Elucidating Prostate Cancer Behaviour During Treatment via Low-pass Whole-genome Sequencing of Circulating Tumour DNA

Semini Sumanasuriya, George Seed, Harry Parr, Rossitza Christova, Lorna Pope, Claudia Bertan, Diletta Bianchini, Pasquale Rescigno, Ines Figueiredo, Jane Goodall, Gemma Fowler, Penelope Flohr, Niven Mehra, Antje Neeb, Jan Rekowski, Mario Eisenberger, Oliver Sartor, Stéphane Oudard, Christine Geffriaud-Ricouard, Ayse OzatilganMustapha Chadjaa, Sandrine Macé, Chris Lord, Joe Baxter, Stephen Pettitt, Maryou Lambros, Adam Sharp, Joaquin Mateo, Suzanne Carreira, Wei Yuan, Johann S. de Bono

Research output: Contribution to journalArticlepeer-review

Abstract

Background: Better blood tests to elucidate the behaviour of metastatic castration-resistant prostate cancer (mCRPC) are urgently needed to drive therapeutic decisions. Plasma cell-free DNA (cfDNA) comprises normal and circulating tumour DNA (ctDNA). Low-pass whole-genome sequencing (lpWGS) of ctDNA can provide information on mCRPC behaviour. Objective: To validate and clinically qualify plasma lpWGS for mCRPC. Design, setting, and participants: Plasma lpWGS data were obtained for mCRPC patients consenting to optional substudies of two prospective phase 3 trials (FIRSTANA and PROSELICA). In FIRSTANA, chemotherapy-naïve patients were randomised to treatment with docetaxel (75 mg/m2) or cabazitaxel (20 or 25 mg/m2). In PROSELICA, patients previously treated with docetaxel were randomised to 20 or 25 mg/m2 cabazitaxel. lpWGS data were generated from 540 samples from 188 mCRPC patients acquired at four different time points (screening, cycle 1, cycle 4, and end of study). Outcome measurements and statistical analysis: lpWGS data for ctDNA were evaluated for prognostic, response, and tumour genomic measures. Associations with response and survival data were determined for tumour fraction. Genomic biomarkers including large-scale transition (LST) scores were explored in the context of prior treatments. Results and limitations: Plasma tumour fraction was prognostic for overall survival in univariable and stratified multivariable analyses (hazard ratio 1.75, 95% confidence interval 1.08–2.85; p = 0.024) and offered added value compared to existing biomarkers (C index 0.722 vs 0.709; p = 0.021). Longitudinal changes were associated with drug response. PROSELICA samples were enriched for LSTs (p = 0.029) indicating genomic instability, and this enrichment was associated with prior abiraterone and enzalutamide treatment but not taxane or radiation therapy. Higher LSTs were correlated with losses of RB1/RNASEH2B, independent of BRCA2 loss. Conclusions: Plasma lpWGS of ctDNA describes CRPC behaviour, providing prognostic and response data of clinical relevance. The added prognostic value of the ctDNA fraction over established biomarkers should be studied further. Patient summary: We studied tumour DNA in blood samples from patients with prostate cancer. We found that levels of tumour DNA in blood were indicative of disease prognosis, and that changes after treatment could be detected. We also observed a “genetic scar” in the results that was associated with certain previous treatments. This test allows an assessment of tumour activity that can complement existing tests, offer insights into drug response, and detect clinically relevant genetic changes.

Original languageEnglish (US)
Pages (from-to)243-253
Number of pages11
JournalEuropean Urology
Volume80
Issue number2
DOIs
StatePublished - Aug 2021

Keywords

  • Cabazitaxel
  • Cell-free DNA
  • cfDNA
  • ctDNA
  • Low-pass whole-genome sequencing
  • lpWGS
  • mCRPC
  • Metastatic castration-resistant prostate cancer
  • Taxanes
  • Tumour fraction

ASJC Scopus subject areas

  • Urology

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