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Radiation Oncology

Alexandra K. Brennan, MD

Sees patients in Seattle, WA · Fort Sam Houston, TX · Los Angeles, CA · Washington, Texas, California

Summary

Dr. Alexandra K. Brennan, MD is a radiation oncologist at 1100 9th Ave, Seattle, WA 98101. May accept Medicare assignment. NPI 1578092508. Source: CMS National Downloadable File, updated October 2, 2026.

  • Specialty: Radiation oncologist (Medicare lists Radiation Oncology)
  • Address: 1100 9th Ave, Seattle, WA 98101 · Directions (2 more locations)
  • Medicare: May accept Medicare assignment
  • Medical school: University Of Texas Medical School At San Antonio · graduated 2017 (9 years since medical school)
  • Gender (as listed): Female

From official Medicare data

This page shows what Medicare's official clinician data says about Alexandra K. Brennan, joined by NPI number (data updated October 2, 2026). It is not a recommendation or a rating. Call the office or hospital to confirm before you go.

In a medical emergency, call 911.

Quick answers

Does Alexandra K. Brennan accept Medicare assignment?
Medicare's clinician data says Alexandra K. Brennan may accept Medicare assignment (as of October 2, 2026). Ask the office whether they accept it for your visit.
What is Alexandra K. Brennan's NPI number?
1578092508. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.

Practice locations

Addresses where Alexandra K. Brennan is enrolled with Medicare (CMS data updated October 2, 2026).

  • 1100 9th AveSeattle, WA 98101
  • 3551 Roger Brooke DrFort Sam Houston, TX 78234
  • PO BoxLos Angeles, CA 90074

Specialties

Find other Radiation Oncology doctors in Washington →

Other radiation oncologists in Seattle

Clinicians with the same Medicare primary specialty in Seattle, WA — not a recommendation.

All radiation oncologists in Seattle →

Clinician information

CredentialMD
Medical schoolUniversity Of Texas Medical School At San Antonio
Graduation year2017 (9 years since medical school)
Gender (as listed)Female
Medicare assignmentMay accept for some services
NPI (National Provider Identifier)1578092508
CorrectionsReport 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

  1. National Downloadable File (Doctors and Clinicians) — CMS, data updated October 2, 2026, retrieved October 29, 2026
  2. NPI Registry — U.S. Department of Health and Human Services (NPPES), the clinician’s official record
  3. Medicare Care Compare — official Medicare tool to look up clinicians