Most doctors know that every patient responds differently to treatment. Often two patients with the same clinical condition, receiving the same treatment, will show a very different clinical course. While one recovers faster or better than expected, the other appears refractory to treatment. This phenomenon, which involves the interplay of several factors such as the patient’s mental strength, the incentive and motivation to recover and the determination to fight the disease, is often as crucial as the treatment and intervention by the doctors.
While healthcare professionals such as doctors and nurses have known this for generations, the reasons are becoming clear only in recent years. In the context of cancer, it has to be viewed as the coming together of three separate trains of thought: One, that human feelings and emotions are expressed in terms of neuro-chemical substances; two, that these neuro-chemicals exert an impact on the immune system (both cell-mediated and humoral); and three, that cancer cells can be combated and even controlled by strengthening the immune system. A combination of these three ideas has given birth to a new discipline of medical research, known as Psycho-Neuro-Immunology or PNI.
In recent years, more and more cancer specialists have started to believe that the human immune system can be an invaluable ally in the battle against malignancy. “One reason that cancer cells thrive is that they are able to hide from your immune system. Certain immunotherapies can mark cancer cells, so that it is easier for the body’s immune system to find and destroy them,” says a recent article published by the National Cancer Institute, a member of the National Institutes of Health (NIH) network. Immune therapies can be of many types: cytokines, monoclonal antibodies, treatment vaccines and even BCG (originally discovered as a preventive against tuberculosis).
Impact of emotions
On the other hand, we also know that emotions are chemical reactions mediated by hormones and other biochemical such as serotonin, dopamine, oxytocin, endorphins, etc. Numerous scientific articles published globally in the past few years have expounded the concept that these same chemicals also affect the immune system – both cell mediated and humoral. In an article in Frontiers in Behavioural Neuroscience published last year (doi: 10.3389/fnbeh/.2018.00056), Aki Takahashi et al, have written that “individuals with high aggression display heightened inflammatory cytokine activity and dysregulated immune responses such as slower wound healing. Similar findings have been observed in patients with depression, and comorbidity of depression and aggression was correlated with stronger human dysregulation.”
So, when we put these two concepts together, what do we get? The perfectly conceivable idea that anger, depression and other negative emotions are capable of slowing down the immune response to cancer and retard the effectiveness of traditional cancer therapies! While this appears quite logical and obvious, we still have to see if it is supported by experimental and scientific evidence.
Much of the existing research, both in India and abroad, focuses on the impact of emotions and behavior on the clinical course of cancer after it has been diagnosed. Thus Dr Raghavendra Mohan Rao and his colleagues in the Centre for Academic Research, HCG Foundation, Bangalore, writing in Indian Journal of Palliative Care (Indian J Palliat Care 2017; 23-225-30) point out: “Treatment-related distress can manifest as anxiety or depressive disorders in some cancer patients, leading to a heightened feeling of hopelessness, a lack of will to survive, a loss of control over one’s life, low self-esteem and other indicators. Studies have also shown that such a state of mind can lead to sleep disturbances, aberrant cortisol rhythms, poor anti-tumor immune response, a decrease in overall and disease-free survival with early relapse/recurrence, and heightened distress.”
Likewise, in a 2013 review article published in Brain, Behaviour and Immunity, Paige Green MacDonald et al. write that stressful experiences in life and a state of depression have been linked with poorer survival rates and greater frequency of death in a wide range of cancers, including those originating in the breast, lung, head and neck, hepatobiliary system and blood.
The article (http://dx.doi.org/10/1016/j.bbi.2013.01.003 ) also points out that symptoms of depression have an adverse impact on the survival of patients with metastatic kidney cancer. On the other hand, amelioration of depressive symptoms was clearly linked with better clinical outcomes in advanced cases of breast cancer. In addition, the potential for damage on account of unsatisfactory or unfulfilling social relationships was as serious as the risk conferred by excessive alcohol and tobacco use!
“People under stress have a lower level of T-cell mediated immunity,” says Dr Navin Salins, a palliative care physician with Kasturba Medical College, Manipal. He also mentions other studies conducted in HCG, Bangalore that have revealed that “mind-body intervention” such as yoga have a definite role in controlling the nausea, vomiting and other symptoms of anti-cancer therapy.
But can this set of ideas be taken one step further, and be used for the prevention of cancer? Perhaps not in the near future, because a number of Indian scientists have pointed out that the evidence on this aspect is insufficient at the present time.
“I have done one retrospective study about five years ago where I found some correlation ‘Fear of Cancer’ and ‘Cancer Recurrence’, keeping in mind this concept that anxiety and stress can compromise our immune system and help cancer to recur,” says Dr Suchitra Mehta, Director and Head, Psycho-Oncology, HCG NCHRI Cancer Centre, Nagpur.
Speaking on similar lines, Bincy Mathew, a psycho-oncologist with Manipal Hospitals, New Delhi and founder of non-profit organization
www.psycho-oncology.in, says: “One’s attitude and its influence on cancer is still a big debate in cancer circles. In my experience, I have not found strong enough scientific evidence that one’s attitude alone can directly impact cancer progression or the immune system. But many studies have proven that one’s emotions may contribute to stronger, better immunity during cancer treatment.”
The jury is therefore out on exactly how much impact psychological factors can have on individual cancer patients and how these findings can be put to use. However, these developments hold out the hope that before too long, mental and psychological training would play a significant part in cancer therapy as a whole.