PubMed Health⌕ Search

Biomedical subjects

Martin C Downer

Publications and source records attributed to Martin C Downer.

5 recordsLinked to original sources
PubMed2006

A systematic review of measures of effectiveness in screening for oral cancer and precancer.

Nine databases were searched for studies reporting a range of measures on the effectiveness of screening for oral cancer and precancer in primary care. Of 1114 papers generated in a search of nine databases, full texts of 90 were scrutinised by two reviewers to ensure that they were concerned with oral cancer/precancer, reported an oral cancer screening programme/exercise and included at least one effectiveness outcome. Criteria for considering studies for the review covered types of studies, participants, interventions and outcome measures. The latter included measures of both end point and interim outcome and also process. Of 90 full text articles screened, examiners agreed on the inclusion of 28 (initial agreement -- kappa=0.60). The remaining 62 were excluded and the reasons recorded. The studies included showed substantial heterogeneity regarding objectives and study design, location and setting, numbers and characteristics of participants, screening personnel, methods of recruitment and types of data collected. Only one study, from the Indian sub-continent, reported a randomised controlled trial: interim results showed 14.9% of intervention subjects died after 3 years compared with 56.3% of non-intervention controls. The review overall produced no evidence in favour of or against the potential benefits associated with an oral cancer screening programme. It was concluded that there are insufficient available data to make an unequivocal determination as to the effectiveness of oral cancer screening programmes at the present time. However, a recent further report on the Indian study published after completion of the review, provides some evidence that screening for oral cancer may be effective, at least in developing countries with a high incidence of the disease.

Humans↗
PubMed2005

Leukoplakia prevalence estimate lower than expected.

DATA SOURCES: Data were sourced using Medline and Embase. STUDY SELECTION: Initial selection criteria were that study samples should be representative of the underlying adult population and that the leukoplakia diagnostic criteria used by the examiners should have been widely accepted ones. Because most published studies did not comply with these requisites, modified criteria were as follows. First, the sample, even if not representative of the underlying study population, should not have been collected from surgical departments of dental hospitals or clinics, where leukoplakia is usually treated (these studies would overestimate the disease prevalence). Secondly, even if the examiners were not calibrated, the diagnostic criteria used should be consistent with the internationally accepted criteria and must have been reported in the text. Thirdly, to make statistical analysis possible even if leukoplakia prevalence was not reported as a proportion, the overall number of sampled subjects and the number with the condition must be easy to extrapolate with a high level of accuracy. DATA EXTRACTION AND SYNTHESIS: Data were pooled using inverse variance weighting and random-effect methods. A sensitivity analysis was performed. RESULTS: A total of 23 primary studies was included, giving point-prevalence estimates with the inverse variance method of 1.49% [95% confidence interval (CI), 1.42-1.56] and 2.60% (95% CI, 1.72-2.74) with the random-effects method. The high between-study heterogeneity and the sensitivity analyses suggested that the second estimate was more reliable. Leukoplakia was significantly more prevalent in males (prevalence ratio, 3.22), but no difference was found between geographical areas and between younger and older adults. Using these data, the crude annual oral cancer incidence rate attributable to leukoplakia would be between 6.2 and 29.1 cases per 100 000 people. CONCLUSIONS: The pooled leukoplakia prevalence estimate was lower than expected. The estimated oral cancer incidence rate due to leukoplakia malignant transformation was high, however, and suggested that the global number of oral cancer cases is probably under-reported, particularly in developing countries.

Comment↗
PubMed2004

A systematic review of test performance in screening for oral cancer and precancer.

Nine databases were searched for studies on test performance in screening for oral cancer and precancer in primary care. Of 481 papers, full texts of 47 were scrutinised by two reviewers. Only prospective investigations of population screening involving examination of the oral mucosa, with gold standard verification (examination by an expert of subjects screened positive and at least a proportion of negatives), were selected. Seven papers describing eight studies were finally included (kappa=0.83). The weighted pooled value of sensitivity, from random effects meta-analysis, was 0.848 (95% CI 0.730, 0.919). The corresponding value for specificity was 0.965 (95% CI 0.930, 0.982). Main sources of clinical heterogeneity occurred between large house-to-house case finding programmes from SE Asia, utilising primary health workers, and smaller studies from England and Japan. Meta-analysis regression showed no difference (P=0.99) in the generally high level of discriminatory ability of the test between these two groups.

Area Under Curve↗
PubMed2004

A comparison of yield in a non-systematic and a systematic review.

OBJECTIVES: To compare the results of a non-systematic (A) and a systematic review (B) of test performance in oral cancer and precancer screening in terms of literature coverage, and qualitative and quantitative information yield. METHOD: For A, two databases were searched using basic search terms. Review B followed published guidelines. Nine databases were searched using three complex facets. In both reviews, one reviewer made the initial selection of relevant studies and, in A, carried out full text screening. In B, two independent reviewers carried out full text screening and then conferred on a final list of studies for inclusion and meta-analysis. RESULTS: In search A, 60 papers, and in B, 481 papers, were retrieved. Thirty from A, and 47 from B were selected for full text screening. From A, six papers, and from B, eight papers (six selected by the first reviewer and eight by the second; kappa = 0.83), were designated for inclusion in meta-analysis. The six papers from A were common to all selections. Seven papers were finally included in B. Compared with the non-systematic review, meta-analysis in the systematic review reduced the 95% CI for sensitivity from 0.594, 0.912 (= 0.318) to 0.713, 0.919 (= 0.189) resulting from the inclusion of a larger number of verified cases. The 95% CI for specificity changed only from 0.941, 0.991 (= 0.050) to 0.930, 0.982 (= 0.052). DISCUSSION: Both reviews had the same exacting and specific inclusion criteria. The papers ultimately included in each were closely matched. Advantages of the systematic review were 1) it afforded a degree of confidence that the literature had been exhaustively and systematically searched, 2) the use of a formal data extraction process ensured that clinical heterogeneity among the studies and its consequences were thoroughly explored, 3) the increased number of verified cases included in the systematic review meta-analysis led to the pooled estimate for sensitivity having greater precision.

Confidence Intervals↗