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Biomedical subjects

C G Cowan

Publications and source records attributed to C G Cowan.

16 recordsLinked to original sources
PubMed2005

Regional variations in oral cancer incidence in Ireland.

Oral cancer has anecdotally been held to have a regional distribution in Ireland, with higher incidence rates in western areas. The first all-Ireland data sets on oral cancer incidence rates were recently published by cancer registries in Northern Ireland and the Republic of Ireland, for the years 1994-1998 and 1994-1997 respectively. The objective of this study was to analyse these rates according to the 12 health administrative regions on the island of Ireland. All rates were standardised to the world population using standard methodology, and were examined separately for lip, intra-oral, salivary and pharyngeal cancers for men and for women. Rates were mapped to highlight any regional variations. In general, the anecdotal evidence for higher incidences in the west of Ireland has not been borne out, except for lip cancers in men, which in turn is reflected in the slight western preponderance in the distribution of all oral cancers. The incidences of intra-oral cancers in both men and women were highest in the regions that include the two large conurbations (Belfast and Dublin). We conclude that the anecdotal evidence for a higher incidence of oral cancer in the west of Ireland was probably based on the distorting effect of the high incidences of lip cancer in men in these regions.

Female↗
PubMed2003

Potentially malignant oral lesions in Northern Ireland: size (extent) matters.

OBJECTIVES: We examined clinical parameters of patients from Northern Ireland with potentially malignant lesions (PML) to determine association with development of intraoral squamous cell carcinoma (SCC). DESIGN: retrospective, cross-sectional, population-based, clinically validated, laboratory-verified. SUBJECTS AND METHODS: All patients who had more than one incisional oral mucosal biopsy diagnosed from 1975-1991 were abstracted from a database of all PML and SCC and their clinical records and biopsies reviewed. Patients were excluded if there was priorlsynchronous SCC or radiotherapy, frictional keratosis or lichen planus, missing clinical records/biopsy material or follow-up of <24 months. From the 50 suitable patients, gender, age, smoking status, site, clinical appearance and extent of lesion(s), treatment and year of diagnosis were recorded. Patients who developed SCC from PML were compared with those who did not. RESULTS: Squamous cell carcinoma occurred significantly more often in patients with single rather than multiple PML, those with 'non-homogenous' PML and in patients diagnosed prior to 1980. In Cox's survival analysis, only the clinical extent was predictive of SCC. CONCLUSIONS: Of all the features considered in our series, size (extent) was the most important clinical factor in determining the risk of future SCC in PML, particularly when several adjacent anatomical sites were affected.

Adolescent↗
PubMed2002

Paradental cysts: a role for food impaction in the pathogenesis? A review of cases from Northern Ireland.

We present the clinical, radiographic and histological findings of 15 paradental cysts. These were the second most common type of cyst associated with mandibular third molars, comprising 25% of all lesions at this site. Ten patients were aged 30 years or younger and 13 gave a history of pericoronitis. There was a close relationship between the site of the cyst and the angle of the impacted tooth; the cyst lay mesially to two mesioangularly impacted teeth, buccal to two vertically impacted teeth and distal/distobuccal to the remainder, all but one of which were distoangular in impaction. The pericoronal follicular space was preserved in nine cases, a useful diagnostic sign. Most cysts were lined with epithelium that resembled that seen in radicular cysts, although the lining of three cysts resembled that of unicystic ameloblastoma, a potential diagnostic pitfall. We propose that the relation between location of cyst and angle of impaction points to a role for food impaction in the pathogenesis of paradental cysts.

Adolescent↗
PubMed2002

Suprabasal p53 immunoexpression is strongly associated with high grade dysplasia and risk for malignant transformation in potentially malignant oral lesions from Northern Ireland.

AIMS: No good predictive marker for the malignant transformation of potentially malignant oral lesions (PMOLs) is currently available. This study re-evaluated the value of p53 immunoexpression to predict malignant transformation of PMOLs after discounting possible confounding factors. METHODS: PMOLs from 18 patients who showed progression to carcinoma, 16 of the respective carcinomas, and PMOLs from 18 matched controls were evaluated by immunohistochemistry (IHC) for p53 expression. A mouse monoclonal antibody that detects wild-type and mutant forms of human p53 was used. The p53 immunostaining pattern was also correlated with the degree of dysplasia. RESULTS: Suprabasal p53 staining was significantly associated with high grades of dysplasia (p < 0.01). The specificity and positive predictive value (PPV) for malignant transformation of suprabasal p53 staining were superior to the assessment of dysplasia, but sensitivity was inferior. All carcinomas derived from PMOLs with suprabasal p53 showed strong p53 immunostaining. However, the absence of suprabasal p53 staining and/or dysplastic changes did not preclude malignant transformation in a considerable proportion of PMOLs. CONCLUSIONS: This study confirms and extends previous findings that suprabasal p53 immunoexpression has a high PPV for malignant transformation of PMOLs and can be used as a specific marker for lesions that are at high risk for malignant transformation. The absence of suprabasal p53 staining (that is, absence of, or basal, p53 staining) is non-informative for prognostic purposes. Because of its limited sensitivity, p53 IHC is not a substitute for the assessment of dysplasia in the evaluation of PMOLs. Instead, p53 IHC emerges as a clinically useful supplement of histopathological assessment in the prognosis of PMOLs.

Adult↗
PubMed2001

Potentially malignant oral lesions in northern Ireland: a 20-year population-based perspective of malignant transformation.

This retrospective laboratory-based study investigates the potential for malignant transformation of oral mucosal lesions in a population of 1.6 million. Over the 20-year period there were 745 patients diagnosed with primary intra-oral squamous cell carcinoma (OSCC), 165 patients with dysplasia and 1182 patients with 'non-dysplastic' lesions (epithelial hyperplasia, hyperkeratosis epithelial atrophy, lichen planus and lupus erythematosus). Malignant transformation occurred in 15% of dysplasias and in 1% of 'non-dysplastic' lesions at average intervals after diagnosis of 48 and 65 months respectively. Only 6% of patients with OSCC had a pre-invasive lesion biopsied. These data suggest that white lesions are only rarely the pre-invasive phase of OSCC. It is possible therefore that early changes are red, small or even microscopic with carcinoma developing without a clinically observable phase. More effective management strategies will require the development of tissue markers to enhance early detection.

Adult↗
PubMed2000

Bcl-2 expression in sequential biopsies of potentially malignant oral mucosal lesions assessed by immunocytochemistry.

OBJECTIVE: To examine, for the first time Bcl-2 expression in sequential (autogenous) oral mucosal biopsies taken from the same sites in a gender, risk-factor matched, Caucasoid sample, over a 21-year period. DESIGN: Retrospective immunocytochemical longitudinal study of archival serial biopsies. MATERIALS AND METHODS: Computer records were used to identify biopsy specimens derived from 12 patients. These were divided into four groups: (1) Histologically innocuous lesions which remained histologically innocuous. (2) Dysplastic lesions which remained dysplastic. (3) Histologically innocuous lesions which later progressed to squamous cell carcinoma (SCC). (4) Dysplastic lesions which later progressed to SCC. This represented 65 biopsies in total. Bcl-2 expression was studied using mouse antihuman BCL-2 oncoprotein clone 124 (Dako, Denmark). RESULTS: Generally, there was a lack of Bcl-2 immunoreactivity in the epithelium, with one exception in dysplastic epithelium from a group (3) patient. CONCLUSION: These findings suggest that in our series, Bcl-2 is not expressed early in oral premalignant lesions and appears to contradict previous reports. Possible explanations for this disparity are considered.

Adult↗
PubMed1999

Antioxidant status of oral mucosal tissue and plasma levels in smokers and non-smokers.

The antioxidant status of an individual is thought to be important in the development of potentially malignant oral lesions (PMOL) and oral squamous cell carcinoma (OSCC). To date, little detailed information on mucosal antioxidant status is available in a United Kingdom population and neither has the relationship between smoking and mucosal antioxidant status been established. Furthermore, it has been implied that serum levels of antioxidants and tissue levels in the oral mucosa should be equivalent, but that is unproven. To address these deficiencies in our knowledge we studied 60 individuals, all of whom had an oral mucosal biopsy and simultaneous venous blood sampling. Antioxidant levels were measured using high performance liquid chromatography. Smokers (n= 19) were found to have significantly lower levels of plasma beta-carotene (P<0.05) and significantly lower levels of tissue alpha-carotene (P<0.05) than non-smokers (n=41). Tissue alpha-carotene correlated with plasma levels, but this was not the case with alpha-tocopherol, retinol, lycopene or beta-carotene. This is the first data on oral mucosal antioxidant levels and provides baseline data from which to study patients with potentially malignant oral lesions and oral squamous cell carcinoma.

Adolescent↗
PubMed1998

A comparison of the management of potentially malignant oral mucosal lesions by oral medicine practitioners and oral & maxillofacial surgeons in the UK.

This study describes the results of a survey undertaken to assess the management of potentially malignant oral mucosal lesions by oral medicine practitioners and compares their approach with that of oral & maxillofacial surgeons that we have previously described. Significant differences were noted between the two groups in the use of photography to document the lesions and in the use of certain special investigations, which included measurement of serum iron, serum ferritin, serum Vit B12, red cell folate and candidal isolation. The groups also varied in the perceived importance of the age of the patient and anatomical site of the lesion when deciding on the need for further biopsy. There was also significant variation in the use of certain treatment modalities, including excising non-dysplastic and severely dysplastic/carcinoma in-situ lesions and eliminating trauma when treating mild/moderately dysplastic and severely dysplastic/carcinoma in-situ lesions. Significant differences in the frequency and duration of follow-up were noted for non-dysplastic lesions. Finally, the two groups differed significantly when asked to rank the perceived importance of certain factors (the histopathology of the most recent biopsy and the anatomical site of the lesion) when deciding the need to follow-up. Possible reasons for the variation are discussed.

Age Factors↗
PubMed1996

Management of potentially malignant oral mucosal lesions by consultant UK oral and maxillofacial surgeons.

This paper describes the results of a recent survey carried out under the auspices of the Professional Education and Evaluation Subgroup of the UK Working Group on Screening for Oral Cancer and Precancer. The aim of this survey was to assimilate information regarding currently used management options of potentially malignant oral lesions as a basis from which to rationalise our future approach to their management. The survey has confirmed that variation exists among oral and maxillofacial consultants in their approaches and a more formal approach to management may therefore be indicated.

Data Collection↗
PubMed1995

Prevention and detection of oral cancer: the views of primary care dentists in Northern Ireland.

Our objective was to describe the management of oral cancer and pre-cancer as stated by primary care dentists and their views on screening. We conducted a survey of all general dental practitioners and community dentists in Northern Ireland (n = 635), to which 428 replied (response rate: 67%). 94% stated that examination of the oral soft tissues constituted part of their usual practice during the regular dental check-up. Suspicious lesions were generally referred early, 68.5% of dentists referring white lesions within one month of presentation. The corresponding figures for red lesions, lumps and persistent ulcers were 80.1%, 89.7% and 91.7%. The incidence of oral cancer was over-estimated (median '70' cases/year, versus the true figure of approximately 40/year) as, in all likelihood, was the percentage by which mortality could be reduced by screening (median: 50%). Accordingly the adoption of a screening programme was favoured over investment in health promotion. Indeed, only 14% said that their patients records routinely contained information about smoking or alcohol habits. Although there are some areas of practice which could improve and the potential of screening is probably over-valued, primary care dentists in Northern Ireland already opportunistically screen and refer patients promptly.

Alcohol Drinking↗
PubMed1995

Linear IgA disease (LAD): immunoglobulin deposition in oral and colonic lesions.

Two cases of adult linear IgA disease (LAD) with oral and colonic involvement are presented. Oral findings, for both patients, were of widespread painful ulceration present for two to three months and diagnosis was confirmed by biopsy and direct immunofluorescence. Colonic symptoms preceded oral symptoms in both cases and a number of investigations were undertaken, including routine histological examination, which suggested either lymphocytic colitis or Crohn's disease. Immunofluorescence studies showed linear IgA deposition confined to the distal colon. These cases highlight that large bowel involvement can be a feature of linear IgA disease and for the first time demonstrate IgA deposition at that site.

Aged↗
PubMed1992

Trends in the relative frequency of histologically diagnosed epithelial dysplasia and intra-oral carcinoma in Northern Ireland, 1975-1989.

Trends in the incidence of histologically diagnosed dysplastic lesions of the intra-oral mucosa have been investigated for the period 1975-89 in a well defined population of 1.5 million. These have been contrasted and compared with trends in the incidence of intra-oral carcinoma. Cases were ascertained from the records of all the histopathology laboratories that serve the Northern Ireland population. Over the 15-year period, there were 135 cases of histologically diagnosed epithelial dysplasia. In contrast to the significant increase in the incidence of intra-oral carcinoma, there was no significant change in the annual age standardised incidence of dysplastic lesions over the period. The ratio of malignant to dysplastic diagnoses rose from 2.5:1 to 5.4:1. Only 24 of the dysplastic lesions were known to have subsequently progressed to malignant carcinoma, representing 4.5% of all invasive tumours diagnosed during 1975-89. The results highlight a number of unresolved issues regarding the natural history of intra-oral carcinoma.

Adolescent↗
PubMed1992

Trends in the incidence of histologically diagnosed intra-oral squamous cell carcinoma in Northern Ireland, 1975-89.

Studies in Britain point to a rise in the incidence of intra-oral cancer in the last 20 years, paralleling trends evident in other European countries. Cases of histologically-diagnosed primary intra-oral squamous cell carcinoma have been ascertained by reviewing the records of pathology departments in Northern Ireland. Trends in the incidence of the disease have been determined for the period 1975-89. There has been a significant increase in the incidence among men, rising from 1.78 to 3.14 per 100,000. In women over the same period the incidence rose from 0.87 to 1.19 per 100,000, but this change was not significant. These trends concur with recent findings from other countries.

Adult↗
PubMed1980

Traumatic bone cysts of the jaws and their presentation.

Two cases of traumatic bone cyst of the mandible are reported exhibiting a considerable variation in their presentation and pathogenesis. This spectrum of behaviour is discussed and comparison made with the solitary unicameral bone cyst.

Adolescent↗