Assessment of Patient Attribution to Care From Medical Oncologists, Surgeons, or Radiation Oncologists After Newly Diagnosed Cancer

As payers implement value-based payments for oncology care, assignment of patients to physician practices is increasingly important to accurately assess quality and reimburse clinicians accordingly. Yet, patient attribution remains a challenge.¹ Most claims-based attribution algorithms assign patients to practices based on the plurality of primary care visits. However, clinician attribution for specialty care is complex. The challenges of attribution are particularly salient in oncology because cancer care is often multidisciplinary—involving medical oncologists, surgeons, and radiation oncologists—rendering it difficult to discern which practice should be held accountable.² We sought to identify practices treating Medicare beneficiaries with a new diagnosis of cancer to inform potential attribution algorithms based on care received in the 6 months after diagnosis.

We used data from the Surveillance, Epidemiology, and End Results (SEER)–Medicare Linked Database (2010-2016) for analyses. The SEER program collects data from population-based cancer registries³; these data are linked with Medicare administrative data.⁴ We identified traditional (fee-for-service) Medicare beneficiaries 65 years or older who had received a new diagnosis of invasive breast, colorectal, lung, or prostate cancer between January 1, 2011, and December 31, 2015 (eTable 1 in eAppendix 1 in the Supplement), and examined claims through 6 months after diagnosis. The Harvard Medical School Committee on Human Studies approved the study. A waiver of patient informed consent was obtained because patient identifiers are not included in the SEER-Medicare data. We followed the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) reporting guideline for cohort studies.

We attributed patients to practices based on outpatient evaluation and management (E&M) claims with a cancer diagnosis in the 6 months after diagnosis (eTables 2 through 7 in eAppendixes 2 through 5 in the Supplement). We attributed patients to the practice with the most E&M visits and to medical oncology, surgery, or radiation oncology practices. We also assessed whether inclusion of inpatient E&M claims improved attribution rates. Finally, we described the proportion of patients who visited more than 1 practice of each type. This analysis was performed between August 1, 2019, and November 30, 2020. No statistical testing was conducted for this descriptive study.

The 301 327 patients with newly diagnosed lung, breast, colorectal, or prostate cancer had a mean (SD) age of 75.1 (7.3) years, 149 485 (49.6%) were male, and 241 232 (80.0%) were White patients (Table 1). Only 77.9% of patients with colorectal cancer and 74.1% of patients with lung cancer were attributed to a practice based on outpatient E&M visits (Table 2). These numbers increased to 90.4% and 87.6%, respectively, when inpatient E&M claims were included. Most patients with breast cancer (73.2%), colorectal cancer (61.6%), and lung cancer (65.3%) had visits with a medical oncologist, but only 11.3% of patients with prostate cancer did.

Attribution based on all cancer-related visits and medical oncology visits varied by cancer type and stage (Table 2). For example, only 34.1% of patients with stage I colorectal cancer had a medical oncology visit within 6 months of diagnosis vs 72.1% of those with stage III cancers. Most patients had cancer-related outpatient visits to multiple practices. For example, 71.4% of patients with breast cancer, 50.8% with colorectal cancer, 50.0% with lung cancer, and 56.7% with prostate cancer had visits to multiple practices (Table 2). Across cancer types, 7.5% to 10.2% of patients had outpatient visits with more than 1 medical oncology practice.

Our analysis reveals the challenges of attribution of patients with newly diagnosed cancer that should be addressed for accurate quality measurement and emerging value-based payments in oncology.^5,6 First, many patients with newly diagnosed lung or colorectal cancer were not attributed to a practice based on outpatient E&M claims alone. Efforts seeking to characterize practice-level quality for patients who may receive only inpatient care (eg, early-stage colon cancer, metastatic lung cancer) should include inpatient E&M or procedure claims.

Second, attribution varied substantially by cancer type and stage, underscoring the importance of considering the clinical context of the care being delivered. For instance, approximately a quarter to a third of patients with breast, colorectal, and lung cancers and 88% of patients with prostate cancer had no medical oncologist visits. These patterns are consistent with medical indications (ie, many patients with early-stage disease do not require chemotherapy) and clinical norms (eg, patients with prostate cancer are primarily treated by urologists). Attribution algorithms ideally would consider cancer stage and tumor characteristics. Unfortunately, such variables are not available in claims data, creating a need to leverage other data sources to collect inputs to attribution algorithms.

Third, many patients have cancer-related visits to multiple practices. The payment methodology and application of quality metrics should be tailored to the type of clinician and type of care delivered by a practice (eg, surgery, systemic therapy, radiation). Some patients have multiple visits to the same type of clinician at different practices (8% to 11% of those who saw a medical oncologist had visits to >1 practice). In such cases, it is challenging to determine the practice accountable for care.

Our study is limited by its focus on traditional Medicare beneficiaries living in SEER areas. The generalizability of our findings to commercially insured populations or individuals in other areas requires further study.

Accepted for Publication: March 9, 2021.

Published: May 10, 2021. doi:10.1001/jamanetworkopen.2021.8055

Open Access: This is an open access article distributed under the terms of the CC-BY License. © 2021 Gondi S et al. JAMA Network Open.

Corresponding Author: Nancy L. Keating, MD, MPH, Department of Health Care Policy, Harvard Medical School, 180 Longwood Ave, Boston, MA 02115 (keating@hcp.med.harvard.edu).

Author Contributions: Ms Meneades and Dr Keating had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.

Concept and design: Gondi, Wright, Landrum, Keating.

Acquisition, analysis, or interpretation of data: Gondi, Landrum, Meneades, Zubizarreta, Chernew, Keating.

Drafting of the manuscript: Gondi, Wright, Meneades, Keating.

Critical revision of the manuscript for important intellectual content: Gondi, Wright, Landrum, Zubizarreta, Chernew, Keating.

Statistical analysis: Landrum, Meneades, Keating.

Obtained funding: Keating.

Administrative, technical, or material support: Meneades.

Supervision: Keating.

Conflict of Interest Disclosures: Dr Chernew reported receiving equity as a member of the Archway Health Advisory Board outside the submitted work. No other disclosures were reported.

Funding/Support: This research was supported by Arnold Ventures (formerly the Laura and John Arnold Foundation) (Drs Landrum, Chernew, and Keating). The collection of cancer incidence data used in this study was supported by the California Department of Public Health as part of the statewide cancer reporting program mandated by California Health and Safety Code Section 103885; the National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER) Program under contract HHSN261201000140C awarded to the Cancer Prevention Institute of California, contract HHSN261201000035C awarded to the University of Southern California, and contract HHSN261201000034C awarded to the Public Health Institute; and the Centers for Disease Control and Prevention’s National Program of Cancer Registries, under agreement U58DP003862-01 awarded to the California Department of Public Health.

Role of the Funder/Sponsor: The funding organizations had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.

Disclaimer: The ideas and opinions expressed herein are those of the author and not necessarily those of Arnold Ventures, its directors, or staff. Endorsement by the State of California Department of Public Health, the National Cancer Institute, and the Centers for Disease Control and Prevention or their contractors and subcontractors is not intended nor should be inferred. This study used the linked SEER-Medicare database. The interpretation and reporting of these data are the sole responsibility of the authors.

Additional Contributions: The authors acknowledge the efforts of the National Cancer Institute; the Centers for Medicare and Medicaid Services’ Office of Research, Development, and Information; Information Management Services; and the SEER Program tumor registries in the creation of the SEER-Medicare Linked Database. We thank Lauren Riedel, MPH (Harvard Medical School), for research assistance, which was performed as part of her employment.