The importance of a supportive environment following a cancer diagnosis cannot be underestimated. For many years, social isolation has been known to be associated with worse outcomes in multiple diseases, including cancer. The risk of mortality among socially isolated patients with breast cancer has been found to be comparable to that of obesity and smoking. New results reveal stress related hormones to hold the key to explaining this surprising effect.
The context
The observed beneficial effects of social support are plenty. In addition to extending the lives of patients with breast cancer, social engagement results in a higher quality of life after the diagnosis and less symptoms. This interaction is not a matter of quantity, as the quality of close relationships has been found to be a better predictor of the effect. Loneliness and other psychological factors don’t increase the risk of cancer but rather how fast it progresses as shown in studies on animal models.
The beneficial health influence of a strong social network is often explained by the so-called “social control theory”. This refers to a type of peer pressure where people in the social circle discourage unhealthy behavior and stimulate healthy actions. However, the ability to reproduce the positive health effects of the social environment in different species from flies to primates, suggests that isolation also has a direct physiological impact.
The nuts and bolts
The mechanisms behind this influence are still under investigation. However, a few hypotheses have been formulated, which are mainly related to the effects of stress. Social isolation leads to the release of stress-hormones. These are divided into two types, which use a different mechanism to exert their effect on the body. Their best know representatives are adrenalin and cortisol. These are being studied as potential targets.
For example, beta-blockers, which inhibit the effects of adrenalin, are associated with less advanced breast cancer and a lower mortality. Phase II clinical trials are underway to see if adding the beta-blocker propranolol to chemotherapy treatment can increase the efficacy in breast cancer patients. Cortisol can influence tumor growth directly, or indirectly by influencing the way the immune system recognizes and eliminates cancer cells. Excess cortisol has also been shown to interfere with chemotherapy treatments, resulting in resistance to the treatment and larger tumors.
Finally, there is also a potential role for oxytocin, which is associated with positive emotions and is released in the body following social and physical contact. It stimulates the bonding between mother and child during breastfeeding and has also been shown to be involved in buffering stress responses. However, not much preclinical data is available on its effects on tumor cell lines and cancer models. This is mainly caused by technical challenges associated with accurately measuring oxytocin. The data that is available shows that oxytocin is present in tumors, can affect tumor cell growth and influence the immune response. These initial findings support further investigation of its importance.
How will this help me?
Overall, loneliness and a lack of social support are detrimental to health. Social isolation and breast cancer survival are clearly associated, and the initial exploration of the physiological mechanisms behind this has begun. Now, it is important to unravel the proposed hormonal pathways further to discover therapeutic targets and help us identify patients that are more heavily impacted by this phenomenon. This can lead to new psychosocial interventions and better breast cancer outcomes.
Source
Breast cancer and social environment: getting by with a little help from our friends – Breast Cancer Research (2016).