Mark Edward Sienko, M.D.
Medical Oncology Physician · Sequim, WA
Mark Edward Sienko, M.D. is a medical oncology physician with a practice address in Sequim, Washington, and NPI 1932146552, issued on Jun 1, 2006. Check the license (Washington MD00046621, as entered in NPPES) on the Washington Medical Commission; the Medicare figures below come from public CMS files.
- Name
- Mark Edward Sienko
- Credential
- M.D.
- Primary taxonomy
- Medical Oncology Physician 207RX0202X
- License number
- MD00046621 WA
Self-reported in NPPES; status is on the state search - Practice location
- 844 N 5TH Ave, Sequim, WA 98382
- Phone
- (360) 683-9895
- Enumerated
- Jun 1, 2006
- Record last updated
- Feb 26, 2020 (not updated in 6 years: call before relying on the address or phone)
- Fax
- (360) 582-5614
- Medicare enrollment
- Enrolled (PECOS I20060628000327); accepts Medicare assignment
- Medical or professional school
- University Of Illinois College Of Med (Chi/Peor/Rock/Chm-Urb), 1989
- Entity
- Type 1 · individual
8 nearest medical oncology physician records → All 183 in Washington → Look up another NPI →
Also registered at 844 N 5TH Ave
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Charene Alderman, ARNPNurse Practitioner1013952738
- Donna Cameron, RNRegistered Nurse1932065075
- Lesley Cruz, DNP, ARNPNurse Practitioner1356047518
- Susan Feeney, MDRadiation Oncology Physician1750321469
- Thomas Fitzgerald, MD PH DHematology & Oncology Physician1336134766
- William Harrer, M.D.Medical Oncology Physician1972584217
Verify Mark Edward Sienko in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersWashington Medical Commission
Search for license MD00046621Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
4% more Medicare Part D claims than the average medical oncology physician in 2024
733 Medicare Part D claims for 164 beneficiaries, against an average of 703 among the 4,230 providers of this specialty who prescribed in Part D. Brand-name drugs were 11% of claims. 40 claims were for opioids.
Most prescribed
- Letrozole72 claims
- Dexamethasone64 claims
- Prednisone51 claims
- Tamoxifen Citrate38 claims
- Olanzapine32 claims
- Hydroxyurea28 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.
The practice group's MIPS final score for 2023 (Medicare payment program): 81 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: $240.13
3 payments; by number, the most common kind was food and beverage; the largest payer was Pfizer Inc. The 3,343 providers of this specialty with any payment received $11,773.47 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 one group practice
- Multicare Health SystemTacoma, WA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Mark Edward Sienko among 183 medical oncology physician records in Washington
Mark Edward Sienko, M.D. is one of 183 medical oncology physician records with a practice address in Washington. 72% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2006, is newer than 12% of them.
- NPI issued2006 · 12% of these records are older, 40% newer
- In a Medicare fileYes · 72% of these records are
- In the CMS Doctors and Clinicians fileYes · 61% of these records are
- Graduated1989 · median 1998 among the 112 with a school on file
- Record last updated2020 · 70% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207RX0202X and a Washington practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
7 medical oncology physician records list a practice address in Sequim
They are 7 of the 530 NPPES records with a practice address in Sequim, and 183 medical oncology physician records in Washington.
All 183 in Washington → Every provider in Sequim → Medical Oncology Physician nationwide →
The 8 medical oncology physician records with the nearest ZIP codes
- William Harrer, M.D.Sequim, WA 983821972584217
- Saifuddin Kasubhai, M.D.Sequim, WA 983821780789958
- Eiko Klimant, MDSequim, WA 983821154354967
- Manuel Macapinlac, M.D.Sequim, WA 983821811975345
- Tina Passalaris, M.D.Sequim, WA 983821508951864
- Jose Ruiz-Bonilla, M.D.Sequim, WA 983821609024710
- Stephen Lemon, MDSilverdale, WA 983831386637288
- Toni Roberts, MD, PHDPoulsbo, WA 983701962701110
Common questions
What is Mark Edward Sienko, M.D.'s NPI number?
Mark Edward Sienko, M.D.'s National Provider Identifier (NPI) is 1932146552, issued on Jun 1, 2006. An NPI identifies a provider in billing; it is not a license.
Where is Mark Edward Sienko, M.D. located?
The NPPES record lists a practice address at 844 N 5TH Ave, Sequim, WA, 98382. Phone: (360) 683-9895. Providers update this record themselves, so call before visiting.
How can I verify Mark Edward Sienko, M.D.'s license?
NPPES lists Washington license number MD00046621, as entered by the provider. Search the Washington Medical Commission at https://wahelms.my.site.com/s/license-search. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Mark Edward Sienko, M.D. prescribe under Medicare Part D?
In 2024, Mark Edward Sienko, M.D. had 733 Medicare Part D claims for 164 beneficiaries; the average among medical oncology physician prescribers was 703. Part D covers Medicare prescriptions only.
What is Mark Edward Sienko, M.D.'s MIPS final score?
The 2023 MIPS final score is 81 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.