Impact of Medicare Advantage (MA) on timely hormonal intensification in metastatic hormone sensitive prostate cancer.

166 Background: As MA plans gain popularity, covering over half of eligible beneficiaries in 2023, concerns have arisen about their ability to manage complex cancer care due to pre-authorization requirements and limited physician networks. The study compares MA and Traditional Medicare (TM) in delivering timely hormonal intensification, specifically through addition of oral novel hormonal therapy (NHT) to castration therapy, which became central part of treating metastatic hormone-sensitive prostate cancer (mHSPC) by 2018. Methods: We utilized nationwide Flatiron Health Electronic Health Record-derived de-identified database to include patients diagnosed with mHSPC on or after 2018 (when abiraterone was approved for mHSPC treatment). Eligible patients were &gt;=65 yr old, had at least one clinic visit within six months of diagnosis, and were covered by either MA or TM. Multivariable logistic regression with Inverse Probability Weighting, adjusting for socioeconomic status (SES), age, race, ECOG, and year of diagnosis, assessed the impact of insurance type on likelihood of initiating NHT within 30, 45, and 90 days of diagnosis (defined as date when the patient began taking prescribed NHT, within the period of interest). Results: 4078 patients &gt;=65 yr old diagnosed with mHSPC after 2018 were identified in Flatiron database; of these 2261 had at least one clinic visit and were enrolled in either MA or TM plans. Most patients were White, aged 75-85, having better SES (SES 4 or 5), de novo mHSPC, and from community hospitals (Table 1). Among the 1752 (77%) patients who received NHT, 1060 (61%) had TM, and 692 (39%) had MA. In adjusted analysis, TM patients were more likely than MA patients to initiate timely NHT intensification within 45 days of mHSPC diagnosis (OR: 0.85; 95% CI: 0.74-0.99). No significant differences were found for NHT initiation at 30 (OR: 0.88; 95% CI: 0.74-1.06) or 90 days (OR: 1.06; 95% CI: 0.93-1.22). Subgroup analyses showed significantly more delays in MA compared to TM among patients with lowest SES and racial minorities. Conclusions: Patients with TM showed a trend toward earlier NHT intensification compared to those with MA. This suggests a need to further examine MA and its impact of pre-authorization and network limitations on equitable high quality cancer care. Key baseline characteristics and outcome comparisons between mHSPC patients enrolled in TA and MA. TA N (%) MA N (%) P Race Asian 21 (2%) 13 (2%) &lt;0.001 Black 91 (7%) 91 (10%) Hispanic/Latino 39 (3%) 49 (6%) White 932 (67%) 527 (60%) Other 299 (22%) 199 (23%) ECOG 0/1 958 (69%) 635 (72%) 0.11 2 125 (9%) 69 (8%) 3/4 23 (2%) 23 (3%) Unknown 276 (20%) 152 (17%) SES 1 147 (11%) 113 (13%) &lt;0.001 2 209 (15%) 167 (19%) 3 248 (18%) 189 (22%) 4 347 (25%) 198 (23%) 5 316 (23%) 149 (17%) Unknown 115 (8%) 63 (7%) <jats:td colspan="1" con