Determinants of participation in a breast cancer screening trial in trivandrum district, India

BACKGROUND

Conspicuous differences in participation rates for breast self-examination (BSE), clinical breast examination (CBE), and referral for further investigations have been observed indicating involvement of a number of different factors. This study analysed determinants for participation in different levels of the breast cancer screening process in Indian females.

MATERIALS AND METHODS

An intervention group of 52,011 women was interviewed in a breast cancer screening trial in Trivandrum district, India. In order to assess demographic, socio-economic, reproductive, and cancer-related determinants of participation in BSE, CBE, and referral, uni- and multi-variate logistic regression was employed.

RESULTS

Of the interviewed women, 23.2% reported practicing BSE, 96.8% had attended CBE, and 49.1% of 2,880 screen-positives attended referral. Results showed an influence of various determinants on participation; women who were currently not married or who had no family history of cancer were significantly less likely to attend the screening process at any level.

CONCLUSIONS

Increasing awareness about breast cancer, early detection methods, and the advantages of early diagnoses among women, and their families, as well as health care workers offering social support, could help to increase participation over the entire screening process in India.

Clinical breast examination: preliminary results from a cluster randomized controlled trial in India

A cluster randomized controlled trial was initiated in the Trivandrum district (Kerala, India) on January 1, 2006, to evaluate whether three rounds of triennial clinical breast examination (CBE) can reduce the incidence rate of advanced disease incidence and breast cancer mortality. A total of 275 clusters that included 115,652 healthy women, aged 30-69 years, were randomly allocated to intervention (CBE; 133 clusters; 55,844 women) or control (no screening; 142 clusters; 59,808 women) groups. Performance characteristics (sensitivity, specificity, false-positive rate, and positive predictive value) of CBE were evaluated. An intention-to-treat analysis was performed for comparison of incidence rates between the intervention and control groups. Preliminary results for incidence are based on follow-up until May 31, 2009, when the first round of screening was completed. Of the 50,366 women who underwent CBE, 30 breast cancers were detected among 2880 women with suspicious findings in CBE screening that warranted further investigations. Sensitivity, specificity, false-positive rate, and positive predictive value of CBE were 51.7% (95% confidence interval [CI] = 38.2% to 65.0%), 94.3% (95% CI = 94.1% to 94.5%), 5.7% (95% CI = 5.5% to 5.9%), and 1.0% (95% CI = 0.7% to 1.5%), respectively. The age-standardized incidence rates for early-stage (stage IIA or lower) breast cancer were 18.8 and 8.1 per 100,000 women and for advanced-stage (stage IIB or higher) breast cancer were 19.6 and 21.7 per 100,000 women, in the intervention and control groups, respectively.

Socio-economic factors & longevity in a cohort of Kerala State, India

BACKGROUND & OBJECTIVES

Even though Kerala State is well-known for its egalitarian policies in terms of healthcare, redistributive actions and social reforms, and its health indicators close to those of high-resource countries despite a poor per-capita income, it is not clear whether socio-economic disparities in terms of life expectancy are observed. This study was therefore carried out to study the impact of socio-economic level on life expectancy in individuals living in Kerala.

METHODS

A cohort of 1,67,331 participants aged 34 years and above in Thiruvananthapuram district, having completed a lifestyle questionnaire at baseline in 1995, was followed up for mortality and cause of death until 2005. Survival estimates were based on the participants' vital status and death rates were calculated separately for men and women and for several socio-economic factors, stratified by age.

RESULTS

At 40 years, men and women were expected to live another 34 and 37 years, respectively. Life expectancy varied across the participants' different socio-economic categories: those from high income households with good housing conditions, materially privileged households and small households, had a 2-3 years longer life expectancy as compared to the deprived persons. Also, those who went to college lived longer than the illiterates. The gaps between categories were wider in men than in women.

INTERPRETATION & CONCLUSIONS

Socio-economic disparity in longevity was observed: wealthy people from Kerala State presented a longer life expectancy.

Association between body-mass index and risk of death in more than 1 million Asians

BACKGROUND

Most studies that have evaluated the association between the body-mass index (BMI) and the risks of death from any cause and from specific causes have been conducted in populations of European origin.

METHODS

We performed pooled analyses to evaluate the association between BMI and the risk of death among more than 1.1 million persons recruited in 19 cohorts in Asia. The analyses included approximately 120,700 deaths that occurred during a mean follow-up period of 9.2 years. Cox regression models were used to adjust for confounding factors.

RESULTS

In the cohorts of East Asians, including Chinese, Japanese, and Koreans, the lowest risk of death was seen among persons with a BMI (the weight in kilograms divided by the square of the height in meters) in the range of 22.6 to 27.5. The risk was elevated among persons with BMI levels either higher or lower than that range--by a factor of up to 1.5 among those with a BMI of more than 35.0 and by a factor of 2.8 among those with a BMI of 15.0 or less. A similar U-shaped association was seen between BMI and the risks of death from cancer, from cardiovascular diseases, and from other causes. In the cohorts comprising Indians and Bangladeshis, the risks of death from any cause and from causes other than cancer or cardiovascular disease were increased among persons with a BMI of 20.0 or less, as compared with those with a BMI of 22.6 to 25.0, whereas there was no excess risk of either death from any cause or cause-specific death associated with a high BMI.

CONCLUSIONS

Underweight was associated with a substantially increased risk of death in all Asian populations. The excess risk of death associated with a high BMI, however, was seen among East Asians but not among Indians and Bangladeshis.

Completed suicide in adults of rural Kerala: rates and determinants

BACKGROUND

India has witnessed a dramatic increase in suicide rates during the past few decades. The southern state of Kerala has been reporting the highest rates of suicide. Since suicide rates are estimated from death registries, they are likely to be under-reported because the civil registration system is incomplete and suicide deaths are poorly reported.

METHODS

A cohort of 132 000 participants (age 35 years and above) in Thiruvananthapuram (erstwhile Trivandrum) district, Kerala was followed up for mortality from 1996 to 2005, after having filled-in a lifestyle questionnaire at baseline. The cause of death was based on verbal autopsy. Suicide methods were recorded and rates were estimated, and suicide risks were calculated according to several socioeconomic factors.

RESULTS

During the follow up period, a total of 11 608 deaths, of which 385 were suicides (3.3% of total deaths), were registered. The overall suicide rate was 39.3/100 000 person-years among adults 35-90 years of age (men: 78/ 100000; women: 16.5/100000). The predominant methods of suicide were hanging, followed by poisoning and drowning. The suicide determinants were male gender, middle-age (40-60 years), Hindu, alcohol drinkers and secondary education level (< or = 7 years). Neither low socioeconomic level, living alone, nor being a married woman was associated with suicide risk.

CONCLUSION

Suicide rates were consistent with the official rates of Thiruvananthapuram district (37/100 000). However, our study population did not include the 14-34-year-old age-group which represents more than 37% of all suicides and hence it is more likely that the official rates are under-reported. Determinants of suicide were in line with previous studies.

Alcohol intake and oral cavity cancer risk among men in a prospective study in Kerala, India

OBJECTIVE

The aim of the study was to evaluate the role of alcohol drinking and patterns of consumption in oral cancer incidence and mortality in a cohort study using data from the Trivandrum Oral Cancer Screening Study, India.

METHODS

At baseline, the study participants completed a lifestyle questionnaire including items on frequency and duration of alcohol consumption. They were followed up for oral cancer incidence and mortality. Data from 32 347 subjects, of whom 134 eventually developed oral cancer, were analysed to estimate risk of oral cancer incidence and mortality according to drinking patterns, using a Cox regression model adjusted for age, religion, education, occupation, body mass index (BMI), standard of living index, chewing habits, smoking habits, and vegetable and fruit intake.

RESULTS

Current and past drinkers were each associated with significantly increased risk of developing oral cancer. The hazard ratio increased significantly by 49% (95% CI = 1-121%) among current drinkers and 90% (95% CI = 13-218%) among past drinkers. A significant dose-response relationship between intake frequency, duration and oral cancer risk (incidence and mortality) was observed.

CONCLUSIONS

As with other lifestyle factors, alcohol intake plays an important role in oral carcinogenesis in this population, and understanding this role is relevant to developing public health policies targeting at-risk population.

Cost-effectiveness of oral cancer screening: results from a cluster randomized controlled trial in India

OBJECTIVE

To evaluate oral cancer screening by visual inspection.

METHODS

A cluster randomized controlled trial was initiated in Trivandrum district, Kerala, India. Of 13 population clusters, seven were randomly allocated to three rounds of screening between 1996 and 2004, while standard care was provided in six (control arm). An activity-based approach was employed to calculate costs associated with various components of the screening trial. Information on the resources used and on clinical events in each trial arm was derived from trial databases. Total costs for each cluster were estimated in 2004 United States dollars (US$). The incremental cost per life-year saved was calculated for all eligible individuals and for high-risk individuals (i.e. tobacco or alcohol users).

FINDINGS

The proportion of oral cancers detected at an early stage (i.e. stage I or II) was higher in the intervention arm than the control arm (42% versus 24%, respectively). The incremental cost per life-year saved was US$ 835 for all individuals eligible for screening and US$ 156 for high-risk individuals. Oral cancer screening by visual inspection was performed for under US$ 6 per person.

CONCLUSION

The most cost-effective approach to oral cancer screening by visual inspection is to offer it to the high-risk population. Targeted screening of this group will ensure that screening can be offered at a reasonable cost in a limited-resource setting.

Body mass index, weight change and mortality risk in a prospective study in India

BACKGROUND

Although the detrimental effect of overweight and obesity has been extensively reported in Western populations, little is known on the association between body weight, weight change and mortality in Asian populations whose weight distribution and mortality differ considerably from the West.

METHODS

A cohort of 75 868 subjects aged 35 years and above, participants of the Trivandrum Oral Cancer Study-a cluster-randomized controlled trial originally implemented to evaluate the efficacy of visual inspection on oral cancer, in Kerala State, South India-were followed up from 1995 to 2004. Weight and height were measured both at baseline and in 3.5-year follow-up surveys. Early years of follow-up were excluded from the analyses. Relative risks of overall death and cause-specific death were estimated according to the body mass index (BMI) category of the WHO Asian population definitions, and to weight changes between two surveys.

RESULTS

Low BMI was a predictor of mortality, while high BMI was not. Mortality risks in men adjusted for age, smoking habits and other potential confounders, as compared with a BMI 18.5-22.9 kg/m(2), were 1.26 (95% CI 1.03-1.55) for BMI < 16 kg/m(2); 1.16 (1.03-1.32) for BMI = 16-18.4 kg/m(2); 0.95 (0.81-1.12) for BMI = 23-24.9 kg/m(2); 0.85 (0.69-1.05) for BMI = 25-27.4 kg/m(2); and 0.89 (0.65-1.21) for BMI >/= 27.5 kg/m(2). Similar findings were observed in women. BMI was not associated with deaths from cancer, cardiovascular and cerebrovascular diseases, and diabetes. A low BMI (<16 kg/m(2)) was associated with increased deaths from chronic respiratory diseases. Smoking and socio-economical status did modify the association. A moderate weight gain of 4-10% between the two surveys was associated with decreased risk of death, while moderate and severe weight loss were predictive factors of death. Similar results were observed in both men and women.

CONCLUSIONS

Among this Indian rural population, mild to severe leanness (BMI < 16 kg/m(2)) and weight loss were important determinants of mortality, especially from chronic respiratory diseases, while overweight and above (BMI > 23 kg/m(2)) did not show any detrimental effect.

Association between diabetes mellitus and pre-malignant oral diseases: A cross sectional study in Kerala, India

Recent studies have suggested role of diabetes mellitus in the development of periodontal diseases, oral inflammatory and neoplastic lesions. We analysed data from randomised oral cancer screening trial in Kerala, India, to study the association between chronic diseases in general, diabetes mellitus in particular, and pre-malignant oral lesions and conditions. A total of 927 subjects with oral leukoplakia, 170 with oral submucous fibrosis, 100 with erythroplakia lesions and 47,773 apparently healthy subjects constituted the cases and controls respectively for our present study. The odds ratio (OR) for oral leukoplakia among women with a history of diabetes mellitus was found to be 2.0 (95% confidence interval (CI) = 1.4-2.9) whereas that for erythroplakia was 3.2 (95% CI = 1.3-7.9), after adjusting for potential confounders. No statistically significant association between diabetes mellitus and oral submucous fibrosis and pre-cancerous lesions/conditions in men was found. An association between diabetes mellitus and pre-malignant oral lesions among women has been observed in our study, although the underlying mechanisms are not clear. This needs to be further evaluated in other settings.

Cervical and oral cancer screening in India

Incidence of both cervical and oral cancer are high in India. Although there are no organized cervical or oral screening programmes in the country, a number of research projects are ongoing or recently completed. In cervical screening, a number of studies of visual inspection with various aids and studies of human papillomavirus (HPV) testing are in progress. Long-term follow-up of these will inform policy on cervical screening in limited resource countries. A randomized trial of oral visual inspection for cancer or premalignant lesions in 192,053 subjects has been conducted in Kerala, South India. In the trial population as a whole, the study group showed a non-significant 21% reduction in mortality from oral cancer compared with the control group. In users of alcohol, tobacco or both, in which more than 90% of oral cancer deaths occurred, the reduction was a significant 34% (relative risk = 0.66, 95% confidence interval 0.45-0.95). On the basis of these results, screening for oral abnormalities has the potential to prevent 37,000 deaths per year worldwide.

High expression levels of nuclear factor kappa B and gelatinases in the tumorigenesis of oral squamous cell carcinoma

BACKGROUND

The cellular mechanisms involved in transformation of a premalignant/potentially malignant oral lesion to a malignant one remain unclear. Previous studies have documented a direct involvement of matrix metalloproteinase (MMP) overexpression in the development and progression of head and neck squamous cell carcinoma (HNSCC). MMP activation, particularly MMP2 and MMP9, observed in different cancers, has been shown to be mediated via the transcription factor nuclear factor kappa B (NF-kappaB). The present study analyzes the clinical significance of gelatinases and NF-kappaB in various histologic phases of human oral tumor progression.

METHODS

Methodology included immunohistochemistry for MMP2, MMP9, p50, and p65 components of NF-kappaB and IkappaBalpha (inhibitor kappaBalpha). Gelatin zymography was carried out to determine the extent of gelatinolytic activity. Western blotting was used to confirm the gelatinolytic bands of zymogram, and electrophoretic mobility shift assay (EMSA) was carried out to confirm NF-kappaB activation.

RESULTS

A gradual increase was evident in the intensity of the expression and gelatinolytic activity of gelatinase paralleling the histologic progression of malignancy. This finding supports the histologic evidence of tumor invasion occurring in the transition between premalignancy and invasive cancer. Nuclear translocation of NF-kappaB (p50-p65 form) gradually progresses through the premalignant phase of oral tissue to the invasive phase, showing NF-kappaB activation during oral tumorigenesis. NF-kappaB activation correlatively paralleled the pattern of expression of gelatinases.

CONCLUSIONS

The results of this study suggest a regulatory role for NF-kappaB on activation of gelatinases during malignant transformation in the oral mucosa.

Single nucleotide polymorphisms of DNA repair genes XRCC1 and XPD and its molecular mapping in Indian oral cancer

Tobacco users with diminished ability to repair somatic mutations may be more susceptible to tobacco attributable cancers. The distribution of single nucleotide polymorphisms (SNPs) in DNA repair genes XRCC1 and XPD in 110 oral carcinoma cases, 84 leukoplakia and 110 controls belonging to the Travancore South Indian population were examined. SNPs investigated included Arg194Trp, Arg280His, and Arg399Gln of the XRCC1 gene and Lys751Gln of the XPD gene. In addition, one of the variants positions, A399G, was mapped onto the BRCT I domain model built by comparative modeling (threading). Presence of the polymorphic variant of XRCC1 codon 194 and 399 and XPD was associated with increased risk of oral cancer compared to the wild genotype. Smokers and betel quid chewers with the variant allele of XRCC1 399 codon and XPD also exhibited increased risk of oral cancer. The A399G variant position mapped onto the surface of the BRCT I domain provides a possible rationale for altered XRCC1 function. These results suggest that polymorphisms in functionally important repair genes, specifically, those that map onto the protein surface may alter protein function without significantly affecting its structure.

Effect of screening on oral cancer mortality in Kerala, India: a cluster-randomised controlled trial

BACKGROUND

Oral cancer is common in men from developing countries, and is increased by tobacco and alcohol use. We aimed to assess the effect of visual screening on oral cancer mortality in a cluster-randomised controlled trial in India.

METHODS

Of the 13 clusters chosen for the study, seven were randomised to three rounds of oral visual inspection by trained health workers at 3-year intervals and six to a control group during 1996-2004, in Trivandrum district, Kerala, India. Healthy participants aged 35 years and older were eligible for the study. Screen-positive people were referred for clinical examination by doctors, biopsy, and treatment. Outcome measures were survival, case fatality, and oral cancer mortality. Oral cancer mortality in the study groups was analysed and compared by use of cluster analysis. Analysis was by intention to treat.

FINDINGS

Of the 96,517 eligible participants in the intervention group, 87,655 (91%) were screened at least once, 53,312 (55%) twice, and 29,102 (30%) three times. Of the 5145 individuals who screened positive, 3218 (63%) complied with referral. 95,356 eligible participants in the control group received standard care. 205 oral cancer cases and 77 oral cancer deaths were recorded in the intervention group compared with 158 cases and 87 deaths in the control group (mortality rate ratio 0.79 [95% CI 0.51-1.22]). 70 oral cancer deaths took place in users of tobacco or alcohol, or both, in the intervention group, compared with 85 in controls (0.66 [0.45-0.95]). The mortality rate ratio was 0.57 (0.35-0.93) in male tobacco or alcohol users and 0.78 (0.43-1.42) in female users.

INTERPRETATION

: Oral visual screening can reduce mortality in high-risk individuals and has the potential of preventing at least 37,000 oral cancer deaths worldwide.

Socioeconomic status, lifestyle factors and oral premalignant lesions

Several studies have suggested that low socioeconomic status (SES) is associated with a higher risk of oral cancer, but the association with oral premalignant lesions has not yet been explored. The aim of this study was to examine the association of education, occupation, income and SES index with oral premalignant lesions. A case-control study was conducted with data from the baseline screening of a randomized oral cancer screening trial in Kerala, India. There were a total of 927 oral leukoplakia, 170 oral submucous fibrosis, 100 erythroplakia and 115 multiple oral premalignant lesion cases and 47,773 controls. Subjects with high SES index had protective ORs for oral premalignant lesions, ranging from 0.6 to 0.7, after adjustment for age, sex, BMI, tobacco chewing, smoking, drinking and fruit/vegetable intake. Higher education levels were also associated with decreased risk of all four oral premalignant lesions. Protective ORs for income were observed for oral leukoplakia and possibly oral submucous fibrosis and erythroplakia. SES may be associated with oral premalignant lesions because of access to medical care, health related behaviors, living environment or psychosocial factors. Though the mechanism for the association is not clear, higher SES index, education and income were associated with decreased risk of oral premalignant lesions in our study.

Interim results from a cluster randomized controlled oral cancer screening trial in Kerala, India

A cluster randomized controlled oral cancer screening trial is on-going in the Trivandrum district, India, to evaluate the efficacy of screening in reducing oral cancer mortality. Subjects, aged 35 years and above, in 13 clusters in the Trivandrum district, India, were randomized to the intervention (screening) group (7 clusters, 78969 subjects) to receive three rounds of screening by oral visual inspection by trained health workers at 3-year intervals or to a control group (6 clusters, 74739 subjects). Two rounds of screening were completed between 1995 and 2002 during which 69896 (88.5%) subjects were screened at least once, and 59.7% of the 4408 screen-positive subjects were further investigated. In the intervention group, 344404 person-years were accrued and 329326 person-years were in the control group. In the intervention group, 149 incident oral cancer cases and 65 deaths from oral cancer were observed, and 106 incident cases and 62 deaths from oral cancer were observed in the control group. The programme sensitivity for detection of oral precancerous lesions and cancer was 81.5% and the programme specificity was 84.8%; the programme positive predictive value was 39.6%. In the intervention group 37.6% of the cases were in stages I-II, as opposed to 18.9% in the control group. The 3 year survival rate was 57.5% in the intervention and 38.8% in the control group (P<0.05). The age standardized oral cancer mortality rates were 21.2/100000 person-years in the intervention and 21.3/100000 in the control group. After completing two rounds of screening, oral cancer mortality rates were similar in both study groups.

Genetic polymorphism of CYP1A1, GSTM1 and GSTT1 genes in Indian oral cancer

Oral cancer ranks first among all cancers in males and is the third most common among females in India. Tobacco-derived carcinogens are involved in the development of oral cancer. Environment-gene interaction in oral carcinogenesis is well demonstrated by phase I and II enzymes that are involved in the metabolism of carcinogens. This study looked at the significance of genetic polymorphisms in CYP1A1, GSTM1 and GSTT1 genes in patients with oral cancer. The study included 98 oral cancer patients and 60 age and sex matched healthy controls. Genotypes of CYP1A1, GSTM1 and GSTT1 were determined by PCR-RFLP. GSTM1 null deletion was observed in 49% of oral cancer cases and 33% of control subjects. For GSTT1, 18% of carcinomas and 8% of controls had the null genotype. In the case of CYP1A1 m2 allele, 51% of oral cancers and 17% of normal controls, respectively, had one or both alleles with the isoleucine-->valine substitution. Digestion of the PCR products with enzyme Nco1 revealed polymorphism for CYP1A1 m2 with bands at 263 bp. There was no association between genotypes with tumor size, stage, grade, and age. Since null genotype individuals may possibly be poor detoxifiers with reduced ability to neutralise the reactive carcinogenic intermediates, they may be a high risk category. The frequency distribution of CYP1A1 m2 (Ile/val) genotypes among oral cancer patients was significantly different that from normal controls. The risk of CYP1A1 can be supported by the functional difference between presence of valine and isoleucine; valine type has higher catalytic and mutagenic activity towards benzo[a] pyrene than the isoleucine type. In conclusion, our results suggest that polymorphism in CYP1A1 m2 gene and/or GSTM1 and GSTT1 null genotype may confer an increased risk for oral cancer.

Apoptosis, angiogenesis and proliferation: trifunctional measure of tumour response to radiotherapy for oral cancer

Local recurrence is a significant problem following radiotherapy in oral carcinoma and hence there is a paramount need for predictive markers. This study therefore analysed the predictive value of pre-treatment status of angiogenesis, apoptosis, expression of apoptosis regulatory p53, bax and bcl-2 proteins as well as tissue proliferation in relation to tumour response to radiotherapy. Sixty-nine histologically defined invasive carcinoma lesions were included in the study. Extent of apoptosis was defined morphologically and by the TUNEL (Tdt-mediated dUTP biotin nick end labelling) assay. Expression of apoptosis regulatory p53, bax and bcl-2 proteins were evaluated by immunocytochemistry. Mutant p53 protein was detected using a mutant p53-specific ELISA. The extent of tissue proliferation was evaluated by cyclin D1 expression. Angiogenesis was evaluated by CD34 antigen expression. All patients were treated with radical radiotherapy and followed up for 36 months. High levels of p53 protein detected by immunocytochemistry were found to be associated with poor response to treatment or disease relapse. Detection of mutant p53 protein also showed significant association with poor prognosis. Low levels of angiogenesis had a correlation with recurrence status. Tumours showing less vascularisation as well as increased apoptosis had a poor prognosis. Expression of p53 and bcl-2 proteins showed direct correlation with angiogenesis. There was no correlation between clinical status and any of the experimental parameters with histopathological grades of invasive lesions. Presence of mutant p53 protein is suggestive of poor tumour response to radiotherapy. Expression of p53 and increased apoptosis in less vascularised tumours is associated with treatment resistance. A predictive assay based on these results designed to analyse individual tumour samples showed presence of apoptotic cells near the vasculature to be indicative of good prognosis, while absence of apoptotic cells or highly proliferative cells and/or expression of bcl-2 protein in cells around the vasculature to be an indicator of poor prognosis.