Screening programmes for the early detection and prevention of oral cancer
Abstract
Background
Screening programmes for major cancers, such as breast and cervical cancer have effectively decreased the mortality rate and helped to reduce the incidence of these cancers. Although oral cancer is a global health problem with increasing incidence and mortality rates, no national population‐based screening programmes for oral cancer have been implemented. To date there is debate on whether to employ screening methods for oral cancer in the daily routine work of health providers.
Objectives
To assess the effectiveness of current screening methods in decreasing oral cancer mortality.
Search methods
Electronic databases (MEDLINE, CANCERLIT, EMBASE (1966 to July 2005) and CENTRAL (The Cochrane Library 2005, Issue 3)), bibliographies, handsearching of specific journals and contact authors were used to identify published and unpublished data.
Selection criteria
Randomised controlled trials of screening for oral cancer or precursor oral lesions using visual examination, toluidine blue, fluorescence imaging or brush biopsy.
Data collection and analysis
The search found 112 citations and these have been reviewed. One randomised controlled trial of screening strategies for oral cancer was identified as meeting the review's inclusion criteria. Validity assessment, data extraction and statistics evaluation were undertaken by two independent review authors.
Main results
One 10‐year randomised controlled trial has been included (n = 13 clusters: 191,873 participants). There was no difference in the age‐standardised oral cancer mortality rates for the screened group (16.4/100,000 person‐years) and the control group (20.7/100,000 person‐years). Interestingly, a significant 34% reduction in mortality was recorded in high‐risk subjects between the intervention cohort (29.9/100,000 person‐years) and the control arm (45.4/100,000). However, this study has some methodological weaknesses. Additionally, the study did not provide any information related to costs, quality of life or even harms of screening from false‐positive or false‐negative findings.
Authors' conclusions
Given the limitation of evidence (only one included randomised controlled trial) and the potential methodological weakness of the included study, it is valid to say that there is insufficient evidence to support or refute the use of a visual examination as a method of screening for oral cancer using a visual examination in the general population. Furthermore, no robust evidence exists to suggest that other methods of screening, toluidine blue, fluorescence imaging or brush biopsy, are either beneficial or harmful. Future high quality studies to assess the efficacy, effectiveness and costs of screening are required for the best use of public health resources. In addition, studies to elucidate the natural history of oral cancer, prevention methods and the effectiveness of opportunistic screening in high risk groups are needed. Future studies on improved treatment modalities for oral cancer and precancer are also required.
PICOs
Plain language summary
Screening programmes for the early detection and prevention of oral cancer
More evidence needed to find out whether screening programmes could detect oral cancer earlier and reduce the number of deaths from this disease.
Cancer of the mouth and back of the throat (oral cancer) has a low survival rate, largely because the disease is often not diagnosed until it is advanced. Screening the general population for oral cancer might make it possible to detect cases of the disease earlier. The most common method is visual inspection by a clinician, but other techniques include the use of a special blue 'dye' and an imaging technique. The review found that there is not enough evidence to decide whether screening by visual inspection reduces the death rate for oral cancer, and no evidence for other screening methods.
