The length of time from either the date of diagnosis or the start of treatment for a disease, such as cancer, that half of the patients in a group of patients diagnosed with the disease are still alive. In a clinical trial, measuring the median survival is one way to see how well a new treatment works. Also called median overall survival.

Example:

Median survival of glioblastoma, the most aggressive variant, is 16 months in patients treated with maximum safe resection, radiotherapy, and concurrent and adjuvant temozolomide in clinical trial populations 1) 2).

1)
Stupp R, Mason WP, van den Bent MJ et al. Radiotherapy plus concomitant and adjuvant temozolomide for glioblastoma. N Engl J Med. 2005;352 (10):987–996.
2)
Weller M, van den Bent M, Hopkins K et al. EANO guideline for the diagnosis and treatment of anaplastic gliomas and glioblastoma. Lancet Oncol. 2014;15 (9): e395–e403.