ORR
Medical abbreviation · Hematology and Oncology
| Stands for | Objective response rate |
|---|---|
| Categories | Medical |
ORR stands for Objective response rate, a hematology and oncology abbreviation.
Proportion of patients whose tumors shrink by a predefined amount, the sum of complete and partial responses under criteria such as RECIST. It is a common end point in early-phase and single-arm trials.
Example: ORR 42% (5% complete, 37% partial) with median duration of response 11 months.
Usage notes
Response rate shows drug activity quickly and is often the basis for accelerated approval of targeted therapies with dramatic tumor shrinkage, but a response does not necessarily mean longer life. Duration of response (DOR) is reported alongside it. Stable disease is not counted, although disease control rate (DCR) includes it.
Related abbreviations
More hematology and oncology abbreviations
- NCI – National Cancer Institute
- NED – No evidence of disease
- NET – Neuroendocrine tumor
- NGS – Next-generation sequencing
- NHL – Non-Hodgkin lymphoma
- NSCLC – Non-small cell lung cancer
- OS – Overall survival
- PCI – Prophylactic cranial irradiation
- pCR – Pathologic complete response
- PD – Progressive disease
- PD-1 – Programmed cell death protein 1
- PD-L1 – Programmed death-ligand 1
See all 144 hematology and oncology abbreviations →
This entry is for general education and is not medical advice. Abbreviation use varies between institutions; always confirm in context.