Participants
The children receiving active treatment for different types of cancer and their parents were recruited from the Department of Pediatrics of 4 general hospitals in Guangzhou, namely Pediatric Malignant Tumor Medical Centers in South China (the First Affiliated Hospital of Sun Yat-sen University), Sun Yat-sen University Cancer Center, Nanfang Hospital (Affiliated to Southern Medical University, Guangzhou, China) and Zhujiang Hospital (Affiliated to Southern Medical University). The eligible participants were between 6 and 18 years of age, had a diagnosis of cancer at least 1 month prior to the enrollment (including both newly diagnosed and recurrent cases), and had no significant cognitive or sensory deficits. Children who reported domestic violence or sexual abuse or were in a critical condition were excluded. One of the parents (father or mother) of a recruited child was invited to participate in the study, and was excluded if they had records of domestic violence or sexual abuse or had ongoing treatment for depression.
The control group consists of healthy children and their parents recruited from a public primary school in Tianhe District of Guangzhou. Specifically, one class was randomly selected from each of the fourth, fifth and sixth grades using the method of pure random numbers, and all the students in the selected class were investigated. The students who reported domestic violence or sexual abuse or had a history of serious illness were excluded. The parents of the students were selected based on the same inclusion and exclusion criteria for parents of children with cancer.