Zachary Stephan Zumsteg, M.D.
Radiation Oncology Physician · Sylmar, CA
Zachary Stephan Zumsteg, M.D. is a radiation oncology physician with a practice address in Sylmar, California, and NPI 1962729004, issued on Apr 29, 2010. Check the license (California A138272, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Zachary Stephan Zumsteg
- Credential
- M.D.
- Primary taxonomy
- Radiation Oncology Physician 2085R0001X
- License number
- A138272 CA
Self-reported in NPPES; status is on the state search - Practice location
- 14445 Olive View Dr., Sylmar, CA 91342
- Phone
- (818) 364-1555
- Enumerated
- Apr 29, 2010
- Record last updated
- Mar 28, 2016 (not updated in 10 years: call before relying on the address or phone)
- Medicare enrollment
- Enrolled (PECOS I20151112003097); accepts Medicare assignment
- Telehealth
- Offers telehealth (CMS)
- Entity
- Type 1 · individual
8 nearest radiation oncology physician records → All 735 in California → Look up another NPI →
Also registered at 14445 Olive View Dr.
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Sharon Hess-Witucki, LCSWClinical Social Worker1518487651
- Maria-Czarina Katalbas, NPNurse Practitioner1487042529
- Kele Kirschenbaum, PSY.D.Clinical Psychologist1972985901
- Justina OtarolaAmbulatory Care Registered Nurse1386164838
- Karla Joyce Otero-Vo, FAMILY NURSE PRACTITNurse Practitioner1558767707
- Guita Rahbar, MDDiagnostic Radiology Physician1942233853
Verify Zachary Stephan Zumsteg in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license A138272Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
The practice group's MIPS final score for 2023 (Medicare payment program): 87.7 of 100
The Merit-based Incentive Payment System score is reported for the practice group, not for one clinician alone. Four categories are weighted into the final score; the average among 454,083 clinicians with a measured score was 83.5.
Source: CMS Quality Payment Program, MIPS performance year 2023, group reporting; category weights for 2023 (qpp.cms.gov).
Industry payments in 2024: $142.01
1 payment: food and beverage; the largest payer was Coherus Biosciences Inc. The 3,275 providers of this specialty with any payment received $1,897.85 on average. Payments are reported by manufacturers, not by the provider, and are not a sign of wrongdoing.
Source: CMS Open Payments, program year 2024 (openpaymentsdata.cms.gov); average among providers of this specialty with at least one payment.
One hospital affiliation
- Cedars-Sinai Medical CenterWest Hollywood, CA · Acute Care Hospitals5 of 5 stars
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through); hospitals matched to CMS Hospital General Information (Care Compare) (data.cms.gov). Star ratings are CMS hospital ratings, not ratings of this provider.
Zachary Stephan Zumsteg among 735 radiation oncology physician records in California
Zachary Stephan Zumsteg, M.D. is one of 735 radiation 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 2010, is newer than 66% of them.
- NPI issued2010 · 66% of these records are older, 31% newer
- In a Medicare fileYes · 83% of these records are
- In the CMS Doctors and Clinicians fileYes · 74% of these records are
- Graduated2010 · median 2005 among the 545 with a school on file
- Record last updated2016 · 55% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 2085R0001X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Radiation Oncology Physician providers in California
There are 735 radiation oncology physician records in California.
All 735 in California → Every provider in Sylmar → Radiation Oncology Physician nationwide →
The 8 radiation oncology physician records with the nearest ZIP codes
- Nina Cote, MDMission Hills, CA 913451396131439
- Nancy EllerbroekValencia, CA 913551821071507
- May Tao, MDValencia, CA 913551144204249
- Marc Botnick, MDTarzana, CA 913561033192844
- Jonathan Abelson, M.D.Thousand Oaks, CA 913601730348053
- Paul Miller, MDThousand Oaks, CA 913601992797526
- Randall Scharlach, MDWoodland Hills, CA 913671477545093
- Caitlin Gomez, M.D.West Hills, CA 913071619294907
Common questions
What is Zachary Stephan Zumsteg, M.D.'s NPI number?
Zachary Stephan Zumsteg, M.D.'s National Provider Identifier (NPI) is 1962729004, issued on Apr 29, 2010. An NPI identifies a provider in billing; it is not a license.
Where is Zachary Stephan Zumsteg, M.D. located?
The NPPES record lists a practice address at 14445 Olive View Dr., Sylmar, CA, 91342. Phone: (818) 364-1555. Providers update this record themselves, so call before visiting.
How can I verify Zachary Stephan Zumsteg, M.D.'s license?
NPPES lists California license number A138272, 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.
What is Zachary Stephan Zumsteg, M.D.'s MIPS final score?
The 2023 MIPS final score is 87.7 of 100, reported for the practice group. The average among 454,083 clinicians with a measured score was 83.5.
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.
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.