Triple-negative breast cancer (TNBC) is an aggressive type of cancer that accounts for approximately 10% -20% of breast cancer diagnoses. Triple negative means that breast cancer has no receptors for estrogen or progesterone or HER2 positivity, which are the three most common receptors for breast cancer. This combination results in highly aggressive breast cancer with poor prognosis and limited treatment options as there are few receptors to actively target with existing therapies. A study by researchers at the University of Texas MD Anderson Cancer Center found a significant association between cholesterol-lowering drugs, commonly known as statins, and the survival rates of patients with triple-negative breast cancer. Since statins are low-cost, easy to access, and produce minimal side effects, this could have a major impact on the outcomes of this aggressive disease. There is already an extensive literature on statins and breast cancer and the results have been inconsistent.
Previous research has considered breast cancer as a single disease, but there are many subtypes of breast cancer, and scientists have wanted to focus on this particularly aggressive form of breast cancer which has limited effective treatment options. The retrospective study selected patients included in the Surveillance, Epidemiology and End Results (SEER) -Medicare registry and the Texas Cancer Registry (TCR) -MediCare, two large databases of patient administrative requests that are eligible for MediCare. Patients had to have Medicare Part D prescription coverage to determine their statin use. The research included data from 23,192 women over the age of 66 with stage I-III breast cancer. From that cohort of patients, 2,281 were occasional statin users, meaning they started taking a statin within one year of being diagnosed with breast cancer. Accidental statin users were 78.1% white, 8.9% black, 8.4% Hispanic, and 4.5% others.
This research extends current knowledge on the association between statin use and triple negative breast cancer and is the first adequately powered study to investigate the association between statins and aggressive breast cancer subtypes. Researchers found a relative improvement of 58% in breast cancer-specific survival; and a 30% relative improvement in overall survival with statin use. The median follow-up was 3.3 years for breast cancer specific survival and 4.4 years for overall survival. Breast cancer stage analysis suggested that the association of accidental statin use with better outcomes may be stronger in women with early stage TNBC. When looking at statin intensity, high-intensity statin use had the strongest effect on overall survival among women with TNBC. The researchers also found a statistically significant association between lipophilic statins (eg, atorvastatin, fluvastatin, pitavastatin) and improved overall survival.
Scientists believe that prospective studies are needed to validate the results of these studies and to better define the potential role of statins in the treatment of TNBC. And there is another novelty on the front of this tumor but on the diagnostic side. The journal Oncotarget published the article “High Sensitivity C-Reactive Protein Association and Breast Cancer Likelihood by Molecular Subtype: Analysis of the MEND Study,” which reported that the authors examined the association between high-sensitivity PCR with probability of breast cancer by molecular subtype among Nigerian women. A recent systematic review found no clear evidence of an association between circulating CRP and breast cancer risk among prospective studies, while a second systematic review observed a modest but significant positive association. Analyses from the women’s health study found that baseline CRP level was not associated with the risk of invasive breast cancer during the 10-year follow-up.
However, in the Women’s Health Initiative, pre-diagnostic CRP was associated with an increased risk of cancer among thin women, while no association was observed among overweight-obese women. In contrast, another study in Europe found a positive association between CRP levels and the risk of postmenopausal breast cancer limited to women with excessive fat. In particular, few epidemiological studies have analyzed the relationship by molecular subtype and the results have been mixed. One study in Italy reported a significant association between high CRP and TNBC and pre-menopausal luminal B breast cancer, while another study in China found an association only for hormone receptor positive and HER2-negative cancer. Among 296 newly diagnosed cancer cases and 259 healthy controls in this study, multivariate logistic regression models were used to estimate 95% confidence intervals for the association between hsPCR and probability of breast cancer overall and by molecular subtype.
High hsPCR was observed in 57% of cases and 31% of controls and was associated with a 4-fold probability of breast cancer after adjustment for socio-demographic, reproductive and clinical variables. The high hsPCR was associated with an increase in the likelihood of TNBC, luminal carcinoma and the histotype enriched with HER2. Future studies in this population are needed to further evaluate a potential role of PCR as a predictive biomarker for breast cancer. It would be a significant diagnostic achievement of procedural simplification, considering that the PCR assay is routinely performed in simple laboratory blood test.
- edited by Dr. Gianfrancesco Cormaci, PhD, specialista in Biochimica Clinica.
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