Metastatic tumor biopsy is not standard practice in prostate cancer, thanks in part to the difficulty of sclerotic bone metastasis in mCRPC that necessitate challenging biopsying and biopsy sample preparation procedures. Another concern is that biopsies from a single metastatic tumor will frequently miss genomic heterogeneity.
Non-invasive biomarker tests might be able to do an end-run around both of those problems, Dr Beltran believes. For example, molecular imaging — already an important tool for prostate cancer diagnosis and staging — can better identify bone metastases than traditional bone scans can and might be a powerful modality for monitoring tumor biomarkers in real time.
These scans can reveal important molecular characteristics of metastatic tumors, such as the presence on cell surfaces of specific tumor proteins.
PSMA molecular imaging with positron emission tomography and computed tomography (PET/CT) sensitively identifies prostate tumor lesions and may detect early recurrences of prostate cancer throughout the body and help visualize details about their protein expression.4
Liquid biopsies analyses of circulating tumor cells or tumor DNA might offer another comprehensive noninvasive approach to interrogate multiple metastatic tumors, analyze their genomic profiles for treatment-predictive biomarkers, and inform treatment decisionmaking, Dr Beltran said.
Information initially gleaned from tumor biopsy research is now being applied toward noninvasive biomarker development. By incorporating different liquid biopsy and molecular imaging biomarkers, it should be possible to gain a more dynamic and comprehensive picture of metastatic tumor biology, Dr Beltran believes.
- Ku SY, Rosario S, Wang Y, et al. Rb1 and Trp53 cooperate to suppress prostate cancer lineage plasticity, metastasis, and antiandrogen resistance. Science. 2017;355(6320):78-83. doi: 10.1126/science.aah4199
- Beltran H, Eng K, Mosquera JM, et al. Whole-exome sequencing of metastatic cancer and biomarkers of treatment response. JAMA Oncol. 2015;1(4):466-474. doi: 10.1001/jamaoncol.2015.1313
- Beltran H, Antonarakis ES, Morris MJ, Attard G. Emerging molecular biomarkers in advanced prostate cancer: translation to the clinic. Am Soc Clin Oncol Educ Book. 2016;35:131-141.
- Leiblich A, Stevens D, Sooriakumaran P. The utility of molecular imaging in prostate cancer. Curr Urol Rep. 2016;17:26. doi: 10.1007/s11934-015-0573-z