No abstract

Sixty-six patients with oral submucous fibrosis were followed-up for a period of 17 yr (median observation 10 yr) in Ernakulam District, Kerala, India. Oral cancer developed in five (7.6%) patients. The malignant transformation rate in the same sample was 4.5% over a 15-yr observation period (median 8 yr). These findings impart a high degree of malignant potential to this condition.

A case-control study to elucidate the etiology of oral submucous fibrosis was conducted in Bhavnagar, Gujarat. Sixty consecutively arriving oral submucous fibrosis patients at a dental clinic were selected as cases. An equal number of controls matched for age, sex, religion and socioeconomic status were selected from individuals who did not exhibit any oral mucosal lesion or condition. Among cases, 98% chewed areca nut regularly in one form or the other whereas among controls 35% chewed areca nut, giving an overall relative risk of 109.6. Areca nut chewing was practiced most commonly in the form of mawa: a mixture containing mainly areca nut (over 90% by weight), some tobacco, and a few drops of lime. Mawa chewers and those who chewed mawa along with other chewing habits showed very high relative risks. The relative risks increased with increase in the frequency as well as the duration of chewing habits. In a bivariate analysis the effect of frequency and duration of chewing appeared to be multiplicative. The present findings confirm areca nut as the most important etiologic factor in oral submucous fibrosis.

Oral submucous fibrosis (OSF) is a high risk precancerous condition, predominantly affecting Indians. Consumption of chilli was hypothesized as an etiologic factor on the basis of ecological observations and a solitary animal experimental study. Subsequent epidemiologic studies that included case-series reports, large cross-sectional surveys, case-control studies, cohort and intervention studies have identified areca nut as the major etiologic agent. Tissue-culture studies involving human fibroblasts, areca nut extracts and areca nut alkaloids supported this etiologic hypothesis by showing fibroblastic proliferation and increased collagen formation. Currently, the role of genetic susceptibility and that of autoimmunity are receiving attention. The influence of nutritional factors, if any, remains unclear.

Pindborg JJ, Murti PR, Bhonsle RB, Gupta PC, Daftary DK, Mehta FS: Oral submucous fibrosis as a precancerous condition. Scand J Dent Res 1984; 92: 224-9.Abstract -An evaluation of the malignant potential of submucous fibrosis, based on observations of 89 patients with the disease in Ernakulam District, Kerala, India was done. Out of the 89 patients, 12 were referred patients and 77 were diagnosed in population based studies. At the time of first examination oral cancer was found to be coexistent in nine (10%) cases. For 66 patients follow-up observations ranging from 4 to 15 yr (median 8 yr) were available. During this period malignant transformation was observed in three patients (4.5%). Considering malignant transformation and coexistence together, oral cancer was observed in 13% of the present material. Leukoplakia was found in 26% of the patients with submucous fibrosis. Out of 42 submucous fibrosis patients biopsied, 12% showed squamous cell carcinoma, 26% epithelial dysplasia, and 76% atrophic epithelium. These findings reinforced the hypothesis that submucous fibrosis is a precancerous condition.