The effect of statins on overall survival and progression-free survival in veterans with prostate cancer: A retrospective single-center experience.

Abstract

169 Background: Prostate cancer is the most common cancer in men in the United States. Death in prostate cancer patients is often related to other medical conditions and not prostate cancer itself. Hence, it is important to optimize other co-morbidities, such as hyperlipidemia, hypertension, and cardiovascular diseases in these patients. However, there are numerous studies portraying the ability of statins to increase progression free survival and overall survival of prostate cancer. This has led to significant interest of statins having anti-cancer properties and ultimately improving long term outcomes. Methods: This is a retrospective observational study with chart review of 1,011 patients diagnosed with prostate cancer from 1995 to 2010 in a VA Hospital in San Antonio, Texas. Variables included age at diagnosis, statin use, type of statin (1st, 2nd, or 3rd generation), dose of statin (4 dosage levels), length of statin use, time followed in months (from diagnosis to death or end of study period), death, cause of death, and time to first progressive disease. Progressive disease was defined using PSWG2 guidelines which is PSA increase > / = 25% and at least 2ng/dl above the nadir. The Cox proportional hazards regression model was used to estimate the hazard function, with age, co-morbities and other cancers used as a covariate. End points were death by prostate cancer (56), death by any cancer (140), and death by all causes (484). We also looked at the effects of statins on progression free survival of prostate cancer. Results: The hazard ratio (HR) for use of statins and death by prostate cancer was 0.35, 95% confidence interval (CI): 0.20-0.62 (p = 0.0003), indicating that statin use has a statistically significant positive effect at delaying death by prostate cancer. Death by any cancer was significantly affected by statins with a HR of 0.47, 95% CI: 0.32-0.65 (p < 0.0001). Death by all causes was also affected significantly by statins with a HR of 0.64, 95% CI: 0.53-0.78 (p < 0.0001). Length of statin use, shorter versus longer than 4 years, showed an inverse association with our primary end point with a HR of 0.53, 95% CI: 0.40-0.69 (p < 0.0001). Dose level of statin, fourth level vs 1, 2, and 3, also showed an inverse association with our primary end point with a HR of 0.73, 95% CI: 0.57-0.94 (p = 0.014). Lastly, statin exposure significantly increased progression-free survival with a HR of 0.71, 95% CI: 0.53-0.95 (p < 0.021). Conclusions: It is clear that concomitant statin use increases overall survival in patients with prostate cancer, potentially even having anti-cancer protective effects against mortality. Longer duration of statin use and higher dose levels of statins increase length of overall survival in patients with prostate cancer. As mortality is often not due to prostate cancer, more interestingly, statin exposure is also shown to increase progression-free survival.