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Biomedical subjects

R Sankaranarayanan

Publications and source records attributed to R Sankaranarayanan.

At least 109 records · Page 6Linked to original sources
PubMed1991

Risk factors for cancer of the oesophagus in Kerala, India.

A case-control study of oesophageal cancer was carried out in Trivandrum, Kerala, involving 267 cases and 895 controls. Risk factors studied in males were pan (betel)-tobacco chewing, bidi and cigarette smoking, drinking alcohol and taking snuff. Only pan-tobacco chewing was investigated in females as very few indulged in the other habits. Among males significant associations with higher risk were observed for bidi smoking (p less than 0.001), bidi plus cigarette smoking (p greater than 0.05) and drinking alcohol (p less than 0.001). While a significant effect of duration of pan-tobacco chewing (p less than 0.005) was observed in males, there was no significant trend, the risk first falling then rising as duration of use increased. This was partly due to confounding with smoking. No effect of pan-tobacco use was observed in females. A step-wise model was fitted, retaining only those risk factors which were significant when adjusted for other factors; the risk factors included were duration of pan-tobacco chewing, duration of bidi smoking, daily frequency of bidi and cigarette smoking and alcohol use (yes or no). An adjusted relative risk of 2.03 was observed for a pan-tobacco habit of more than 40 years' duration, of 4.70 for more than 20 years of bidi smoking, of 4.80 for more than 20 bidis/cigarettes per day, and of 2.33 for regular alcohol use (in each category relative to a baseline of those never indulging in the relevant habit).

Adult↗
PubMed1991

Evaluation of salvage surgery in heavily irradiated cancer of the buccal mucosa.

This report describes the authors' experience with salvage surgery in 78 patients with carcinoma of the buccal mucosa who failed after high-dose radical radiation therapy at Regional Cancer Centre, Trivandrum, India. Forty-four patients (56%) required a hemimandibulectomy for adequate tumor clearance. Fifty-four patients (69%) required a primary reconstructive procedure for wound closure. Follow-up periods ranged from 28 months to 63 months (median follow-up, 41 months). Thirteen patients (17%) developed nonfatal postoperative complications. Thirty-one patients recurred after surgery, five of whom were again salvaged by further surgery. Overall, the recurrence rate was 36%. Most of the recurrences (26/31) were at the primary site. The overall 5-year actuarial disease-free survival after salvage surgery was 59.7%. T stage of the recurrent tumor and its skin infiltration emerged as factors which significantly influenced disease-free survival (P less than 0.05).

Adult↗
PubMed1991

Remission of precancerous lesions in the oral cavity of tobacco chewers and maintenance of the protective effect of beta-carotene or vitamin A.

Participants in the intervention trials were fishermen (Kerala, India), who chewed tobacco-containing betel quids daily before and throughout the study period. Frequency of oral leukoplakia, micronuclei in oral mucosal cells, and alterations in nuclear textures were used as endpoints. Administration of vitamin A (60 mg/wk) for 6-mo resulted in complete remission of leukoplakias in 57% and a reduction of micronucleated cells in 96% of tobacco-chewers. beta-carotene (2.2 mmol/wk) induced remission of leukoplakia in 14.8% and reduction of micronucleated cells in 98%. Vitamin A completely suppressed and beta-carotene suppressed by 50% formation of new leukoplakia within the 6-mo trial period. After withdrawal of vitamin A or beta-carotene treatment, oral leukoplakias reappeared, frequency of micronuclei in oral mucosa increased, and nuclear textures reverted to those present before the administration of chemo-preventive agents. The protective effect of the original treatment could be maintained for at least 8 additional months by administration of lower doses of vitamin A or beta-carotene.

Areca↗
PubMed1991

Remission of oral precancerous lesions of tobacco/areca nut chewers following administration of beta-carotene or vitamin A, and maintenance of the protective effect.

Designs of intervention trials are based on results from a multitude of disciplines. In this study, a comparative analysis of various chewing mixtures used by groups from different geographical locations (Guam, Peru, Taiwan, the Philippines, and India) and their link to oral cancer incidences was used to trace the ingredients responsible for oral carcinogenesis among chewers. The usefulness of applying intermediate endpoints in intervention trials was examined by comparing the response of micronucleated mucosal cells and oral leukoplakia of chewers of tobacco-containing betel quids to the twice weekly administration of beta-carotene (180 mg/week), vitamin A (100,000 IU/week or 200,000 IU/week), and beta-carotene (180 mg/week) plus vitamin A (100,000 IU/week). A reduced frequency of micronucleated mucosal cells and remission of leukoplakias resulted following a 3- to 6-month treatment. The development of new leukoplakias was also inhibited. The various endpoints differed in degree and time course to the administration of beta-carotene and vitamin A. Following termination of the beta-carotene or vitamin A administration, micronucleated cells and leukoplakia recurred in the oral cavity of chewers who continued this habit throughout the trial period. Attempts were made to maintain the protective effect achieved by the treatment with relatively high doses of the chemopreventive agents. Vitamin A given at a level of 50,000 IU/week was able to keep the frequency of micronucleated mucosal cells at low levels for at least a 12-month post-treatment period, whereas beta-carotene administered at 60 mg/week was less effective in maintaining the protective effect.(ABSTRACT TRUNCATED AT 250 WORDS)

Areca↗
PubMed1990

Tobacco and alcohol as risk factors in cancer of the larynx in Kerala, India.

A case-control study of cancer of the larynx was carried out in Kerala, Southern India, on 191 male cancer cases and 549 male hospital-based controls. Risk factors investigated were pan(betel)-tobacco chewing, bidi and cigarette smoking, drinking alcohol and inhaling snuff. Significant positive associations with risk were observed for bidi smoking (p less than 0.001), bidi and cigarette smoking (p less than 0.001) and drinking alcohol (p less than 0.001). A predisposing effect of smoking cigarettes alone approached significance (0.1 less than p less than 0.05). What appeared to be an almost significant protective effect of pan-tobacco chewing (0.1 less than p less than 0.05) was found to be an artefact of confounding with smoking, and indeed a significant predisposing effect was observed of occasional chewing (p less than 0.001). After a stepwise logistic regression to eliminate those factors which were not significant when adjusted for other factors, significant effects remained of durations of bidi smoking and cigarette smoking, daily frequency of bidi and cigarette smoking and duration of alcohol drinking. Relative risks of 7.12, 5.18 and 2.58 were observed for durations of more than 20 years of bidi smoking, cigarette smoking and drinking alcohol respectively, and a relative risk of 12.68 was observed for those smoking more than 20 bidis/cigarettes per day, in each case relative to a baseline of those negative for the relevant habit.

Adult↗
PubMed1990

Oral cancer in India: an epidemiologic and clinical review.

This article reviews the epidemiologic and clinical aspects of oral cancer in India, where the disease ranks number one among all cancers in male patients and number three among cancers in female patients. Causal association between oral cancer and the chewing of betel quids containing tobacco leaves or stem and other tobacco habits has been extensively studied. But there is need for more in-depth studies on the role of alcohol, diet, and oral hygiene practices in India. The exciting opportunity provided by the well-established oral precancerous lesions for intervention and early detection programs is also discussed. The peak age frequency of occurrence is at least a decade earlier than that described in Western literature. Sex ratio reveals a 2:1 preponderance of male patients. Only 10% to 15% of cases present in localized stages. The poor survival revealed by existing studies is mainly due to the overwhelming proportion of advanced cases. The excellent opportunity for more research and efforts in prevention and control of oral cancer in India is highlighted in this review.

Alcoholic Beverages↗
PubMed1990

Risk factors for cancer of the buccal and labial mucosa in Kerala, southern India.

STUDY OBJECTIVE: The aim was to investigate risk factors for cancer of the buccal and labial mucosa in Kerala, southern India. DESIGN: The investigation was a case-control study. SETTING: Regional Cancer Centre, Trivandrum, Kerala, and local teaching hospitals. PARTICIPANTS: Cases were all those registered with oral cancers at the Regional Cancer Centre during 1983 and 1984 (n = 414). Controls (n = 895) were selected from admissions to the cancer centre who were found to have non-malignant conditions, or from patients attending outpatients in teaching hospitals of Trivandrum medical college with non-malignant conditions. MEASUREMENTS AND MAIN RESULTS: The risk in males of the following habits was investigated: pan (betel)-tobacco chewing, bidi and cigarette smoking, drinking alcohol, and taking snuff. Only pan-tobacco chewing was investigated in females as very few indulged in other habits. Among males predisposing effects were found for pan-tobacco chewing (p less than 0.001), bidi smoking (p less than 0.001), drinking alcohol (p less than 0.001), and taking snuff (p less than 0.01). As in males, pan-tobacco chewing also had a predisposing effect in females (p less than 0.001). Duration of use was a better predictor of risk than either daily frequency of use or total lifetime exposure, both for pan-tobacco chewing (especially if the habit started before age 21 years) and bidi smoking. However, there were also very high risks associated with the current occasional use of both factors. Pan-tobacco chewing was the most important risk factor, with relative risk of 13.24 with 31-40 years' use, and 37.75 with greater than 40 years' use among males. Corresponding relative risks in females were 21.30 and 54.93. No effect of cigarette smoking was observed (relative risk 0.64, p greater than 0.1). CONCLUSIONS: A substantial majority of cases of buccal and labial cancers are attributable to chewing pan-tobacco. This has obvious implications for instituting preventive measures.

Adult↗
PubMed1990

Evaluation of local control, survival and pattern of failure with radiotherapy in cancer of the tongue.

105 patients with cancer of the tongue were treated with radical radiotherapy in 1982 at the Regional Cancer Centre, Trivandrum, India. The overall local control rate was 55% and the 3-year actuarial disease-free survival was 36% with radiotherapy. The analysis revealed a close correlation between stage of the disease and local control as well as survival. 45% of the patients with clinically positive cervical nodes had their disease controlled by radiotherapy. Since the best results were obtained with early disease, the need for clinical downstaging by early detection is stressed.

Adult↗
PubMed1990

Quantitation of chromatin patterns by image analysis as a predictive tool in chemopreventive trials with vitamin A.

Nuclear textures of oral mucosal cells were quantitated by image analysis, and their suitability as markers in a chemopreventive trial explored. Subjects were chewers of tobacco-containing betel quids with well established oral leukoplakias. Treatment consisted of a weekly oral administration of vitamin A (200,000 IU/week) for six months. Leukoplakias regressed in 57.1% of the 21 trial participants. The original leukoplakias did not redevelop within four months after termination of treatment. For image analysis, biopsies were taken from leukoplakias of five chewers before administration of vitamin A, at the end of the administration, and four months after termination of treatment. Sections of paraffin-embedded biopsies were stained with the Feulgen reaction and submitted to quantitative image analysis of two parameters: variance of intensity and entropy. Both these parameters were significantly reduced in all five trial participants as a result of the six-month vitamin A treatment. During the post-treatment period, nuclei with condensed chromatin, as measured by the variance of intensity, reappeared in the mucosa of four of the five chewers examined, although no leukoplakias were detectable on visual examination of the oral cavity. The results indicate that the quantitation of nuclear textures in a small subpopulation of a chemopreventive trial could conceivably be a simple marker with a predictive value.

Biomarkers, Tumor↗
PubMed1989

A case-control investigation of cancer of the oral tongue and the floor of the mouth in southern India.

A case-control study of cancer of the oral tongue and floor of mouth was conducted in Kerala, Southern India, on 228 cases and 453 hospital-based controls, matched for age, sex and religion. We studied pan(betel)-tobacco-chewing, bidi (local type of cigarette)-and-cigarette-smoking, alcohol-drinking and snuff use, for their associations with risk, in males. Among females, only pan-tobacco-chewing was analyzed, as very few females indulged in the other habits. In males, a significantly increased risk was observed in association with pan-tobacco-chewing, bidi-smoking, bidi-plus-cigarette-smoking (but not cigarette-smoking alone) and alcohol-drinking (p less than 0.001 in all cases), although the effect of alcohol was no longer significant when adjusted for the other significant predisposing factors. Among females, pan-tobacco-chewing had a similar predisposing effect to that observed in males (p less than 0.001). In males an adjusted relative risk of 6.14 was associated with chewing 10 or more pan-tobacco quids per day (relative to those who never chewed). The corresponding relative risk in females was 9.27. In males, an adjusted relative risk of 7.46 was observed for those smoking 20 or more bidis per day (relative to never-smokers).

Age Factors↗
PubMed1989

Tobacco chewing, alcohol and nasal snuff in cancer of the gingiva in Kerala, India.

A case-control study of cancer of the gingiva was carried out in Kerala, Southern India, using 187 cases and 895 hospital-based controls. We investigated the effects on risk in males of pan (betel)-tobacco chewing, bidi and cigarette smoking, drinking alcohol and taking snuff. In females only pan-tobacco chewing was investigated as very few females indulged in the other habits. Among males, significant positive associations with risk were observed for pan-tobacco chewing (P less than 0.001), bidi smoking (P less than 0.001) alcohol drinking (P less than 0.001) and snuff use (P less than 0.05). In females, pan-tobacco chewing had a similar predisposing effect (P less than 0.001). Daily frequency of pan-tobacco chewing was the strongest predictor of risk in males, with a relative risk of 15.07 associated with chewing ten or more quids per day. The corresponding relative risk among females was 13.69. In males a relative risk of 3.20 was associated with smoking more than 20 bidis per day, and relative risks of 2.62 and 3.90 were associated with regular use of alcohol and snuff respectively. Surprisingly high relative risks were observed in association with occasional use of pan-tobacco, bidi, cigarettes, alcohol and snuff. A stepwise logistic regression analysis yielded four predictors: pan-tobacco daily frequency, duration of bidi use, and alcohol and snuff use (regular versus never). There were also significantly elevated risks associated with occasional indulgence in these four habits. Total lifetime exposure was no better at predicting risk than daily frequency or duration of habits.

Adult↗
PubMed1988

Remission of oral leukoplakias and micronuclei in tobacco/betel quid chewers treated with beta-carotene and with beta-carotene plus vitamin A.

Fishermen from Kerala (India) who chewed tobacco-containing betel quids daily (17.2 +/- 9.6 quids per day) and had well-developed oral leukoplakias with elevated frequencies of micronucleated cells participated in a short-term intervention trial. Beta-carotene (180 mg/week) (Group I), beta-carotene (180 mg/week) plus vitamin A (100,000 IU/week) (Group II), and placebo (Group III) capsules were given twice weekly for 6 months under strict supervision. The remission of oral leukoplakias, the inhibition of new leukoplakias, and the reduction of micronucleated oral mucosal cells were recorded at the 3rd and 6th months of the trial period. After 3 months, the frequency of micronucleated cells was significantly reduced in Group I (from 4.09% to 1.1% in areas of leukoplakia, and from 4.1% to 1.0% in the normal mucosa). At this time, remission of oral leukoplakias did not differ significantly from that observed in the placebo group. After 6 months of treatment, remission of leukoplakias in Group I (14.8%) and Group II (27.5%) differed significantly from that seen in Group III (3.0%). The development of new leukoplakias during the 6-month period was strongly inhibited in Group II (7.8%), and to a lesser degree in Group I (14.8%), as compared to Group III (21.2%). During the trial period, all participants continued to chew tobacco-containing betel quids in their accustomed manner. Thus, remission and inhibition of new oral leukoplakias and reduction of micronucleated mucosal cells occurred in the groups receiving beta-carotene and beta-carotene plus vitamin A during the continuous presence of carcinogens derived from tobacco and areca nut.

Areca↗