A systematic review and meta-analysis of studies on cancer treatment delay and mortality found that a four-week delay in treatment is associated with increased mortality across seven major cancer types: bladder, breast, colon, rectum, lung, cervix, and head and neck. The study analyzed data from 34 studies involving 1,272,681 patients. For surgery, each four-week delay was linked to a 6-8% increase in mortality risk. For radiotherapy, a four-week delay was associated with a 9% increased risk for head and neck cancer and a 13% increased risk for adjuvant systemic treatment for colorectal cancer. Systemic treatment showed varied effects, with hazard ratios ranging from 1.01 to 1.28. The study emphasized the importance of minimizing system-level delays in cancer treatment initiation to improve population-level survival outcomes. It also highlighted the need for standardized estimates of treatment delay effects for most treatment indications. The findings suggest that even a four-week delay in treatment can significantly impact mortality, and longer delays have even greater consequences. The study underscores the importance of addressing system-level delays to enhance cancer care outcomes. The results are particularly relevant in the context of the COVID-19 pandemic, where delays in treatment have been observed. The study recommends policies focused on reducing delays to improve survival outcomes. The analysis also noted that the impact of treatment delay on mortality is not fully understood, and further research is needed to explore the effects of delays on local control, functional outcomes, and quality of life. The study concludes that minimizing system-level delays in cancer treatment initiation is crucial for improving population-level survival outcomes.A systematic review and meta-analysis of studies on cancer treatment delay and mortality found that a four-week delay in treatment is associated with increased mortality across seven major cancer types: bladder, breast, colon, rectum, lung, cervix, and head and neck. The study analyzed data from 34 studies involving 1,272,681 patients. For surgery, each four-week delay was linked to a 6-8% increase in mortality risk. For radiotherapy, a four-week delay was associated with a 9% increased risk for head and neck cancer and a 13% increased risk for adjuvant systemic treatment for colorectal cancer. Systemic treatment showed varied effects, with hazard ratios ranging from 1.01 to 1.28. The study emphasized the importance of minimizing system-level delays in cancer treatment initiation to improve population-level survival outcomes. It also highlighted the need for standardized estimates of treatment delay effects for most treatment indications. The findings suggest that even a four-week delay in treatment can significantly impact mortality, and longer delays have even greater consequences. The study underscores the importance of addressing system-level delays to enhance cancer care outcomes. The results are particularly relevant in the context of the COVID-19 pandemic, where delays in treatment have been observed. The study recommends policies focused on reducing delays to improve survival outcomes. The analysis also noted that the impact of treatment delay on mortality is not fully understood, and further research is needed to explore the effects of delays on local control, functional outcomes, and quality of life. The study concludes that minimizing system-level delays in cancer treatment initiation is crucial for improving population-level survival outcomes.