A new study published in the journal Cancer has found that emotional wellbeing does not influence the prognosis of patients with head and neck cancer.
Researchers at the University of Pennsylvania School of Medicine studied 1,093 patients who were enrolled in clinical trials with the Radiation Oncology Group.
Participants completed a questionnaire which revealed details about their quality of life, including emotional wellbeing.
A total of 646 patients died during the study and the researchers found that emotional status was not a predictor of survival, regardless of a patient's gender or how far their cancer had progressed.
Dr James Coyne, professor of psychology in psychiatry at the university, said: "The belief that a patient's psychological state can impact the course and outcome of their cancer is one that has been prominent among patients and medical professionals alike.
"This belief leads people to seek psychotherapy in the hopes of promoting survival."
Dr Coyne, who is also co-leader of the Cancer Control and Outcomes Programme at the Abramson Cancer Centre, said that patients who want psychotherapy or to attend a support group should be given the opportunity to do so, as there can be "lots of emotional and social benefits".
"But they should not seek such experiences solely on the expectation that they are extending their lives," he insisted.
The expert concluded: "While this study may not end the debate, it does provide the strongest evidence to date that psychological factors are not independently prognostic in cancer management."
Julia Frater, senior cancer information nurse at Cancer Research UK, said: "People with cancer can feel under pressure to cope well with their disease and treatment and to stay on top of things. They are often urged to feel positive.
"These results should reassure them that if they don't feel like this it's okay. Many people do feel worried or low following a diagnosis and this isn't likely to affect the outcome of their treatment."
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