Measurable residual disease is the small number of cancer cells that can remain after treatment and are too few to see on routine tests. It is measured with sensitive laboratory methods rather than standard microscopy alone. It is most commonly used in blood cancers such as leukemia, lymphoma, and multiple myeloma. In some settings, similar “minimal disease” concepts are being explored in solid tumors using blood-based testing.

MRD stands for **measurable residual disease** (also called **minimal residual disease**). It describes **very small amounts of cancer** that may remain after treatment, even when standard tests look normal. MRD is most commonly discussed in **blood cancers** such as leukemia, lymphoma, and myeloma. It is also being studied and used in selected **solid tumors**, often through blood-based testing.

Minimal residual disease means a very small number of cancer cells that remain after treatment, even when tests show a complete response. It is most commonly discussed in blood cancers such as leukemia, lymphoma, and multiple myeloma. Minimal residual disease is measured using sensitive laboratory methods on blood or bone marrow samples. Clinicians use it to better understand relapse risk and the depth of response to therapy.

Clinical benefit rate is a way to summarize how many people’s cancers improve or stay controlled on a treatment. It usually counts tumor shrinkage and meaningful periods where the cancer does not grow. It is most commonly used as an outcome measure in oncology clinical trials and some research reports.

Objective response rate is a way to measure how many people’s cancers shrink or disappear after treatment. It is usually reported as a percentage of patients who have a complete or partial response. It is commonly used in cancer clinical trials and in oncology research reports. Clinicians may also reference it when discussing how treatments performed in studies.

Time to progression is a way of measuring how long a cancer stays controlled before it grows or spreads again. It is usually reported as a time interval, such as from the start of treatment until objective worsening is found. It is commonly used in oncology clinical trials, research studies, and some quality-improvement reporting. It helps describe treatment effect when overall survival is not yet known or is influenced by later therapies.

Disease-free survival is a way of describing how long a person remains free of detectable cancer after treatment. It is most often used after treatment given with curative intent, such as surgery with or without additional therapy. Clinicians and researchers use it to track recurrence risk over time and to compare treatments in studies. It is commonly reported in oncology clinic follow-up discussions and in clinical trial results.

Event-free survival is a way to measure how long a person remains free of a defined “event” after diagnosis or treatment. An “event” can mean cancer progression, relapse, a second cancer, or death, depending on the study. Event-free survival is commonly used in cancer clinical trials and treatment-outcome reporting. It helps clinicians and researchers compare how well different treatment approaches control cancer over time.

Progression-free survival is the length of time a person lives with cancer without the cancer getting worse. It is commonly used as an outcome measure in oncology clinical trials and in routine cancer follow-up. “Getting worse” usually means the tumor grows, new lesions appear, or cancer-related symptoms and findings clearly progress. Progression-free survival helps describe how long a treatment can keep a cancer under control.

Overall survival is the length of time people are alive after a defined starting point, such as cancer diagnosis or start of treatment. It counts death from any cause, not only death from cancer. Overall survival is widely used in cancer clinical trials and in oncology outcome reporting. It helps clinicians, researchers, and patients understand how treatments and disease factors relate to life expectancy in a population.