Background: Systemic anticancer therapy (SACT) administered near the end of life (EOL) is associated with higher costs, driven by pharmaceuticals and associated acute care use that occurs when patients continue treatment in lieu of transition to hospice. Since 2015 overall rates of systemic therapy at the EOL have remained stable, while some chemotherapy has been replaced by costly immunotherapy. It is not known whether immunotherapy is associated with the same impact on total cost of care (TCOC) as chemotherapy. We evaluated the relationship between type of SACT vs no SACT within 30 days of death on categories of cost. Methods: We identified patients from the SEER-Medicare database diagnosed between 2005 and 2019 with solid tumors (ST) and liquid tumors (LT) who died from 2015-2020. We assessed differences in Medicare cost within 30 days of death by subtype of SACT: combination chemo-immunotherapy (CI), immunotherapy only (IO), chemotherapy only (CO) and no SACT. Dependent variables were TCOC (including all Medicare claims), as well as cost of drugs, hospitalizations, emergency department (ED), and hospice normalized and adjusted for inflation. Results: 6.2% (27,317/440,349) of ST decedents and 12.7% (7,544/59,449) LT decedents received SACT at EOL. See table. Among ST patients who received SACT, the mean TCOC was $26,282 (standard deviation (SD) $26,700) and was highest among patients receiving CI, $27,973 (SD: $26,285) vs. $17,642 (SD: $29,798) for patients without SACT (p<.001). Among LT patients who received SACT, the mean TCOC was $26,282 (SD $26,700) and was highest among CI patients $33,632 (SD: $26,283) vs. $24,689 (SD: $39,735) for patients with no SACT (p<.001). We observed higher cost for drugs, hospitalizations (except for LT patients receiving CI vs. no SACT), ED and lower hospice costs for patients receiving each SACT subgroup compared with no SACT. All results except those noted in table were significant (p <.001). Conclusions: Receipt of SACT within 30 days of death was associated with significantly higher Medicare costs. Higher TCOC in those who received SACT is only partially explained by drug costs; most acute care costs were also significantly higher among patients who received any type of SACT including CI, IO, CO than among those who did not.

All p-values <.001 for difference between each individual SACT subgroup and No SACT unless.

^╪where p-value >0.05.