Breast cancer survivors – stress
According to a report and survey published in Psychooncology a substantial part of women who had survived breast cancer believe that there is a link between breast cancer and psychological stress.
In this report, Stewart DE et al., from the University Health Network Women’s Health Program, University of Toronto, Canada surveyed 378 women breast cancer survivors about their views on the cause and lack of recurrence of their breast cancer.
Interestingly, women who responded to the question about the cause of breast cancer attributed it mostly to stress (42.2%), genetics (26.7%), environment (25.5%) and hormones (23.9%).
Thus, the majority (42%) believed stress was one of the main causes of their disease.
Despite the high profile of families with a genetic link in recent years, only 27% thought genetics was a factor, with almost the same number suggesting environmental factors had played a part in causing their cancer.
According to a BBC news report (see below), Dr. Donna Stewart, who led the study, said the belief that stress had caused their disease, and lifestyle changes following it could help women feel they had control over the condition.
Emerging evidence and other recent studies indicate a link between psychological stress, or stress hormones and breast cancer. Noteworthy, a search (January 17, 2026) using the following keywords: (psychological stress) AND (breast cancer) at PubMed (search engine at the United States National Library of Medicine, the NIH, Bethesda, MD) provides 3,325 results (see Figure at left).
Source: Psychooncology, 2001, 10:179-83
Updates
A 2014 systematic review included 22 studies that met the inclusion criteria. Results indicated a consistent belief among survivors that their own breast cancer could be attributed to family history, environmental factors, stress, fate, or chance.
The findings of this review indicated that beliefs about the causes of breast cancer among affected women are not always consistent with the judgement of experts. Breast cancer survivors did not regularly identify causal factors supported by expert consensus such as age, physical inactivity, breast density, alcohol consumption, and reproductive history.
A 2015 study by Thayse Fachin Cormanique et al. demonstrated that women presenting with a history of chronic distress were significantly overweight, and these stressed women also had a significant percentage of aggressive breast cancer subtype, the HER2 amplified tumor.
The authors concluded that their observation suggests an interaction among chronic psychological stress, overweight, and the development of more aggressive breast tumors.
A 2018 study assessed the risk factors for breast cancer from the point of view of survivors. These authors ran a survey with open- and closed-ended questionnaires on patients’ opinions about risks factors both for women in general and for their own case.
Of note, most patients had no opinion, but for the rest, most frequently cited risk factors were stress, then genetic causes, and poor diet.
Another 2018 aimed to understand how stressfulness appraisal of salient Life Events (LEs) influences breast cancer risk. The study included 664 female cases identified through the Cancer Surveillance Program of Orange County, CA.
The results indicated that the cumulative adverse LEs perceived as stressful were associated with increased breast cancer risk in a dose response fashion. Of note, pre/peri-menopausal women who were nulliparous or who had their first child at ≥30 years of age were especially prone to the effects of appraised stress on increased breast cancer risk.
The authors of this study concluded that their results suggest that LEs differentially influence breast cancer risk according to stress perception. This is consistent with previous research highlighting the importance of stress appraisal in altering the physiological stress system.
Importantly, these authors found that negative valence LEs were those to have the greatest likelihood of being perceived as “stressful”. Therefore, negative valence, cumulative LEs perceived as stressful seem to be most influential in increasing breast cancer risk.
Furthermore, a history of personal illness, defined as ‘serious illness or injury of oneself’ was significantly associated with increased breast cancer risk both when perceived as stressful and when perceived as non-stressful. Of note, these results are in line with a previous study by Helgesson et al. where perceived stress was associated with an approximately 2-fold increase in breast cancer risk.
A 2022 systematic review indicates that, in addition to the known risk factors, psychological factors may play an important role in the etiology of both breast and lung cancer.
According to the authors of this study, in 2020 breast cancer had the highest number of new cases, and lung cancer was second in number of new cases and the first in number of deaths. This review demonstrated that some adverse life events/trauma are statistically associated to an increased risk of breast cancer.
In particular, the self-reported events perceived at baseline with psychological distress stand out, such as the death of a friend, close family member, or spouse. Death as an adverse life event/trauma seems to contribute the most to breast tumor development. Therefore, psychological treatment of adverse life events/trauma can reduce the occurrence of breast cancer in females.
Another question reviewed was the existence of an association between depression and breast cancer risk. Previous work indicates that depression was the most studied psychological factor, being associated with a small to moderate breast cancer risk in females.
Thus, these results support the evidence already described in the literature, that depression is a factor to be considered in the subsequent development of overall cancer. However, 15 of the 20 studies included in this systematic review did not support this relationship.
The authors concluded that the psychological factors in cancer should be considered and deserve further investigation. Importantly, to consider psychological factors as a variable that affects cancer development may be fundamental to opening new avenues for prevention and intervention.
A 2023 study by Yifeng Zheng et al. demonstrated that chronic unpredictable mild stress (CUMS) significantly promoted breast cancer growth and metastasis, accompanied by tumor-associated macrophages (TAMs) accumulation in the microenvironment.
Graphical Abstract
CXCL1 was identified as a crucial chemokine in TAMs facilitating pre-metastatic niche (PMN) formation in a glucocorticoid receptor (GR)-dependent manner. Interestingly, the spleen index was significantly reduced under CUMS, and splenic MDSCs were validated as a key factor mediating CXCL1-induced PMN formation.
The molecular mechanism study revealed that TAM-derived CXCL1 enhanced the proliferation, migration, and anti-CD8+ T cell functions of MDSCs via CXCR2. Moreover, CXCR2 knockout and CXCR2−/−MDSCs transplantation significantly impaired CUMS-mediated MDSC elevation, PMN formation, and breast cancer metastasis.
The authors concluded that the study demonstrated that chronic psychological stress promotes breast cancer progression via activating TAM/CXCL1 signaling in a GC/GR-dependent manner. The study also revealed the role of CXCL1-CXCR2 signaling in mobilizing spleen MDSCs into the lung to establish PMN, thereby facilitating metastasis.
A 2025 study by Dandan Zhan et al. reported that chronic unpredicted mild stress (CUMS) was able to promote breast cancer (BC) growth and metastasis with increased adipocyte lipolysis, reactive oxygen species (ROS) burst, and mitochondrial fission. Metabolomic analysis identified tryptophan (TRP) as the main responding metabolite, which markedly induced macrophage M2 polarization and the chemokine (C-X-C motif) ligand 1 (CXCL1) expression, and in turn promoted adipocyte lipolysis.
Background: Over the past decade, multiple downstream signaling, such as elevated glucocorticoid, altered gut microbiota, enhanced stemness, and suppressed immune microenvironment, have been reported to facilitate CUMS-induced cancer progress. Notably, it has been increasingly recognized that adipocyte lipolysis plays an important role in mediating the growth of solid malignancies, particularly for BC.
The authors discussed that their findings not only provided the novel role of TRP in mediating BC adipocyte lipolysis via recruiting tumor-associated macrophages (TAMs) but also uncovered the novel mechanisms of KEAP1 (Kelch-like ECH-associated protein 1) m6A demethylation in promoting adipocyte lipolysis via CXCL1-mediated FTO enhancement.
Taken together, the authors concluded that their study demonstrated that CUMS promoted BC growth and metastasis via enhancing TRP-induced adipocyte lipolysis by activating TAMs/CXCL1/KEAP1 signaling.
A 2026 study by Pengfei Liu et al., published in Cancer Research demonstrated a stress–neutrophil–cancer axis that promotes lung metastasis in breast cancer but also provides potential strategies for reducing lung metastasis by targeting CSP neutrophils or CCR1+ breast cancer cells.
The authors found that activation of the glucocorticoid receptor NR3C1 by the stress hormone corticosterone induced expression of Cebpb in neutrophils, which then promoted transcription of Ccl3 and Ccl4. The differentiation of neutrophils into the CSP subtype promoted lung metastasis of CCR1+ breast cancer cells via CCL3/CCL4-mediated recruitment.
The investigators concluded that stress induces a neutrophil subtype in the lungs that secretes CCL3 and CCL4 to stimulate metastasis of breast cancer cells by activating CCR1, offering potential strategies for preventing or treating metastasis.
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