minimal residual disease
Small number of leukemic cells remaining after treatment that are undetectable by standard microscopy but can be measured by sensitive molecular techniques.
Full Definition
Minimal residual disease (MRD) refers to the small number of leukemic cells that persist in patients who have achieved morphological remission after treatment for acute leukemia. These cells are below the detection threshold of conventional light microscopy (which can detect approximately 1 in 20 cells) but can be identified using more sensitive techniques such as flow cytometry or PCR-based methods that can detect 1 leukemic cell among 10,000-100,000 normal cells. In pediatric oncology, MRD assessment has become crucial for risk stratification and treatment decisions, as patients with persistent MRD have higher risk of relapse and may require intensified therapy.
Usage
Usage note: Abbreviate as MRD after first use; critical for modern leukemia treatment protocols.
In Context
- "Flow cytometric analysis detected minimal residual disease at 0.01% after induction chemotherapy." — Laboratory report
- "The patient's treatment plan was intensified based on positive minimal residual disease status at the end of induction." — Pediatric oncology team meeting