Marin Cancer Care Data Breach Exposes PHI and PII of Patients

Published
February 24, 2026
Updated
February 24, 2026
Marin Cancer Care Data Breach Exposes PHI and PII of Patients
Marin Cancer Care

Affected by the

Marin Cancer Care

data breach?

Join the Lawsuit

Marin Cancer Care, a privately held cancer treatment center in Greenbrae, CA, experienced a data breach that impacted patients’ protected health information and personally identifiable information. The incident occurred on Nov. 19, 2015, and was discovered by the organization on or about Dec. 8, 2015.

The breach involved unauthorized access to sensitive information, including names, health insurance information and medical information. The specific method of compromise has not been detailed publicly.

At this time, the total number of individuals in the United States affected has not been disclosed as the investigation is ongoing.

The U.S. Department of Health and Human Services has published details about the incident. Additionally, Marin Cancer Care has posted a notice of the event on its website.

Marin Cancer Care's response

Those who believe they may have been affected are encouraged to monitor their health insurance statements and medical records for signs of suspicious activity. It is also advisable to contact their health insurer for additional support and consider placing a fraud alert on their credit files.

Affected individuals can find more information and updates through the official notice provided by Marin Cancer Care. Marin Cancer Care’s office hours are 8 a.m. to 5 p.m., Monday through Friday, with emergency contact available after hours.

Types of INFORMATION affected
  • Names
    Names
  • Social security numbers
    Social Security Numbers
  • Dates of birth
    Dates of Birth
  • Addresses
    Addresses
  • Government IDs
    Government IDs
  • Medical Information
    Medical Info
  • Financial Info
    Financial Info
  • Affected information types not yet disclosed

Notice Letter

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