Enumerating the Oncology Specialist Workforce in Medicaid: Applying a Triangulated Approach

Objective: To develop a novel method for enumerating the oncology specialist workforce triangulating taxonomy codes, board certification data, and clinical diagnosis codes in Medicaid claims, and to describe oncology specialists' Medicaid participation, their patient panels, and ascertain the concentration of types of cancers they treated. Study Setting and Design: We identified oncology specialists using multiple data sources and conducted an exploratory analysis of their patient panels using multi-state Medicaid claims data. We used cluster analysis of diagnosis code patterns in claims to accurately determine the concentration of cancers by site in oncologists' panels. Data Sources and Analytic Sample: We used data from 2016 to 2020 Transformed Medicaid Statistical Information System (T-MSIS) and physician certification data. We included board-certified oncology physicians specialized in medical and radiation oncology, hematology, hematology-oncology, gynecologic oncology, and pediatric hematology-oncology. To identify surgical oncologists, we combined board certification and Medicare Provider Enrollment, Chain, and Ownership System (PECOS) data. We identified Medicaid beneficiaries with malignant neoplasms by cancer site using ICD-10-CM codes. Principal Findings: In 2016, about 89% of oncology specialists participated in Medicaid; this proportion decreased slightly to 86% in 2020. The trends in Medicaid participation and the mean number of beneficiaries differed by oncology specialty. Panels of pediatric hematologist-oncologists had a higher proportion of Hispanic Medicaid beneficiaries with cancer (26%) relative to other specialists. Cluster analysis identified 565 out of 5395 medical oncologists that had high concentration (at least 58%) of breast cancer patients in their panels. Among 6970 hematologist-oncologists, 269 had high concentrations in breast cancer (more than 60%), and 944 in hematological cancer (more than 59%). Conclusions: Our study offers a pragmatic approach to understand the oncology specialist workforce available to Medicaid beneficiaries. The findings provide baseline estimates to track this workforce and provide policymakers with an opportunity to develop targeted strategies to improve access to cancer care.