How Stress Impacts Cancer Risk
I am a doctor who helps individuals with cancer.
What comes to your mind when I ask what causes cancer?
Ask me what causes cancer, and you’ll probably hear me blabber on about lifestyle things such as tobacco, alcohol, sun exposure, and weight.
And I’ll mention genetics, of course.
But stress?
The clinical literature generally says nope.
Yet so many of my patients report an association between stress and a cancer diagnosis.
Unfortunately, anecdotes provide a level of evidence that is too low to establish a link.
Now, a new study suggests my patients may be on to something when they point to a stress-cancer relationship.
Stress and Cancer: A New Study
This week, a new study delves deeper into the connection between stress and cancer, revealing how stress specifically alters immune function in ways that may foster the growth of malignant cells.
US National Cancer Institute (NCI) researchers reported their study “Multilevel Stressors and Systemic and Tumor Immunity in Black and White Women With Breast Cancer,” JAMA Network Open.
They examined 121 women with primarily early-stage breast cancer, with an average age of 56.
The cohort consisted of 65 self-identified white women and 56 self-identified Black women.
Study Details
While the study is a cohort one, it seems to be a deep phenotyping (“-omics”) investigation.
The investigators extensively measured biomarkers in cancer cells, the tissue surrounding the malignancy, and blood.
They analyzed 92 immune-cancer protein markers and thousands of RNA and DNA markers.
Here are the four domains for which they measured stress:
- Daily stresses (work, family, etc.)
- Racial discrimination
- Social isolation
- Neighborhood deprivation
Study Results – How Stress Impacts Cancer Risk
The study found associations between stress (including inadequate social support, racial/ethnic discrimination, and neighborhood deprivation) and negative changes at the genomic, transcriptomic, and proteomic levels.
Stress also changes the body, the tumor, and its microenvironment.
The researchers suggest understanding how biology contributes to cancer health disparities could help us offer preventative measures and public health interventions.
The Study Has Flaws
The researchers admit that their study has several limitations.
The cohort size, while substantial, could be larger.
The cross-sectional design prevented them from drawing causal conclusions.
- The study population included only individuals from Baltimore, Maryland (USA) and surrounding areas.
- The researchers lacked longitudinal data on residential history, which prevented them from fully capturing the impact of neighborhood deprivation over time.
- The Perceived Stress Scale, while useful, measures stress after a breast cancer diagnosis and may not fully reflect chronic stress experienced before diagnosis.
- The stepwise approach to analyzing the association between stress and proteomic biomarkers may have underestimated the variance. Sociodemographic and sociostructural variables were entered sequentially, resulting in shared variance being attributed to these variables.
My Take – How Stress Impacts Cancer Risk
As a doctor working with cancer patients, I’ve always focused on the usual suspects like alcohol, tobacco, physical activity, and genetics.
While my patients often mention stress, it hasn’t been a major focus in the literature.
However, this new study is making me reconsider that.
The research suggests that stress might impact cancer development and could even explain some health disparities.
The study has limitations, like its size and design, but I’ll consider stress and cancer more.
What is your biggest daily stressor? How do you cope with it?
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