another with ⁶⁸Ga-DOTATATE. The SUVmax was measured in all lesions. The correlative images, histopathology and/or clinical and biochemical follow-up were taken as the reference standard.

RESULTS

The overall detection rate per patient was 48.43% for ⁶⁸Ga-DOTATATE and 46.87% for ¹¹C-choline. The results were concordant in 53 cases (82.81%). The maximum SUV of ¹¹C-choline was significantly higher than that of ⁶⁸Ga-DOTATATE for all the concordant lesions (n=130): 6.17 (1.7-15.5) versus 4.38 (1.37-26.7), median (range) for each radiotracer, respectively (p < .0001). The sensitivity and specificity values per patient were the same for both techniques: 0.82 (0.65-0.93) and 0.9 (0.73-0.98), respectively. Although the difference was not significant, the sensitivity was lower in patients with lower PSA levels: 0.63 vs. 0.89; p=.13. A significant correlation was found between the SUVmax of both tracers (r = 0.41, n = 130, p <.0001).

CONCLUSIONS

⁶⁸Ga-DOTATATE PET/CT and ¹¹C-choline PET/CT seem to have a high capacity to detect pathological lesions in the assessment of patients with prostate cancer with biochemical relapse. Further studies are required to test the potential complementary value of these PET/CT techniques, and to evaluate the potential role of ⁸Ga-DOTATATE for planning somostatin receptor-mediated therapies (¹⁷⁷Lu-DOTATATE).

Imaging of Prostate Cancer Using 11C-Choline PET/Computed Tomography

This article reviews the role of ¹¹C-choline-PET/computed tomography (CT) in patients with prostate cancer for diagnosis, staging, and restaging the disease in case of biochemical recurrence after primary treatment. The main application of this imaging procedure is restaging of the disease in case of biochemical recurrence. ¹¹C-Choline-PET/CT proved its value for metastases-directed salvage therapies and for monitoring therapy response in castration-resistant patients. Prostate-specific antigen and prostate-specific antigen kinetics values confirmed their correlation with ¹¹C-choline PET/CT sensitivity.¹¹C-CholinePET/CT, despite low sensitivity to stage disease or in case of biochemical failure with low PSA levels, has an important impact on the management of patients with prostate cancer.

Extended robotic salvage lymphadenectomy in patients with 'node-only' prostate cancer recurrence: initial experience

Introduction

Biochemical relapse (BR) after a primary radical prostatectomy may occur in up to 40 percent of cases. Salvage lymphadenectomy has been proposed in patients with ‘node-only’ driven BR, following a definitive treatment of primary prostate cancer (PCa). We present our initial series of 10 consecutive patients who underwent an extended robotic salvage pelvic lymph node dissection (eRSPLND) for ‘node-only’ recurrent PCa.

Materials and methods

It was a prospective study, including patients who presented with biochemical relapse after a primary radical prostatectomy at a median of 3.6 years prior. Clinical work-up that was done, including Magnetic resonance Imaging of chest/abdomen/pelvis and a bone scan, did not reveal any abnormalities. All patients underwent 11Choline PET (Positron Emission Tomography)/CT (Computed Tomography), which identified ‘node-only’ metastases.

Results

The median operative time was 73.4 mins, blood loss of 100 cc and hospital stay of 2 days. No patient had intra-operative complications, required an open conversion or any blood transfusion. Clavien II grade complications occurred in 1 patient (10%) and were managed conservatively. On histopathology, the median number of total and positive nodes per patient was 15 and 6, respectively. Overall, in our 10 patients, of the 157 total excised nodes, 38.8% were positive. Overall the median (range) PSA (prostate specific antigen) pre-operatively was 3.5 (1.6–3.7) ng/ml. At 3 months post-operatively, the median (range) PSA was 1.1 (0.2–3.4) ng/ml. This reflects an overall median PSA decrease of 31.4%. In no patient did the post-eRSPLND (extended Robotic Salvage pelvic lymphadenectomy) PSA reach zero.

Conclusions

eRSPLND allows the majority of patients to postpone hormonal treatment, which can theoretically decrease the cost of the treatment. 11Choline PET/CT identifies patients who are suitable for the eRSPLND. Longer follow-up is necessary to assess the oncologic outcomes.

Oligometastatic prostate cancer and salvage lymph node dissection: systematic review

INTRODUCTION

We provide a comprehensive description of the physio-pathological theories behind oligometastatic prostate cancer (PCa) and analyze modern imaging techniques, presenting a systematic review of the available evidences regarding salvage lymph node dissection (sLND).

EVIDENCE ACQUISITION

A systematic review was attempted. The PubMed/Medline database was searched for "salvage" AND ("lymph node dissection" OR "lymphadenectomy") AND "prostate" AND "cancer." Only English publications were targeted. Relevant original articles addressing the role of sLND in PCa were selected.

EVIDENCE SYNTHESIS

Biochemical response (BR) was reported in 10-79.5% of the cases overall. These results were not durable and biochemical recurrence occurred in 54.5-93.8% of the cases, within 5 years. Furthermore, 50-80% of patients received some kind of adjuvant treatment right after sLND, regardless post-operative prostate-specific antigen levels. Surgery-related morbidity was low, with a 0-27% incidence of Clavien-Dindo III complications. No sLND-related deaths were observed.

CONCLUSIONS

sLND is not associated with a durable response over time but may postpone HT and its related complications, in selected patients. Although a limited morbidity was reported, sLND remains technically demanding and a careful selection of patients is advisable.

18F-choline PET/MRI in suspected recurrence of prostate carcinoma

OBJECTIVE

To evaluate the usefulness of simultaneous ¹⁸F-choline PET/MRI in the suspicion of prostate cancer recurrence and to relate ¹⁸F-choline PET/MRI detection rate with analytical and pathological variables.

MATERIAL AND METHODS

27 patients with prostate cancer who received local therapy as primary treatment underwent a ¹⁸F-choline PET/MRI due to suspicion of recurrence (persistently rising serum PSA level). ¹⁸F-choline PET/MRI findings were validated by anatomopathological analysis, other imaging tests or by biochemical response to oncological treatment.

RESULTS

¹⁸F-choline PET/MRI detected disease in 15 of 27 patients (detection rate 55.56%). 4 (15%) presented exclusively local recurrence, 5 (18%) lymph node metastases and 7 (26%) bone metastases. Mean PSA (PSA_med) at study time was 2.94ng/mL (range 0.18-10ng/mL). PSA_med in patients with positive PET/MRI was 3.70ng/mL (range 0.24-10ng/mL), higher than in patients with negative PET/MRI, PSA_med 1.97ng/mL (range 0.18-4.38ng/mL), although without statistically significant differences. Gleason score at diagnosis in patients with a positive study was 7.33 (range 6-9) and in patients with a negative study was 7 (range 6-9), without statistically significant differences.

CONCLUSION

¹⁸F-choline PET/MRI detection rate was considerable despite the relatively low PSA values in our sample. The influence of Gleason score and PSA level on ¹⁸F-choline PET/MRI detection rate was not statistically significant.

68Ga-PSMA and 11C-Choline comparison using a tri-modality PET/CT-MRI (3.0 T) system with a dedicated shuttle

Background

The aim of this study was to prospectively compare the detection rate of ⁶⁸Ga-PSMA versus ¹¹C-Choline in men with prostate cancer with biochemical recurrence and to demonstrate the added value of a tri-modality PET/CT-MRI system.

Methods

We analysed 36 patients who underwent both ¹¹C-Choline PET/CT and ⁶⁸Ga-PSMA PET/CT scanning within a time window of 1-2 weeks. Additionally, for the ⁶⁸Ga-PSMA scan, we used a PET/CT-MRI (3.0 T) system with a dedicated shuttle, acquiring MRI images of the pelvis.

Results

Both scans were positive in 18 patients (50%) and negative in 8 patients (22%). Nine patients were positive with ⁶⁸Ga-PSMA alone (25%) and one with ¹¹C-Choline only (3%). The median detected lesion per patient was 2 for ⁶⁸Ga-PSMA (range 0-93) and 1 for ¹¹C-Choline (range 0-57). Tumour to background ratios in all concordant lesions (n = 96) were higher for ⁶⁸Ga-PSMA than for ¹¹C-Choline (110.3 ± 107.8 and 27.5 ± 17.1, mean ± S.D., for each tracer, respectively P = 0.0001). The number of detected lesions per patient was higher for ¹¹C-Choline in those with PSA ≥ 3.3 ng/mL, while the number of detected lesions was independent of PSA levels for ⁶⁸Ga-PSMA using the same PSA cut-off value. Metastatic pelvic lesions were found in 25 patients (69%) with ⁶⁸Ga-PSMA PET/CT, in 18 (50%) with ¹¹C-Choline PET/CT and in 21 (58%) with MRI (3.0 T). MRI was very useful in detecting recurrence in cases classified as indeterminate by means of PET/CT alone at prostate bed.

Conclusions

In patients with prostate cancer with biochemical recurrence ⁶⁸Ga-PSMA detected more lesions per patient than ¹¹C-Choline, regardless of PSA levels. PET/CT-MRI (3.0 T) system is a feasible imaging modality that potentially adds useful relevant information with increased accuracy of diagnosis.

The relationship between local recurrences and distant metastases in prostate cancer: can 11C-choline PET/CT contribute to understand the link?

PURPOSE

Previous studies in prostate cancer (PCa) patients tried to correlate the onset of local recurrence (LR) with the development of distant metastases and formulated, based on theoretical and experimental data, hypotheses linking the two events. We aimed to address this issue with ¹¹C-choline positron emission tomography/computed tomography (PET/CT).

METHODS

This retrospective study included 491 PCa patients previously treated with radical prostatectomy who had undergone ¹¹C-choline PET/CT owing to biochemical failure. Further inclusion criteria were availability of clinical and pathological variables for survival analysis. Statistical significance was taken at P < 0.05.

RESULTS

Seventy-two patients (14.7%) had evidence of LR at ¹¹C-choline PET/CT. The frequency of LR increased from 13.8% in the interval 0-4 years after prostatectomy, to 23.9% in the 12-16-year interval (P = 0.080). On the contrary, the frequency of lymph node metastases (overall rate in the 0-16 years interval after prostatectomy: 26.3%) and of bone metastases (overall rate: 13.8%) decreased significantly over time. Kaplan-Meier curves showed no significant group difference in the rates of lymph node or bone metastases between patients with LR and patients without LR. LR significantly predicted PCa-specific survival at univariate analysis, but the statistical significance was lost at multivariate analysis.

CONCLUSION

We found no differences in the rates of lymph node and bone metastases between patients with and without LR. An inverse time-dependent trend was observed in the frequency of LR on one side and of lymph node and bone metastases on the other side. These findings were discussed in relation to previous theories linking LR to distant metastases and our study design.

Innovations in imaging modalities for recurrent and metastatic prostate cancer: a systematic review

INTRODUCTION

The last decade has witnessed tremendous changes in the management of advanced and metastatic castration resistant prostate cancer. In the current systematic review, we analyze novel imaging techniques in the setting of recurrent and metastatic prostate cancer (PCa), exploring available data and highlighting future exams which could enter clinical practice in the upcoming years.

EVIDENCE ACQUISITION

The National Library of Medicine Database was searched for relevant articles published between January 2012 and August 2017. A wide search was performed including the combination of following words: "Prostate" AND "Cancer" AND ("Metastatic" OR "Recurrent") AND "imaging" AND ("MRI" OR "PET"). The selection procedure followed the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) principles and is presented using a PRISMA flow chart.

EVIDENCE SYNTHESIS

Novel imaging techniques, as multiparametric magnetic resonance imaging (MRI), whole-body MRI and Choline and prostate-specific membrane antigen (PSMA) PET imaging techniques are currently revolutioning the treatment planning in patients with advanced and metastatic PCa, allowing a better characterization of the disease. Multiparametric MRI performs well in the detection of local recurrences, with sensitivity rates of 67-98% and overall diagnostic accuracy of 83-93%, depending on the type of magnetic field strength (1.5 vs. 3T). Whole body MRI instead shows a high specificity (>95%) for bone metastases. PET imaging, and in particular PSMA PET/CT, showed promising results in the detection of both local and distant recurrences, even for low PSA values (<0.5 ng/mL). Sensitivity varies from 77-98% depending on PSA value and PSA velocity.

CONCLUSIONS

Whole body-MRI, NaF PET, Choline-PET/CT and PSMA PET/CT are flourishing techniques which find great application in the field of recurrent and metastatic PCa, in the effort to reduce treatment of "PSA only" and rather focus our therapies on clinical tumor entities. Standardization is urgently needed to allow adequate comparison of results and diffusion on a large scale.

Prostate cancer as a paradigm of multidisciplinary approach? Highlights from the Italian young radiation oncologist meeting

Aims and background

The diagnostic and therapeutic approach to prostate cancer has evolved rapidly in last decades. Young professionals need an update about these recent developments in order to improve the care of patients treated in their daily clinical practice.

Methods

On May 18, 2013, AIRO Giovani (the young section of the Italian Association of Radiation Oncology) organized a multidisciplinary meeting involving, as speakers, several young physicians from many parts of Italy actively involved in the diagnostic and therapeutic approach to prostate cancer. The meeting was specifically addressed to young physicians (radio-oncologists, urologists, medical oncologists) and presented the state-of-the-art of the diagnostic/therapeutic approach based on the latest evidence on the issue. Highlights of the congress are summarized and presented in this report.

Results

The large participation in the meeting (more than 120 participants were present) confirmed the interest of young radiation oncologists in improving their skills in prostate cancer management. The contributions of the speakers confirmed the need for regular updates, considering the promising results of recently published studies and the many new ongoing trials, on the diagnostic and therapeutic approaches to prostate cancer.

Conclusions

Multidisciplinary meetings are helpful to improve the skills of young professionals.

Trigger pSA predicting recurrence from positive choline PET/CT with prostate cancer after initial treatment

Purpose

To assess the relationship between the diagnostic accuracy of Choline positron emission tomography/computed tomography (PET/CT) and the trigger prostate-specific antigen (PSA) level in patients with a biochemical recurrence of prostate cancer.

Materials and Methods

A meta-analysis was conducted to synthesize data across multiple studies.

Results

The pooled sensitivity and specificity of choline PET/CT were 82% (95% Confidence Interval (CI):80-84%) and 92% (95%CI: 90-93%), respectively. The pooled sensitivity and specificity of ¹⁸F-choline PET/CT were 81% (95%CI: 78-84%) and 90% (95%CI: 85-93%), respectively. The pooled sensitivity and specificity of ¹¹C-choline PET/CT were 83% (95% CI: 80-86%) and 92% (95% CI: 90-94%), respectively. The pooled detection rate of ¹⁸F-choline PET/CT and ¹¹C-choline PET/CT were 58% (95% CI: 48-68%) and 58% (95%CI: 49-68%), respectively.

Conclusions

Trigger PSA is an important risk factor for positive findings of Choline PET/CT and the detection rate of Choline PET/CT for recurrent prostate cancer increased in parallel with raises in PSA-values. Choline PET/CT got higher detection rate while the trigger PSA > 2ng/ml.

A review discussing fluciclovine (18F) PET/CT imaging in the detection of recurrent prostate cancer

A significant number of patients radically treated for prostate cancer (PCa) will develop prostate-specific antigen recurrence (27-53%). Localizing the anatomical site of relapse is critical, in order to achieve the optimal treatment management. To date the diagnostic accuracy of standard imaging is low. Several desirable features have been identified for the amino-acid-based PET agent, fluciclovine (¹⁸F) including: long ¹⁸F half-life which allows more practical use in centers without a cyclotron onsite; acting as a substrate for amino acid transporters upregulated in PCa or associated with malignant phenotype; lacking of incorporation into protein; and limited urinary excretion. Fluciclovine (¹⁸F) is currently approved both in USA and Europe with specific indication in adult men with suspected recurrent PCa based on elevated prostate-specific antigen following prior treatment.

Contribution of 11C-Choline PET/CT in prostate carcinoma biochemical relapse with serum PSA level below 1 ng/ml

OBJECTIVE

¹¹C-choline PET/CT has demonstrated good results in the restaging of prostate cancer (PCa) with high serum prostate specific antigen (PSA), but its use in patients with low serum PSA is controversial. Our aim was to evaluate the contribution of ¹¹C-choline PET/CT in patients with PCa, biochemical relapse and PSA <1 ng/ml.

MATERIAL AND METHOD

Fifty consecutive patients (mean age: 65.9±5.6 years) with biochemical relapse of PCa and serum PSA <1ng/ml were evaluated retrospectively. PET/CT was performed 20min after intravenous administration of 555-740 MBq of ¹¹C-choline. Minimum follow up time was 30 months.

RESULTS

Twenty-one out of 50 patients (42%) had an abnormal ¹¹C-choline PET/CT. In 7 out of 21 patients (14%) tumor was confirmed (4 in prostatic bed, 4 in pelvic lymph nodes, 2 in mediastinal lymph nodes and one synchronous sigmoid carcinoma), and in all cases the initial therapeutic planning was modified. In 2 patients (4%) subsequent tests diagnosed a benign disease (one sarcoidosis, one tuberculosis sequelae) and in 3 patients (6%) they ruled out pathology. The other 9 patients (18%) had no further assessment (7 mediastinal and 4 pelvic lymph nodes). Twenty-nine out of 50 patients (58%) had a normal PET/CT. At 30 months, follow up recurrence was confirmed only in 2 of these patients.

CONCLUSIONS

¹¹C-choline PET/CT proved its usefulness in demonstrating tumor in 14% of patients with BR of PCa and serum PSA <1ng/ml, with therapeutic implications. In 4% of patients a benign condition was detected. A normal ¹¹C-choline PET/CT was associated with a very low rate of recurrence at 30 months.

Imaging for the Detection of Locoregional Recurrences in Biochemical Progression After Radical Prostatectomy-A Systematic Review

CONTEXT

Local and regional recurrence after radical prostatectomy (RP) can be treated using salvage radiotherapy (SRT). If the recurrence can be delineated on diagnostic imaging, this could allow for increasingly individualized SRT.

OBJECTIVE

This systematic review aimed at evaluating the evidence regarding the usefulness of positron emission tomography (PET) and magnetic resonance imaging (MRI) in identifying local and regional recurrences, with the aim to further individualize the SRT treatment.

EVIDENCE ACQUISITION

A systematic PubMed/Medline search was conducted in December 2015. Studies included were imaging studies of post-RP patients focusing on local and/or regional recurrence where sensitivity and specificity of MRI or PET were the primary end points. Only studies using biopsy, other histological analysis, and/or treatment follow-up as reference standard were included. Quality Assessment of Diagnostic Accuracy Studies-2 was used to score the study quality. Twenty-five articles were deemed of sufficient quality and included in the review.

EVIDENCE SYNTHESIS

[¹¹C]Acetate had the highest pooled sensitivity (92%), while [¹¹C]choline and [¹⁸F]choline had pooled sensitivities of 71% and 84%, respectively. The PET tracer with highest pooled specificity was [¹¹C]choline (86%). Regarding MRI, MR spectroscopy combined with dynamic contrast enhanced (DCE) MRI showed the highest pooled sensitivity (89%). High pooled sensitivities were also seen using multiparametric MRI (84%), diffusion-weighted MRI combined with T2-weigthed (T2w) imaging (82%), and DCE MRI combined with T2w imaging (82%). These also showed high pooled specificities (85%, 89%, and 92%, respectively).

CONCLUSIONS

Both MRI and PET have adequate sensitivity and specificity for the detection of prostate cancer recurrences post-RP. Multiparametric MRI, using diffusion-weighted and/or DCE imaging, and the choline-labeled tracers showed high pooled sensitivity and specificity, although their ranges were broad.

PATIENT SUMMARY

After reviewing imaging studies of recurrent prostate cancer after prostatectomy, we concluded that choline positron emission tomography and diffusion-weighted magnetic resonance imaging can be proposed as the current standard, with high sensitivity and specificity.

Role of PET-CT with 18F-fluorocholine in biochemical recurrence after treatment of prostate cancer with curative intent

OBJECTIVES

To analyse the ability of the PET-CT with ¹⁸F-fluorocholine (¹⁸F-FCH) to detect disease on biochemical recurrence after treatment with curative intent. To determine the clinical variables that would be able to optimise the test's diagnostic yield.

MATERIAL AND METHODS

A retrospective study of PET-CTs with ¹⁸F-fluorocholine performed on 61 patients with prostate cancer who had undergone treatment with curative intent and met the criteria for biochemical recurrence. The results of the PET-CT were categorised into positive or negative and were validated using pre-established criteria. The relationship between the result of the PET-CT and the initial PSA nadir, PSA trigger, rising PSA velocity (PSAva) and PSA doubling time (PSAdt). The relationship between the metastatic sites on the PET-CT and the remaining variables was analysed.

RESULTS

There was a 34.4% detection rate of the disease. The initial PSA, PSA nadir, PSA trigger and PSAva showed statistically significant differences according to the result of the PET-CT. The best discriminatory cut-off point between a positive or negative PET-CT for PSA trigger and PSAva was 3.5ng/ml and 0.25ng/ml/month respectively. The PSAdt was significantly lower in patients with remote disease compared to patients with localised disease (5.1 vs 16.8 months, P=.01). The probability that the PET-CT would detect remote disease vs localised disease was 3.2 times higher if the PSAdt was under 6 months (80% vs 20%, OR: 3.2, P=.02). In the multivariate analysis, only the initial PSA and not having undergone radical prostatectomy were demonstrated as independent predictive factors of a positive PET-CT result.

CONCLUSIONS

The PET-CT with ¹⁸F-FCH can detect disease in a high percentage of patients with biochemical recurrence and provides information on its anatomical location. PSA kinetics and the patient's previous treatment are key variables in increasing the test's diagnostic.

68 Ga-PSMA-PET for radiation treatment planning in prostate cancer recurrences after surgery: Individualized medicine or new standard in salvage treatment

BACKGROUND

⁶⁸ Ga-PSMA-PET imaging is a novel promising diagnostic tool to locate early biochemical failure after radical prostatectomy (RP) in prostate cancer (PC) patients. Exact knowledge of the relapse location may result in changes of the therapy concept aside from changes to the TNM stage. To gain data for this approach, we evaluated PC patients receiving ⁶⁸ Ga-PSMA-PET imaging before salvage radiotherapy (RT).

METHODS AND MATERIALS

In this study, 100 patients with biochemical failure after RP± prior RT who underwent ⁶⁸ Ga-PSMA PET/CT or PET/MRI were evaluated undergoing salvage RT in our department. We analyzed TNM staging changes due to ⁶⁸ Ga-PSMA-PET imaging and its influence on RT planning and treatment.

RESULTS

Uptake indicative for tumor recurrence in ⁶⁸ Ga-PSMA-PET was found in 76% of the patients with biochemical recurrent PC. Median PSA level was 1.0 ng/mL (range 0.12-14.7 ng/mL). Of these, 80% showed no morphological correlate in the corresponding CT or MRI. A 43% of all patients experienced a change in TNM stage due to ⁶⁸ Ga-PSMA-PET imaging. Patients had changes from Tx to rcT+ (28%), 12% from pN0 to rcN1, 1% from pN0/cM0 to rcM1a, and 8% from cM0 to rcM1b. Due to the additional knowledge of ⁶⁸ Ga-PSMA-PET imaging, initial planned RT planning was adapted in 59% of all cases. An additional simultaneous integrated boost (SIB) to the prostate bed or lymph nodes was given to 32% and 63%, respectively. Ten patients received stereotactic body RT (SBRT) to single bone metastases.

CONCLUSION

⁶⁸ Ga-PSMA-PET imaging showed a high clinical impact on staging and RT management in patients with biochemically recurrent PC, even at low serum PSA levels. With 43% changes in staging and 59% in radiotherapy planning ⁶⁸ Ga-PSMA-PET could lead to an indispensable tool in guiding radiation treatment in recurrent PC.

Evaluation of Prostate Cancer with 11C-Choline PET/CT for Treatment Planning, Response Assessment, and Prognosis

The aim of this review is to report on the value of ¹¹C-choline PET imaging as a diagnostic procedure for metastasis-directed therapies. Furthermore, the role of ¹¹C-choline PET/CT as a diagnostic tool for monitoring castration-resistant prostate cancer patients treated with systematic therapy is assessed. Finally, the role of ¹¹C-choline PET/CT in the prediction of survival in both castration-resistant prostate cancer patients and hormone-naïve patients is investigated.

11C- or 18F-Choline PET/CT for Imaging Evaluation of Biochemical Recurrence of Prostate Cancer

Recurrence of prostate cancer is suspected when an increase in the prostate-specific antigen level is detected after radical treatment; the recurrence could be local relapse, distant relapse, or both. Differentiation between the two patterns of relapse is critical for choosing the proper treatment strategy. Choline PET/CT could be of help in discriminating patients with local, lymph node, and bone recurrences, thus having an impact on patient management.

PET and PET/CT with radiolabeled choline in prostate cancer: a critical reappraisal of 20 years of clinical studies

We here aim to provide a comprehensive and critical review of the literature concerning the clinical applications of positron emission tomography/computed tomography (PET/CT) with radiolabeled choline in patients with prostate cancer (PCa). We will initially briefly summarize the historical context that brought to the synthesis of [¹¹C]choline, which occurred exactly 20 years ago. We have arbitrarily grouped the clinical studies in three different periods, according to the year in which they were published and according to their relation with their applications in urology, radiotherapy and oncology. Studies at initial staging and, more extensively, studies in patients with biochemical failure, as well as factors predicting positive PET/CT will be reviewed. The capability of PET/CT with radiolabeled choline to provide prognostic information on PCa-specific survival will also be examined. The last sections will be devoted to the use of radiolabeled choline for monitoring the response to androgen deprivation therapy, radiotherapy, and chemotherapy. The accuracy and the limits of the technique will be discussed according to the information available from standard validation processes, including biopsy or histology. The clinical impact of the technique will be discussed on the basis of changes induced in the management of patients and in the evaluation of the response to therapy. Current indications to PET/CT, as officially endorsed by guidelines, or as routinely performed in the clinical practice will be illustrated. Emphasis will be made on methodological factors that might have influenced the results of the studies or their interpretation. Finally, we will briefly highlight the potential role of positron emission tomography/magnetic resonance and of new radiotracers for PCa imaging.

Imaging of Prostate Cancer Using 11C-Choline PET/Computed Tomography

This article reviews the role of ¹¹C-choline-PET/computed tomography (CT) in patients with prostate cancer for diagnosis, staging, and restaging the disease in case of biochemical recurrence after primary treatment. The main application of this imaging procedure is restaging of the disease in case of biochemical recurrence. ¹¹C-Choline-PET/CT proved its value for metastases-directed salvage therapies and for monitoring therapy response in castration-resistant patients. Prostate-specific antigen and prostate-specific antigen kinetics values confirmed their correlation with ¹¹C-choline PET/CT sensitivity.¹¹C-CholinePET/CT, despite low sensitivity to stage disease or in case of biochemical failure with low PSA levels, has an important impact on the management of patients with prostate cancer.

New frontiers in prostate cancer imaging: clinical utility of prostate-specific membrane antigen positron emission tomography

Prostate-specific membrane antigen positron emission tomography (PSMA PET) is a relatively new method of imaging prostate cancer that increases diagnostic accuracy in detecting and guiding management in various stages of the disease pathway. Gallium-68-labelled PSMA PET has increased the sensitivity of detection of disease recurrence at low PSA levels, thus allowing an optimal window for salvage treatment. Apart from its use in disease recurrence, PSMA PET has the potential for increasing sensitivity and specificity for primary tumour localisation and in detecting lymph node disease, leading to a more accurate initial staging of the condition. In advanced disease, the use of PSMA PET may be able to assess response to treatment and also guide treatment with radionuclide therapy. Newer ligands under development might provide avenues for theranostic or personalised therapy applications with early data showing high PSA response rates. The rate of translation of PSMA PET into clinical practice has been remarkable. The use of this modality is likely to increase with future efforts to modify the radiotracer including ¹⁸F labelling to improve availability.

68Ga-PSMA-PET/CT in Patients With Biochemical Prostate Cancer Recurrence and Negative 18F-Choline-PET/CT

PURPOSE

Investigating the value of Ga-PSMA-PET/CT in biochemically recurring prostate cancer patients with negative F-choline-PET/CT.

PATIENTS AND METHODS

One hundred thirty-nine consecutive patients with biochemical recurrence after curative (surgery and/or radiotherapy) therapy were offered participation in this sequential clinical imaging approach. Patients first underwent an F-choline-PET/CT. If negative, an additional Ga-PSMA-PET/CT was offered. One hundred twenty-five of 139 eligible patients were included in the study; 32 patients underwent additional Ga-PSMA-PET/CT. Patients with equivocal findings (n = 5) on F-choline-PET/CT and those who declined the additional Ga-PSMA-PET/CT (n = 9) were excluded. Images were analyzed visually for the presence of suspicious lesions. Findings on PET/CT were correlated with PSA level, PSA doubling time (dt), and PSA velocity (vel).

RESULTS

The overall detection rates were 85.6% (107/125) for the sequential imaging approach and 74.4% (93/125) for F-choline-PET/CT alone. Ga-PSMA-PET/CT detected sites of recurrence in 43.8% (14/32) of the choline-negative patients. Detection rates of the sequential imaging approach and F-choline-PET/CT alone increased with higher serum PSA levels and PSA vel. Subgroup analysis of Ga-PSMA-PET/CT in F-choline negative patients revealed detection rates of 28.6%, 45.5%, and 71.4% for PSA levels of 0.2 or greater to less than 1 ng/mL, 1 to 2 ng/mL, and greater than 2 ng/mL, respectively.

CONCLUSIONS

The sequential imaging approach designed to limit Ga-PSMA imaging to patients with negative choline scans resulted in high detection rates. Ga-PSMA-PET/CT identified sites of recurrent disease in 43.8% of the patients with negative F-choline PET/CT scans.