Mary Uan-Sian Feng, M.D.
Radiation Oncology Physician · San Francisco, CA
Mary Uan-Sian Feng, M.D. is a radiation oncology physician with a practice address in San Francisco, California, and NPI 1720106693, issued on Mar 27, 2007. Check the license (California C143118, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Mary Uan-Sian Feng
- Credential
- M.D.
- Primary taxonomy
- Radiation Oncology Physician 2085R0001X
- License numbers
- C143118 CA
4301079982 MI
Self-reported in NPPES; status is on the state search - Practice location
- 1825 4TH Street, L1101, San Francisco, CA 94143
- Phone
- (415) 502-7222
- Enumerated
- Mar 27, 2007
- Record last updated
- Sep 27, 2022
- Medicare enrollment
- Enrolled (PECOS I20160819001417); accepts Medicare assignment
- Medical or professional school
- Washington University School Of Medicine, 2002
- Telehealth
- Offers telehealth (CMS)
- Entity
- Type 1 · individual
Verify Mary Uan-Sian Feng in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license C143118Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
85% fewer Medicare Part D claims than the average radiation oncology physician in 2024
20 Medicare Part D claims for 13 beneficiaries, against an average of 134 among the 4,851 providers of this specialty who prescribed in Part D.
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.
The practice group's MIPS final score for 2023 (Medicare payment program): 74.5 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: $273.67
2 payments; by number, the most common kind was food and beverage; the largest payer was Array Biopharma 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.
Bills Medicare through 2 group practices
- Ucsf Medical Group Business ServicesSan Francisco, CA
- University OF California San FranciscoSan Francisco, CA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Radiation Oncology Physician providers in California
There are 735 radiation oncology physician records in California.
Other radiation oncology physician records in California
- Christina Abel, NURSE PRACTITIONEROrange, CA1033638911
- Jonathan Abelson, M.D.Thousand Oaks, CA1730348053
- Roy Abendroth, MDSan Francisco, CA1811988421
- Sunil Advani, M.D.La Jolla, CA1669649844
- Faisal Ahmed, MDStanford, CA1427314855
- Eugene Ahn, MDSimi Valley, CA1912999533
- Matthew Allen, MDRedding, CA1235301714
- Zahora Ally, MDAntioch, CA1306839915
- Munther Alqaisi, M.D.San Bernardino, CA1356454300
- Alessandra Amadeo, MDTorrance, CA1225011034
Common questions
What is Mary Uan-Sian Feng, M.D.'s NPI number?
Mary Uan-Sian Feng, M.D.'s National Provider Identifier (NPI) is 1720106693, issued on Mar 27, 2007. An NPI identifies a provider in billing; it is not a license.
Where is Mary Uan-Sian Feng, M.D. located?
The NPPES record lists a practice address at 1825 4TH Street, L1101, San Francisco, CA, 94143. Phone: (415) 502-7222. Providers update this record themselves, so call before visiting.
How can I verify Mary Uan-Sian Feng, M.D.'s license?
NPPES lists California license number C143118, 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 Mary Uan-Sian Feng, M.D. prescribe under Medicare Part D?
In 2024, Mary Uan-Sian Feng, M.D. had 20 Medicare Part D claims for 13 beneficiaries; the average among radiation oncology physician prescribers was 134. Part D covers Medicare prescriptions only.
What is Mary Uan-Sian Feng, M.D.'s MIPS final score?
The 2023 MIPS final score is 74.5 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.