Trajectories of Traumatic Stress Symptoms Among Siblings of Children With Cancer: The First Two Years Post-Diagnosis.

Objective: Identify and describe trajectories of cancer-related posttraumatic stress symptoms (PTSS) among siblings of children with cancer within two years of diagnosis.

Method: Siblings (aged 8-18; M = 11.2 years) across the United States, and for each, one caregiver, were recruited for a cohort sequential longitudinal study with three data collection points six months apart beginning at 6- or 12-months after cancer diagnosis. Siblings (N = 229; 42% of eligible/approached; 53% identifying as female; 68% identifying as non-Hispanic White) completed the Child Posttraumatic Stress Disorder Symptom Scale. Caregivers completed the Strengths and Difficulties Questionnaire (SDQ). Latent class growth analysis (LCGA) and growth mixture modeling (GMM) identified PTSS patterns across time.

Results: Fit statistics supported models with three to five PTSS trajectories. The three-class LCGA model included a large mild PTSS group (61%), a moderate PTSS group (35%), and a small (4%) stable severe PTSS group. The four-class LCGA and three- and four-class GMM included groups improving from moderate to mild PTSS (7-21%) and worsening to moderate PTSS across time (12-17%). Across models, siblings with mild PTSS had fewer caregiver-reported emotional and behavioral difficulties on the SDQ.

Conclusions: A large group of siblings of children with cancer demonstrate resiliency, however, substantial subsets experience patterns of PTSS that include levels in the moderate-to-severe range during the first two years post-diagnosis. Future research should examine these patterns in more diverse/representative samples and identify factors associated with increasing and sustained severe PTSS to inform intervention targets and reduce cancer-related burden on families.