Scientists believe that a woman's chances of surviving a recurrence of breast cancer can be increased by psychological help to address stress.
US researchers designed a psychological intervention programme that reduced the risk of women dying by 59% after the disease had returned.
Women who enrolled into the programme learned problem-solving and relaxation techniques.
They were also offered advice on coping with treatment side-effects, as well as tips on exercise and diet.
The latest study, published in the journal Clinical Cancer Research, is part of Ohio State University's Stress and Immunity Breast Cancer Project.
Of the 227 women studied since 1995, 62 suffered a recurrence of breast cancer. Among those who died after recurrence, the patients in the intervention group survived an average of six months longer.
Professor Barbara Andersen, director of clinical training at the university, said: "Everyone was understandably distraught when they received their recurrence diagnosis, but the stress remained high for those who didn't participate in the intervention.
"Stress declined for those who had been in the intervention group. They had learned how to cope and they put those lessons into practice."
"If psychological interventions are offered early to breast cancer patients they may provide enduring late benefits, and possibly longer survival."