133,918 Individuals Affected by Phishing Attack on Cancer Treatment Centers

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A phishing attack impacted several cancer care organizations of the Integrated Oncology Network (ION). All impacted entities released identical breach notices concerning the attack. According to the breach notices, the sophisticated phishing attack allowed unauthorized individuals to access a few employee email and SharePoint accounts.

ION took immediate action to protect the impacted accounts and investigated the incident to find more about the nature and scope of the attack and data breach. As per forensic investigation, the account compromise happened in three days from December 13, 2024 to December 16, 2024. Certain breached accounts included patient data. The analysis of the accounts showed that they included names, addresses, birth dates, financial account details, Social Security numbers, diagnoses, laboratory results, prescription drugs, treatment data, dates of treatment, medical insurance and claims data, and healthcare provider names.

The impacted cancer care organizations didn’t find any proof of misuse of patient data; nevertheless, as a safety measure, the impacted people were provided free credit monitoring, identity restoration, and dark web monitoring services. On June 13, 2025, ION mailed breach notification letters to the impacted oncology physician practices. On June 27, 2025, personal breach notification letters were sent to the impacted patients. ION stated that the breach of email accounts was likely meant to execute a phishing plan; nevertheless, the attacker(s) also accessed SharePoint accounts. ION provided the workforce with more cybersecurity training (which is also required in HIPAA training) to lessen the chance of related incidents later on.

Breach reports submitted by the impacted oncology physician practices are now being posted on the HHS’ Office for Civil Rights breach website. More will likely be added to the listing of affected entities below over the coming days.

  1. California Cancer Associates for Research and Excellence in High Desert, CA – 17,250 individuals affected
  2. Lake City Cancer Care, LLC in Florida – 15,142 individuals affected
  3. Lake City Cancer Care, LLC in Florida – 15,142 individuals affected
  4. Radiation Oncology Network of Southern California, LLC in California – 12,944 individuals affected
  5. Rocky Mountain Oncology Care in Wyoming – 10,268 individuals affected
  6. e+ Oncologics Louisiana, LLC in Los Angeles – 8,270 individuals affected
  7. California Cancer Associates for Research and Excellence in Fresno, CA – 7,670 individuals affected
  8. Southwest Urology in Ohio – 7,214 individuals affected
  9. PET Imaging of Northern Colorado in Colorado – 4,824 individuals affected
  10. Mojave Radiation Oncology Medical Group in California – 4,403 individuals affected
  11. Fairbanks Urology in Arkansas – 4,289 individuals affected
  12. South Georgia Center for Cancer Care in Georgia – 4,108 individuals affected
  13. PET Imaging of Tulsa in Oklahoma – 3,159 individuals affected
  14. PET Imaging of The Woodlands in Texas – 2,978 individuals affected
  15. Denali Biomedical in Arkansas – 2,413 individuals affected
  16. Acadiana Radiation Therapy, LLC in Los Angeles – 2,219 individuals affected
  17. Golden State Radiation Oncology in California – 2,130 individuals affected
  18. PET Imaging of Dallas Northeast in Texas – 1,935 individuals affected
  19. Orange County Radiation Oncology Medical Group in California -1,911 individuals affected
  20. PET Imaging of Sugar Land in Texas – 1,808 individuals affected
  21. PET Imaging of Houston Medical Center in Texas TX – 1,236 individuals affected
  22. Bardmoor Cancer Center in Florida – 991 individuals affected
  23. Cancer Care Center of North Florida in Lake Butler – 976 individuals affected
  24. California Cancer Associates for Research and Excellence in San Diego, California – 638 individuals affected

Total of individuals affected – 133,918

James Keogh

James Keogh has been writing about the healthcare sector in the United States for several years and is currently the editor of HIPAAnswers. He has a particular interest in HIPAA and the intersection of healthcare privacy and information technology. He has developed specialized knowledge in HIPAA-related issues, including compliance, patient privacy, and data breaches. You can follow James on Twitter https://x.com/JamesKeoghHIPAA and contact James on LinkedIn https://www.linkedin.com/in/james-keogh-89023681 or email directly at [email protected]