August 12, 2019

expert reaction to taking aspirin before diagnosis and breast cancer outcomes

Research, published in Cancer, reports on the possible connection between taking aspirin before a breast cancer diagnosis, and the potential outcomes.

Prof Paul Pharoah, Professor of Cancer Epidemiology, University of Cambridge, said:

“There is some evidence (not very strong) that regular aspirin use at the time of diagnosis of breast cancer is associated with a lower risk of dying from breast cancer.  The authors of this study have investigated whether this potential benefit of aspirin may be restricted to women with tumours that have a specific type of modification of the DNA called methylation.

“While the study has been carefully conducted, the number of women in the study is too small to provide findings that are statistically robust and the assertion in the press release that “in certain areas of the genome may live longer if they take aspirin before they are diagnosed with breast cancer” is not supported by the data.

“The specific finding that has been highlighted is that they have found evidence for an interaction – a statistical interaction – between aspiring use before diagnosis and DNA methylation of the gene BRCA1.  The statistical evidence is very weak and is dependent on the rather unlikely finding that aspirin is associated with a better outcome in women with a tumour with unmethylated BRCA1 and it is associated with a worse outcome in women with a tumour with methylated BRCA1.  Neither or these two observations are statistically significant in themselves.  The conclusion that aspirin use can help a subgroup of breast cancer patients to live longer cannot be justified by these findings.

“In short, the headline findings from this study are highly likely to have occurred by chance and so they have no implications for breast cancer patients.”

Prof Justin Stebbing, NIHR Research Professor of Cancer Medicine and Medical Oncology, Imperial College London, said:

“In spite of massive advances in detection and treatment, breast cancer is still the second leading cause of death in women. A new study in 1,266 women with breast cancer diagnosed in the 1990s suggests that women with specific DNA characteristics (they looked at chemical changes called epigenetic modifications), in certain areas of the genome may live longer if they take aspirin before they are diagnosed with breast cancer. This is a relatively small group for such a common disease, so it needs to be validated further in more women, and also more genes need to be looked at.

“Aspirin is a low-cost, readily available drug that is considered (not without controversy) a potential therapy for both the prevention and the treatment of breast cancer. There are lots of mechanisms with both clinical and laboratory evidence supporting this possibility. But thus far human studies of aspirin use and breast cancer survival have shown inconclusive results likely because of the different biology of different types of breast cancer, different timings of aspirin use, and definitions of when aspirin is taken and the dose too. Because of studies like this, at Imperial we have a trial called Add-Aspirin which -after diagnosis of many cancer types not before – involves giving an aspirin or placebo.

“Studies like this one, although not perfect in establishing causality, whether it’s to do with prevention or even treatment effects, are a critical component of translational research. Translational research aims to move the needle forward by providing evidence to support new clinical treatments, programs, and policies for advancing health.”

‘Prediagnosis Aspirin Use, DNA Methylation, and Mortality After Breast Cancer: A Population-Based Study’ by Tengteng Wang et al. was published in Cancer on Monday 12 August 2019. 

DOI: 10.1002/cncr.32364

Declared interests

Prof Paul Pharaoh: I have no conflicts of interest to declare

None others received.