Introduction: Patients with cancer face psychosocial and physical problems that may have an impact on the patient's quality of life. Psychologists believe that specific cognitive attitudes towards life may interfere with mental health and ultimately quality of life. Therefore, the main objective of the present research was to study the relationship between metacognitive beliefs and quality of life and mental health of patients with cancer.

Methods: In this case-control study, 50 female patients diagnosed with cancer and 50 female patients without cancer (matched by age and gender) in 5th of Azar hospital (2015) were recruited by convenience sampling. Data were collected using standard metacognitive beliefs questionnaires, quality of life, and mental health. Reliability questionnaires through the Cronbach's alpha test was measured. Data were collected and analyzed using SPSS 16 software and descriptive and inferential statistics (t test and Pearson correlation test).

Results: The results showed that most patients of both groups were aged between 40 and 50 years old. The Pearson correlation test showed a significant negative relationship between metacognitive beliefs and quality of life in cancer patients (P < 0.05), yet, there was no significant difference in patients without cancer (P > 0.05). Also, there was a significant positive relationship between metacognitive beliefs and mental health in both groups (P < 0.05). The t test showed a significant difference between quality of life in the two groups (P < 0.05).

Conclusions: According to the findings of the present research, meta-cognitive domains of patients with cancer compared with healthy controls have a relationship with quality of life and mental health. Given the importance and necessity of metacognitive awareness, considering strategies for training programs and psychological interventions, can improve the mental health status and quality of life of patients with cancer.