One of the common consequences of advanced cancer is the apathy that patients encounter, including the loss of appetite and lack of motivation. Such patients giving up on life and the will to be fit again is one of the major problems doctors face in treating cancer. The condition is called cachexia. In cancer cases, while the patients with advanced conditions lose appetite, doctors say, the body needs more nutrition for metabolism. This leads to the body losing weight.

According to doctors, this condition is because of the release of interleukin 6 in the blood, which inhibits the release of dopamine in the area postrema (AP) region of the brain, which is also called the chemoreceptor trigger zone.

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Dopamine is a neurotransmitter and hormone that plays a crucial role in many bodily functions like movement, motivation and mood.

A study published in a science magazine by US researchers says cancer ‘hijacks’ a part of the brain (AP) that controls motivation.

Dr Rajiv Bhattacharya, oncologist at Peerless Hospital, says scientists always wanted to know why cachexia happens, whether it is because of cancer or some other reason. They had some preliminary research, and they realised that there is an inflammatory process associated with all cancers. There are various chemicals which cause inflammation. One such chemical is interleukin 6 (IL 6).

“The research paper is on the effect of interleukin 6 on cachexia. This study was done on mice. What happened is, there is an area in the brain called the area postrema, also associated with dopamine release. What the scientists did was they injected interleukin 6 into the AP of mice. The mice stopped eating and developed cachexia. Then they did genetic engineering through a device called CRISPR. This can cause a genetic mutation in genes. The target, which IL-6 binds, modified it so that IL-6 cannot work on the brain. As soon as they did that, they realised that the mice started eating and had behavioural changes; they became active again,” said Dr Bhattacharya.

“The scientists postulated that if this can happen in mice, it can also be replicated in humans. They are trying to decipher that the behavioural changes in patients are not psychological but organic. But this is a hypothesis. And if we can develop drugs which can inhibit IL-6, it can be path-breaking. We do not know if this study on mice will be corroborated in humans. This may be a breakthrough in how we treat cancer patients,” added Dr Bhattacharya.

Dr Tanmoy Mandal, onco medicine, Manipal Hospital Dhakuria, says tumours release specific cytokines which interfere with the brain function, particularly affecting areas which are responsible for motivation. “In the brain, what happens is that there is an imbalance between the two neuro-transmitters, excitatory neuro-transmitters and inhibitory neuro-transmitters. When we use antidepressants, they act in such a manner that the excitatory neurotransmitters are at a higher level. They diminish the level of negative transmitters and improve the level of excitatory neurotransmitters. So, if you are in a good mood, it affects the outcome of the treatment. The study is about drug repurposing,” said Dr Mondal.

Dr Ashish Upadhyay, medical oncologist at Fortis Hospital, Anandapur, feels one way is by increasing the production of dopamine by giving separate drugs, and the other is by silencing the gene which is negatively regulating dopamine.

“These are studies on mice. In humans, what the impact will be is too early to comment. We have to do more research. Depression has always been a part of all cancer patients. The use of antidepressants has also been in practice. But I would suggest a judicious use of infrastructure. Instead of targeting the anti-depressant component of a patient with say Rs 10-20 lakh, I would suggest a medicine worth Rs 4-5 lakh, which can increase the life expectancy of the patient in the Indian context,” said the doctor at Fortis Hospital Kolkata.