Daniel O'Neil

Dr. Daniel O’Neil, MD, MPH, is an Assistant Clinical Professor of Medicine (Medical Oncology) at Yale School of Medicine and a clinical member of Yale Cancer Center. He specializes in breast cancer care at Smilow Cancer Hospital and focuses on global oncology research in low-resource settings. Affiliated with the Yale Institute for Global Health, his work emphasizes improving breast cancer care quality in sub-Saharan Africa and understanding HIV’s impact on breast cancer outcomes.

Education & Training:

• MD: Albert Einstein College of Medicine
• MPH in Epidemiology: Harvard T.H. Chan School of Public Health
• Residency: Brigham and Women’s Hospital (Internal Medicine & Global Health Equity)
• Fellowship: Columbia University Irving Medical Center (Hematology/Oncology)

Research Interests: Dr. O’Neil investigates breast cancer care quality in low- and middle-income countries, particularly addressing treatment delays, adherence to therapies, and comorbid HIV’s role in mortality disparities. He collaborates with South African and Rwandan teams to adapt US/European quality metrics to local contexts.

Recent Article Trends: His work highlights disparities in breast cancer survival linked to HIV co-infection, identifies systemic barriers to timely care in resource-limited settings, and explores tumor biology differences in HIV-positive patients. Key themes include global health equity, oncology quality measurement, and interdisciplinary approaches to cancer care.

Grants/Labs: Engaged in projects funded by NIH and global health organizations, focusing on implementation science and clinical trials in sub-Saharan Africa. Collaborates with Johannesburg and New Haven teams on tumor-immune interaction studies in HIV-positive breast cancer patients.

Labs/Teams: Active in the Yale Cancer Center’s Global Oncology group and the South African Breast Cancer and HIV Outcomes Study consortium.