Her2 Expression in Circulating Tumor Cells Is Associated with Poor Outcomes in Patients with Metastatic Castration-Resistant Prostate Cancer

HER2-dependent signaling may support the development of metastatic castration-resistant prostate cancer (mCRPC) by activating androgen receptor signaling through ligand-independent mechanisms. From 41 mCRPC patients (including 31 treated with Androgen Receptor Signaling Inhibitors [ARSI]), Circulating Tumor Cells (CTCs) were prospectively enriched with AdnaTest platform and analyzed with a multiplexed assay for HER2 and AR-V7 mRNA expression. Then, we evaluated the impact of HER2 expression on PSA-response, Progression Free Survival (PFS) and Overall Survival (OS). HER2 expression was detected in CTCs of 26 patients (63%). Although PSA response was similar regardless of HER2 status, patients with HER2 positive CTCs had shorter PSA-PFS (median: 6.2 months versus 13.0 months, p = 0.034) and radiological-PFS (6.8 months versus 25.6 months, p = 0.022) than patients without HER2 expression. HER2 expression was also associated with a shorter OS (22.7 months versus not reached, p = 0.05). In patients treated with ARSI, multivariate analyses revealed that the prognostic impact of HER2 status on PSA-PFS was independent of AR-V7 expression and of the detection of CTCs by an AdnaTest. We showed for the first time the poor prognostic value of HER2 expression in CTCs from patients with mCRPC. The therapeutic interest of targeting this actionable pathway remains to be explored.

[Prostate cancer: promising biomarkers related to aggressive disease]

BACKGROUND

Although a rapidly growing number of candidate biological markers of prognosis and/or response to specific treatments in prostate cancer, none have to date showed ability to completely prognosticate prostate cancer on evidence based urology.

OBJECTIVE

To review the pertinent literature on the issue.

ACQUISITION OF EVIDENCE

A comprehensive review of the current literature was done focusing on promising biomarkers related to aggressive prostate cancer.

SUMMARY OF EVIDENCE

Combined with the heterogeneous nature of the disease, mixed case series are the most common study design, impeding robust results and the development of an effective therapeutic strategy. Improvement in prostate cancer patient survival requires not only the identification of new therapeutic target based on detailed understanding of the biological mechanisms involved in metastatic dissemination and tumor growth but strong clinical studies as well.

CONCLUSION

Better study design involving potential markers and including well-classified and staged patients with robust methodology and adequate outcomes (mainly survival) are necessary to the field evolution.

Off-label therapies in oncology

Az indikáción kívüli (off-label) kezelések speciális problémát jelentenek az onkológiában, mivel a jogi szabályozás és a szabad orvosi gyakorlat határterületén állnak. Bár Magyarországon az off-label kezelés a 2008. október végén életbe léptetett rendelet megjelenéséig engedély nélküli klinikai vizsgálatnak minősült, egyes szakemberek mégis azzal érveltek alkalmazása mellett, hogy a klinikai gyakorlat gyorsabban változik, mint az alkalmazási előirat. Mi több, a gyártók még megfelelő evidencia esetén sem kötelesek az indikáció bővítésére. Az off-label kezelések szabályozása egyaránt meg kell hogy feleljen a szabad orvosi gyakorlatnak, az evidencián alapuló medicinának, a betegek új esélyekhez való igényének és a hatóságok elvárásainak. A közleményben a hazai helyzet és a törvény bírálata, illetve a nemzetközi gyakorlat áttekintése után egy, a fenti szempontoknak megfelelő lehetséges szabályozás kereteit vázolja a szerző, külön-külön kifejtve a kezelőorvos és a hatóságok szerepét.