Marin Cancer Care Data Breach Exposes Patient Information in 2015 Incident
Marin Cancer Care, a California-based cancer treatment center, disclosed a data breach that occurred in November 2015, with unauthorized access detected on December 8 of that year. The breach exposed sensitive patient data, including names, health insurance details, and medical records.
Located in Greenbrae, CA, Marin Cancer Care has provided oncology and supportive care services since 1952. Following the discovery, the organization engaged third-party cybersecurity investigators to assess the scope of the incident. While the exact number of affected individuals remains unknown, the breach was reported to the U.S. Department of Health and Human Services on February 6, 2026.
The investigation into the incident is ongoing. Legal firms are currently reviewing potential compensation claims for impacted patients. Marin Cancer Care has published details of the breach on its website.
Source: https://www.claimdepot.com/investigations/marin-cancer-care-data-breach-2026
Marin Cancer Care TPRM report: https://www.rankiteo.com/company/marin-cancer-care
"id": "mar1771972795",
"linkid": "marin-cancer-care",
"type": "Breach",
"date": "11/2015",
"severity": "85",
"impact": "4",
"explanation": "Attack with significant impact with customers data leaks"{'affected_entities': [{'industry': 'Healthcare',
'location': 'Greenbrae, CA, USA',
'name': 'Marin Cancer Care',
'type': 'Healthcare Provider'}],
'data_breach': {'personally_identifiable_information': 'Names, health '
'insurance details, '
'medical records',
'sensitivity_of_data': 'High',
'type_of_data_compromised': ['Names',
'Health insurance details',
'Medical records']},
'date_detected': '2015-12-08',
'date_publicly_disclosed': '2026-02-06',
'description': 'Marin Cancer Care, a California-based cancer treatment '
'center, disclosed a data breach that occurred in November '
'2015, with unauthorized access detected on December 8 of that '
'year. The breach exposed sensitive patient data, including '
'names, health insurance details, and medical records.',
'impact': {'data_compromised': 'Sensitive patient data, including names, '
'health insurance details, and medical records',
'legal_liabilities': 'Potential compensation claims for impacted '
'patients'},
'investigation_status': 'Ongoing',
'references': [{'source': 'Marin Cancer Care Website'}],
'regulatory_compliance': {'legal_actions': 'Potential compensation claims for '
'impacted patients',
'regulatory_notifications': 'Reported to the U.S. '
'Department of Health '
'and Human Services'},
'response': {'communication_strategy': 'Published details of the breach on '
'its website',
'third_party_assistance': 'Engaged third-party cybersecurity '
'investigators'},
'title': 'Marin Cancer Care Data Breach Exposes Patient Information',
'type': 'Data Breach'}