Liquid biopsy a promising tool for monitoring patients with bladder cancer
Detection of circulating tumour cells (CTCs), circulating tumour DNA (ctDNA) and microRNA (miRNA) using blood samples (liquid biopsy) instead of cancer tissue proved useful in detecting progression and predicting prognosis of patients with bladder cancer, according to data presented at the recent 15th Urological Association of Asia Congress (UAA 2017) held in Hong Kong.
“Tumour heterogeneity is a problem in profiling bladder cancer. This may be resolved by doing biopsies of multiple foci, but this is invasive for the patients. Liquid biopsy can provide a temporal, genetic landscape of the cancer in a less invasive manner,” said Dr Masayoshi Nagata of the Department of Urology, Juntendo University, Tokyo, Japan.
In a pilot study of 12 patients with bladder cancer, CTCs were detected by CytoQuest in 92 percent of the patients. There was no significant difference in the number of median CTCs before (median, 7; range 1–16) and after transurethral resection of bladder tumour (TUR-Bt) (median, 7; range 2–26). [Nagata M, et al, UAA 2017; http://www.abnova.com/products/CytoQuest-CR-M0014.html]
“These results demonstrated that performance of TUR-Bt did not cause dissemination of the tumour,” Nagata said.
In a study of 188 patients who underwent radical cystectomy (RC) without neoadjuvant chemotherapy, CTCs were noted to be present in 21 percent of patients. The detection of CTCs correlated with reduced recurrence-free survival (RFS) and cancer-specific survival (p≤0.016). [BJU Int 2017;119:854-861]
In another study, 11 percent of 403 bladder cancer patients who underwent RC were found to have FGFR3 and P1K3CA high mutated DNA in ctDNA analysis, which showed significant correlation with poor RFS (p=0.031). [Eur Urol 2017;71:961-969]
“The results of this study showed that ctDNA from patients with bladder cancer can be monitored for disease progression and detection of metastasis,” commented Nagata.
A retrospective pilot study of 377 samples from 12 patients with recurrent or progressive/metastatic bladder cancer showed significantly higher levels of ctDNA in plasma and urine before disease progression (p=0.032) vs patients with recurrent disease (p=1.3×10-6). [Eur Urol 2016;70:75-82]
In genome-wide analyses of serum miRNA in 207 patients with muscle-invasive bladder cancer (MIBC), low expression of the miRNAs miR-486-3p (p=0.002) and miR-103a-3p (p=0.034) was noted to be correlated to worse overall survival. [Oncotarget 2016;7:36733-36742]
“Serum miRNA signatures might have considerable clinical values in predicting and providing prognostic information in MIBC,” Nagata said.
“Detection and quantification of CTCs, ctDNA and miRNA by liquid biopsy can temporally provide the genetic landscape of bladder cancer in a less invasive manner, although circulating biomarkers are not yet established in clinical practice… In the future, liquid biopsy will serve as a tool for the selection of effective precision medicine for bladder cancer patients,” he concluded.