Background: Breast cancer affects patients' quality of life, which is influenced by the body's functional abilities and the patients' spiritual well-being. Currently, there is no research on the spiritual determinants that affect quality of life in the Indonesian context. Purpose: This research analyzes the determinants of spiritual well-being in terms of breast cancer patients' quality of life using the Functional Assessment of Chronic Illness Therapy-Spiritual Well-Being (FACIT-Sp). Methods: A cross-sectional study was conducted with 112 participants who were selected using purposive sampling. Women with breast cancer who had a Palliative Performance Scale version 2 score of 60 and who were able to read and write were included. The instruments used included the RAND SF-36 Quality of Life Questionnaire, which was modified to the Indonesian context and was used to survey breast cancer patients (Cronbach coefficient of >0.90), in addition to the FACIT-Sp (Cronbach coefficient of 0.768). The multivariate data were analyzed using logistic regression. Results: The determinants of spiritual well-being for the participants' quality of life included meaning (odds ratio of 0.436) and peace (odds ratio of 0.303). Conclusion: The meaning and peace domains of spiritual well-being significantly affect breast cancer patients' quality of life.
Keywords: breast cancer; meaning; peace; quality of life; spiritual well-being.