Urine Extracellular Vesicle GATA2 mRNA Discriminates Biopsy Result in Men with Suspicion of Prostate Cancer

PURPOSE

Prostate specific antigen has limited performance in detecting prostate cancer. The transcription factor GATA2 is expressed in aggressive prostate cancer. We analyzed the predictive value of urine extracellular vesicle GATA2 mRNA alone and in combination with a multigene panel to improve detection of prostate cancer and high risk disease.

MATERIALS AND METHODS

GATA2 mRNA was analyzed in matched extracellular vesicles isolated from urines before and after prostatectomy (16) and paired urine and tissue prostatectomy samples (19). Extracellular vesicle GATA2 mRNA performance to distinguish prostate cancer and high grade disease was tested in training (52) and validation (165) cohorts. The predictive value of a multigene score including GATA2, PCA3 and TMPRSS2-ERG (GAPT-E) was tested in both cohorts.

RESULTS

Confirming its prostate origin, urine extracellular vesicle GATA2 mRNA levels decreased significantly after prostatectomy and correlated with prostate cancer tissue GATA2 mRNA levels. In the training and validation cohort GATA2 discriminated prostate cancer (AUC 0.74 and 0.66) and high grade disease (AUC 0.78 and 0.65), respectively. Notably, the GAPT-E score improved discrimination of prostate cancer (AUC 0.84 and 0.72) and high grade cancer (AUC 0.85 and 0.71) in both cohorts when compared with each biomarker alone and PT-E (PCA3 and TMPRSS2-ERG). A GAPT-E score for high grade prostate cancer would avoid 92.1% of unnecessary prostate biopsies, compared to 61.9% when a PT-E score is used.

CONCLUSIONS

Urine extracellular vesicle GATA2 mRNA analysis improves the detection of high risk prostate cancer and may reduce the number of unnecessary biopsies.

Costs of early adjuvant radiation therapy after radical prostatectomy: a decision analysis

BACKGROUND

This analysis was carried out to evaluate the cost-effectiveness of adjuvant radiation therapy (ART) versus observation, using a decision analysis model based primarily upon the published results of the Southwest Oncology Group prospective trial (SWOG 8794).

PATIENTS AND METHODS

A decision analysis model was designed to compare ART versus observation over a 10-year time horizon. Probabilities of treatment success, utilization of salvage treatments, and rates of adverse events were taken from published results of SWOG 8794. Cost inputs were based on 2010 Medicare reimbursement rates. Primary outcome measure was incremental cost per prostate-specific antigen (PSA) success (i.e. serum PSA level <0.4 ng/ml).

RESULTS

ART results in a higher PSA success rate than observation with probability of 0.43 versus 0.22. The mean incremental cost per patient for ART versus observation was $6023. The mean incremental cost-effectiveness ratio was $26,983 over the 10-year period.

CONCLUSIONS

ART appears cost effective compared with observation based upon this decision analysis model. Future research should consider more costly radiation therapy (RT) approaches, such as intensity-modulated RT, and should evaluate the cost-effectiveness of ART versus early salvage RT.

Do urologists and radiation oncologists agree on adjuvant radiation therapy for prostate cancer? A web-based patterns-of-care survey

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Background: Three randomized trials support adjuvant radiation therapy (ART) over observation after radical prostatectomy (RP) for prostate cancer (PC) patients with adverse pathologic features (APFs), but many clinicians instead favor early salvage RT (SRT) for a rising PSA. We conducted a web-based survey of U.S. radiation oncologists (RO) and urologists (U) regarding ART and SRT.

Methods: We designed a web-based survey to evaluate beliefs about post-RP RT and treatment policies. Survey invitations were e-mailed to SUO members and a list of 926 RO ASTRO members with an interest in PC. One email was sent to limit message burden. Only those responses at least 50% complete were included in the analysis. Differences in ART recommendation rates were evaluated by chi square test.

Results: Responses were received from 231 RO and 101 U, resulting in 302 analyzable responses (88 U, 214 RO). 79% of U and 32% of RO respondents were academic physicians. ART was recommended based on APF alone (78% RO, 44% U), based on APF plus Gleason score or PSA (14% RO, 35% U), only for detectable PSA (7% RO, 14% U), or never (2% RO, 7% U). When asked the effect of ART on outcomes, most respondents replied “improves survival” (71% RO, 63% U) or “improves biochemical control but not survival” (29% RO, 30% U), but 9% of U replied “delays PSA recurrence, but no durable benefit” or “no improvement in any outcomes” (versus 0% RO). A recommendation for ART based on APFs alone was made for: seminal vesicle invasion (SVI) (76% RO, 59% U; p=0.003), extracapsular extension (ECE) (70% RO, 32% U; p<0.001), positive surgical margin (PSM) (91% RO, 48% U; p<0.002). For patients with Gleason score 8-10 PC, ART was recommended for: SVI (75% RO, 56% U; p=0.001), ECE (73% RO, 45% U; p<0.001), PSM (93% RO, 74% U; p<0.001). Reported PSA threshold for SRT was: any detectable (36% RO, 23% U), 0.2-0.3 (50% RO, 36% U), 0.4-0.5 (9% RO, 30% U), 0.6-0.8 (3% RO, 10% U) ng/mL, or higher (1% RO, 1% U).

Conclusions: Despite similar rates of belief that ART improves survival or biochemical control, U were less likely than RO to recommend ART based solely on APFs after RP. Upcoming results of clinical trials of ART versus SRT may provide consensus for decisions in this setting.

No significant financial relationships to disclose.