People search 21st Century Oncology data breach timeline because the brand sits on billions of accounts, credentials, and cloud workloads. BreachHistory indexes 2 21st Century Oncology-linked incidents, with headline counts up to 2.2M+ in catalog rows. This page maps every attested event through 2026 with internal links to canonical records.
Why 21st Century Oncology breach history matters
21st Century Oncology operates in Technology (United States). Across indexed rows, recurring themes include mixed intrusion and disclosure events. Understanding the chronological pattern helps security teams, customers, and regulators separate confirmed disclosures from forum marketing.
Full timeline through 2026
2016 — — 21st Century Oncology: Oct 2015 (disclosed Mar 2016), 2.2M records
Cataloged incident. Oct 2015 (disclosed Mar 2016). Unauthorized access to patient database at Fort Myers cancer care provider (145 centers). Exposed: names, SSNs, insurance data, diagnosis/treatment info, physician names. FBI notified Nov 2015; delayed disclosure for investigation. Affected all 50 states and several countries. One year credit monitoring offered. Exposed categories include Names, SSNs, insurance, diagnosis, treatment, physician names. BreachHistory cites approximately 2.2M+ affected records in this row. See the 21st-century-oncology2016 and canonical BreachHistory entry.
2015 — — 2.2M records
Cataloged incident. Hacked. 2.2M records. Exposed categories include Names, emails, addresses, and other PII. BreachHistory cites approximately 22 affected records in this row. See the 21st-century-oncology2015 and canonical BreachHistory entry.
Patterns and analysis
- Mixed intrusion and disclosure events — appears across multiple 21st Century Oncology catalog entries; prioritize controls that address this class of failure.
- Record-count hygiene — BreachHistory indexes actor-cited figures separately from company-confirmed totals; read each row's technicalWriteup before treating counts as fact.
- 2026 monitoring — New disclosures roll into this timeline as they are verified or labeled unverified per catalog policy.
What to do if you may be affected
- Step 1: Enable phishing-resistant MFA on every account tied to this brand.
- Step 2: Use unique passwords and a password manager—breach rows often involve credential reuse.
- Step 3: Monitor official company breach notices and regulator filings, not dark-web downloads.
- Step 4: Review OAuth app permissions and revoke unused third-party integrations.
- Step 5: Bookmark the 21st Century Oncology company page for new 2026+ disclosures.
Canonical BreachHistory hub
Explore every indexed row: breachhistory.com/21st-century-oncology · Latest: 21st-century-oncology2016.
Sources: BreachHistory catalog (2 rows for 21st Century Oncology), company and regulator disclosures cited in individual breach records.