Validity and utility of blood tumor mutational burden (bTMB) is dependent on circulating tumor DNA (ctDNA) shed: SCRUM-Japan MONSTAR-SCREEN

Analytical Validation of Next-Generation Sequencing-Based Comprehensive Liquid Biopsy Assay for Therapy Selection

Liquid biopsies are an increasingly important tool for the real-time monitoring of biomarkers, cancer recurrence, and disease burden in oncology practice. Tempus xF+ is a liquid biopsy assay that detects cell-free DNA in blood samples of patients with advanced solid tumors. The xF+ panel covers 523 genes spanning approximately 1.8 Mb of the human genome and can detect single-nucleotide variants and insertions-deletions in 522 genes. It also detects copy number gains in 7 genes and translocations (gene rearrangements) in 10 genes. Furthermore, the larger panel size allows for the calculation of blood tumor mutational burden. This work highlights the analytical validation performed for the xF+ assay, comparing it with a smaller panel liquid biopsy assay, calculating blood tumor mutational burden, and exploring its potential clinical utility.

FGFR2/3 Gene Alterations and Clinical Outcomes in Advanced/Metastatic Urothelial Cancer in Japan: MONSTAR-SCREEN Database Study

Advanced/metastatic urothelial cancer (a/m UC) still has a poor prognosis despite the recent medical advances. Recent studies demonstrated that fibroblast growth factor receptor (FGFR) gene alterations (GAs) may be driver genes for UC; however, the proportion of UC genetic panel testing in Japan remains low. We clarified the proportion of patients with FGFR2/3 GAs, treatment patterns, and clinical outcomes in a/m UC patients in Japan. This study was a descriptive epidemiological study using the MONSTAR-SCREEN database, and 138 patients with a/m UC were evaluated. The primary endpoint was the proportion of patients with FGFR2/3 GAs. The secondary endpoints included treatment patterns, clinical outcomes, genomic status before and after treatment, etc. The proportion of FGFR GA-positive patients in a/m UC was 11.9%. The most common FGFR mutation variant and fusion gene were S249C (4.4%) and FGFR3-TACC3 fusion (3.7%), respectively. Fifty-one patients were tested two or more times; a few changes were observed in the FGFR GA status, regardless of the treatment regimen. Co-occurrence association was observed in FGFR1 with TET2, and in FGFR3 with CHEK2 or MLL2. During the first-, second-, and third-line treatment, median progression-free survival (PFS) of GA-positive patients was 7.3, 2.9, and 6.2 months, while for GA-negative patients, 6.9, 3.1, and 6.9 months, respectively. This study revealed that one in eight a/m UC patients had FGFR2/3 GAs, and a few changes were observed in FGFR GA status before and after treatment. Genetic testing will be beneficial for the selection of appropriate treatments after a diagnosis of a/m UC.

Circulating tumour DNA and circulating tumour cells in bladder cancer - from discovery to clinical implementation

Liquid biopsies, indicating the sampling of body fluids rather than solid-tissue biopsies, have the potential to revolutionize cancer care through personalized, noninvasive disease detection and monitoring. Circulating tumour DNA (ctDNA) and circulating tumour cells (CTCs) are promising blood-based biomarkers in bladder cancer. Results from several studies have shown the clinical potential of ctDNA and CTCs in bladder cancer for prognostication, treatment-response monitoring, and early detection of minimal residual disease and disease recurrence. Following successful clinical trial evaluation, assessment of ctDNA and CTCs holds the potential to transform the therapeutic pathway for patients with bladder cancer - potentially in combination with the analysis of urinary tumour DNA - through tailored treatment guidance and optimized disease surveillance.

Benefits of Combining Circulating Tumor DNA With Tissue and Longitudinal Circulating Tumor DNA Genotyping in Advanced Solid Tumors: SCRUM-Japan MONSTAR-SCREEN-1 Study

PURPOSE

The utility of capturing heterogeneity by circulating tumor DNA (ctDNA) genotyping combined with tissue analysis or applying it in a sequential manner remains uncertain.

METHODS

We assessed the clinical value of ctDNA genotyping using data from 2,187 patients with advanced solid tumors enrolled in SCRUM-Japan MONSTAR-SCREEN-1, a nationwide cancer genome screening project, which examined ctDNA from longitudinally collected blood samples and tumor tissue samples (UMIN 000036749).

RESULTS

Among 667 patients with both baseline ctDNA and tissue genotyping results, 51 (7.6%) had actionable biomarkers identified exclusively through ctDNA genotyping. The most frequent targets of genotype-matched therapy guided by solely ctDNA were immune checkpoint, estrogen receptor, and poly(ADP-ribose) polymerase (PARP). Comparison of objective response rates (ORRs) and progression-free survival (PFS) between patients treated based on tissue versus ctDNA alone showed no significant difference, with ORRs of 34.0% versus 23.1% (P = .54) and a median PFS of 11.5 versus 13.8 months (hazard ratio [HR], 1.4 [95% CI, 0.72 to 2.80]), respectively. Among 924 patients undergoing sequential ctDNA genotyping, the detection of actionable biomarkers increased from 63.2% to 72.5% following subsequent ctDNA. Targets for genotype-matched therapy guided by subsequent ctDNA alone commonly included PARP, immune checkpoint, and BRAF. The ORR was 23.2% and 26.7% (P = .75), and the median PFS was 5.2 and. 3.7 months (HR, 1.5 [95% CI, 0.79 to 2.80]) for genotype-matched therapy based on initial versus subsequent ctDNA alone, respectively.

CONCLUSION

Combining ctDNA with tissue analysis, followed by sequential ctDNA assessments, effectively enhances the identification of actionable biomarkers. This strategy facilitates clinically beneficial, genetically informed therapies, underscoring its significant value in precision oncology.

Genomic characterization of metastatic patterns in prostate cancer using circulating tumor DNA data from the SCRUM-Japan MONSTAR SCREEN project

Purpose

Genomic characterization of the predisposition of tumors to metastasize to specific sites has been performed in a few studies using mainly tissue-derived genomes. This nationwide prospective observational study investigated the association between genomic characteristics using circulating tumor DNA (ctDNA), and the synchronous and metachronous metastasis of tumors to specific target organs in advanced prostate cancer.

Methods

Patients with advanced prostate cancer undergoing systemic treatment were included. ctDNA was analyzed using the FoundationOne®Liquid CDx assay at enrollment. Associations between genomic characteristics and metastatic status were examined.

Results

Alterations in the genes MYC, APC, and BRCA2 and the DNA repair, MYC, and WNT pathways were associated with lung and liver metastasis. PTEN gene alterations and PI3K pathway alteration were associated with synchronous lung metastasis. RB1 gene alteration and RAS/RAF/MAPK pathway alteration were associated with synchronous liver metastasis. RB1 and BRCA2 gene alterations predicted metachronous lung metastasis, while TP53 and MYC gene alterations predicted metachronous liver metastasis.

Conclusions

This study identifies genomic alterations in ctDNA associated with synchronous and metachronous metastases. These findings may be clinically helpful for treating, managing, and monitoring cancer.

Prediction of undetectable circulating tumor DNA by comprehensive genomic profiling assay in metastatic prostate cancer: the SCRUM-Japan MONSTAR SCREEN project

BACKGROUND

Undetectable circulating tumor DNA (ctDNA) is an obstacle to performing comprehensive genomic profiling in daily practice to identify genomic alterations. We investigated the associations between clinicopathological factors and undetectable ctDNA using a commercially available comprehensive genomic profiling assay in metastatic prostate cancer.

PATIENTS AND METHODS

Patients treated with systemic treatment for metastatic prostate cancer were included. ctDNA was analyzed by FoundationOne®Liquid CDx at enrollment. The associations between clinicopathological characteristics and ctDNA detection were analyzed.

RESULTS

The number of bone metastasis was associated with ctDNA detection (odds ratio [95% confidence interval], 13.6 [1.71-108], P = 0.014). An algorithm predicting ctDNA detection using clinicopathological parameters was created. If ≥ 4 bone metastases were observed, ctDNA detection was estimated to be 98.9%. Among the patients with < 4 bone metastases, if two or three features among ISUP grade group 5, PSA level ≥ 10 ng/ml, and castration resistance were present, the ctDNA detection rate was 96.7% while the ctDNA detection rate was 86.3% if no or only one feature was present.

CONCLUSIONS

An algorithm created in this study is helpful in determining when to undertake comprehensive genomic profiling assay using blood.

Putting comprehensive genomic profiling of ctDNA to work: 10 proposed use cases

Liquid biopsy profiling of circulating tumor DNA (ctDNA) has become established as a compelling, pragmatic diagnostic in the care of cancer patients and is now endorsed by multiple cancer care guidelines. Moreover, ctDNA profiling technologies have advanced significantly and offer increasingly comprehensive and reliable insights into cancer. In this review, we focus on applications of ctDNA and propose that a critical untapped opportunity is in considering how we utilize these accessible, scalable technologies across diverse potential applications. With a specific focus on clinical applications, rather than research uses, we describe 10 use cases for ctDNA profiling across four categories: (1) established and (2) emerging applications of ctDNA profiling for therapy selection, (3) incidental detection of secondary genomic findings, and (4) quantification of plasma DNA tumor content.

Genomic profiling and clinical utility of circulating tumor DNA in metastatic prostate cancer: SCRUM-Japan MONSTAR SCREEN project

BACKGROUND

Circulating tumor DNA (ctDNA) testing has emerged as a novel tool for cancer precision medicine. This study investigated the genomic profiling and clinical utility of ctDNA in metastatic prostate cancer.

METHODS

This is a nation-wide prospective observational study. Patients treated with systemic treatment for metastatic castration-sensitive prostate cancer (mCSPC) and metastatic castration-resistant prostate cancer (mCRPC) were included. ctDNA was analyzed using FoundationOne Liquid®CDx at enrollment. In a subset of patients, ctDNA after disease progression and tissue prior to the initiation of treatment were examined using FoundationOne Liquid®CDx and FoundationOne®CDx, respectively.

RESULTS

The frequency of AR alterations and homologous recombination repair (HRR) defect was higher in mCRPC compared with mCSPC. Tumor mutational burden was correlated between tissue and ctDNA at pre-treatment, as well as ctDNA between at pre-treatment and at post-treatment. Patients with HRR defect were associated with shorter time to castration resistance in androgen deprivation therapy/combined androgen blockade, but not in androgen receptor pathway inhibitor, compared with patients without HRR defect in mCSPC. Time to treatment failure in patients with AR amplification or AR mutation was shorter compared with patients without AR alterations in mCRPC.

CONCLUSIONS

This study revealed valuable findings for the clinical care of metastatic prostate cancer. Especially, predictive factors such as HRR defect in mCSPC should be validated in the future.