1. Introduction
very year, thousands of children in the world are diagnosed with cancer. However, with significant advances in cancer treatment (such as surgery, chemotherapy, radiotherapy, bone marrow transplantation, etc.), over the past decades, the 5-year survival rate for most types of cancers in childhood is more than 75% [1]. Childhood cancer is a stressful experience for all members of the family. Because of the need to take care of the patient’s baby, the whole family has to change its lifestyle and everyday routine. As a result, parents’ attention is focused on the suffering child, and the access of healthy siblings to their parents decreases [3, 2].
The families of children with cancer are confronted with uncertainties about treatment and long-term treatment of the disease. Because of the need for at least one parent to accompany a child in a hospital or at home, as well as an increase in the level of parents’ anxiety, it may make the parents less accessible physically and emotionally. Changes in the daily routine of life and roles may disrupt the daily performance of healthy hemorrhages, which may cause some siblings to have more responsibility at home [7 ,6]. With all of these changes, it is not surprising that these children may experience some emotional and behavioral disturbances [6].
However, there is growing evidence that siblings of children with cancer are significantly suffering from mental distress. These studies show that the siblings of children with cancer often experience tension, anxiety, and impairment in their daily routine, which may be severe enough to require parents to support their healthy children [16].
Thus, considering the contradictory results of studies on the effect of cancer on siblings of children suffering from cancer and the lack of history of such a study in Iran, the present study compares emotional problems (internalization problems), behavior (externalization problems), and the symptoms of post-traumatic stress disorder that are common in the siblings of children with cancer and a control group.
2. Methods 
This study is a causal-comparative study. The statistical population includes the siblings of children with cancer in the post-pediatric educational center of Imam Ali (clinical group). The sample consisted of 30 siblings from 11 to 18 years old children with cancer and 30 controls that were matched for gender and age. Data was collected through availability sampling. Because of the unavailability of the siblings, the conditions of implementation and the importance of research for parents were described and they were reassured about the confidentiality of the personal information of the siblings, and then the demographic information and questions related to the criteria for inclusion in the research was obtained. For inclusion in the study, adolescents were selected in both groups between the ages of 11 and 18, and the companions in the clinical sample had a brother or sister with cancer who received treatment during the course of the study, and their treatment was between 4 months to 2 years. 
Parents and adolescents’ consent in both groups was sought to participate in the study. Exit criteria (psychotic disorders, bipolar disorder, developmental disturbances, and mental retardation) were also measured using the parental report and demographic information. If the conditions for inclusion in the research were fulfilled, consent forms and questionnaires were provided to parents to give to their healthy children (11 to 18 years of age) and after a few days, by returning to the hospital, the questionnaires were collected. A total of 50 questionnaires were distributed, but some forms were incomplete and due to lack of cooperation of some participants, 30 completed questionnaires were completed and included in the analysis. 
The control group was also randomly selected from students in Tehran who had no siblings with cancer. 50 students were randomly selected from the list of students. They were asked by phone to parents of the participants, demographic information, and criteria for participation in the study. If they matched the criteria for inclusion, a questionnaire was provided to them. A total of 60 questionnaires entered the statistical analysis stage. In this research, the Achenbach Youth Self-Report (YSR) questionnaire and PTSD Symptom Scale- Self Report (PSS-SR) questionnaires were used.
3. Results
The Mean±SD of age in both groups is 15±1.51 years old and 12 (40%) of the participants in each group are boys and 18 (60%) of the participants in each group are girls. The duration of the disease in the patient group is 8±3.15 months.
Multivariate Analysis of Variance (MANOVA) was used to examine the effect of group (clinical and control) variables on the subscales of internalization problems, extraversion, general problems, and post-traumatic stress symptoms. The results of the study for the effect of clinical and control groups variables using Wilkes Lambda test on the linear combination of dependent variables showed a significant effect (P=0.001, P=0.001, P=P0.001, P=P0.001) . One-way ANOVA was used to assess the effect of clinical and control groups in each subscale. The results of the analysis of variance are shown in Table 1. 



Based on the results of the analysis, internalization problems, extraversion problems and general problems were more significant in the clinical group than in the normal group. The results of the research on signs of post-traumatic stress also showed a significant difference between the groups in these symptoms; the clinical group reported significantly more symptoms than stress based on symptoms, re-experience avoidance and arousal.
4. Discussion
Based on the results, the siblings of children with cancer experience more behavioral emotional problems and post-traumatic stress symptoms than the control group and these findings further reveal the vulnerability in this group and suggest guidelines for appropriate interventions.
Limitations:
- Differences in selection criteria for the clinical and control groups;
- Unable to accurately control exclusion criteria. 
- Adolescents use self-report tools;
- Non-alignment in socio-economic status.
Ethical Considerations
Compliance with ethical guidelines
Iran University of Medical Sciences ethically approved this research (Code: IR.IUMS.REC.1394.9211556222). All ethical principles were considered in this article. The participants were informed about the purpose of the research and its implementation stages; they were assured about the confidentiality of their information; moreover, they were allowed to leave the study whenever they wish.
Funding
This research was extracted from the MSc. thesis of the first author, Department of Clinical Psychology, Tehran Institute of Psychiatry, School of Behavioral Sciences and Mental Health, Iran University of Medical Sciences.
Authors contributions
Conceptualization, validation, analysis, project administration: All authors; Methodology: Asma Aghebati, Fariba Hosseini; Investigation, sources, preparation, writing-review & editin: Fariba Hosseini.
Conflicts of interest
This authors declared no conflict of interest.
Acknowledgements
The authors would like to thank the staff of  Ali Asghar Hospital for their support.

References