[Perceived stress in Mexican patients newly diagnosed with breast cancer].

Background: Cancer diagnosis has been described as a significant factor causing psychological stress, which may increase a vulnerability to develop psychological disorders, decrease quality of life levels and affect the response to cancer treatment. Objective: To validate the Newly Diagnosed Breast Cancer Stress Scale (NDBCSS) and to explore the differences concerning clinical and sociodemographic variables. Material and methods: Cross-sectional study. Patients recently diagnosed with breast cancer on the day they received the definitive cancer diagnosis were invited to participate. The Perceived Stress Scale (PSS) and the NDBCSS were completed; the latter previously underwent a validation process into Spanish (reliability, content validity, structure -EFA- and convergent validity). Results: 176 patients participated; their mean age was of 52.8 years. The scale obtained a content validity of 0.53 and reliability of 0.791; the EFA showed 2 factors explaining 42.31% of the variance. Stress levels were 23.05 (PSS) and 13.2 (NDBCSS). Concern about side effects, the progression of the illness and the lack of information were reported as the most critical stressors for these patients. Conclusions: The NDBCSS showed acceptable psychometric properties for its application in Mexican patients and probably for patients with similar personal characteristics and linguistic and cultural contexts. Based on the results, it is possible to design precise interventions addressed to the stressors they face, such as the impact of the disease and the treatment.