The Clinicopathological Characteristics of Androgen Receptor Splicing Variant 7 (AR-V7) Expression in Patients with Castration Resistance Prostate Cancer: A Systematic Review and Meta‐Analysis

Abstract BACKGROUND Accumulating studies indicate AR-V7 may be related to the poor prognosis of castration resistance prostate cancer (CRPC), while the evidence of the clinicopathological characteristics of AR-V7 is rare. METHODS To evaluate the clinicopathological features of AR-V7 in CRPC patients. A search of PubMed, Embase, and the Web of Science was performed using the keywords prostate cancer, prostate tumor, prostate neoplasm, prostate carcinoma; AR-V7, AR3, androgen receptor splicing variant-7, or androgen receptor-3. Twenty-four trials published due February 2020 were enrolled. RESULTS The proportion of Gleason score ≥ 8 was significantly higher in AR-V7-positive CRPC (69.5%) than negative (54.9%) (OR 1.68, 95% CI 1.25–2.25, P<0.001), while the rate of T3/T4 stage (OR 1.16, 95% CI 0.60–2.24, P=0.65) and N1 stage (OR 0.99, 95% CI 0.65–1.51, P=0.96) were not statistically related to AR-V7 status. AR-V7-ositive patients had a significantly higher proportion of any site metastasis (61.3% versus 35.0%) (OR 2.19, 95% CI 1.57–3.05, P<0.001) and bone metastasis (81.7% versus 69.0%) (OR 1.97, 95% CI 1.44–2.69, P<0.001), and a trend close to significance was expected in visceral metastasis (28.8% versus 22.1%) (OR 1.29, 95% CI 0.96–1.74, P=0.09). The percentage of pain presence in AR-V7-positive CRPC (54.6%) was prominently higher than negative (28.1%) (OR 4.23, 95% CI 2.52–7.10, P<0.001), line with worse ECOG performance status (56.7% versus 35.0%, OR 2.18, 95% CI 1.51–3.16, P<0.001). Limitations of the study include the differences in study sample size and design, AR-V7 detection assay, and disease characteristics. CONCLUSIONS AR-V7 positivity was associated with higher Gleason score, bone or any site metastasis, presence of pain and worse ECOG performance score in CRPC, but not related to tumor stage or lymph node metastasis. More studies are needed to confirm these findings.