Title: Applying a multilevel framework to investigating racial and ethnic disparities in robot-assisted surgery and associated outcomes for prostate cancer
Description: Radical prostatectomy is the main surgical treatment for prostate cancer and is associated with various short-term complications. Racial and ethnic minority patients have worse postoperative outcomes than White patients following prostate cancer surgery. One of the factors that may contribute to the racial differences in postoperative outcomes is the differential use of new medical technology of robot-assisted surgery (RAS) across racial and ethnic groups. Patients undergoing robot-assisted radical prostatectomy (RARP) have been shown to have reduced short-term complications, length of stay (LOS), and readmissions and comparable long-term survival compared with patients undergoing open radical prostatectomy (ORP). Previous studies demonstrated that racial and ethnic minority patients with prostate cancer were less likely to receive RARP than White patients. However, critical gaps remain in 1) understanding current evidence on racial and ethnic disparities related to RAS in pelvic cancer surgery thoroughly; 2) determining the impact of RARP on racial and ethnic disparities in postoperative outcomes among prostate cancer patients, and; 3) investigating the role of surgeons on the differential use of RARP across racial and ethnic groups.

To address these gaps, this dissertation conducted a systematic review to comprehensively understand racial and ethnic disparities in the use of RAS in four major pelvic cancer treatments (prostate, uterine, bladder, and rectal cancers). Following the systematic review, empirical analyses were performed using linked New York State Cancer Registry and statewide discharge records to determine the contribution of RARP to racial and ethnic disparities in the short-term outcomes after prostate cancer surgery, including determining the presence and pattern of interaction between race/ethnicity and RARP use. Based on a multilevel framework, two important hypotheses were also tested to assess surgeons’ influence on the use of RARP across racial and ethnic groups through access to care and the process of care. The systematic review found consistent evidence that Black and Hispanic patients were less likely to receive RAS than White patients in all four pelvic cancer surgeries. There is a lack of formal assessment to determine the impact of RAS use on racial and ethnic disparities in postoperative outcomes.

The systematic review also found that racial and ethnic minorities were less likely to receive treatment at RAS-performing or high-technology centers than White patients. But there is a paucity of research examining physician-level factors that may be related to differential use of RAS across racial and ethnic groups. The first empirical analysis detected a statistical interaction between race/ethnicity and procedure approach that was present on the additive scale but not on the multiplicative scale. Specifically, when undergoing RARP rather than ORP, non-Hispanic Black (NHB) and Hispanic men with prostate cancer, as compared to non-Hispanic White (NHW) men, experienced a greater reduction in the risk of adverse short-term outcomes of major events (NHB vs. NHW: RERI -0.32, 95% CI (-0.70,-0.01); Hispanic vs. NHW: RERI -0.28, 95% CI (-0.74,0.09)) and prolonged LOS (NHB vs. NHW: RERI -0.32, 95% CI (-0.70,-0.01); Hispanic vs. NHW: RERI -0.28, 95% CI(-0.74,0.09)) on the absolute risk (additive) scale.

The second empirical analysis confirmed the two hypotheses related to surgeons’ role in the racial and ethnic disparities related to RARP use. First, NHB and Hispanic patients were more likely to be treated by surgeons who were low-RARP users (NHB vs. NHW: OR 1.73, 95% CI 1.58-1.90; Hispanic vs. NHW: OR 2.14, 95% CI 1.90-2.41) or by surgeons at non-RARP facilities (NHB vs. NHW: OR 4.26, 95% CI 3.45-5.27; Hispanic vs. NHW: OR 4.01, 95% CI 3.44-4.67) than NHW patients, supporting racial and ethnic disparities in access to care. Second, when treated by the same surgeon and having similar conditions, NHB and Hispanic patients were less likely to receive RARP than NHW patients (NHB vs. NHW: OR 0.73, 95% CI 0.59-0.91; Hispanic vs. NHW: OR 0.72, 95% CI 0.55-0.96), supporting racial and ethnic disparities in the process of care. In summary, this dissertation identified gaps in current literature and showed that NHB and Hispanic patients with prostate cancer were less likely to receive but benefitted more from RARP than NHW patients.

Increasing equitable penetration of robot-assisted technology may help reduce racial disparities in patient outcomes after radical prostatectomy. This dissertation also revealed that NHB and Hispanic patients were less likely to be treated by high-RARP-use surgeons and less likely to receive RAPR when treated for similar conditions by the same surgeons than NHW patients. Addressing structural barriers faced by racial and ethnic minority patients during care-seeking and the process of care can help reduce disparities in RAS use.