The use of anticoagulants improves biochemical control of localized prostate cancer treated with radiotherapy

BACKGROUND: Substantial experimental evidence suggests that anticoagulants (ACs) may inhibit cancer growth and metastasis, although the limited data from clinical trials have been inconsistent. The potential antineoplastic effect of ACs was investigated in patients who received radiotherapy for localized prostate cancer. METHODS: The study cohort consisted of 662 patients with adenocarcinoma of the prostate who received radiotherapy (RT) with curative intent. Among those 622 men, 243 (37%) were receiving ACs (warfarin, clopidogrel, and/or aspirin). All patients received external-beam RT, permanent seed implantation, or a combination of both. Prostate-specific antigen (PSA) values were monitored for biochemical control of disease. RESULTS: At a median follow-up of 49 months, the biochemical control rate at 4-years was significantly better in patients who received ACs at 91% compared with 78% in patients who did not receive ACs (P = .0002). The distant metastasis rate at 4 years also was reduced in the AC group compared with the non-AC group (1% vs 5%; P = .0248). In subgroup analysis, the improvement in biochemical control was significant only for patients with high-risk disease. Along with Gleason score, T classification, and initial PSA, the use of AC therapy was associated independently with improved biochemical control in multivariate analysis. CONCLUSIONS: AC therapy was associated with an improvement in biochemical control in patients with prostate cancer who received RT with curative intent. The effect was most prominent in patients who had high-risk disease.