Barriers to and clinical outcomes with next-generation sequencing testing in metastatic prostate cancer.

171 Background: Since 2020, guidelines recommend somatic next-generation sequencing (NGS) in patients with metastatic (M1) prostate cancer. Nationwide, genetic testing rates are low with known disparities in access. Whether prostate cancer disease characteristics and courses differ between those with and without testing are unknown. In this study, we determined the NGS testing rate in M1 prostate cancer at a single academic center and assessed social and clinical features by NGS testing status. In those without NGS testing, we reported the most likely reasons for lack of testing. Finally, we compared survival among those with and without testing. Methods: Retrospective chart review of M1 patients with prostate cancer seen as a new visit between 2020-2022 with at least one follow-up. Sociodemographics, comorbidities, prostate cancer clinical features, and vital status were obtained from the electronic medical record (EMR). Reasons for lack of NGS testing were assessed through chart review. A multivariable (MV) logistic regression assessed predictors of NGS testing (covariates: age, Gleason grade group, marital status, M1 diagnosis year). Survival analysis was conducted from the date of first visit with M1 disease to the date of death/last follow-up (covariates: age, Gleason grade group, M stage at initial diagnosis, NCI comorbidity index, days from M1 diagnosis date to first visit date). Results: 258 (59%) of 435 patients had NGS ordered. Patients who were older and not married were less likely to have NGS testing, which remained in MV analysis [age: odds ratio (95% confidence interval) = 0.96 (0.94-0.98); unmarried vs. married/partnered 0.62 (0.38-1.00)]. (Table 1). The most common likely underlying reason for no NGS testing ordered were perceived patient/disease factors (28%), no tissue available (16%), and shared care with another oncologist (18%). There was no clear reason in 22% of patients. Those with testing ordered had worse survival than those without [adjusted hazard ratio (95% confidence interval) = 1.43 (1.03-1.99)]. Conclusions: NGS testing remains underutilized in men with metastatic prostate cancer, particularly among older and unmarried individuals. Those without NGS testing had longer survival, contrary to what is seen in other diseases. Future research is needed to develop and assess interventions to improve NGS testing rates. Multivariable analysis of predictors of ordering next-generation sequencing (NGS) in metastatic (M1) prostate cancer (N=419). Variables Odds Ratio 95% confidence interval p-value Age at M1 diagnosis 0.96 0.94-0.98 <0.01 Gleason score at initial diagnosis 0.07 Group 1-3 1 ref Group 4 1.59 0.84-3.01 Group 5 1.78 1.09-2.91 Gleason score never performed 2.20 1.05-4.59 Marital Status 0.05 Married/partnered 1 ref Not married/partnered 0.62 0.38-1.00 Year of M1 diagnosis 0.07 2019 or earlier 1 ref 2020-2022 0.62 0.36-1.05