"Every effort should be made to reduce the cost of molecular testing and expand their access," writes Ashley Ross, MD, PhD.
Dr. Ross is a urologist at Texas Urology Specialists in McKinney, TX.
Over the past decade, multiple studies have demonstrated that the analysis of tumor genomics and genetics can improve the management of cancer. In the case of localized prostate cancer, the majority of published studies on clinically available assays have focused on prognostic assays that allow for superior risk stratification. Some critics of genomic and genetic testing have suggested that cost can be considerable and utility may be limited.
Genomic and genetic testing has often centered on RNA analysis (ie, multiplexed RT-PCR, microarray data, and RNAseq) or DNA analysis (ie, next generation sequencing) with an emphasis often on being more comprehensive rather than cost effective. In a study presented at this year’s Genitourinary Cancers Symposium, Dr. Leapman and colleagues compared relatively affordable immunohistochemistry (IHC) assays measuring PTEN, ERG, and Ki67 status to Prolaris, an RNA-based test examining cell cycle progression associated transcripts (J Clin Oncol 2018; 36 [suppl 6S; abs. 118]). As expected from previously published research, IHC of PTEN, ERG, and KiG7 were independently prognostic for oncologic outcomes (Molecular prognostic tests for prostate cancer. UpToDate.com 2018; bit.ly/2I0guX3).
Importantly, RNA-derived cell cycle progression testing provided prognostic information beyond that of IHC testing, and it is not clear whether their IHC testing would be equivalent or provide an adequate alternative to Prolaris or other genomic tests in clinically relevant scenarios (such as selecting men for surveillance or treatment or selecting men for intensification of local therapy).
The authors conclude that work to develop less expensive assays might expand access of molecular tools. Indeed, every effort should be made to reduce the cost of molecular testing and expand their access. These efforts should include those by industry to lower the cost of proven existing assays and those by industry and academia to develop effective low-cost tests.
It is also critical to note that genomic assays can provide both prognostic and predictive information (ie, regarding radiation sensitivity or androgen sensitivity) and that cost-effective alternatives for many molecular signatures may need to be developed for use in various clinical contexts (Lancet Oncol 2016; 17:1612-20; JAMA Oncol 2017; 3:1663-72).
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