Aspirin use and the risk of prostate cancer mortality in men treated with prostatectomy or radiotherapy

Abstract

Purpose: Experimental evidence suggests that anticoagulants (ACs) may inhibit cancer growth and metastasis, but clinical data have been limited. We investigated whether use of ACs was associated with the risk of death from prostate cancer.

Patients and methods: This study comprised 5,955 men in the Cancer of the Prostate Strategic Urologic Research Endeavor database with localized adenocarcinoma of the prostate treated with radical prostatectomy (RP) or radiotherapy (RT). Of them, 2,175 (37%) were receiving ACs (warfarin, clopidogrel, enoxaparin, and/or aspirin). The risk of prostate cancer-specific mortality (PCSM) was compared between the AC and non-AC groups.

Results: After a median follow-up of 70 months, risk of PCSM was significantly lower in the AC group compared with the non-AC group (3% v 8% at 10 years; P < .01). The risks of disease recurrence and bone metastasis were also significantly lower. In a subgroup analysis by clinical risk category, the reduction in PCSM was most prominent in patients with high-risk disease (4% v 19% at 10 years; P < .01). The benefit from AC was present across treatment modalities (RT or RP). Analysis by type of AC medication suggested that the PCSM reduction was primarily associated with aspirin. Multivariable analysis indicated that aspirin use was independently associated with a lower risk of PCSM (adjusted hazard ratio, 0.43; 95% CI, 0.21 to 0.87; P = .02).

Conclusion: AC therapy, particularly aspirin, was associated with a reduced risk of PCSM in men treated with RT or RP for prostate cancer. The association was most prominent in patients with high-risk disease.

Fig 1.

Prostate cancer–specific mortality (PCSM) by anticoagulant (AC) use. Men undergoing AC therapy had a 10-year PCSM of 3% compared with 8% for men not taking an AC (P < .01 by log-rank test).

Fig 2.

Prostate cancer–specific mortality (PCSM) by the treatment modality. The improved PCSM in the anticoagulant (AC) group was observed whether patients were treated with (A) radical prostatectomy or (B) radiotherapy.