Metastasis-directed Therapy in Treating Nodal Oligorecurrent Prostate Cancer: A Multi-institutional Analysis Comparing the Outcome and Toxicity of Stereotactic Body Radiotherapy and Elective Nodal Radiotherapy

BACKGROUND

Stereotactic body radiotherapy (SBRT) and elective nodal radiotherapy (ENRT) are being investigated as metastasis-directed treatments in oligorecurrent prostate cancer (PC); however, comparative data are still lacking.

OBJECTIVE

To compare outcome and toxicity between both treatments. Primary endpoint was metastasis-free survival, adjusted for selected variables (aMFS).

DESIGN, SETTING, AND PARTICIPANTS

This was a multi-institutional, retrospective analysis of 506 (SBRT: 309, ENRT: 197) patients with hormone-sensitive nodal oligorecurrent PC (five or fewer lymph nodes (LNs; N1/M1a), treated between 2004 and 2017. Median follow-up was 36 mo (interquartile range 23-56).

INTERVENTION

SBRT was defined as a minimum of 5 Gy per fraction to each lesion with a maximum of 10 fractions. ENRT was defined as a minimum dose of 45 Gy in up to 25 fractions to the elective nodes, with or without a simultaneous boost to the suspicious node(s). The choice of radiotherapy (RT) was at the discretion of the treating physician, with treatments being unbalanced over the centers.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

In total, 506 patients from 15 different treatment centers were included. Primary treatment was radical prostatectomy, RT, or their combination. Nodal recurrences were detected by positron emission tomography/computer tomography (97%) or conventional imaging (3%). Descriptive statistics was used to summarize patient characteristics.

RESULTS AND LIMITATIONS

ENRT was associated with fewer nodal recurrences compared with SBRT (p < 0.001). In a multivariable analysis, patients with one LN at recurrence had longer aMFS after ENRT (hazard ratio: 0.50, 95% confidence interval 0.30-0.85, p = 0.009). Late toxicity was higher after ENRT compared with that after SBRT (16% vs. 5%, p < 0.01). Limitations include higher use of hormone therapy in the ENRT cohort and nonstandardized follow-up.

CONCLUSIONS

ENRT reduces the number of nodal recurrences as compared with SBRT, however at higher toxicity. Our findings hypothesize that ENRT should be preferred to SBRT in the treatment of nodal oligorecurrences. This hypothesis needs to be evaluated in a randomized trial.

PATIENT SUMMARY

This study investigated the difference between stereotactic and elective nodal radiotherapy in treating limited nodal metastatic prostate cancer. Nodal relapse was less frequent following elective nodal radiotherapy than following stereotactic body radiotherapy, and thus elective nodal radiotherapy might be the preferred treatment.

Consensus on molecular imaging and theranostics in prostate cancer

Rapid developments in imaging and treatment with radiopharmaceuticals targeting prostate cancer pose issues for the development of guidelines for their appropriate use. To tackle this problem, international experts representing medical oncologists, urologists, radiation oncologists, radiologists, and nuclear medicine specialists convened at the European Association of Nuclear Medicine Focus 1 meeting to deliver a balanced perspective on available data and clinical experience of imaging in prostate cancer, which had been supported by a systematic review of the literature and a modified Delphi process. Relevant conclusions included the following: diphosphonate bone scanning and contrast-enhanced CT are mentioned but rarely recommended for most patients in clinical guidelines; MRI (whole-body or multiparametric) and prostate cancer-targeted PET are frequently suggested, but the specific contexts in which these methods affect practice are not established; sodium fluoride-18 for PET-CT bone scanning is not widely advocated, whereas gallium-68 or fluorine-18 prostate-specific membrane antigen gain acceptance; and, palliative treatment with bone targeting radiopharmaceuticals (rhenium-186, samarium-153, or strontium-89) have largely been replaced by radium-223 on the basis of the survival benefit that was reported in prospective trials, and by other systemic therapies with proven survival benefits. Although the advances in MRI and PET-CT have improved the accuracy of imaging, the effects of these new methods on clinical outcomes remains to be established. Improved communication between imagers and clinicians and more multidisciplinary input in clinical trial design are essential to encourage imaging insights into clinical decision making.

Outcomes after a first and/or second salvage treatment in patients with oligometastatic prostate cancer recurrence detected by (18-F) choline PET-CT

OBJECTIVE

The primary objective of this study was to assess clinical outcomes in patients with oligometastatic prostate cancer recurrence after single or repeated salvage radiation treatment.

METHODS

Forty-nine consecutive prostate cancer patients diagnosed with oligometastatic recurrence on Ch-PET have been prospectively treated. Seven (23%) patients had castrate-resistant disease. Clinical outcomes were assessed using the Kaplan-Meier method. Potential prognostic factors were examined using univariate proportional hazards regression.

RESULTS

The treatments administered to the initial oligorecurrence sites were intensity-modulated radiotherapy (IMRT) ± ADT (26 patients; 53%) and stereotactic ablative radiotherapy (SABR) ± ADT (23 patients; 47%). With a median follow-up of 24 months (range 6-39), 24 patients developed a biochemical failure. Twenty out of the 24 relapsed patients underwent a second Ch-PET/CT. Seven patients presented poly-metastatic relapse and 10 oligometastatic diseases. Six of 10 patients with a second oligorecurrence were treated again with SABR. Overall, 102 lesions were treated. Local control was detected in 45 (91.8%) patients. No relevant (grade ≥ 2) toxicity was reported, and there was no grade 3 toxicity. On univariate analysis, none of the variables were significantly predicted for clinical disease-free survival. At last follow-up visit, 24 patients (40%) were free from biochemical failure and 37 (71%) patients were free from clinical disease. The 2-year OS and PCSS were 91.8% and 95.9% respectively.

CONCLUSION

Salvage IMRT or SBRT of oligometastatic prostate cancer recurrence is associated with a prolonged cDFS. This may result in a longer time to develop castrate-resistant disease and a longer time without systemic therapies.

Circulating tumor DNA in patients with metastatic urothelial cancer: concordance of genomic findings with matched tissue biopsies

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Background: Patients (pts) with metastatic urothelial cancer (mUC) now have access to many different treatment options. This creates an incentive for molecular profiling of their tumors, with the aim of developing biomarkers. Genomic profiling may leverage the presence of circulating tumor DNA (ctDNA), but it has not been shown whether this recapitulates the findings from tissue samples. Methods: Whole blood samples were collected for next-generation sequencing of leukocyte and cell-free DNA (cfDNA). Deep targeted sequencing was performed across a UC-specific custom 50-gene panel (median depth of 986x). Matched archival tissue was profiled using the same assay for 65 pts. Results: Between 11/2011 and 12/2017, 90 pts developed mUC (87 evaluable). Baseline characteristics: median age 67, 83% male, 14% upper-tract disease, 17% stage IV at initial presentation. Treatments delivered: 76% platinum-based chemotherapy, 47% PD-1/PD-L1 inhibitor. At a median follow-up of 12.8 mo., 45% remain alive. We found ctDNA fractions above 2% in at least one blood collection in 81% of cases. For 17 pts, matched metastatic biopsies and cfDNA collection were available; in those cases 82% of coding somatic mutations identified in tissue were independently detected in cfDNA. Half of discordant findings could be attributed to low ctDNA fraction. Most (89%) mutations detected in primary tissue (cystectomy or nephrectomy) were present in later cfDNA collections. ctDNA detected mutations in TP53 and ARID1A in 64% and 29% of pts, respectively. A tumor mutation burden ≥25 mutation per Mb was observed in 27% of cases. Conclusions: There is a high concordance between genomic findings from ctDNA and matched tissue of pts with mUC. This supports the use of liquid biopsies to study potential biomarkers in this disease.

Phase 2 Trial of Nivolumab Combined With Stereotactic Body Radiation Therapy in Patients With Metastatic or Locally Advanced Inoperable Melanoma

PURPOSE

Nivolumab improves survival in patients with metastatic melanoma. Unfortunately, most patients do not respond to this treatment. Preclinical data indicate that radiation therapy could work synergistically with nivolumab and improve response rates.

METHODS AND MATERIALS

We conducted a phase 2 trial in 20 patients with inoperable or metastatic melanoma with ≥2 measurable lesions (Response Evaluation Criteria in Solid Tumors v1.1). Stereotactic body radiation therapy (SBRT) of 3 × 8 Gy to the largest lesion was delivered before the second nivolumab cycle. The primary endpoint was overall response rate (ORR) in the nonirradiated lesions (Response Evaluation Criteria in Solid Tumors v1.1). Secondary endpoints included toxicity. An exploratory endpoint was mutant BRAF and NRAS circulating tumor DNA (ctDNA) on serial blood samples.

RESULTS

An ORR of 45% was noted with 3 complete and 6 partial responses. Three patients experienced stable disease and 7 had progressive disease as best response. All patients with a complete response in the nonirradiated lesions exhibited a local complete response in the irradiated lesion. Grade 1 to 2 treatment-related adverse events (AEs) occurred in 17 patients; 3 patients experienced grade 3 AEs (lymphopenia, gastroenteritis, and bullous pemphigoid). No grade 4 to 5 AEs occurred. ctDNA was detected in 8 patients, and changes corresponded to clinical response and suggested that a subset of patients with a low programmed death ligand-1 score only started responding after SBRT.

CONCLUSIONS

We conclude that the combination treatment was well tolerated and led to an ORR of 45% in patients with metastatic or inoperable melanoma, similar to historical response rates of nivolumab monotherapy. Although underpowered, our data therefore do not indicate a substantial abscopal response. Nonetheless, serial ctDNA analyses suggest that a subset of patients responded only after the addition of SBRT.

Pelvic lymph node dissection in prostate cancer staging: evaluation of morbidity and oncological outcomes

BACKGROUND

To evaluate the morbidity of different surgical approaches for pelvic lymph node dissection (PLND), to evaluate the influence of morbidity on radiotherapy (RT) planning and to evaluate a possible therapeutic effect of a more extensive yield of PLND.

METHODS

From 2000-2016, 228 patients received staging PLND before primary RT in a single tertiary care center. Nine patients were excluded for the evaluation of morbidity. Fifty patients were operated in an open approach, 96 laparoscopic and 73 robot-assisted (RA). Clavien-Dindo classification was used for evaluating complications. Predictors of biochemical recurrence (BCR), clinical relapse (CR), cancer-specific survival (CSS) and overall survival (OS) were evaluated by regression analyses to determine a possible therapeutic effect.

RESULTS

Minimal invasive surgery (laparoscopic or RA) caused five times less major complications (22% vs. 4.3%, p = .001) and a median 3 days shorter hospital stay (5 days versus 2 days, p < .001). Major complications resulted in a delayed (23 days, p < .001) RT start but no oncological effect was seen. Independent oncological predictors were the number of positive nodes (BCR, CR, CSS, OS), a lower age (CR), a higher level of initial prostate-specific antigen (PSA) (BCR) and post-RT PSA (BCR).

CONCLUSION

Minimal invasive surgery can diminish major complications which delay RT start. Nodal staging proved to be of importance for prognosis but no therapeutic effect was seen of performing PLND as such.

TP53 Outperforms Other Androgen Receptor Biomarkers to Predict Abiraterone or Enzalutamide Outcome in Metastatic Castration-Resistant Prostate Cancer

PURPOSE

To infer the prognostic value of simultaneous androgen receptor (AR) and TP53 profiling in liquid biopsies from patients with metastatic castration-resistant prostate cancer (mCRPC) starting a new line of AR signaling inhibitors (ARSi).Experimental Design: Between March 2014 and April 2017, we recruited patients with mCRPC (n = 168) prior to ARSi in a cohort study encompassing 10 European centers. Blood samples were collected for comprehensive profiling of CellSearch-enriched circulating tumor cells (CTC) and circulating tumor DNA (ctDNA). Targeted CTC RNA sequencing (RNA-seq) allowed the detection of eight AR splice variants (ARV). Low-pass whole-genome and targeted gene-body sequencing of AR and TP53 was applied to identify amplifications, loss of heterozygosity, mutations, and structural rearrangements in ctDNA. Clinical or radiologic progression-free survival (PFS) was estimated by Kaplan-Meier analysis, and independent associations were determined using multivariable Cox regression models.

RESULTS

Overall, no single AR perturbation remained associated with adverse prognosis after multivariable analysis. Instead, tumor burden estimates (CTC counts, ctDNA fraction, and visceral metastases) were significantly associated with PFS. TP53 inactivation harbored independent prognostic value [HR 1.88; 95% confidence interval (CI), 1.18-3.00; P = 0.008], and outperformed ARV expression and detection of genomic AR alterations. Using Cox coefficient analysis of clinical parameters and TP53 status, we identified three prognostic groups with differing PFS estimates (median, 14.7 vs. 7.51 vs. 2.62 months; P < 0.0001), which was validated in an independent mCRPC cohort (n = 202) starting first-line ARSi (median, 14.3 vs. 6.39 vs. 2.23 months; P < 0.0001).

CONCLUSIONS

In an all-comer cohort, tumor burden estimates and TP53 outperform any AR perturbation to infer prognosis.See related commentary by Rebello et al., p. 1699.

Genomic concordance between profiling of circulating tumor DNA (ctDNA) and matched tissue in metastatic urothelial carcinoma

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Background: Biomarkers are urgently needed to facilitate tumor molecular stratification in metastatic urothelial carcinoma (mUC), thus potentially enabling patient selection for targeted- and immuno-therapies. We aimed to assess concordance for clinically-relevant driver gene alterations between same-patient tumor tissue and ctDNA. Methods: Whole blood samples were collected from 90 mUC patients (162 samples in total) for next-generation sequencing of cell-free DNA (cfDNA) and leukocyte DNA. Deep targeted sequencing was performed across a custom 50 bladder cancer gene panel (median cfDNA depth of 986x). Matched archival primary tissue and/or metastatic tissue biopsy was available from 65 patients, and profiled using the same assay. Results: 81% of mUC patients (73/90) had ctDNA fractions above 2% in at least one blood collection (median ctDNA fraction 22%). A high tumor mutation burden (≥25 mutations per Mb) was observed in ctDNA from 20 patients (27%). From ctDNA, TP53 and ARID1A were mutated in 64% and 29% of patients, respectively. Tissue from distant metastatic lesions was available from 17 patients; 82% (62/76) of coding somatic mutations identified were independently detected in the matched ctDNA sample; however, 7/14 discordant calls were attributable to the paired sample having a low ctDNA fraction. Similarly, 89% (88/99) of coding somatic mutations detected in archival primary tissue (cystectomy or nephrectomy) were present in later cfDNA collections. Sequencing multiple sites from archival cystectomies revealed spatially and genomically distinct subclones in 2/4 cases. Conclusions: In mUC, tumor tissue and ctDNA demonstrate remarkably high concordance; our findings support the use of either approach in the characterization of truncal driver gene alterations.

Randomized phase I trial of pembrolizumab with neo-adjuvant versus concomitant stereotactic body radiotherapy in metastatic urothelial carcinoma: Clinical and translational results

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Background: Preclinical data indicates that stereotactic body radiotherapy (SBRT) works synergistically with pembrolizumab, but the effect and potential toxicity might depend on the timing of SBRT. The current study assessed the safety of two different SBRT schedules in combination with pembrolizumab for metastatic urothelial carcinoma (mUC), and explored correlative biomarkers including circulating tumor DNA (ctDNA). Methods: An open-label phase 1 trial was conducted at Ghent University Hospital in patients with mUC to assess the dose-limiting toxicity (DLT) of the combination of pembrolizumab (200mg intravenously, 3-weekly) and SBRT (3x8Gy to the largest lesion). Patients were randomized (1:1) to receive SBRT either prior to the first (arm A) or the third (arm B) cycle of pembrolizumab. Blood was collected throughout the trial for biomarker analysis. Adverse events (AEs) were assessed according to the Common Terminology Criteria for Adverse Events version 4.0. Secondary endpoints included best overall response measured per Response Evaluation Criteria in Solid Tumors v1.1 (RECISTv1.1). The trial was approved by the Ethical Committee of Ghent University Hospital and is registered on ClinicalTrials.gov (NCT02826564). Funding was provided by Merck Sharp & Dohme. Results: Eighteen patients were randomized (nine to each arm) and started trial treatment. No DLT occurred. Treatment-related AEs grade 1-2 occurred in 6/9 and 9/9 patients in arm A and B respectively. One patient in arm B experienced lymphopenia grade 3, unrelated to SBRT. No treatment-related AEs grade 4-5 occurred. An objective response rate as per RECISTv1.1 of 0% and 44·4% was noted in arm A and B respectively. Targeted sequencing of tissue DNA and ctDNA revealed high genomic concordance. A decline in ctDNA was observed in responding patients. Conclusions: Neo-adjuvant and concomitant SBRT combined with pembrolizumab is safe, with potentially superior responses in the latter. ctDNA monitoring is feasible during disease evolution and suggests a shared driver gene status throughout disease progression. Clinical trial information: NCT02826564.

Author Correction: Association analyses of more than 140,000 men identify 63 new prostate cancer susceptibility loci

In the version of this article initially published, the name of author Manuela Gago-Dominguez was misspelled as Manuela Gago Dominguez. The error has been corrected in the HTML and PDF version of the article.

Nonsurgical Salvage Local Therapies for Radiorecurrent Prostate Cancer: A Systematic Review and Meta-analysis

CONTEXT

Different nonsurgical therapeutic strategies can be adopted for intraprostatic relapse of prostate cancer after primary radiotherapy, including re-irradiation (with brachytherapy [BT] or external beam radiotherapy [EBRT]), high-intensity focused ultrasound (HIFU), and cryotherapy. The main issues to consider when choosing nonsurgical salvage local therapies are local tumor control and significant genitourinary toxicity.

OBJECTIVE

To conduct a systematic review and meta-analysis of the role of nonsurgical salvage modalities in patients with radiorecurrent prostate cancer and associated clinical outcomes and toxicity profiles.

EVIDENCE ACQUISITION

We performed a critical review of the Medline, Scopus, and ClinicalKey databases from January 1, 2000 through February 1, 2018 according to the Preferred Reporting Items and Meta-Analyses statement. To assess the overall quality of the literature reviewed, we used a modified Delphi tool for case-series studies.

EVIDENCE SYNTHESIS

A total of 64 case-series studies were included, corresponding to a cohort of 5585 patients. The modified Delphi checklist evidenced high methodological quality overall (mean quality score of 80.6%). Biochemical control rates were lowest for patients treated with HIFU (58%, 95% confidence interval [CI] 47-68%) and highest for patients treated with BT (69%, 95% CI 62-76%) and EBRT (69%, 95% CI 53-83%). The lowest prevalence of incontinence was for patients treated with BT (3%, 95% CI 0-6%; I²=63.4%) and the highest was among patients treated with HIFU (28%, 95% CI 19-38%; I²=89.7%).

CONCLUSIONS

Nonsurgical therapeutic options, especially BT, showed good outcomes in terms of biochemical control and tolerability in the local recurrence setting.

PATIENT SUMMARY

The current analysis demonstrated that nonsurgical salvage local therapies offer a chance of a curative local approach in radiorecurrent prostate cancer. However, high-quality data from prospective trials are needed to validate long-term outcomes from nonsurgical strategies for the treatment of intraprostatic recurrence after previous radiotherapy.

Randomized Phase 1 Trial of Pembrolizumab with Sequential Versus Concomitant Stereotactic Body Radiotherapy in Metastatic Urothelial Carcinoma

Preclinical data indicate that radiotherapy works synergistically with pembrolizumab, but the effect and toxicity of this combination may depend on radiotherapy timing. We conducted a randomized phase 1 trial combining pembrolizumab with either sequential (A) or concomitant (B) stereotactic body radiotherapy (SBRT) in metastatic urothelial carcinoma (mUC). No dose-limiting toxicity occurred. Treatment-related adverse events (trAEs; Common Terminology Criteria for Adverse Events v4.0) of grade 1-2 occurred in six of nine and all nine patients in arms A and B, respectively. One grade 3 trAE occurred in arm B. No grade 4-5 trAEs occurred. Overall response rates of 0% and 44.4% were noted in arms A and B, respectively, as per Response Evaluation Criteria in Solid Tumors v1.1. The trial was not powered to compare efficacy between arms. Targeted sequencing of tissue DNA and circulating tumor DNA (ctDNA) revealed high genomic concordance. Treatment response was associated with ctDNA fraction decline. We conclude that sequential and concomitant SBRT can be safely combined with pembrolizumab in mUC and that the effect of SBRT timing on efficacy is worth exploring further. PATIENT SUMMARY: This study assessed the safety of pembrolizumab combined with radiotherapy at two different time points in metastatic bladder cancer. We conclude that the combination treatment was well tolerated.