| Abbreviation | Definition |
|---|---|
| CMO | Center for Molecular Oncology |
| CMRO | Central Maryland Radiation Oncology |
| CMV | CytoMegalo Virus |
| CNA | California Nurses Association |
| CNB | Core Needle Biopsy |
| COA | Community Oncology Alliance |
| COC | Care Oncology Clinic |
| COCA | Children's Oncology Camping Association |
| COIN | Clinical Oncology Information Network |
| COMS | Collaborative Ocular Melanoma Study |
| CONFIRM | Colonoscopy versus Fecal Immunochemical Test In Reducing Mortality |
| COOF | Clinical Oncology Online Forums |
| COPE | Center for Oncology Psychology Excellence |
| COPTRG | Community Oncology and Prevention Trials Research Group |
| CORE | Cancer Outreach And Relief Effort |
| COS | Canadian Oncology Society |
| COTC | Comparative Oncology Trials Consortium |
| CPC | Choroid Plexus Carcinoma |
| CPCC | Chicago Prostate Cancer Center |
| CPHO | Clinical Pediatric Hematology Oncology |