Assessing Cancer Disparities among Pacific Islanders with Metastatic Cancer for Survival, Time-to-Metastasis, and Time-to-Radiotherapy Using a Novel Informatics Consult Approach

Abstract

<h3>Purpose/Objective(s)</h3> Native Hawaiians and Other Pacific Islanders (NHPI) are 1 of 5 federally defined races, yet are often excluded in oncology research. NHPI patients have higher mortality for multiple cancers when properly disaggregated, however appropriate statistical methods and databases are limited to compare outcomes among small samples, masking NHPI cancer disparities. This study aims to evaluate 1) overall survival (OS) 2), time-to-metastasis (TTM) and 3) time-to-RT (TTR) among NHPI patients using a high dimensionality propensity score matching approach. <h3>Materials/Methods</h3> NHPI patients diagnosed with the 13 most common cancers were identified at a single, large tertiary hospital, between 2015-2022, with at least 6-month follow-up. A randomized matching cohort of non-NHPI (White, Black, and Asian) were selected to control for demographic, clinical, and treatment characteristics. An advanced cohort informatics consult for high dimensionality propensity score matching was used to control for pre-treatment differences and adjust for confounders to compare OS, TTM (diagnosis-to-metastasis), and TTR (diagnosis-to-RT) between NHPI and non-NHPI. RT analysis included stereotactic body RT (SBRT), stereotactic radiosurgery (SRS), intensity modulated RT (IMRT), and brachytherapy. Cox proportional hazard regression calculated hazard ratios (HR) and 95% confidence intervals (95%CI). <h3>Results</h3> Of 24,357 NHPI patients, 539 (2.2%) were diagnosed with a common cancer. A randomized cohort of 69,690 non-NHPI patients with cancer were identified. Compared to non-NHPI, NHPI patients were significantly more often female (63% <i>v</i> 53%), younger (mean age 59 <i>v</i> 64 years), higher BMI (31 <i>v</i> 27), and diabetic (22% <i>v</i> 12%). Mortality was higher in NHPI patients compared to non-NHPI patients (11.5% v 7.7% mortality) with a HR of 1.71 (95%CI=1.01-2.90). More NHPI presented with metastatic disease (17%) compared to non-NHPI (15%). On a subset analysis of patients not diagnosed with metastatic disease at presentation, consisting of 447 NHPI and 59,351 non-NHPI patients, TTM was significantly faster for NHPI patients (125 days; HR=1.48 [95%CI=1.07-2.07]) compared to non-NHPI (284 days). NHPI patients had significantly higher rates of all RT (18% vs 14%), but no difference in SBRT/SRS (3.6% vs 2.2%), brachytherapy (2.7% v 1.5%), and IMRT (6.3% v 5.4%), compared to non-NHPI patients. There were also no differences in TTR with any RT modality. <h3>Conclusion</h3> Using a novel informatics consult approach with high dimensionality propensity analysis, NHPI patients with common cancers were found to have worse survival at a large tertiary cancer center, compared to non-NHPI patients. NHPI had more rapid onset of metastasis, despite no differences in time to radiation. Strategies are needed to improve outcomes for NHPI patients with metastatic disease despite having timely treatment.