Chen, Li

AbstractBackgroundBereaved parents experience life‐long grief after the death of their child from cancer. Parents who can integrate their grief and maintain their social functioning early in bereavement, even in the setting of concurrent psychosocial distress, have improved outcomes. Identifying the factors associated with bereaved parents' early social functioning can guide future supportive interventions.MethodsThe authors surveyed parents of children who died from cancer at two large centers 6–24 months after death, assessing bereavement experiences using validated and pilot tested tools. Univariable and multivariable logistical regression models were used to examine which family and child demographic, treatment, and end‐of‐life (EOL) factors were associated with maintained parental social functioning (T scores ≥40 on the Patient‐Reported Outcomes Measurement Information System Ability to Participate in Social Roles and Activities‐Short Form questionnaire).ResultsOne hundred twenty‐eight parents of 88 children participated (38% household response rate); most parents identified as female (63%) and White (88%). Parents' median age was 47 years (interquartile range, 10 years); and the median time from the child's death to survey completion was 13 months (interquartile range, 10 months). In multivariate modeling, parents without household material hardship and those who felt prepared for EOL circumstances had increased odds of maintained social functioning (odds ratio, 4.7 [95% confidence interval, 1.6–13.7; p < .004] and 5.5 [95% confidence interval, 1.9–15.9; p < .002], respectively).ConclusionsParents who felt prepared for their child's EOL and those without household material hardship were more likely to have maintained social functioning in the first 2 years after their child’s death. Interventions targeting EOL preparedness and alleviating household material hardship may improve bereavement outcomes.

11509 Background: uLMS is an aggressive sarcoma subtype of smooth muscle origin. Chemotherapy provides limited benefit for advanced disease. 18-25% of uLMS harbor deleterious alterations in homologous recombination (HR) DNA repair genes. uLMS exhibits high levels of replicative stress. These findings prompted a phase 2 study of O+T in pretreated uLMS where O+T demonstrated activity: ORR 27%, mPFS 6.9 mos (Ingham M. et. al. ASCO 2021: #11506) Methods: NCI protocol #10250 is a single-arm, multicenter, phase 2 trial evaluating O+T in advanced uLMS pts with progression on ≥1 prior line. Pre-treatment (Pre) and on-treatment (On) biopsies were collected from 22 pts. In prespecified analysis, we evaluated for a relationship between clinical outcomes and HR gene alterations by whole exome sequencing (WES), SLFN11/MGMT expression by RNAseq, and RAD51 foci formation (functional assay). HRD scores were calculated from WES using scarHRD. Gene expression was evaluated using a Spearman rank-order correlation analysis to identify genes associated with PFS (p < 0.01) and overexpressed in sensitive (S: PFS > 240d) or resistant (R: PFS < 240d) pts. Gene set enrichment analysis (GSEA) was performed (q = FDR-adjusted p value). Pts with available results: WES/RNAseq (16), Pre HRD score (13), Pre RAD51 foci (12). Results: 31% (5/16) pts had a mutation (Mut) or homozygous deletion (Hd) in the HR panel: ATRX Mut (2), ATR Mut, PALB2 Hd, RAD51B Hd. Pts with PALB2 and RAD51B Hd had longest PFS on study. Recurrent alterations also occurred in TP53 (56%) and RB1 (19%). Median HRD score in Pre samples was 51 (range 36-66) and 10/13 had HRD scores ≥ 42. Pre and On SLFN11 and MGMT RNA expression were not correlated with ORR/PFS. 6/13 Pre samples were HR-deficient by the RAD51 foci assay. Of pts with PFS ≥ 200d, 4/6 were HR-deficient. In Pre samples, 81 genes were overexpressed in S pts and 73 in R pts. In On samples, 146 genes were overexpressed in S pts and 127 in R pts. In On samples, GSEA identified the epithelial-mesenchymal transition enriched in S pts (q = 3.38e-7) and cell cycle pathways (E2F targets, G2M checkpoint) in R pts (q = 7.43e-4). Only 2 genes, CXCL10 and PCDH15, were differentially expressed between paired Pre and On samples (both increased in On). Gene expression signatures for replicative stress showed borderline association with worse PFS. Conclusions: Most uLMS tumors exhibit HR defects as measured by HRD scores. A subset of pts with greater benefit from O+T were identified by WES for HR genes and the RAD51 assay. There was no correlation between SLFN11 and MGMT expression and outcomes. GSEA identified pathways differentially expressed in S and R pts in On samples. O+T induced CXCL10 which has been associated with T-cell trafficking to tumors. A randomized phase 3 trial of O+T versus investigator’s choice is planned. These results provide insight into which pts may benefit most from this novel drug combination. Clinical trial information: NCT03880019.