[11C]Choline PET/CT in therapy response assessment of a neoadjuvant therapy in locally advanced and high risk prostate cancer before radical prostatectomy

PURPOSE

Recent studies have shown promising results of neoadjuvant therapy in prostate cancer (PC). The aim of this study was to evaluate the potential of [11C]Choline PET/CT in therapy response monitoring after combined neoadjuvant docetaxel chemotherapy and complete androgen blockade in locally advanced and high risk PC patients.

RESULTS

In [11C]Choline PET/CT there was a significant decrease of SUVmax and SUVmean (p = 0.004, each), prostate volume (p = 0.005) and PSA value (p = 0.003) after combined neoadjuvant therapy. MRI showed a significant prostate and tumor volume reduction (p = 0.003 and 0.005, respectively). Number of apoptotic cells was significantly higher in prostatectomy specimens of the therapy group compared to pretherapeutic biopsies and the control group (p = 0.02 and 0.003, respectively).

METHODS

11 patients received two [11C]Choline PET/CT and MRI scans before and after combined neoadjuvant therapy followed by radical prostatectomy and pelvic lymph node dissection. [11C]Choline uptake, prostate and tumor volume, PSA value (before/after neoadjuvant therapy) and apoptosis (of pretherapeutic biopsy/posttherapeutic prostatectomy specimens of the therapy group and prostatectomy specimens of a matched control group without neoadjuvant therapy) were assessed and tested for differences and correlation using SPSS.

CONCLUSIONS

The results showing a decrease in choline uptake after combined neoadjuvant therapy (paralleled by regressive and apoptotic changes in histopathology) confirm the potential of [11C]Choline PET/CT to monitor effects of neoadjuvant therapy in locally advanced and high risk PC patients. Further studies are recommended to evaluate its use during the course of neoadjuvant therapy for early response assessment.

Radiation Dosimetry for 177Lu-PSMA I&T in Metastatic Castration-Resistant Prostate Cancer: Absorbed Dose in Normal Organs and Tumor Lesions

Prostate-specific membrane antigen (PSMA)-targeted radioligand therapy is increasingly used in metastatic castration-resistant prostate cancer. We aimed to estimate the absorbed doses for normal organs and tumor lesions using ¹⁷⁷Lu-PSMA I&T (I&T is imaging and therapy) in patients undergoing up to 4 cycles of radioligand therapy. Results were compared with pretherapeutic Glu-NH-CO-NH-Lys-(Ahx)-[⁶⁸Ga(HBEDCC)] (⁶⁸Ga-PSMA-HBED-CC) PET. Methods: A total of 34 cycles in 18 patients were analyzed retrospectively. In 15 patients the first, in 9 the second, in 5 the third, and in 5 the fourth cycle was analyzed, respectively. Whole-body scintigraphy was performed at least between 30-120 min, 24 h, and 6-8 d after administration. Regions of interest covering the whole body, organs, and up to 4 tumor lesions were drawn. Organ and tumor masses were derived from pretherapeutic ⁶⁸Ga-PSMA-HBED-CC PET/CT. Absorbed doses for individual cycles were calculated using OLINDA/EXM. SUVs from pretherapeutic PET were compared with absorbed doses and with change of SUV. Results: The mean whole-body effective dose for all cycles was 0.06 ± 0.03 Sv/GBq. The mean absorbed organ doses were 0.72 ± 0.21 Gy/GBq for the kidneys; 0.12 ± 0.06 Gy/GBq for the liver; and 0.55 ± 0.14 Gy/GBq for the parotid, 0.64 ± 0.40 Gy/GBq for the submandibular, and 3.8 ± 1.4 Gy/GBq for the lacrimal glands. Absorbed organ doses were relatively constant among the 4 different cycles. Tumor lesions received a mean absorbed dose per cycle of 3.2 ± 2.6 Gy/GBq (range, 0.22-12 Gy/GBq). Doses to tumor lesions gradually decreased, with 3.5 ± 2.9 Gy/GBq for the first, 3.3 ± 2.5 Gy/GBq for the second, 2.7 ± 2.3 Gy/GBq for the third, and 2.4 ± 2.2 Gy/GBq for the fourth cycle. SUVs of pretherapeutic PET moderately correlated with absorbed dose (r = 0.44, P < 0.001 for SUV_max; r = 0.43, P < 0.001 for SUV_mean) and moderately correlated with the change of SUV (r = 0.478, P < 0.001 for SUV_max, and r = 0.50, P < 0.001 for SUV_mean). Conclusion: Organ- and tumor-absorbed doses for ¹⁷⁷Lu-PSMA I&T are comparable to recent reports and complement these with information on an excellent correlation between the 4 therapy cycles. With the kidneys representing the critical organ, a cumulative activity of 40 GBq of ¹⁷⁷Lu-PSMA I&T appears to be safe and justifiable. The correlation between pretherapeutic SUV and absorbed tumor dose emphasizes the need for PSMA-ligand PET imaging for patient selection.

A 2-Gene Panel Derived From Prostate Cancer-Enhanced Transcripts in Whole Blood Is Prognostic for Survival and Predicts Treatment Benefit in Metastatic Castration-Resistant Prostate Cancer

BACKGROUND

To determine a prognostic model derived from prostate cancer-enhanced transcripts in whole blood of castration-resistant prostate cancer (CRPC) patients and explore its applicability as a surrogate of treatment response.

METHODS

Six out of twenty-three selected transcripts were identified as specific for detection of metastatic prostate cancer cells in peripheral blood using quantitative polymerase chain reaction (qPCR). Their prognostic value was explored in whole blood samples of a training cohort (n = 22 CRPC patients, New York, USA). A resulting 2-gene panel (2GP) including KLK2 and TMPRSS2 was validated in an independent cohort with pre- and post-treatment blood draws after 9-16 weeks of systemic treament (n = 86 CRPC patients, Munich, Germany). Overall survival (OS), prostate-specific antigen progression-free survival (PSA-PFS), and clinical PFS were analyzed. Kaplan-Meier and cox regression analyses were performed.

RESULTS

An unfavorable 2GP (≥1 marker positive) identified patients with poor survival (median OS 10.0 months [95%CI 5.7-14.2] vs. not reached; P = 0.023). This was validated in an independent cohort at pre-treatment (median OS 7.8 [95%CI 6.5-9.2] vs. 17.3 months [95%CI 10.7-23.8]; P = 0.004) and post-treatment blood draw (median OS 5.0 [95%CI 0.0-10.0] vs. 18.0 months [95%CI 9.5-26.6]; P = 0.003). The 2GP independently predicted OS on multivariate analysis (hazard ratio 2.1 [95%CI 1.1-4.0]; P = 0.034) and performed better than PSA decline at correlation with OS. Conversion to favorable 2GP during treatment correlated with improved OS (7.8 to 20.9 months), PSA-PFS (2.8 to 12.0 months), and clinical PFS (4.6 to 8.0 months).

CONCLUSIONS

The established 2GP is prognostic for survival at pre- and post-treatment blood draw in CRPC patients and conversion to favorable 2GP predicts treatment benefit. Prostate 76:1160-1168, 2016. © 2016 Wiley Periodicals, Inc.

Prospective evaluation of [11C]Choline PET/CT in therapy response assessment of standardized docetaxel first-line chemotherapy in patients with advanced castration refractory prostate cancer

PURPOSE

The aim of this study was to prospectively evaluate the value of [¹¹C] Choline PET/CT in monitoring early and late response to a standardized first-line docetaxel chemotherapy in castration refractory prostate cancer (mCRPC) patients.

METHODS

Thirty-two patients were referred for [¹¹C] Choline PET/CT before the start of docetaxel chemotherapy, after one and ten chemotherapy cycles (or - in case of discontinuation - after the last administered cycle) for therapy response assessment. [¹¹C] Choline uptake (SUV_max, SUV_mean), CT derived Houndsfield units (HU_max, HU_mean), and volume of bone, lung, and nodal metastases and local recurrence were measured semi-automatically at these timepoints. Change in SUV_max, SUV_mean, HU_max, HU_mean, and volume was assessed between PET 2 and 1 (early response assessment, ERA) and PET 3 and 1 (late response assessment, LRA) on a patient and lesion basis. Results of PET/CT were compared to clinically used RECIST 1.1 and clinical criteria based therapy response assessment including PSA for defining progressive disease (PD) and non-progressive disease (nPD), respectively. Relationships between changes of SUV_max and SUV_mean (early and late) and changes of PSA_early and PSA_late were evaluated. Prognostic value of initial SUV_max and SUV_mean was assessed. Statistical analyses were performed using SPSS.

RESULTS

In the patient-based ERA and LRA there were no statistically significant differences in change of choline uptake, HU, and volume between PD and nPD applying RECIST or clinical response criteria. In the lesion-based ERA, decrease in choline uptake of bone metastases was even higher in PD (applying RECIST criteria), whereas in LRA the decrease was higher in nPD (applying clinical criteria). There were only significant correlations between change in choline uptake and PSA in ERA in PD, in LRA no significant correlations were discovered. Initial SUV_max and SUV_mean were statistically significantly higher in nPD (applying clinical criteria).

CONCLUSION

There is no significant correlation between change in choline uptake in [¹¹C] Choline PET/CT and clinically routinely used objective response assessment during the early and late course of docetaxel chemotherapy. Therefore, [¹¹C] Choline PET/CT seems to be of limited use in therapy response assessment in standardized first-line chemotherapy in mCRPC patients.

Comparison of bone scintigraphy and 68Ga-PSMA PET for skeletal staging in prostate cancer

PURPOSE

The aim of our study was to compare the diagnostic performance of ⁶⁸Ga-PSMA PET and ^99mTc bone scintigraphy (BS) for the detection of bone metastases in prostate cancer (PC) patients.

METHODS

One hundred twenty-six patients who received planar BS and PSMA PET within three months and without change of therapy were extracted from our database. Bone lesions were categorized into benign, metastatic, or equivocal by two experienced observers. A best valuable comparator (BVC) was defined based on BS, PET, additional imaging, and follow-up data. The cohort was further divided into clinical subgroups (primary staging, biochemical recurrence, and metastatic castration-resistant prostate cancer [mCRPC]). Additionally, subgroups of patients with less than 30 days delay between the two imaging procedures and with additional single-photon emission computed tomography (SPECT) were analyzed.

RESULTS

A total of 75 of 126 patients were diagnosed with bone metastases. Sensitivities and specificities regarding overall bone involvement were 98.7-100 % and 88.2-100 % for PET, and 86.7-89.3 % and 60.8-96.1 % (p < 0.001) for BS, with ranges representing results for 'optimistic' or 'pessimistic' classification of equivocal lesions. Out of 1115 examined bone regions, 410 showed metastases. Region-based analysis revealed a sensitivity and specificity of 98.8-99.0 % and 98.9-100 % for PET, and 82.4-86.6 % and 91.6-97.9 % (p < 0.001) for BS, respectively. PSMA PET also performed better in all subgroups, except patient-based analysis in mCRPC.

CONCLUSION

Ga-PSMA PET outperforms planar BS for the detection of affected bone regions as well as determination of overall bone involvement in PC patients. Our results indicate that BS in patients who have received PSMA PET for staging only rarely offers additional information; however, prospective studies, including a standardized integrated x-ray computed tomography (SPECT/CT) protocol, should be performed in order to confirm the presented results.

Chromogranin A and neurone-specific enolase serum levels as predictors of treatment outcome in patients with metastatic castration-resistant prostate cancer undergoing abiraterone therapy

OBJECTIVE

To determine the impact of elevated neuroendocrine serum markers on treatment outcome in patients with metastatic castration-resistant prostate cancer (mCRPC) undergoing treatment with abiraterone in a post-chemotherapy setting.

PATIENTS AND METHOD

Chromogranin A (CGa) and neurone-specific enolase (NSE) were determined in serum drawn before treatment with abiraterone from 45 patients with mCRPC. Outcome measures were overall survival (OS), prostate-specific antigen (PSA) response defined by a PSA level decline of ≥50%, PSA progression-free survival (PSA-PFS), and clinical or radiographic PFS.

RESULTS

The CGa and NSE serum levels did not correlate (P = 0.6). Patients were stratified in to low- (nine patients), intermediate- (18) or high-risk (18) groups according to elevation of none, one, or both neuroendocrine markers, respectively. The risk groups correlated with decreasing median OS (median OS not reached vs 15.3 vs 6.6 months; P < 0.001), decreasing median clinical or radiographic PFS (8.3 vs 4.4 vs 2.7 months; P = 0.001) and decreasing median PSA-PFS (12.0 vs 3.2 vs 2.7 months; P = 0.012). In multivariate Cox regression analysis the combination of CGa and NSE (≥1 marker positive vs both markers negative) remained significant predictors of OS, clinical or radiographic PFS, and PSA-PFS. We did not observe a correlation with PSA response (63% vs 35% vs 31%; P = 0.2).

CONCLUSION

Chromogranin A and NSE did not predict PSA response in patients with mCRPC treated with abiraterone. However, we observed a correlation with shorter PSA-PFS, clinical or radiographic PFS, and OS. This might be due to an elevated risk of developing resistance under abiraterone treatment related to neuroendocrine differentiation.

[Update 2016 - Immunotherapy for urothelial carcinoma]

Advanced urothelial carcinoma of the bladder is an aggressive tumor with a poor prognosis. Besides surgical therapy, classical chemotherapy with platinum compounds is the mainstay of advanced bladder cancer treatment. In recent years, immune modulating therapies have come into the focus of clinical trials. This review provides an overview of the biological mechanisms and immuno-oncological drugs that are currently being analyzed in clinical trials as well as established standard therapies.

IMvigor 210, a phase II trial of atezolizumab (MPDL3280A) in platinum-treated locally advanced or metastatic urothelial carcinoma (mUC)

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Background: The ORR and survival of mUC patients (pts) who progress after platinum-based chemotherapy (pctx) are poor. Atezolizumab (atezo) reinvigorates antitumor immunity by targeting PD-L1 and has shown promising Ph 1 activity in mUC. Methods: IMvigor 210 cohort 2 (NCT02108652) enrolled 316 mUC pts who progressed during or following pctx. Pts received atezo at 1200 mg IV q3w until loss of clinical benefit. The SP142 IHC assay centrally assessed PD-L1 expression. Pts/investigators were blinded to PD-L1 status. Co-primary endpoints were confirmed ORR by RECIST v1.1 per central review (IRF) and modified (m) RECIST per investigator, which were met if null hypothesis (ORR = 10%) was rejected (α = 5%). ORR endpoints were stratified by PD-L1 tumor-infiltrating immune cell (IC) status: IC2/3, IC1/2/3, all comers. Results: Efficacy/safety-evaluable pts (N = 311) had a median age of 66 y, CrCl < 60 mL/min (35%) and ≥ 2 prior regimens for mUC (40%). Many had poor prognostic factors (Table). At 5/5/15 data cutoff (follow up ≥ 24 w), 43/47 responding pts had ongoing responses. Both IRF (Table) and mRECIST ORR correlated with IC status. Durable responses were seen including poor prognostic subgroups (Table). mDOR was not reached in any PD-L1 or prognostic subgroup. mPFS was 2.1 mo in all PD-L1 subgroups. Median treatment duration was 12 w (range 0-46). Treatment-related AEs (most commonly fatigue) occurred in 66% of pts (all Grade); 15% had G3-4 related AE and 4% had G3-4 immune-mediated AE. 27% of AEs led to dose interruption and 3% led to withdrawal. No renal toxicity was seen. Conclusions: IMvigor 210, the first Ph 2 study targeting PD-L1/PD-1 in mUC, demonstrated significantly improved ORR vs historic controls. Responses were durable and associated with higher PD-L1 IC expression; poor prognostic factors did not preclude response. Atezo was well tolerated, and a randomized Ph 3 study vs ctx is ongoing (IMvigor 211; NCT02302807). Clinical trial information: NCT02108652. [Table: see text]

[YB-1-based virotherapy: A new therapeutic intervention for transitional cell carcinoma of the bladder?]

Therapeutic intervention using oncolytic viruses is called virotherapy. This type of virus is defined by the ability to replicate in tumor cells only and to destroy these cells upon replication. In addition, this virus type is able to induce a tumor-directed immune response. Early clinical trials have confirmed the safety profile of oncolytic viruses. Currently, different groups are working on the development of oncolytic viruses with a focus on treatment of nonmuscle invasive bladder cancer (NMIBC). A preliminary active recruiting clinical phase II/III trial ongoing in patients with a NMIBC was recently implemented in the United States. Our research group developed an oncolytic adenovirus that will soon enter a clinical phase I trial in patients diagnosed with glioma. This virus is being further modified for the treatment of NMIBC. In this review article, recent developments in the design and use of virotherapy in bladder cancer are summarized.

Detection of Circulating Tumor Cells in Locally Advanced High-risk Prostate Cancer During Neoadjuvant Chemotherapy and Radical Prostatectomy

AIM

Circulating tumour cells (CTCs) may be prognostic for biochemical recurrence-free survival (bRFS) in patients with locally advanced high-risk prostate cancer (LAPC) undergoing neoadjuvant chemohormonal therapy (NCHT) and radical prostatectomy (RP).

PATIENTS AND METHODS

CTCs were detected before and after NCHT, after RP and at follow-up using the CellSearch™-System for 59 blood samples (20 ml) from patients with LAPC (n=15) and, additionally, for 15 control samples.

RESULTS

The median 5-year progression risk was 90%. CTCs (≥1/20 ml) were detected in 53.3% of patients, with a detection rate of 18.6% in sample-adjusted analysis. CTCs were detected at baseline in 20% of patients with LAPC and 6.7% of controls (p=0.6). CTC findings displayed no association with clinicopathological characteristics. The median bRFS of CTC-negative vs. CTC-positive patients was 43.7 (95% confidence interval not reached) vs. 29.2 months (95% confidence interval=26.8-60.6 months), without statistical significance (p=0.76).

CONCLUSION

During NCHT and RP, longitudinal CTC presence seems to some extent stochastic, although patients with persistant CTCs post-RP developed biochemical recurrence. No significant association with clinicopathological characteristics or bRFS was observed in patients with LAPC, despite a trend for reduced bRFS in patients with detectable CTCs.

Human papilloma virus is not detectable in samples of urothelial bladder cancer in a central European population: a prospective translational study

Background

Previous investigations on the association of human papillomavirus (HPV) and human bladder cancer have led to conflicting results. The aim of this study was to determine if low and high risk HPV play a role in the etiology of superficial low grade and invasive high grade urothelial carcinoma of the bladder.

Methods

We prospectively collected tumor samples of urothelial carcinoma of the bladder from 109 patients treated with transurethral resection or cystectomy, with bladder tissue from transurethral resection of the prostate serving as control. Unfixed, frozen tumor samples were analyzed for the presence of 14 high risk HPV types using real time PCR. Additionally, all specimens were tested for 35 low risk HPV types with a conventional PCR using degenerate primers located in the L1 region. Six frozen samples of cervical carcinoma served as positive controls.

Results

We included 109 cases of bladder cancer with 41 superficial (pTa low grade) tumors, 56 invasive (pT1-T4) high grade tumors and 12 others (pTa high grade + pTis). We have not detected HPV-DNA in any sample (95 % Confidence Interval [CI] 0–3.3 %), superficial tumors (95 % CI 0–6.4 %) or in invasive tumors (95 % CI 0–8.6 %) with correct positive controls.

Conclusions

Using a broad, sensitive assay with prospectively collected specimens of a Central European population we could not detect HPV-DNA in any of the cases. Our results suggest that it is unlikely that HPV infections play a major role in the development of urothelial bladder cancer.

CDK4/6 Inhibition Controls Proliferation of Bladder Cancer and Transcription of RB1

PURPOSE

The retinoblastoma signaling network is frequently altered in advanced bladder cancer. We investigated the potential of CDK4/6 as a therapeutic target and determined biomarkers for patient stratification.

MATERIALS AND METHODS

Genetic alterations were analyzed using public databases, including TCGA (The Cancer Genome Atlas), COSMIC (Catalogue of Somatic Mutations in Cancer) and CCLE (Cancer Cell Line Encyclopedia). Effects of the CDK4/6-inhibitor PD-0332991 or LY2835219 were examined in 10 bladder cancer cell lines by immunoblot, cell viability, apoptosis and cell cycle progression. Efficacy of the PD-0332991 and cisplatin combination was analyzed using the combination index. Gene expression level was determined by quantitative polymerase chain reaction. Cytomegalovirus promoter regulated recombinant retinoblastoma was used for reconstitution. Three-dimensional xenografts were grown on chicken chorioallantoic membrane and analyzed by measuring tumor weight and immunohistochemical expression of total retinoblastoma and Ki-67.

RESULTS

PD-0332991 treatment decreased the proliferation of retinoblastoma positive bladder cancer cell lines and was synergistic in combination with cisplatin. PD-0332991 or LY2835219 treatment decreased the phosphorylation, total protein and transcript level of retinoblastoma. Treatment resulted in a decrease in E2F target gene expression (CCNA2 and CCNE2) and cell cycle progression from G0/G1 to the S-phase but did not affect apoptosis. In retinoblastoma negative cells reconstituted with recombinant retinoblastoma PD-0332991 affected only phosphorylation and not the total retinoblastoma level. These cells remained resistant to treatment. In 3-dimensional retinoblastoma xenografts, treatment resulted in reduced tumor weight and decreased expression of total retinoblastoma and Ki-67.

CONCLUSIONS

We provide preclinical evidence that CDK4/6 inhibition is a potential therapeutic strategy for retinoblastoma positive bladder cancer that probably acts by negatively regulating retinoblastoma transcription.

A robust blood gene expression-based prognostic model for castration-resistant prostate cancer

BACKGROUND

Castration-resistant prostate cancer (CRPC) is associated with wide variations in survival. Recent studies of whole blood mRNA expression-based biomarkers strongly predicted survival but the genes used in these biomarker models were non-overlapping and their relationship was unknown. We developed a biomarker model for CRPC that is robust, but also captures underlying biological processes that drive prostate cancer lethality.

METHODS

Using three independent cohorts of CRPC patients, we developed an integrative genomic approach for understanding the biological processes underlying genes associated with cancer progression, constructed a novel four-gene model that captured these changes, and compared the performance of the new model with existing gene models and other clinical parameters.

RESULTS

Our analysis revealed striking patterns of myeloid- and lymphoid-specific distribution of genes that were differentially expressed in whole blood mRNA profiles: up-regulated genes in patients with worse survival were overexpressed in myeloid cells, whereas down-regulated genes were noted in lymphocytes. A resulting novel four-gene model showed significant prognostic power independent of known clinical predictors in two independent datasets totaling 90 patients with CRPC, and was superior to the two existing gene models.

CONCLUSIONS

Whole blood mRNA profiling provides clinically relevant information in patients with CRPC. Integrative genomic analysis revealed patterns of differential mRNA expression with changes in gene expression in immune cell components which robustly predicted the survival of CRPC patients. The next step would be validation in a cohort of suitable size to quantify the prognostic improvement by the gene score upon the standard set of clinical parameters.