1. Introduction
Cancer is a chronic disease responsible for high number of deaths in the world. Given the rising trend of this disease in the world including Iran, there is a need to address its various aspects. Several studies have been conducted on the causes of cancer. The hypothesis that psychological factors related to stress have an effect on the onset of cancer has long been considered by many researchers and some have reported contradictory results. Some studies have differentiated stressors in terms of being chronic or acute. One of chronic stressor is childhood trauma. Our experiences in childhood will be the basis of our mental and physical health in adulthood. It is obvious that stressful events especially chronic stressors can impair our immune system and make us prone to diseases.
Another psychological factor that affects the past and present of the person is Integrative Self-Knowledge (ISK) which reflects one’s past, present and future self-experience. If a person faces traumatic events in childhood, such events will affect their ISK. When facing traumatic events, people give habit-based responses without thinking and understanding the event to control the environment. This is called mindfulness which is the ability to be present at the moment without judgment. Its seems that childhood trauma may limit one’s ability to understand the present situations without judgment. Study of the relationship between thee mentioned psychological factors and cancer can help use preventive and interventional strategies to reduce the incidence of trauma in future generations.

2. Methods
This descriptive-analytical study was conducted on 139 patients with cancer and 139 healthy people referred to Firoozgar Hospital and SAMAR Charity House who were selected by a convenience sampling method. The sample size was determined using Cohen’s formula by considering a test error of 5% and test power of 80%. Participants were asked to complete ISK questionnaire, Childhood Trauma Questionnaire (CTQ) and Mindfulness Attention Awareness Scale (MAAS). Data were analyzed using descriptive statistics (mean, standard deviation) and inferential statistics including MANOVA.

3. Results
Based on the results of MANOVA, there was a significant difference between the two groups in terms of childhood trauma (P=0.001), ISK (P=0.001), and mindfulness (P=0.001) (Tables 1 and 2). Healthy people had higher ISK and MAAS scores and lower CTQ score compared to cancer patients.







4. Discussion and Conclusion
According to the findings of the present study, there was a significance difference between cancer patients and healthy people in three psychological factors (childhood trauma, mindfulness, and ISK). Cancer patients had lower ISK and mindfulness but higher childhood trauma in comparison with healthy people. So far, there have been no study on the ISK of cancer patients but some studies have shown the relationship of this variable with depression and anxiety [16]. Regarding mindfulness, we found no similar study on cancer patients, but some studies examined mindful attention awareness and they have proved its role in physical and mental health also in the immune system’s function [20].
Having cancer and the inevitability of living with it can be one of the most painful stages of any human life. Special attention should be paid to its prevention, diagnosis and early treatment. The relationship between mind and body is one of the most important relationships that has been widely considered in recent years. Our mind and what happens to it simply can affect our body, and there should be a mechanism to justify this effect. The role of environmental and genetic factors in cancer development is obvious, but the role of psychological factors is still unclear. Further studies are needed to investigate their role.

Ethical Considerations
Compliance with ethical guidelines
 This study was approved by Ethics Committee of University of Social Welfare and Rehabilitation Sciences (Code: IR.USWR.REC.1397.146). All ethical principles are considered in this article. The participants were informed about the purpose of the research and its implementation stages. They were also assured about the confidentiality of their information and were free to leave the study whenever they wished, and if desired, the research results would be available to them.

Funding
The paper was extracted from the MA. thesis of the second author at Department of Counseling, University of Social Welfare and Rehabilitation, Tehran.

Authors contributions
Conceptualization, methodology, editing & review: All authors; Investigation, resources, original draft preparation, visualization: Shadan Mosavat; Supervision: Mohammad Saeed Khanjani, Bahman Bahmani; Data analysis: Enayatollah Bakhshi.

Conflicts of interest
The authors declare no conflict of interest.

Acknowledgements
The authors would like to thank the staff of SAMAR Charity House and Firoozgar Hospital. 

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