NPPES file of Aug 9, 2026

Hematology & Oncology Physician in California

1,583 NPPES records list hematology & oncology physician with a practice address in California, 4.1 per 100,000 residents, the 19th highest rate of 51. Los Angeles and San Diego have the most; each record links to the provider's NPI and the California license search. Page 22 of 32.

CMS NPPES registry, file of Aug 9, 2026; 2023 Census estimates · NUCC 207RH0003X · method

Written with AI tools from the named public files; every figure is computed from those files (how it is made).

Los Angeles has the most, 153

  1. Los Angeles153
  2. San Diego88
  3. Sacramento77
  4. San Francisco64
  5. Orange63

Hematology & Oncology Physician records in California

  1. David Oblon, MDOceanside, CA 920561215072434
  2. Mihail Obrocea, M.D.Valencia, CA 913551942284559
  3. Jose Ochoa-Bayona, M.D.Walnut Creek, CA 945981669475158
  4. Margaret Odonnell, MDSouth Pasadena, CA 910301316955230
  5. Elizabeth Odumakinde, M.D.Concord, CA 945201952408999
  6. Foluso Ogunleye, MDCerritos, CA 907031972766772
  7. Annie Oh, M.D.Riverside, CA 925051205028404
  8. David OhSan Francisco, CA 941431891084349
  9. Michael Oh, MDSanta Monica, CA 904041285088187
  10. David Okun, M.D.Laguna Hills, CA 926531306839287
  11. Olga Olevsky, M.D.Santa Monica, CA 904041841306743
  12. Caspian Oliai, M.D.Los Angeles, CA 900951366737231
  13. Rebecca Olin, MDSan Francisco, CA 941431043373681
  14. Gregg Olsen, M.D.Burbank, CA 915051427078070
  15. Tiong S Ong, MDOrange, CA 928681467532606
  16. Karlos Oregel, M.D.Huntington Beach, CA 926481184913006
  17. Allan Orenstein, M.D.La, CA 900451780619882
  18. Leo Orr, M.D.Los Angeles, CA 900171730102286
  19. Denise Oseguera, NPLos Angeles, CA 900951407876683
  20. Stephanie OssowskiSan Diego, CA 921201417301482
  21. Pamela Oster, M.D.Marysville, CA 959011982735262
  22. Stavroula Otis, M.D.Orange, CA 928681477677557
  23. Sai-Hong I Ou, MDOrange, CA 928681639259872
  24. John Oval, MDSan Diego, CA 921201720136617
  25. David Oveisi, MDLos Angeles, CA 900481386006369
  26. Halline Overby, M.D.Lynwood, CA 902621912062001
  27. Lay Owyong, MDStockton, CA 952101871667477
  28. Anantanarayan Padmanabhan, M.D.Fresno, CA 937201891742441
  29. Aswini Padmanabhan, MDBaldwin Park, CA 917061295883221
  30. James Padova, M.D.Orange, CA 928681770535908
  31. Jonathan PaiWalnut Creek, CA 945981285196105
  32. Anuradha Pakanati, MDPanorama City, CA 914021164581740
  33. Nicolaos Palaskas, M.D.Santa Monica, CA 904041750545448
  34. David Palchak, M.D.Arroyo Grande, CA 934201396815965
  35. Chuan-Ju Pan, M.D.Orange, CA 928681609003961
  36. Darren PanSan Francisco, CA 941431841721347
  37. Elizabeth PanLos Angeles, CA 900891952842379
  38. Roy Panares, MDFullerton, CA 928351285837229
  39. Lalita Pandit, M.D.Fountain Valley, CA 927081578521266
  40. Wendy Pang, MDStanford, CA 943051760758916
  41. Marie Krielle Tasha Pantino, MDRancho Mirage, CA 922701962060012
  42. Ronald Paquette, MDLos Angeles, CA 900951992725576
  43. Ritesh Parajuli, MDOrange, CA 928681710189543
  44. Amar Parikh, M.D.Culver City, CA 902321013448125
  45. Mamta Parikh, M.D., M.S.Sacramento, CA 958171649595026
  46. Cathleen Park, M.D.Orange, CA 928681700319043
  47. Dorothy Park, M.D.Beverly Hills, CA 902111083610596
  48. Mihee Park, M.D.Los Angeles, CA 900331144607904
  49. Soo Park, M.D.La Jolla, CA 920931821351198
  50. Barbara Parker, M.D.La Jolla, CA 920931629093927

Source: CMS NPPES, primary taxonomy 207RH0003X: records by practice city and the list of records, file of Aug 9, 2026.

California ranks 19 of 51 per resident

  1. Ohio4.4
  2. New Jersey4.3
  3. Louisiana4.1
  4. California4.1
  5. Nebraska4.0
  6. Virginia4.0
  7. 50 states and D.C.4.2

Source: CMS NPPES, primary taxonomy 207RH0003X by practice state, file of Aug 9, 2026; records per 100,000 residents, 2023 Census estimates.

83.1% of these records appear in a Medicare file, against 82.9% nationally

A Medicare file here is Part D prescribing (2024), a MIPS score (2023), an Open Payments record (2024) or Medicare group billing (CMS Doctors and Clinicians). A record outside them may still see patients: these files cover Medicare only.

  1. California83.1%
  2. United States82.9%

Hematology & Oncology Physician records in California, measured

  • In a Medicare file1,315 of 1,583 · 83.1% here, 82.9% nationally
  • In the CMS Doctors and Clinicians file1,126 · 71.1% here, 71.3% nationally
  • Not updated in five years or more917 · 57.9% here, 54.3% nationally
  • Median graduation year2003 · the 1,124 records with a school on file

Source: CMS NPPES, file of Aug 9, 2026 (primary taxonomy 207RH0003X); CMS Medicare Part D Prescribers 2024, MIPS 2023, Open Payments 2024 and Doctors and Clinicians, matched by NPI.

What the count covers

1,583 NPPES records list hematology & oncology physician (207RH0003X) as their primary taxonomy with a practice address in California: 4.1 per 100,000 residents against 4.2 nationally (50 states and D.C.). Los Angeles has 153 of them (10%).

A record is a registration a provider made and keeps up to date: it shows neither that the provider is licensed nor that they still practice there. The state's own license search is the check.

States with a similar number

  1. New York1,163
  2. Texas922
  3. Florida818
  4. Pennsylvania784

States with a similar rate per 100,000

  1. Nebraska4.0
  2. Louisiana4.1
  3. Virginia4.0
  4. North Carolina4.0

The largest states

  1. New York1,163
  2. Texas922
  3. Florida818
  4. Pennsylvania784
  5. Illinois666

Source: CMS National Plan and Provider Enumeration System (NPPES), file of Aug 9, 2026 (NPPES files on CMS.gov); NUCC Health Care Provider Taxonomy; 2023 Census population estimates. A registry record is not a license.

Figures on PlainDoctor are read from the federal files each page names (CMS NPPES, Medicare Part D, MIPS, Open Payments; the HHS-OIG exclusion list only as counts) and from Census population estimates, with the file date shown beside them. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of Aug 9, 2026.