Mortality due to cancer treatment delay: systematic review and meta-analysis.

OBJECTIVE: To quantify the association of cancer treatment delay and mortality for each four week increase in delay to inform cancer treatment pathways. DESIGN: Systematic review and meta-analysis. DATA SOURCES: Published studies in Medline from 1 January 2000 to 10 April 2020. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Curative, neoadjuvant, and adjuvant indications for surgery, systemic treatment, or radiotherapy for cancers of the bladder, breast, colon, rectum, lung, cervix, and head and neck were included. The main outcome measure was the hazard ratio for overall survival for each four week delay for each indication. Delay was measured from diagnosis to first treatment, or from the completion of one treatment to the start of the next. The primary analysis only included high validity studies controlling for major prognostic factors. Hazard ratios were assumed to be log linear in relation to overall survival and were converted to an effect for each four week delay. Pooled effects were estimated using DerSimonian and Laird random effect models. RESULTS: The review included 34 studies for 17 indications (n=1 272 681 patients). No high validity data were found for five of the radiotherapy indications or for cervical cancer surgery. The association between delay and increased mortality was significant (P