NPPES file of Aug 9, 2026

Cassandra Leigh Thomas, M.D.

Hematology & Oncology Physician · Ventura, CA

Cassandra Leigh Thomas, M.D. is a hematology & oncology physician with a practice address in Ventura, California, and NPI 1376787416, issued on Apr 20, 2009. Check the license (California C184675, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.

Record from CMS NPPES, file of Aug 9, 2026 · Medicare files 2024 · method · Verify with CMS →

NPPES recordNPPES file of Aug 9, 2026
1376787416
Name
Cassandra Leigh Thomas
Credential
M.D.
Primary taxonomy
Hematology & Oncology Physician 207RH0003X
License numbers
C184675 CA
25MA10384800 NJ
MD446164 PA
Self-reported in NPPES; status is on the state search
Practice location
300 Hillmont Ave Ste 501, Ventura, CA 93003
Phone
(805) 652-6218
Enumerated
Apr 20, 2009
Record last updated
Nov 17, 2025
Medicaid IDs
102756150 PA
0311057 NJ
Medicare enrollment
Enrolled (PECOS I20240408000130); accepts Medicare assignment
Telehealth
Offers telehealth (CMS)
Entity
Type 1 · individual
Public record from CMS NPPES (open it on the CMS NPI Registry). Enrollment, assignment, school and telehealth: CMS Doctors and Clinicians file, Aug 2026. A record is not a license: verify it with the state board.
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8 nearest hematology & oncology physician records → All 1,583 in California → Look up another NPI →

Also registered at 300 Hillmont Ave Ste 501

A shared address usually means a shared clinic or building; it does not show who employs whom.

  1. Beth Molineux, M.S., PH.D.Marriage & Family Therapist1174712608

Verify Cassandra Leigh Thomas in five checks

  1. 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
  2. 2LicenseActive license and public ordersMedical Board of California
    Search for license C184675    Check the board
  3. 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
  4. 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
  5. 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
Open the California license search

PlainDoctor does not match the HHS-OIG exclusion list to individual records: most entries carry no NPI. Search the OIG exclusion list by name.

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74% fewer Medicare Part D claims than the average hematology & oncology physician in 2024

232 Medicare Part D claims for 39 beneficiaries, against an average of 877 among the 10,784 providers of this specialty who prescribed in Part D. Brand-name drugs were 37% of claims. 18 claims were for opioids.

  1. Cassandra Thomas232
  2. Specialty average877

Most prescribed

  1. Anastrozole28 claims
  2. Ondansetron Hcl27 claims
  3. Verzenio26 claims
  4. Procrit20 claims
  5. Letrozole18 claims
  6. Eliquis14 claims

Source: CMS Medicare Part D Prescribers by Provider and Drug, 2024 (data.cms.gov). Part D covers prescriptions for Medicare patients only; drugs with fewer than 11 claims are not published.

Industry payments in 2024: $43.08

1 payment: food and beverage; the largest payer was Abbvie Inc. The 8,560 providers of this specialty with any payment received $7,481.41 on average. Payments are reported by manufacturers, not by the provider, and are not a sign of wrongdoing.

  1. Cassandra Thomas$43.08
  2. Specialty average$7,481.41

Source: CMS Open Payments, program year 2024 (openpaymentsdata.cms.gov); average among providers of this specialty with at least one payment.

Bills Medicare through 2 group practices

  1. Community Memorial Health SystemVentura, CA
  2. County OF VenturaVentura, CA

Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).

Cassandra Leigh Thomas among 1,583 hematology & oncology physician records in California

Cassandra Leigh Thomas, M.D. is one of 1,583 hematology & oncology physician records with a practice address in California. 83% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2009, is newer than 66% of them.

  • NPI issued2009 · 66% of these records are older, 30% newer
  • In a Medicare fileYes · 83% of these records are
  • In the CMS Doctors and Clinicians fileYes · 71% of these records are
  • Graduated2009 · median 2003 among the 1,124 with a school on file
  • Record last updated2025 · 58% of these records were not updated in five years or more

Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207RH0003X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).

Hematology & Oncology Physician providers in California

There are 1,583 hematology & oncology physician records in California.

All 1,583 in California → Every provider in Ventura → Hematology & Oncology Physician nationwide →

The 8 hematology & oncology physician records with the nearest ZIP codes

  1. Isabella Chen, M.D.Ventura, CA 930031053621730
  2. Manasi Ghatge, MDVentura, CA 930031891322459
  3. Lynn Kong, MDVentura, CA 930031952356933
  4. Joshua Rosenberg, MDVentura, CA 930031124280896
  5. Ann SalahuddinVentura, CA 930031053350231
  6. Irena Vidito, D.O.Ventura, CA 930031689735227
  7. Keith Eilerman, M.D.Camarillo, CA 930101316004559
  8. Kevin Chang, MDOxnard, CA 930301649219452

Common questions

What is Cassandra Leigh Thomas, M.D.'s NPI number?

Cassandra Leigh Thomas, M.D.'s National Provider Identifier (NPI) is 1376787416, issued on Apr 20, 2009. An NPI identifies a provider in billing; it is not a license.

Where is Cassandra Leigh Thomas, M.D. located?

The NPPES record lists a practice address at 300 Hillmont Ave Ste 501, Ventura, CA, 93003. Phone: (805) 652-6218. Providers update this record themselves, so call before visiting.

How can I verify Cassandra Leigh Thomas, M.D.'s license?

NPPES lists California license number C184675, as entered by the provider. Search the Medical Board of California at https://www.mbc.ca.gov/License-Verification/default.aspx. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.

How much does Cassandra Leigh Thomas, M.D. prescribe under Medicare Part D?

In 2024, Cassandra Leigh Thomas, M.D. had 232 Medicare Part D claims for 39 beneficiaries; the average among hematology & oncology physician prescribers was 877. Part D covers Medicare prescriptions only.

Source: CMS National Plan and Provider Enumeration System (NPPES), file of Aug 9, 2026 (NPPES files on CMS.gov); NUCC Health Care Provider Taxonomy. Medicare files from data.cms.gov. An NPI identifies who bills; it is not a license.

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

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.