Disease surveillance in patients with bladder cancer is important for early diagnosis of progression and metastasis and for optimised treatment.
To develop urine and plasma assays for disease surveillance for patients with FGFR3 and PIK3CA tumour mutations.
Design, setting, and participants
Droplet digital polymerase chain reaction (ddPCR) assays were developed and tumour DNA from two patient cohorts was screened for FGFR3 and PIK3CA hotspot mutations. One cohort included 363 patients with non–muscle-invasive bladder cancer (NMIBC). The other cohort included 468 patients with bladder cancer undergoing radical cystectomy (Cx). Urine supernatants (NMIBC n = 216, Cx n = 27) and plasma samples (NMIBC n = 39, Cx n = 27) from patients harbouring mutations were subsequently screened using ddPCR assays.
Outcome measurements and statistical analysis
Progression-free survival, recurrence-free survival, and overall survival were measured. Fisher's exact test, the Wilcoxon rank-sum test and Cox regression analysis were applied.
Results and limitations
In total, 36% of the NMIBC patients (129/363) and 11% of the Cx patients (44/403) harboured at least one FGFR3 or PIK3CA mutation. Screening of DNA from serial urine supernatants from the NMIBC cohort revealed that high levels of tumour DNA (tDNA) were associated with later disease progression in NMIBC (p = 0.003). Furthermore, high levels of tDNA in plasma samples were associated with recurrence in the Cx cohort (p = 0.016). A positive correlation between tDNA levels in urine and plasma was observed (correlation coefficient 0.6). The retrospective study design and low volumes of plasma available for analysis were limitations of the study.
Increased levels of FGFR3 and PIK3CA mutated DNA in urine and plasma are indicative of later progression and metastasis in bladder cancer.
Urine and plasma from patients with bladder cancer may be monitored for diagnosis of progression and metastasis using mutation assays.
Keywords: Biomarker, Cell-free DNA, Liquid biopsy, Personalised analysis, FGFR3, PIK3CA, Droplet digital polymerase chain reaction.
a Department of Molecular Medicine, Aarhus University Hospital, Aarhus, Denmark
b Department of Pathology, Aarhus University Hospital, Aarhus, Denmark
c Department of Pathology, Erasmus MC Cancer Institute, Rotterdam, The Netherlands
d Department of Oncology, Aarhus University Hospital, Aarhus, Denmark
e Department of Urology, Aarhus University Hospital, Aarhus, Denmark
Corresponding author. Department of Molecular Medicine, Aarhus University Hospital, Palle Juul-Jensens Boulevard, DK-8200 Aarhus N, Denmark. Tel. +45 78455320.
© 2016 European Association of Urology, Published by Elsevier B.V.