Multiparametric Magnetic Resonance Imaging Is an Independent Predictor of Salvage Radiotherapy Outcomes After Radical Prostatectomy

Prostate-Specific Membrane Antigen Positron Emission Tomography/Computed Tomography-Based Clinical Target Volume Delineation Guideline for Postprostatectomy Salvage Radiation Therapy: The PERYTON Guideline

PURPOSE

Prostate-specific membrane antigen positron emission tomography/computed tomography (PSMA PET/CT) scan is the standard imaging procedure for biochemical recurrent prostate cancer postprostatectomy because of its high detection rate at low serum prostate-specific antigen levels. However, existing guidelines for clinical target volume (CTV) in prostate bed salvage external beam radiation therapy (sEBRT) are primarily based on experience-based clinical consensus and have been validated using conventional imaging modalities. Therefore, this study aimed to optimize CTV definition in sEBRT by using PSMA PET/CT-detected local recurrences (LRs).

METHODS AND MATERIALS

Patients with suspected LR on PSMA PET/CT postprostatectomy were retrospectively enrolled in 9 Dutch centers. Anonymized scans were centrally reviewed by an expert nuclear medicine physician. Each boundary of the CTV guideline from the Groupe Francophone de Radiothérapie en Urologie (GFRU) was evaluated and adapted to improve the accuracy and coverage of the area at risk of LR (CTV) on PSMA PET/CT. The proposed CTV adaptation was discussed with the radiation oncologists of the participating centers, and final consensus was reached. To assess reproducibility, the participating centers were asked to delineate 3 new cases according to the new PERYTON-CTV, and the submitted contours were evaluated using the Dice similarity coefficient (DSC).

RESULTS

After central review, 93 LRs were identified on 83 PSMA PET/CTs. The proposed CTV definition improved the coverage of PSMA PET/CT-detected LRs from 67% to 96% compared with the GFRU-CTV, while reducing the GFRU-CTV by 25%. The new CTV was highly reproducible, with a mean DSC of 0.82 (range, 0.81-0.83).

CONCLUSIONS

This study contributes to the optimization of CTV definition in postprostatectomy sEBRT by using the pattern of LR detected on PSMA PET/CT. The PERYTON-CTV is highly reproducible across the participating centers and ensures coverage of 96% LRs while reducing the GFRU-CTV by 25%.

ESTRO ACROP consensus recommendation on the target volume definition for radiation therapy of macroscopic prostate cancer recurrences after radical prostatectomy

Background

The European Society for Radiotherapy & Oncology (ESTRO) Advisory Committee for Radiation Oncology Practice (ACROP) panel on prostate bed delineation reflected on macroscopic local recurrences in patients referred for postoperative radiotherapy (PORT), a challenging situation without standardized approach, and decided to propose a consensus recommendation on target volume selection and definition.

Methods

An ESTRO ACROP contouring consensus panel consisting of 12 radiation oncologists and one radiologist, all with subspecialty expertise in prostate cancer, was established. Participants were asked to delineate the prostate bed clinical target volumes (CTVs) in two separate clinically relevant scenarios: a local recurrence at the seminal vesicle bed and one apically at the level of the anastomosis. Both recurrences were prostate-specific membrane antigen (PSMA)-avid and had an anatomical correlate on magnetic resonance imaging (MRI). Participants also answered case-specific questionnaires addressing detailed recommendations on target delineation. Discussions via electronic mails and videoconferences for final editing and consensus were performed.

Results

Contouring of the two cases confirmed considerable variation among the panelists. Finally, however, a consensus recommendation could be agreed upon. Firstly, it was proposed to always delineate the entire prostate bed as clinical target volume and not the local recurrence alone. The panel judged the risk of further microscopic disease outside of the visible recurrence too high to safely exclude the rest of the prostate bed from the CTV. A focused, "stereotactic" approach should be reserved for re-irradiation after previous PORT. Secondly, the option of a focal boost on the recurrence was discussed.

Conclusion

Radiation oncologists are increasingly confronted with macroscopic local recurrences visible on imaging in patients referred for postoperative radiotherapy. It was recommended to always delineate and irradiate the entire prostate bed, and not the local recurrence alone, whatever the exact location of that recurrence. Secondly, specific dose-escalation on the macroscopic recurrence should only be considered if an anatomic correlate is visible. Such a focal boost is probably feasible, provided that OAR constraints are prioritized. Possible dose is also dependent on the location of the recurrence. Its potential benefit should urgently be investigated in prospective clinical trials.

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

OBJECTIVE

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSION

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

The Prognostic Value of DCE-MRI Findings before Salvage Radiotherapy after Radical Prostatectomy

BACKGROUND

To investigate the predictive role of dynamic contrast-enhanced-magnetic resonance imaging (DCE-MRI) findings before salvage radiotherapy after radical prostatectomy (RP).

METHODS

This retrospective study selected patients with biochemical failure (BF) after RP restaged with DCE-MRI. Patients underwent sRT in 30 fractions delivering 66-69 Gy and 73.5 Gy to the prostatic fossa and to the local failure as per DCE-MRI, respectively. Pelvic nodes were treated to 54 Gy in selected patients. The endpoint was BF after sRT.

RESULTS

In total, 236 patients were analyzed and 146 (61.9%) had presumed local failure at DCE-MRI: 54.8%, 23.8% and 21.4% were found at the vesico-urethral anastomosis (VUA), the bladder neck and the retro-vesical space, respectively. The presence of a local failure at DCE-MRI halved the risk of BF; VUA-only location and lesion volume were independently correlated with survival without evidence of biochemical failure (bNED) at multivariable analysis. For patients with VUA-only disease up to 0.4 cc, the 4-year-bNED was 94.6% (95%CI: 80.2-98.6%) as opposed to 80.9% (95%CI: 71.6-87.4%) and 73.7% (95%CI: 63.1-81.8%) for other lesions and no macrodisease, respectively.

CONCLUSIONS

DCE-MRI at restaging for BF after RP provides predictive and therapeutic information. Patients with small lesions at the VUA have an excellent prognosis after sRT.

Mapping of Local Recurrences After Radical Prostatectomy Using 68-Gallium-Prostate-Specific Membrane Antigen Positron Emission Tomography/Computed Tomography: Implications for Postprostatectomy Radiation Therapy Clinical Target Volumes

PURPOSE

Our objective is to describe the distribution of local recurrences after radical prostatectomy (RP) as delineated using 68-Gallium-prostate-specific membrane antigen positron emission tomography/computed tomography (⁶⁸Ga-PSMA PET/CT) to identify areas where current consensus guideline clinical target volumes (CTVs) are insufficient or excessive and to identify predictors of recurrence location within the fossa.

METHODS AND MATERIALS

Retrospective review of databases from 2 tertiary referral centers was performed to identify patients who underwent ⁶⁸Ga-PSMA PET/CT for biochemical recurrence after RP. Those with a component of local recurrence were included for further analysis. The epicenter of each recurrence was defined relative to reference points in 3 axes, categorized into 1 of 7 levels in the superior/inferior axis relative to the vesicourethral anastomosis, and recorded as within or outside the Faculty of Radiation Oncology Genito-urinary Group (FROGG) and Radiation Therapy Oncology Group consensus CTVs. Univariate and multivariate analysis was performed to identify predictors of recurrence location based on clinical and histopathologic variables.

RESULTS

One thousand forty-nine ⁶⁸Ga-PSMA PET/CT scans were reviewed. One hundred forty sites of local recurrence were identified on 132 scans. Relative to the vesicourethral anastomosis, 13 (9%), 31 (22%), 17 (12%), 24 (17%), 27 (19%), 20 (14%), and 8 (6%) recurrences occurred >5 mm inferior; within 5 mm above or below; and 6 to 15 mm, 16 to 25 mm, 26 to 35 mm, 36 to 45 mm, and >45 mm superiorly, respectively. Thirteen (9%) and 2 (1.4%) recurrences occurred beyond the FROGG and Radiation Therapy Oncology Group consensus CTVs, respectively, with all below the inferior CTV margin.

CONCLUSIONS

In the largest study to date mapping local recurrences after RP in 3-dimensions, we provide several insights to inform future contouring guidelines; in particular, 9% of recurrences occurred inferior to the FROGG CTV.

Can Pre-treatment Quantitative Multi-parametric MRI Predict the Outcome of Radiotherapy in Patients with Prostate Cancer?

RATIONALE AND OBJECTIVES

To investigate whether pre-treatment quantitative multiparametric MRI can predict biochemical outcome of prostate cancer (PCa) patients treated with primary radiotherapy (RT).

MATERIALS AND METHODS

Fifty-one patients with biopsy confirmed PCa underwent prostate multiparametric MRI on 3T MR scanner prior to RT. Thirty-seven men (73%) were treated with external beam RT alone, 12 men (24%) were treated with brachytherapy monotherapy, and two men (4%) were treated with external beam RT with brachytherapy boost. The index lesion was outlined by a radiologist and quantitative apparent diffusion coefficient (ADC), T2 and DCE parameters were measured. Biochemical failure was defined using the Phoenix criteria.

RESULTS

After a median follow-up of 65 months, seven patients had biochemical failure. ADC had an area under the receiver operating characteristic curve of 0.71 for predicting RT outcome with significantly lower ADC (0.78 ± 0.17 vs 0.96 ± 0.26 µm²/ms, p = 0.04) of the index lesion in men with biochemical failure. Ideal ADC cutoff point (Youdens index) was 0.96 µm²/ms which had a sensitivity of 100% and specificity of 48% for predicting biochemical failure. Kaplan-Meier analysis showed that lower ADC values were associated with significantly lower freedom from biochemical failure (FFBF, p = 0.03, no failures out of 20 men if ADC ≥ 0.96 µm²/ms; seven of 31 with failures if ADC < 0.96 µm²/ms). On multivariable analysis, ADC was associated with FFBF (HR 0.96 per increase in ADC of 0.01 um²/ms [95% CI, 0.92-1.00]; p = 0.042) after accounting for National Comprehensive Cancer Network risk category (p = 0.064) and receipt of androgen deprivation therapy (p = 0.141). Quantitative T2 and DCE parameters were not associated with biochemical outcome.

CONCLUSION

Our results suggest that quantitative ADC values of the index lesion may predict biochemical failure following primary radiotherapy in patients with PCa. Lower ADC values were associated with inferior biochemical control.

Targeting Local Recurrence After Surgery With MRI Imaging for Prostate Cancer in the Setting of Salvage Radiation Therapy

Magnetic resonance imaging (MRI) is being increasingly used for imaging suspected recurrence in prostate cancer therapy. Functional MRI with diffusion and perfusion imaging has the potential to demonstrate local recurrence even at low PSA value. Detection of recurrence can modify the management of postprostatectomy biochemical recurrence. MRI scan acquired before salvage radiotherapy is useful for the localization of recurrent tumors and also in the delineation of the target volume. The objective of this review is to assess the role and potential impact of MRI in targeting local recurrence after surgery for prostate cancer in the setting of salvage radiation therapy.

A Prospective Study Assessing the Post-Prostatectomy Detection Rate of a Presumed Local Failure at mpMR with Either 64CuCl2 or 64CuPSMA PET/CT

Simple Summary

The role of PET/CT with two novel tracers was investigated in prostate cancer patients with both a biochemical failure after surgery and a presumed local failure at multiparametric MR. Overall, both PET tracers detected only about 50% of local failures. Therefore, multiparametric MR remains the exam of choice to investigate the prostatic fossa in patients who fail surgery.

Abstract

Background: We aimed assess the detection rate (DR) of positron emission tomography/computed tomography with two novel tracers in patients referred for salvage radiotherapy (sRT) with a presumed local recurrence at multiparametric magnetic resonance (mpMR) after radical prostatectomy (RP). Methods: The present prospective study was conducted at a single institution between August 2017 and June 2020. Eligibility criteria were undetectable PSA after RP; subsequent biochemical recurrence (two consecutive PSA rises to 0.2 ng/mL or greater); a presumed local failure at mpMR; no distant metastases at ¹⁸F-fluorocholine PET/CT (CH/PET); no previous history of androgen deprivation therapy. Patients were offered both ⁶⁴CuCl₂ PET/CT (CU/PET) and ⁶⁴Cu-PSMA PET/CT (PSMA/PET) before sRT. After image co-registration, PET findings were compared to mpMR ones in terms of DR and independent predictors of DR investigated at logistic regression. Results: A total of 62 patients with 72 nodules at mpMR were accrued. Compared to mpMR (DR = 100%, 95%CI: 94.9–100%), DRs were 47.2% (95%CI: 36.1–58.6%) and 54.4% (95%CI: 42.7–65.7%) for CU/PET and PSMA/PET, respectively (p < 0.001 for both). Both experimental PET/CT performed particularly poorly at PSA levels consistent with early sRT. Conclusions: The two novel radiotracers are inferior to mpMR in restaging the prostatic fossa for sRT planning purposes, particularly in the context of early salvage radiotherapy.

Salvage therapy for prostate cancer after radical prostatectomy

More than 40% of men with intermediate-risk or high-risk prostate cancer will experience a biochemical recurrence after radical prostatectomy. Clinical guidelines for the management of these patients largely focus on the use of salvage radiotherapy with or without systemic therapy. However, not all patients with biochemical recurrence will go on to develop metastases or die from their disease. The optimal pre-salvage therapy investigational workup for patients who experience biochemical recurrence should, therefore, include novel techniques such as PET imaging and genomic analysis of radical prostatectomy specimen tissue, as well as consideration of more traditional clinical variables such as PSA value, PSA kinetics, Gleason score and pathological stage of disease. In patients without metastatic disease, the only known curative intervention is salvage radiotherapy but, given the therapeutic burden of this treatment, importance must be placed on accurate timing of treatment, radiation dose, fractionation and field size. Systemic therapy also has a role in the salvage setting, both concurrently with radiotherapy and as salvage monotherapy.

Pathological stage, surgical margin and lymphovascular invasion as prognostic factors after salvage radiotherapy for post-prostatectomy relapsed prostate cancer - outcomes and optimization strategies

Background

Salvage radiotherapy (sRT) is the main potentially curative treatment after biochemical failure/locoregional relapse post-radical prostatectomy (RP). The aim of the study was to characterize the population who underwent sRT after RP at our Department, to understand the influence of several potential prognosis factors, and to determine possible optimization strategies.

Materials and methods

We retrospectively analyzed patients undergoing sRT at our department between 2012 and 2017, evaluating patient, tumor and treatment characteristics, restaging procedures and clinical outcomes - namely biochemical relapse-free survival (BC-RFS), clinical relapse-free survival (C-RFS), additional hormone therapy-free survival (HT-FS) and overall survival (OS). We assessed potential prognostic factors by univariate and multivariate models (MVA).

Results

We included 277 patients (median age 68 years). Median pre-sRT PSA was > 0.5ng/mL in 54.9%. All underwent prostate bed irradiation. Pelvic lymph nodes were included in 9.7%. Outcome analysis was performed for 264 patients (35.6 months median follow-up). At 3 years, BC-RFS was 61.4%, C-RFS was 81.3%, HT-FS was 79.9% and OS was 96.6%. Most relapses occurred in regional lymph nodes only (47.9% patients who relapsed). On MVA, lymphovascular invasion, advanced pT-stages and negative margins negatively influenced BC-RFS (p = 0.029, p = 0.002 and p < 0.001) and HT-FS (p = 0.001, p = 0.029 and p = 0.002). C-RFS was worsened by lymphovascular invasion (p = 0.009) and negative margins (p = 0.015). These had no effect on OS. BC-RFS and HT-FS were improved when sRT started while PSA ≤ 0.5 ng/mL (p < 0.05).

Conclusion

Lymphovascular invasion, higher pT-stages and negative margins negatively affected prognosis. An early start of sRT (PSA ≤ 0.5 ng/mL) predicted better BC-RFS and HT-FS.

The prognostic value, sensitivity, and specificity of multiparametric magnetic resonance imaging before salvage radiotherapy for prostate cancer

AIM

To determine the operational characteristics of pelvic magnetic resonance imaging (MRI) prior to salvage radiation therapy (SRT) for biochemically recurrent prostate cancer following radical prostatectomy.

METHODS AND MATERIALS

We reviewed the medical records of 386 patients who underwent MRI prior to SRT. We assessed associations of pre-SRT MRI findings with biochemical recurrence (BCR), distant metastasis (DM), prostate cancer-specific mortality (PCSM), and salvage androgen deprivation therapy (ADT) use following SRT. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of MRI for detecting local recurrence were also calculated.

RESULTS

Pre-SRT MRI was positive for local recurrence in 216 patients (56%), indeterminate in 46 (12%), and negative in 124 (32%). On univariate analysis, BCR following SRT was significantly less likely for patients with positive (HR: 0.58, 95% CI: 0.42-0.8) or indeterminate (HR: 0.6: 0.36-1) MRI findings, compared to patients with negative imaging (p = 0.003). These associations remained significant on multivariate analysis (p < 0.05) and across pre-SRT PSA groups. For the entire cohort, the sensitivity of MRI for local recurrence was 61.0% (53.5-68.1%), specificity 60.0% (44.3-73.0%), PPV 86.1% (78.9-91.5%) and NPV 27.6% (19.0-37.5%). Sensitivity of MRI was better in men with higher pre-SRT PSA (80.0% for PSA > 1.0), and specificity was improved with lower pre-SRT PSA (73.9% for PSA 0.1-0.5).

CONCLUSIONS

Positive or indeterminate MRI findings prior to SRT were associated with improved biochemical control following SRT, across PSA levels. The sensitivity and specificity of MRI for local recurrence were 61% and 58.7%, respectively.

Detecting recurrent prostate Cancer using multiparametric MRI, influence of PSA and Gleason grade

BACKGROUND

The utility of multiparametric MRI (mpMRI) in detecting suspected local recurrence post radical prostatectomy (RP) may be associated with PSA and Gleason grade. The purpose of the study was to evaluate the likelihood of detecting locally recurrent prostate cancer utilizing mpMRI in patients with suspected recurrence following radical prostatectomy (RP) parsed by PSA and Gleason grade.

METHODS

One hundred ninety five patients with suspected local recurrence were imaged on a 1.5 T MRI with torso array and endorectal coil in this retrospective study. mpMRI interpretations were stratified by PSA and lower (Gleason < 7) vs. higher grade tumors (Gleason 8-10). Recursive partitioning was used to determine whether mpMRI interpretations could be classified as positive or negative.

RESULTS

The majority of mpMRI interpretations in patients with lower Gleason grade tumors and PSA < 0.5 ng/mL were negative (68/78, 87.2%, p = 0.004). The majority of mpMRI interpretations in patients with higher Gleason grade tumors and PSA > 1.5 ng/mL were positive (8/9, 88.9%, p = 0.003). Findings were corroborated by recursive partitioning, which identified a PSA = 0.5 ng/ml in patients with lower grade tumors and a PSA = 1.5 ng/mL in patients with higher grade tumors as differentiating negative and positive mpMRIs.

CONCLUSION

In the setting of suspected recurrence after RP, mpMRI results are associated with PSA and Gleason grade, both of which can help guide when mpMRI may find utility. mpMRI is likely to be low diagnostic yield and negative for recurrence (87%) in the setting of lower Gleason grade tumors and PSA < 0.5 ng/mL. mpMRI is likely to be of low diagnostic value and positive for recurrence (89%) in the setting of PSA > 1.5 ng/mL and higher grade tumors; in this case, mpMRI findings may be more useful for directing biopsy and local therapy. Between these extremes, PSA > 0.5 ng/mL and lower grade tumors or PSA < 1.5 ng/mL and higher grade tumors, mpMRI results are less predictable, suggesting greater diagnostic value for detecting recurrence post prostatectomy.

Post-treatment prostate MRI

Accurate early detection of recurrent prostate cancer after surgical or nonsurgical treatment is increasingly relevant in the era of evolving options for salvage therapy. The importance of differentiating between local tumor recurrence, distant metastatic disease, and a combination of both in a patient with biochemical recurrence of prostate cancer is essential for appropriate treatment selection. Magnetic resonance imaging (MRI) is the best test for localization and characterization of locally residual or recurrent prostate cancer. It is essential for the radiologist involved in prostate MRI interpretation to be familiar with key imaging findings and advantages of different sequences to reach a confident diagnosis in the post-treatment setting. In this pictorial review, we present imaging findings of post-treatment prostate MRI including expected post-treatment anatomy and imaging characteristics, and the typical appearances of local tumor recurrence after radical prostatectomy, radiation therapy, and focal therapy for prostate cancer. While a multi-parametric MRI approach remains key just as in the treatment-naïve gland, this review emphasizes the much greater importance of the dynamic contrast-enhanced MRI sequence for evaluation in the post-treatment setting.

Prostate cancer: more effective use of underutilized postoperative radiation therapy

Introduction: Adverse pathological features at radical prostatectomy such as extracapsular extension, seminal-vesicle involvement, positive surgical margins and/or lymph node invasion define a particular subgroup of patients that might benefit from additional treatment after surgery, in particular radiation therapy.Areas covered: Post-prostatectomy radiation is intended as adjuvant, early-salvage or salvage depending on the timing and PSA levels at the treatment. After providing the most used definitions, the high-level evidence supporting adjuvant radiation is reviewed together with the limitations affecting its utilization. In recent years early-salvage radiation was hypothesized to be a non-inferior alternative based on good-quality retrospective data. Recently, preliminary results of ongoing trials provide additional evidence. In light of the need to identify patients that will truly benefit from adjuvant radiation, clinically based and molecular tools available for this purpose are reviewed.Expert opinion: In order to tailor treatment for the patient after radical prostatectomy, there is a need for a tool that could both improve the oncological outcomes and be cost-effective. To date, genomic testing provides the most promising results that will be reasonably improved in the coming years.

Response on DCE-MRI predicts outcome of salvage radiotherapy for local recurrence after radical prostatectomy

OBJECTIVE

To assess the predictive role of response on dynamic contrast enhancement on magnetic resonance imaging (DCE-MRI) of visible local lesions in the setting of salvage radiotherapy (sRT) after radical prostatectomy.

METHODS

All patients referred for sRT for biochemical failure after radical prostatectomy from February 2014 to September 2016 were considered eligible if they had been restaged with DCE-MRI and had been found to have a visible lesion in the prostatic bed, but no distant/nodal disease on choline positron emission tomography (PET)-computed tomography (CT). Eligible patients were contacted during follow-up and offered reimaging with serial DCE-MRI until lesion resolution. Complete response (CR) was defined as the disappearance of the target lesion on DCE-MRI; prostate-specific antigen (PSA) recurrence was defined as a 0.2 ng/mL PSA rise above the nadir. Median follow-up after sRT was 41.5 months (range, 12.1-61.2 months).

RESULTS

Fifty-nine patients agreed to undergo repeated DCE-MRI for a total of 64 studied lesions. Overall, 57 lesions (89.1%) showed a CR after 1 (51 patients) or 2 (6 patients) scans, while 7 lesions did not show any change (no response [NR]). At 42 months, no evidence of biochemical disease (bNED) survival was 74.7±6.4% and 64.3±21.0% for patients with CR and NR lesions, respectively (hazard ratio [HR], 3.181; 95% confidence interval [CI], 0.157-64.364; p = 0.451). When only patients treated with sRT without androgen deprivation were selected (n = 41), bNED survival rates at 42 months were 72.1±8.0% and 0, respectively (HR, 52.830; 95% CI, 1.893-1474.110; p = 0.020).

CONCLUSIONS

Patients whose lesions disappear during follow-up have a better outcome than those with unchanged lesions after sRT alone.

The Contribution of Multiparametric Pelvic and Whole-Body MRI to Interpretation of 18F-Fluoromethylcholine or 68Ga-HBED-CC PSMA-11 PET/CT in Patients with Biochemical Failure After Radical Prostatectomy

Our purpose was to assess whether the addition of data from multiparametric pelvic MRI (mpMR) and whole-body MRI (wbMR) to the interpretation of 18F-fluoromethylcholine (18F-FCH) or 68Ga-HBED-CC PSMA-11 (68Ga-PSMA) PET/CT (=PET) improves the detection of local tumor recurrence or of nodal and distant metastases in patients after radical prostatectomy with biochemical failure. Methods: The current analysis was performed as part of a prospective, multicenter trial on 18F-FCH or 68Ga-PSMA PET, mpMR, and wbMR. Eligible men had an elevated level of prostate-specific antigen (PSA) (>0.2 ng/mL) and high-risk features (Gleason score > 7, PSA doubling time < 10 mo, or PSA > 1.0 ng/mL) with negative or equivocal conventional imaging results. PET was interpreted with mpMR and wbMR in consensus by 2 radiologists and compared with prospective interpretation of PET or MRI alone. Performance measures of each modality (PET, MRI, and PET/mpMR-wbMR) were compared for each radiotracer and each individual patient (for 18F-FCH, or 68Ga-PSMA for patients who had 68Ga-PSMA PET) and to a composite reference standard. Results: There were 86 patients with PET (18F-FCH [n = 76] and/or 68Ga-PSMA [n = 26]) who had mpMR and wbMR. Local tumor recurrence was detected in 20 of 76 (26.3%) on 18F-FCH PET/mpMR, versus 11 of 76 (14.5%) on 18F-FCH PET (P = 0.039), and in 11 of 26 (42.3%) on 68Ga-PSMA PET/mpMR, versus 6 of 26 (23.1%) on 68Ga-PSMA PET (P = 0.074). Per patient, PET/mpMR was more often positive for local tumor recurrence than PET (P = 0.039) or mpMR (P = 0.019). There were 20 of 86 patients (23.3%) with regional nodal metastases on both PET/wbMR and PET (P = 1.0) but only 12 of 86 (14%) on wbMR (P = 0.061). Similarly, there were more nonregional metastases detected on PET/wbMR than on PET (P = 0.683) or wbMR (P = 0.074), but these differences did not reach significance. Compared with the composite reference standard for the detection of disease beyond the prostatic fossa, PET/wbMR, PET, and wbMR had sensitivity of 50%, 50%, and 8.3%, respectively, and specificity of 97.1%, 97.1%, and 94.1%, respectively. Conclusion: Interpretation of PET/mpMR resulted in a higher detection rate for local tumor recurrence in the prostatic bed in men with biochemical failure after radical prostatectomy. However, the addition of wbMR to 18F-FCH or 68Ga-PSMA PET did not improve detection of regional or distant metastases.

Recurrent prostate cancer after radical prostatectomy: restaging performance of 18F-choline hybrid PET/MRI

To evaluate the diagnostic performance of a whole-body 18F-choline (FCH) hybrid PET/MRI for prostate cancer patients at biochemical relapse after radical prostatectomy (RP) compared to pelvic multiparametric MRI (mpMRI), one of the standard imaging modality for this patient population. From 2010 to 2016, 58 whole-body FCH PET/MRI studies with mpMRI acquisitions were performed in 53 prostate cancer patients relapsing after curative RP. Median PSA and PSA doubling time (PSA DT) at PET study were 1.5 ng/ml and 6.5 months, respectively. The overall positivity rate of FCH PET/MRI was 58.6% (n = 34), dropping to 44% in patients with a PSA ≤ 2 ng/ml (n = 36). Median PSA values in positive and negative PET/MRI studies were 2.2 ng/ml and 0.8 ng/ml, respectively, with no differences in PSA DT (6.5 vs. 6.6 months). A PSA value ≥ 1.5 ng/ml was a significant predictor of positivity on PET/MRI studies. Compared to PET, mpMRI identified more local relapses (17 vs. 14, p = 0.453) while PET outperformed whole-body Dixon MRI for regional (16 vs. 9, p = 0.016) and distant (12 vs. 6, p = 0.031) metastases. Compared to pelvic mpMRI, the treatment approach turned out to be influenced more frequently using whole-body FCH hybrid PET/MRI studies (58.6% vs. 38%). In prostate cancer patients with biochemical recurrence after RP, whole-body FCH PET/MRI achieved a higher detection rate of nodal/distant metastases compared to pelvic mpMRI alone, increasing the change of treatment strategy by more than 20%.

Prognostic Value of Biochemical Recurrence Following Treatment with Curative Intent for Prostate Cancer: A Systematic Review

CONTEXT

In men with prostate cancer (PCa) treated with curative intent, controversy exists regarding the impact of biochemical recurrence (BCR) on oncological outcomes.

OBJECTIVE

To perform a systematic review of the existing literature on BCR after treatment with curative intent for nonmetastatic PCa. Objective 1 is to investigate whether oncological outcomes differ between patients with or without BCR. Objective 2 is to study which clinical factors and tumor features in patients with BCR have an independent prognostic impact on oncological outcomes.

EVIDENCE ACQUISITION

Medline, Medline In-Process, Embase, and the Cochrane Central Register of Controlled Trials were searched. For objective 1, prospective and retrospective studies comparing survival outcomes of patients with or without BCR following radical prostatectomy (RP) or radical radiotherapy (RT) were included. For objective 2, all studies with at least 100 participants and reporting on prognostic patient and tumor characteristics in patients with BCR were included. Risk-of-bias and confounding assessments were performed according to the Quality in Prognosis Studies tool. Both a narrative synthesis and a meta-analysis were undertaken.

EVIDENCE SYNTHESIS

Overall, 77 studies were included for analysis, of which 14 addressed objective 1, recruiting 20 406 patients. Objective 2 was addressed by 71 studies with 29 057, 11 301, and 4272 patients undergoing RP, RT, and a mixed population (mix of patients undergoing RP or RT as primary treatment), respectively. There was a low risk of bias for study participation, confounders, and statistical analysis. For most studies, attrition bias, and prognostic and outcome measurements were not clearly reported. BCR was associated with worse survival rates, mainly in patients with short prostate-specific antigen doubling time (PSA-DT) and a high final Gleason score after RP, or a short interval to biochemical failure (IBF) after RT and a high biopsy Gleason score.

CONCLUSIONS

BCR has an impact on survival, but this effect appears to be limited to a subgroup of patients with specific clinical risk factors. Short PSA-DT and a high final Gleason score after RP, and a short IBF after RT and a high biopsy Gleason score are the main factors that have a negative impact on survival. These factors may form the basis of new BCR risk stratification (European Association of Urology BCR Risk Groups), which needs to be validated formally.

PATIENT SUMMARY

This review looks at the risk of death in men who shows rising prostate-specific antigen (PSA) in the blood test performed after curative surgery or radiotherapy. For many men, rising PSA does not mean that they are at a high risk of death from prostate cancer in the longer term. Men with PSA that rises shortly after they were treated with radiotherapy or rapidly rising PSA after surgery and a high tumor grade for both treatment modalities are at the highest risk of death. These factors may form the basis of new risk stratification (European Association of Urology biochemical recurrence Risk Groups), which needs to be validated formally.

Prospective, Multisite, International Comparison of 18F-Fluoromethylcholine PET/CT, Multiparametric MRI, and 68Ga-HBED-CC PSMA-11 PET/CT in Men with High-Risk Features and Biochemical Failure After Radical Prostatectomy: Clinical Performance and Patient Outcomes

A significant proportion of men with rising prostate-specific antigen (PSA) levels after radical prostatectomy (RP) fail prostate fossa (PF) salvage radiation treatment (SRT). This study was done to assess the ability of 18F-fluoromethylcholine (18F-FCH) PET/CT (hereafter referred to as 18F-FCH), 68Ga-HBED-CC PSMA-11 PET/CT (hereafter referred to as PSMA), and pelvic multiparametric MRI (hereafter referred to as pelvic MRI) to identify men who will best benefit from SRT. Methods: Prospective, multisite imaging studies were carried out in men who had rising PSA levels after RP, high-risk features, and negative/equivocal conventional imaging results and who were being considered for SRT. 18F-FCH (91/91), pelvic MRI (88/91), and PSMA (31/91) (Australia) were all performed within 2 wk. Imaging was interpreted by experienced local/central interpreters who were masked with regard to other imaging results, with consensus being reached for discordant interpretations. Expected management was documented before and after imaging, and data about all treatments and PSA levels were collected for 3 y. The treatment response to SRT was defined as a reduction in PSA levels of >50% without androgen deprivation therapy. Results: The median Gleason score, PSA level at imaging, and PSA doubling time were 8, 0.42 (interquartile range, 0.29-0.93) ng/mL, and 5.0 (interquartile range, 3.3-7.6) months. Recurrent prostate cancer was detected in 28% (25/88) by pelvic MRI, 32% (29/91) by 18F-FCH, and 42% (13/31) by PSMA. This recurrence was found within the PF in 21.5% (19/88), 13% (12/91), and 19% (6/31) and at sites outside the PF (extra-PF) in 8% (7/88), 19% (17/91), and 32% (10/31) by MRI, 18F-FCH, and PSMA, respectively (P < 0.004). A total of 94% (16/17) of extra-PF sites on 18F-FCH were within the pelvic MRI field. Intrapelvic extra-PF disease was detected in 90% (9/10) by PSMA and in 31% (5/16) by MRI. 18F-FCH changed management in 46% (42/91), and MRI changed management in 24% (21/88). PSMA provided additional management changes over 18F-FCH in 23% (7/31). The treatment response to SRT was higher in men with negative results or disease confined to the PF than in men with extra-PF disease (18F-FCH 73% [32/44] versus 33% [3/9] [P < 0.02], pelvic MRI 70% [32/46] versus 50% [2/4] [P was not significant], and PSMA 88% [7/8] versus 14% [1/7] [P < 0.005]). Men with negative imaging results (MRI, 18F-FCH, or PSMA) had high (78%) SRT response rates. Conclusion:18F-FCH and PSMA had high detection rates for extra-PF disease in men with negative/equivocal conventional imaging results and rising PSA levels after RP. These findings affected management and treatment responses, suggesting an important role for PET in triaging men being considered for curative SRT.