Jia-Li Feng

Lipid-lowering medication use and cancer-specific survival among endometrial or lung cancer patients: an Australian nationwide cohort study

Inconsistent results of lipid-lowering medications (LLMs) on improved cancer survival need more investigations. We tested the hypothesis that adherence to the drug would be associated with a lower cancer-specific mortality in a homogeneous population who has ever used the drug. Utilising data from the Australian Cancer database, linked to the Pharmaceutical Benefits Scheme data and the National Death Index, we identified two separate cohorts of 4519 and 3083 women patients with newly diagnosed endometrial and lung cancer respectively between 2003 and 2013. Adherence to this drug was calculated by proportion of days covered. Cox regression models with time-varying covariates were used to estimate the multivariable-adjusted cause-specific hazard ratios (HRs) and 95% confidence intervals (CIs) for the association of adherence to LLMs, statins, lipophilic and hydrophilic statins, and cancer-specific mortality. Each 10% increase in 1-year adherence to LLMs reduced cancer-specific mortality among women with endometrial cancer (adjusted HR=0.93, 95% CI 0.90-0.96) or lung cancer (adjusted HR=0.95, 95% CI 0.93-0.97). The inverse associations remained unchanged in different subgroup analyses. The reductions in lung cancer mortality were not apparent for women who adhered to lipophilic statins albeit better endometrial cancer survival appeared in the lipophilic statin group and borderline statistical improvement in the hydrophilic statin group. Among LLM users, adherence to this drug is inversely associated with reduced cancer-specific mortality. Together with previous evidence, randomised controlled trials are called for to confirm whether LLMs could be considered as an adjuvant treatment to improve prognosis.

Statin use and survival among women with ovarian cancer: an Australian national data-linkage study

Five-year ovarian cancer survival rates are below 50%; there is considerable interest in whether common medications like statins may improve survival. We identified women diagnosed with ovarian cancer in Australia from 2003 to 2013 through the Australian Cancer Database and linked these records to national medication and death databases. We used Cox proportional hazards regression to estimate hazard ratios (HR) and confidence intervals (CI) for associations between statins and survival. Pre-diagnosis statin use was not associated with survival overall but was associated with better survival among women with endometrioid cancers. Statin use after diagnosis was associated with better ovarian cancer-specific survival (OVS, HR = 0.87, 95%CI 0.81-0.94), but this association was largely restricted to women who started using statins after their cancer diagnosis (OVS HR = 0.68, 0.57-0.81 vs. HR = 0.94, 0.87-1.01 for continuing users). The association was strongest for endometrioid cancers (OVS HR = 0.48, 0.29-0.77). Use of statins may confer a survival benefit for women with ovarian cancer but it is impossible to rule out bias in observational studies. Particularly problematic are reverse causation where disease status affects statin use, confounding by indication and the absence of data for women with normal cholesterol levels. A randomised trial is required to provide definitive evidence.