Objectives: To examine the relative length of the patient and primary care intervals in symptomatic oral cancer.Design: Quantitative systematic review. Search strategy: Oral cancer OR oral squamous cell carcinoma OR oropharyngeal cancer AND time interval OR diagnostic delay.Setting: Primary and secondary care.Participants: Oral and oropharyngeal cancer patients. Main outcome measures:We computed five measures (patient, primary care, diagnosis, total diagnosis and total treatment intervals). Most studies did not provide any dispersion measure. We then used the sample size of each study to compute a weighted average of the mean intervals. When the median was provided, we assumed normality of the distribution of the means and used the median as a proxy of the mean.Results: A total of 1089 articles were identified, and 22 met the inclusion criteria, reporting on 2710 patients from Europe, USA, India, Australia, Japan, Argentina and Iran. The weighted average of patient interval was 80.3 days. Primary care interval was five times shorter: 15.8 days. The diagnostic interval was appreciably shorter (47.9 days) when compared with the patient interval during symptomatic period.Conclusions: Patient interval represents the major component of waiting times since the detection of the first signs/symptoms to the definitive diagnosis of oral cancer. Thus, strategies focused on high-risk patients should be prioritised. Interventions aimed at optimising the health systems should be implemented by monitoring and facilitating diagnostic and treatment pathways of patients with oral cancer.

Specialist time interval is a short time interval in oral cancer diagnosis, imposing a limited time burden in the context of the whole interval until diagnosis. However, there seems to be room for improvement and a possible target for future interventions to shorten STI particularly for patients at early stages after their disease has been disclosed.