Authors' objectives

The authors aimed to assess the effectiveness and cost-effectiveness of toluidine blue dye as an adjunct to visual screening for oral cancer in primary dental care. They found limited studies in primary care so, in actuality, the authors included mostly studies from secondary care.

Searching

MEDLINE, PubMed and the Cochrane Library were searched from 1955 to 1999; the search terms used were listed. The authors also checked the reference lists from identified studies. There were no language restrictions. An unpublished study was obtained from an expert in the field.

Study selection

Assessment of study quality

The authors used a checklist of validity criteria to assess the study design, setting, blinding, calibration and inter-examiner reproducibility. One reviewer assessed the papers according to the checklist, while a second reviewer checked 10% of the validity assessments.

Data extraction

Two reviewers independently extracted the data. Data were extracted on the study type, number of participants, population, age of participants, setting, dye technique used, and the number of participants with oral carcinoma and dysplasia.

Methods of synthesis

Results of the review

Fifteen studies were included in the review; the number of participants was not specified in all studies. Fourteen published case series assessed the use of toluidine blue dye in secondary care (2,937 lesions). One unpublished prospective cohort study assessed the acceptability of toluidine blue dye for people in primary care (140 participants).

The authors found no evidence that toluidine blue dye is an effective or cost-effective strategy for identifying oral cancer in primary care. In secondary care, the reported sensitivity ranged from 40 to 100% and the reported specificity ranged from 31 to 91%. For every person cured using toluidine blue dye as an adjunct to clinical examination, 45,000 people would receive a false-positive result. The authors suggested that this is likely to generate substantial anxiety.

Cost information

The authors estimated that it would cost £2,080,000 to screen 100,000 people with toluidine blue dye. If 5-year survival is used as a proxy measure of cure, the cost would be £2,872,333 per person cured. The authors noted that this may be an underestimate and that it does not consider the costs of treatment.

Authors' conclusions

There is little evidence that toluidine blue dye is a cost-effective method for identifying oral cancer in primary dental care.

CRD commentary

The authors used standardised procedures to assess the relevance and validity of the included studies, and described the validity assessment and data extraction in some detail. However, while the research question was clearly defined, the authors included data that did not relate to this research question. Most of the studies included in the review focused on secondary care, although the stated focus was primary care. The authors acknowledged that the findings may not be generalisable to general dental practice, but inserting figures from secondary care may confuse the issue.

The authors searched a number of bibliographic databases without applying any language restrictions. However, the strategy used to search for unpublished material may have been limited: apart from one study brought to the reviewers' attention by an expert in the field, the authors do not appear to have searched for unpublished studies. As the only study with a primary care focus was unpublished, the review may have benefited from a broader search for unpublished literature.

The authors did not identify studies on the effectiveness of toluidine blue dye in primary care and, consequently, concluded that toluidine blue dye is not effective in primary care. However, a lack of research on the topic does not demonstrate that the dye is ineffective, so this conclusion should be interpreted with caution. A conclusion that there was insufficient evidence to assess the effectiveness of toluidine blue dye as an adjunct to visual examination in primary dental care may have been more valid. Finally, the cost data were based on the reviewers' own assumptions and calculations, rather than trials or other studies.

Implications of the review for practice and research

Practice: The authors suggested that toluidine blue dye should not be used routinely to detect oral cancer in general dental practice. Toluidine blue dye may, however, be useful when assessing high-risk populations.

Research: The authors suggested that further research into toluidine blue dye as an adjunct to visual examination in primary dental care is unlikely to be an effective use of resources.

Funding

The review was conducted by people funded by the NHS.

Bibliographic details

Gray M, Gold L, Burls A, Elley K. The effectiveness of toluidine blue dye as an adjunct to oral cancer screening in general dental practice. Birmingham: University of Birmingham, Department of Public Health and Epidemiology. West Midlands Development and Evaluation Service Report; 24. 2000.

Original Paper URL

http://www.birmingham.ac.uk/Documents/college-mds/haps/projects/WMHTAC/REPreports/2000/toludine_blue.pdf

Indexing Status

Subject indexing assigned by CRD

MeSH

Coloring Agents /diagnostic use; Mouth Neoplasms /diagnosis; Tolonium Chloride /diagnostic use

AccessionNumber

12001008228

Database entry date

30/06/2004

Record Status

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.