Temozolomide: Chemotherapy Drug Treating Brain Cancer May Increase Vulnerability to Depression

Depression is a common and a serious mood disorder that is unrecognized among cancer patients. Chemotherapy drug to treat brain cancer may increase the chances of depression by stopping the brain cells from growing, finds a new study from King’s College London. The research study was published in Translational Psychiatry.

In an early animal study, findings suggested that chemotherapy could cause behavioral or biological changes in the brain which causes depression.

This could be separate from the psychological distress that results in a cancer diagnosis.

Depression is More Vulnerable in Cancer Patients
A recent research finds that there is an increased vulnerability of depression among 30% of the brain cancer patients.The disorder is highly under-diagnosed.

Example: 90% of the patients pointed self-reported symptoms of depression and around 20% of them classified as having clinical depression.

Chemotherapy for Cancer Patients
Chemotherapy drugs are used as lifesaving medicines for cancer treatment. These drugs may stop all the cells from dividing. The outcome of the treatment is to kill the tumor cells.

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However, disrupting the killing could cause potential side effects which are related to cell division like hair loss. This finding has recently found that chemotherapy in animal studies could actually stop the growth of new brain cells.

Effect of Chemotherapy on New Brain Cells
The effect of chemotherapy on neurogenesis (growing new brain cells ) could actually alter the biological brain mechanisms which increase depression. Administering Chemotherapy Drug
Scientists administered a chemotherapy drug called temozolomide to mice. These animals showed a significant reduction in the growth of the new brain cells.

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The study findings revealed that more the drug decreased the neurogenesis process, the greater would be the exposure to stress.

Behavior of the Mice Following Treatment
Several changes related to depression were observed following the treatment with the chemotherapy drug.

• Deficits in novelty processing
• Decrease in the preference of rewarding sugar solution
• Lack of pleasure seeking

‘Although these preliminary findings are based on mice, our results suggest that chemotherapy may stunt the growth of new brain cells, which has biological and behavioural consequences that may leave people less able to cope with the stress of having cancer,’ said Dr Martin Egeland, author of the study, Institute of Psychiatry, Psychology & Neuroscience (IoPPN) at King's College London.

'Despite the potential side effects, chemotherapy is essential for increasing survival rates in cancer patients. However, understanding the specific effects of chemotherapy on mood could lead to improved treatments and increase quality of life for those affected by cancer.'

Another doctor Sandrine Thuret, senior author of the study from King’s College London, said, 'Our study highlights the importance of protecting brain stem cells or building up a reserve of cells before cancer treatment. This could help to preserve the mood and cognitive functions these cells are known to regulate, and could also improve quality of life for people with cancer.’

Further research is required to explore whether the drugs that enhance the process of growing new brain cells can relieve depression in the new brain cells after chemotherapy.

References

1. M Egeland, C Guinaudie, A Du Preez, K Musaelyan, P A Zunszain, C Fernandes, C M Pariante, S Thuret. Depletion of adult neurogenesis using the chemotherapy drug temozolomide in mice induces behavioural and biological changes relevant to depression. Translational Psychiatry, 2017; 7 (4): e1101 DOI: 10.1038/tp.2017.68
2. Depression - (https://www.nimh.nih.gov/health/topics/depression/index.shtml)

Source-Medindia