HHS OCR report ยท 2026
Marin Cancer Care data breach
OCR report facts
- Covered entity
- Marin Cancer Care
- Entity type
- Healthcare Provider
- State
- California
- Individuals affected
- 27,332
- Submission date
- Feb 6, 2026
- Type of breach
- Hacking/IT Incident
- Location of breached information
- Network Server
- Business associate present
- No
- Status
- Archive (closed)
OCR description
The covered entity (CE), Marin Cancer Care, reported that it experienced a cybersecurity incident that affected the protected health information (PHI) of 27,332 individuals. The PHI involved included demographic, clinical, and financial information. The CE notified HHS, affected individuals, and provided media notice. In response to the breach, the CE implemented additional administrative and technical safeguards.
Text as published on the HHS OCR breach portal.
Frequently asked questions
How many people were affected by the Marin Cancer Care data breach?
The report to HHS OCR lists 27,332 individuals affected.
When was it reported to HHS?
It was submitted to HHS OCR on Feb 6, 2026.
What type of breach was it?
The OCR portal lists the type of breach as Hacking/IT Incident, with the breached information located in: Network Server.
Is the investigation still open?
No. The report is in the OCR portal archive, which holds reports where OCR has closed its review.
Is a breach notice letter from Marin Cancer Care legitimate?
This site cannot verify letters. Check the sender against the organisation's official website and the HHS OCR breach portal, and avoid calling numbers or clicking links only listed in an unexpected message. See our guide on what to do after a data breach notice.
Source: HHS OCR Breach Portal, OCR export October 2026. Network USA is not affiliated with HHS or Marin Cancer Care.