Quick answers
- Which hospitals does Mark E. Sienko work at?
- Medicare's official clinician data lists Mark E. Sienko at 5 hospitals: Deaconess Medical Center, Good Samaritan Regional Medical Center, Multicare Valley Hospital, Samaritan Lebanon Community Hospital and Tacoma General Allenmore Hospital. This is where the clinician works or has privileges; call the hospital to confirm.
- Where does Mark E. Sienko see patients?
- Medicare's clinician data lists 6 practice locations, including Tacoma, WA, Corvallis, OR and Gig Harbor, WA. Call before your visit to confirm the address.
- What is Mark E. Sienko's specialty?
- Medicare lists Medical Oncology as the primary specialty, and also Hematology.
- Does Mark E. Sienko accept Medicare assignment?
- Yes. Medicare's clinician data says Mark E. Sienko accepts Medicare assignment (the Medicare-approved amount as full payment for covered services), as of 2026-10-02. Ask the office to confirm before your visit.
- What is the phone number for Mark E. Sienko?
- (541) 768-1261, as listed in official Medicare / NPI Registry data.
- What is Mark E. Sienko's NPI number?
- 1932146552. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.
Hospitals where Mark E. Sienko works
Medicare's Facility Affiliation Data lists Mark E. Sienko at these hospitals (updated 2026-10-02). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians.
- Deaconess Medical CenterSpokane, WA · Acute Care Hospital · CCN 500044
- Good Samaritan Regional Medical CenterCorvallis, OR · Acute Care Hospital · CCN 380014
- Multicare Valley HospitalSpokane Valley, WA · Acute Care Hospital · CCN 500119
- Samaritan Lebanon Community HospitalLebanon, OR · Critical Access Hospital · CCN 381323
- Tacoma General Allenmore HospitalTacoma, WA · Acute Care Hospital · CCN 500129
Practice locations
Addresses where Mark E. Sienko is enrolled with Medicare (CMS data updated 2026-10-02). The first 5 of 6; the Medicare profile lists all.
- 311 S L StTacoma, WA 98405
- 3600 NW Samaritan DrCorvallis, OR 97330
- 3600 NW Samaritan Dr, Suite 227Corvallis, OR 97330 (541) 768‑1261
- 441 NW Elks DrCorvallis, OR 97330
- 4700 Point Fosdick DrGig Harbor, WA 98335
Group practices
Medicare enrollment lists Mark E. Sienko as a member of these groups (CMS data updated 2026-10-02).
- Multicare Health System2,325 clinicians in the group
- Good Samaritan Hospital Corvallis380 clinicians in the group
Specialties
- Medical Oncologyprimary
- Hematologyalso
Other oncologists in Tacoma
Clinicians with the same Medicare primary specialty in Tacoma, WA — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Medical school | University Of Illinois College Of Med (chi/peor/rock/chm-Urb) |
| Graduation year | 1989 |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1932146552 |
| Corrections | Report an error or suggest an update → |
Most corrections must be made at the source: clinicians update their NPI Registry record (NPPES) and their Medicare enrollment (PECOS); this page follows the next data release.
Sources
- Facility Affiliation Data — Centers for Medicare & Medicaid Services (CMS), data updated 2026-10-02, retrieved 2026-10-29
- National Downloadable File (Doctors and Clinicians) — CMS, data updated 2026-10-02, retrieved 2026-10-29
- NPI Registry — U.S. Department of Health and Human Services (NPPES), the clinician’s official record
- Medicare Care Compare — official Medicare tool to look up clinicians