Evidence map›Paper›PMID 40789182›Full record

ArticleAnnals of internal medicine2025

Geographic Variation in the Utilization of Cancer Care From Subspecialized Medical Oncologists in the United States, 2008 to 2020.

René Karadakic, Christopher Manz, Arno Cai, David C Chan, Bruce E Landon, Jukka-Pekka Onnela, Nancy L Keating, Michael L Barnett

Abstract read
In one paragraph

Article in Annals of internal medicine, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 3 papers.

0numbers the graph read from it
0cells of the map it votes in
3citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

3 citing papers in PubMed.

  1. Interpreting vaccine-associated survival differences in immune checkpoint inhibitor therapy.Proceedings of the National Academy of Sciences of the United States of America · 2026
    Article
  2. Article
  3. Article
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

8 authors.

René KaradakicDepartment of Health Policy and Management, Harvard T.H. Chan School of Public Health, Boston, Massachusetts (R.K., A.C.).ORCID 0000-0002-3219-014X
Christopher ManzDepartment of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts (C.M.).ORCID 0000-0003-0928-3492
Arno CaiDepartment of Health Policy and Management, Harvard T.H. Chan School of Public Health, Boston, Massachusetts (R.K., A.C.).
David C ChanHaas School of Business, University of California, Berkeley, Berkeley, California; and Department of Veterans Affairs, Palo Alto, California (D.C.C.).
Bruce E LandonDepartment of Health Care Policy, Harvard Medical School, Boston; and Division of Primary Care and General Internal Medicine, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts (B.E.L.).ORCID 0000-0003-4912-0647
Jukka-Pekka OnnelaDepartment of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, Massachusetts (J.-P.O.).
Nancy L KeatingDepartment of Health Care Policy, Harvard Medical School, Boston; and Division of General Internal Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts (N.L.K.).ORCID 0000-0002-8274-4681
Michael L BarnettDepartment of Health Services, Policy & Practice, Brown School of Public Health, Providence, Rhode Island; and Division of General Internal Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts (M.L.B.).ORCID 0000-0002-4884-6609

Funding

Physician Subspecialization and the Health and Health Care of Older AmericansR01AG076580 · NIA · HARVARD UNIVERSITY D/B/A HARVARD SCHOOL OF PUBLIC HEALTH · PI BARNETT, MICHAEL LAWRENCE · 2022 to 2025
$2.4M
NIA NIH HHS R01 AG076580
6 · The paper itself

Abstract

backgroundThe growing complexity of cancer care may be driving an increase in subspecialized medical oncologists who focus on treating specific cancer types. However, little is known about trends in subspecialization among oncologists and differences in utilization of subspecialists.

objectiveTo quantify trends in oncologist subspecialization and assess differences in utilization of subspecialized cancer care in the United States.

designRetrospective cohort study using Medicare claims data from 2007 to 2021.

settingNational, fee-for-service Medicare.

participantsMedicare beneficiaries initiating chemotherapy between 2008 and 2020. MEASUREMENTS: Chemotherapy episodes were defined using methods from the Oncology Care Model. Subspecialization was identified based on whether oncologists managed more than 80% of chemotherapy episodes within a single cancer category. Outcomes included the annual share of oncologists classified as subspecialists, and the share of chemotherapy episodes managed by these oncologists, stratified by cancer type, geography, and socioeconomic characteristics.

resultsAmong 18 633 oncologists and 9.25 million chemotherapy episodes, the proportion of episodes managed by subspecialists increased from 9% in 2008 to 18% in 2020. Utilization varied widely across cancer types and regions, with the highest levels observed in large metropolitan areas. Differences by income widened over time: in 2020, 27.6% of episodes in the highest-income counties were managed by subspecialists, compared with only 8.8% in the lowest-income counties, despite higher cancer mortality in the latter. LIMITATIONS: Analyses were limited to fee-for-service Medicare beneficiaries and excluded patients treated with surgery or radiation alone. Subspecialization was defined using practice patterns rather than formal training, and the study does not assess patient outcomes or causal effects.

conclusionSubspecialization in oncology is increasing but is unevenly distributed, with growing differences in utilization across income groups and regions. PRIMARY FUNDING SOURCE: National Institute on Aging.

Indexed as

Medical OncologyNeoplasmsOncologistsPractice Patterns, Physicians'SpecializationAgedFee-for-Service PlansFemaleHumansMaleMedicareRetrospective StudiesUnited States

Identifiers

PMID40789182
PMCPMC12432991

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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.