21st Century Oncology Data Breach History
Website21st Century Oncology was a Fort Myers-based cancer care provider operating 145 treatment centers in the US.
This page shows all data breaches of 21st Century Oncology. View the complete breach timeline, records exposed, root causes, and AI breach risk score. BreachHistory tracks disclosed data breaches worldwide.
Data Breach Timeline — All 21st Century Oncology Breaches
- 2016 2016 — 21st Century Oncology: Oct 2015 (disclosed Mar 2016), 2.2M records 2.2M records Share
- 2015 2015 — 2.2M records Unknown records Share
21st Century Oncology Data Breach Summary
This page tracks the 21st Century Oncology data breach history and cybersecurity incidents affecting 21st Century Oncology (United States). BreachHistory currently indexes 2 publicly disclosed or catalogued incidents spanning 2015 through 2016, with approximately 2.2 million records reported as exposed across all indexed events. These totals may include overlapping datasets or third-party estimates and should not be interpreted as unique affected users.
The 21st Century Oncology breach timeline includes major data breaches, cyber attacks, data leaks, credential exposures, API abuse, and other security incidents. Each incident provides details on the estimated records exposed, attack method, affected data types, and supporting public sources. Currently, 0 incidents are company-confirmed.
Largest 21st Century Oncology Data Breaches
The largest indexed incidents include the 2016 — 21st Century Oncology: Oct 2015 (disclosed Mar 2016), 2.2M records. Record counts originating from threat actors or leak sites should be treated as estimates unless confirmed by 21st Century Oncology or a regulator. Below is the list of large data breaches:
- 2016 2016 — 21st Century Oncology: Oct 2015 (disclosed Mar 2016), 2.2M records — about 2.2M records exposed · Catalogued incident
What Information Was Exposed?
Depending on the incident, exposed data may include email addresses, Social Security numbers and national IDs, names, physical addresses, and other personal information (PII). The exact data varies between incidents, so review each breach page before assuming your information was affected.
21st Century Oncology Data Breach 2026
At the time of this update, no 21st Century Oncology data breach has been catalogued for 2026. New incidents are added as official disclosures, regulatory filings, or credible cybersecurity reports become available.
What To Do If You Were Affected
If you believe your account may have been involved in a 21st Century Oncology data breach, change any reused passwords, enable multi-factor authentication (MFA), monitor your account for suspicious activity, and be cautious of phishing emails or fake breach notifications.
This 21st Century Oncology breach history is maintained by BreachHistory using public disclosures, regulatory filings, security research, and clearly labelled third-party claims. For the complete breach timeline, records exposed, incident details, and AI Breach Risk Score, explore the sections on this page.