Are depression and cancer linked?
A pair of new studies is highlighting the links between mental health and cancer survival rates. Researchers at the BC Cancer Agency and the University of British Columbia found that lung cancer patients with anxiety and depression have a higher risk of mortality than those without, while a comprehensive review in United Kingdom found that people suffering from anxiety and depression had a 32 per cent greater risk of dying from cancer than others not so afflicted.
The Vancouver-based study published in the Journal of Pain and Symptom Management looked at 684 patients receiving treatment at the BC Cancer Agency in Vancouver and Surrey for stage III non-small cell lung cancer, a disease whose survival rate after one year is only 30 to 46 per cent. Researchers found that five years after diagnosis, 82 per cent of patients with anxiety and 86 per cent with depression had died, while 81 per cent of patients with neither afflictions had died.
“The question of whether anxiety and depression affect survival in cancer patients has been of interest to scientists for decades, but long-term research has been limited,” said Andrea Vodermaier, the study’s lead author and postdoctoral fellow in UBC’s Department of Psychology. “Our study confirms that there is indeed a link for lung cancer patients, and that it’s important for health-care providers to treat not only their tumour but also focus on the full emotional experience of the patient.”
The causal relationship between depression, anxiety and lung cancer survival is not known but researchers point to the effect that depression and anxiety can have on bodily systems as well as their ability to hamper people from effectively quitting smoking, the primary cause of lung cancer.
“Stress might affect the immune system and inflammatory responses,” said study co-author, Wolfgang Linden of UBC’s Department of Psychology. “However, it might also occur because being preoccupied with anxiety can make it harder for patients to adhere to treatments and fully engage in the treatment process.”
The other study by researchers at the University College London and published in the British Medical Journal reviewed 16 studies involving medical records for more than 160,000 people in the UK, 4,353 of whom had died from cancer. The researchers found that accounting for differences in age, sex, education, weight, socioeconomic class and whether or not the people smoked or drank, those with anxiety and depression had a 32 per cent greater risk of dying from all types of cancers.
Again, the reason for the association was speculated upon, with researchers saying that depression can make sufferers live a more unhealthy lifestyle and less often seek medical attention when it’s needed and that emotional and psychological distress impact immune function, hormone triggers and DNA repair. The researchers point to the fact that so-called lifestyle-related cancers like bowel and pancreatic cancers were more commonplace among those with depression and anxiety and that prostate cancer, a hormone-related cancer, also had higher death rates among those with emotional distress.