CYP1A2, 2A13, and 3A4 network and interaction with aflatoxin B1

Aspergillus fungi are known to produce aflatoxins, among which aflatoxin B1 (AFB1) is the most potent carcinogen that is metabolised by cytochrome P450 (CYP450). In the liver, AFB1 is metabolised into exo-8,9-epoxide by the CYP1A2 enzymes. The resulting epoxide can react with guanine to cause DNA damage. Natural inhibitors are being identified. However, the modes of action are poorly understood. In the current study, we have investigated the mode of action of AFB1 with CYP1A2, CYP3A4 and CYP2A13 using molecular dynamic simulation (MD simulation) approaches. The interaction network and paths among CYP1A2, CYP3A4, and CYP2A13 have been investigated using the STRING database and PathLinker plugin of Cytoscape. CYP3A4 is the most active protein involved in interactions with AFB1 during its metabolism. Residues 362ARG, 445SER, 450LEU and 451PHE of CYP1A2 are important, interacting with AFB1 and converting it to toxic exo-AFB1-8,9-epoxide (AFBEX). The pathway shows that microsomal epoxide hydrolase (EPHX1) may acts as initiator in the signalling pathway where CYP1A2, CYP3A4 and CYP2A13 interact in a sequential order. The interaction network shows there to be a strong association in expression among CYP1A2, CYP3A4 and CYP2A13 along with other metabolising enzymes. The complex of AFB1 and CYP1A2 was found to be stable during the MD simulation. This study provides a better understanding of the mode of action between AFB1 and CYP1A2, CYP3A4 and CYP2A13 which relates to the effective management of AFB1 toxicity. EPHX1 in the protein network may be an ideal target when designing inhibitors to prevent the toxin’s activation. Peptide inhibitors may be designed to block the substrate site residues of CYP1A2 in order to prevent the conversion from AFB1 into AFBEX. This would either neutralise or reduce its toxicity.

Multi-modality imaging evaluation of the dorsal arachnoid web

PURPOSE

Dorsal arachnoid web (DAW) is a rare intradural abnormality which is associated with progressive myelopathy. Our objective was to review multi-modality imaging techniques demonstrating the scalpel sign appearance in evaluation of DAW.

METHODS

We retrospectively reviewed various imaging modalities of patients found to have DAW at our institution during January 2015 to February 2020. Five patients underwent surgical decompression with pathological correlation. The remaining patients were presumptively diagnosed based on the characteristic finding of scalpel sign. Clinical data were evaluated and correlated to imaging findings. All imaging modalities demonstrated the characteristic scalpel sign.

RESULTS

Sixteen patients (10 females, and six males) with multi-imaging modalities were evaluated. Their mean age was 52 year (range 23-74 years). Fifteen patients underwent conventional spine MRI. Further high-resolution MR imaging techniques, e.g. 3D T2 myelographic sequence, were utilized with two patients. MRI spine CSF flow study was performed to evaluate the flow dynamic across the arachnoid web in one patient. Eight patients were evaluated with CT myelogram. Syrinx formation was discovered in seven (44%) patients; five (71%) of them underwent surgical resection and decompression. Two patients underwent successful catheter-directed fenestration of the web with clinical improvement. We found a statically significant positive correlation between the degree of cord displacement and compression with syrinx formation (r = 0.55 and 0.65 with p-value of 0.03 and 0.009, respectively).

CONCLUSION

DAW has characteristic scalpel sign independent of imaging modality. Multi-modality imaging evaluation of DAW is helpful for evaluation and surgical planning.

Cross-Sectional Imaging Evaluation of Congenital Temporal Bone Anomalies: What Each Radiologist Should Know

Hearing loss in pediatric age group is associated with many congenital temporal bone disorders. Aberrant development of various ear structures leads into either conductive or sensorineural hearing loss. Knowledge of the embryology and anatomical details of various compartments of the ear help better understanding of such disorders. In general, abnormalities of external and middle ears result in conductive hearing loss. Whereas abnormalities of inner ear structures lead into sensorineural hearing loss. These abnormalities could occur as isolated or part of syndromes. Temporal bone disorders are a significant cause of morbidity and developmental delays in children. Imaging evaluation of children presented with hearing loss is paramount in early diagnosis and proper management planning. Our aim is to briefly discuss embryology and anatomy of the pediatric petrous temporal bones. The characteristic imaging features of commonly encountered congenital temporal bone disorders and their associated syndromes will be discussed.

Expression of cytochrome P450 1A1/2 and 3A4 in liver tissues of hepatocellular carcinoma cases and controls from Taiwan and their relationship to hepatitis B virus and aflatoxin B1-and 4-aminobiphenyl-DNA adducts

Cytochrome P450 enzymes play a major role in the metabolism of several of the chemical carcinogens involved in the development of hepatocellular carcinoma (HCC). To investigate by immunohistochemistry interindividual differences in these enzymes, polyclonal antisera and immunoperoxidase staining were used to detect the expression of CYP1A1/2 and 3A4 in 37 surgical control tissues and 105 tumour and adjacent nontumour tissues of HCC cases from Taiwan. There was variability in the expression and staining pattern for both CYP1A1/2 and 3A4 in all tissue types. In tissues from controls, there was no correlation between P450 expression and smoking history or hepatitis B virus antigen status. Since these samples had been previously analysed for the DNA adducts of aflatoxin B1 (AFB1), a dietary mould contaminant, and 4-aminobiphenyl (4-ABP), a component of cigarette smoke, we also investigated the relationship between P450 levels and DNA adducts. 4-ABP-DNA adducts were higher in tissues with elevated levels of CYP1A1/2 (p = 0.02). Overall there was no relationship between CYP1A1/2 or CYP3A4 and AFB1-DNA adducts in control tissues. Staining intensity for CYP1A1/2 and 3A4 followed the order: tumour tissues < control tissues < adjacent non-tumour tissues. CYP1A1/2 levels tended to be lower in tumour and adjacent non-tumour tissues than for CYP3A4. In HCC cases, 4-ABP-DNA adducts were higher in subjects with higher levels of CYP1A1/2, stratified by tissue type, but these differences were not significant. For CYP3A4, in contrast to control tissues, there was a significant association with AFB1-DNA adducts in tumour and adjacent non-tumour tissue of HCC cases. These results suggest that one factor influencing carcinogen-DNA adducts is levels of specific P450 enzymes. However, adduct formation in vivo is a complex processes dependent upon numerous genetic and environmental factors.

Body mass, tobacco smoking, alcohol drinking and risk of cancer of the small intestine--a pooled analysis of over 500,000 subjects in the Asia Cohort Consortium

BACKGROUND

The evidence for a role of tobacco smoking, alcohol drinking, and body mass index (BMI) in the etiology of small intestine cancer is based mainly on case-control studies from Europe and United States.

SUBJECTS AND METHODS

We harmonized the data across 12 cohort studies from mainland China, Japan, Korea, Singapore, and Taiwan, comprising over 500,000 subjects followed for an average of 10.6 years. We calculated hazard ratios (HRs) for BMI and (only among men) tobacco smoking and alcohol drinking.

RESULTS

A total of 134 incident cases were observed (49 adenocarcinoma, 11 carcinoid, 46 other histologic types, and 28 of unknown histology). There was a statistically non-significant trend toward increased HR in subjects with high BMI [HR for BMI>27.5 kg/m2, compared with 22.6-25.0, 1.50; 95% confidence interval (CI) 0.76-2.96]. No association was suggested for tobacco smoking; men drinking>400 g of ethanol per week had an HR of 1.57 (95% CI 0.66-3.70), compared with abstainers.

CONCLUSIONS

Our study supports the hypothesis that elevated BMI may be a risk factor for small intestine cancer. An etiologic role of alcohol drinking was suggested. Our results reinforce the existing evidence that the epidemiology of small intestine cancer resembles that of colorectal cancer.

Cerebral fungal infection with mycotic aneurysm of basilar artery and subarachnoid haemorrhage

A 28-year-old Pakistani man was admitted with unresolved severe headaches for the past four weeks. Magnetic resonance (MR) imaging and MR angiography showed an enhancing mass in the sphenoid sinus, bilateral cerebellar infarcts and aneurysmal dilatation of the basilar artery. The differential diagnosis included fungal infection versus neoplastic lesion. The scrappings taken through the endoscope from the sphenoid sinus were initially negative for fungal infection. However, the second biopsy, done after putting him on antifungal, itraconazole 200 mg twice daily, revealed the presence of a fungal infection (aspergillosis). MR imaging revealed extension of the fungal infection from the sphenoid sinus into the clivus, and then intracranially. Imaging also revealed aneurysmal dilatation of the basilar artery and infarctions in the cerebellum and subarachnoid haemorrhage. Despite aggressive antifungal treatment, the patient died after 29 days. This case report describes the probable mechanism of fungal mycotic aneurysmal vascular dilatation and growth. It also points to the need for a rapid diagnosis of potential cases and an aggressive treatment approach of confirmed cases of fungal infections of the central nervous system.

Parity and breastfeeding are protective against breast cancer in Nigerian women

As the relation between reproductive factors and breast cancer risk has not been systematically studied in indigenous women of sub-Saharan Africa, we examined this in a case–control study in Nigeria. In-person interviews were conducted using structured questionnaires to collect detailed reproductive history in 819 breast cancer cases and 569 community controls between 1998 and 2006. Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CI). Compared with women with menarcheal age <17 years, the adjusted OR for women with menarcheal age ⩾17 years was 0.72 (95% CI: 0.54–0.95, P=0.02). Parity was negatively associated with risk (P-trend=0.02) but age at first live birth was not significant (P=0.16). Importantly, breast cancer risk decreased by 7% for every 12 months of breastfeeding (P-trend=0.005). It is worth noting that the distribution of reproductive risk factors changed significantly from early to late birth cohorts in the direction of increasing breast cancer incidence. Our findings also highlight the heterogeneity of breast cancer aetiology across populations, and indicate the need for further studies among indigenous sub-Saharan women.

Serum levels of the extracellular domain of the epidermal growth factor receptor in individuals exposed to arsenic in drinking water in Bangladesh

Epidermal growth factor receptor-dependent mechanisms have been implicated in growth signal transduction pathways that contribute to cancer development, including dermal carcinogenesis. Detection of the extracellular domain of the epidermal growth factor receptor (EGFR ECD) in serum has been suggested as a potential biomarker for monitoring this effect in vivo. Arsenic is a known human carcinogen, producing skin and other malignancies in populations exposed through their drinking water. One such exposed population, which we have been studying for a number of years, is in Bangladesh. The purpose of this study was to examine the EGFR ECD as a potential biomarker of arsenic exposure and/or effect in this population. Levels of the EGFR ECD were determined by enzyme-linked immunosorbent assay in the serum samples from 574 individuals with a range of arsenic exposures from drinking water in the Araihazar area of Bangladesh. In multiple regression analysis, serum EGFR ECD was found to be positively associated with three different measures of arsenic exposure (well water arsenic, urinary arsenic and a cumulative arsenic index) at statistically significant levels (p<or=0.034), and this association was strongest among the individuals with arsenic-induced skin lesions (p <or= 0.002). When the study subjects were stratified in tertiles of serum EGFR ECD levels, the risk of skin lesions increased progressively for each increase in all three arsenic measures (also stratified in tertiles) and this increasing risk became more pronounced among subjects within the highest tertile of EGFR ECD levels. These results suggest that serum EGFR ECD levels may be a potential biomarker of effect of arsenic exposure and may indicate those exposed individuals at greatest risk for the development of arsenic-induced skin lesions.

Clinics in diagnostic imaging (102)

A 19-year-old man presented with cough and haemoptysis of ten days duration. He also had mild right hypochondrial pain. Chest radiograph and computed tomography (CT) showed a rounded soft tissue density opacity with an air crescent sign. CT showed multiple cystic lesions in the liver with a daughter cyst in its lateral wall. Diagnosis of hydatid disease of lung and liver was made. The contents of the liver cyst were aspirated, hypertonic saline instilled, re-aspirated, and absolute alcohol injected. Hydatid disease is endemic in certain parts of the world. Although the lungs and liver are most frequently affected, the disease can arise in any part of the body and should be kept in differential diagnosis whenever a cystic lesion is encountered. Hydatid cysts typically demonstrate characteristic imaging findings, however, the appearances may become complicated due to cyst rupture or secondary infection. Ultrasonography is the imaging modality of choice particularly in hepatic disease. CT best demonstrates cyst wall calcification and cyst infection.

Reliability of a commercial kit to test groundwater for arsenic in Bangladesh

A comparison of field and laboratory measurements of arsenic in groundwater of Araihazar, Bangladesh, indicates that the most widely used field kit correctly determined the status of 88% of 799 wells relative to the local standard of 50 microg/L As. Additional tests showthatthe inconsistencies, mainly underestimates in the 50-100 microg/L As range, can be avoided by increasing the reaction time from 20 to 40 min. Despite this limitation, the field data already compiled for millions of wells by the Bangladesh Arsenic Mitigation and Water Supply Project, in combination with information on well location and depth, should prove to be extremely useful to prioritize interventions in thousands of affected villages.

Oxygen free radicals and systemic autoimmunity

Reactive oxygen species generated during various metabolic and biochemical reactions have multifarious effects that include oxidative damage to DNA leading to various human degenerative and autoimmune diseases. The highly reactive hydroxy radical (*OH) can interact with chromatin and result in a wide range of sugar and base-derived products, DNA-protein cross-links and strand breaks. Studies from our laboratory have demonstrated that after modification the DNA becomes highly immunogenic and the induced antibodies exhibit variable antigen-binding characteristics. Systemic lupus erythematosus, a prototype autoimmune disease, is characterized by the presence of autoantibodies to multiple nuclear antigens. The detection of 8-hydroxyguanosine in the immune complex derived DNA of systemic lupus erythematosus patients reinforces the evidence that reactive oxygen species may be involved in its pathogenesis. Increased apoptosis and decreased clearance of apoptotic cells as observed in systemic lupus erythematosus (SLE) might well be a contributory factor in systemic autoimmunity. Clinically, titres of autoantibodies are closely related to the degree of renal inflammation. Anti-DNA antibodies may combine with circulating antigen and contribute to the deposition of immune complexes in renal glomeruli.

Cancer patterns in Karachi division (1998-1999)

OBJECTIVE

A minimal cancer incidence data for Karachi, the largest city of Pakistan, is being presented here, for the years 1998-1999. The city has a population of 9,802,134; males 5,261,712 (52.6%) and females 4,540,422 (47.4%); census 1998.

METHODOLOGY

A predominantly mixed (passive and active) registration system has evolved in Karachi, the data sources being the hospitals within the Karachi Division. The reported/retrieved cancer data sets at the Karachi Cancer Registry are checked, coded, computerised in an analytical format and analysed.

RESULTS

The incident cancer cases registered in Karachi, during the 2-year period, 1st January 1998 to 31st December 1999 were analysed. The age-standardised incidence rate (ASR) of cancer, all sites was 132.4/100,000 for the males. Cancer of the lung 10.8%; ASR 17.3 was the most frequently recorded malignancy, followed by oral cavity 10.5%; ASR 13.2 and larynx 5.0%; ASR 7.4. The age-standardised incidence rate (ASR) of cancer, all sites was 133.0/100,000 in the females. Cancer of the breast, 32.0%; ASR 40.7 was the most frequently recorded malignancy, followed by oral cavity 8.1%; ASR 11.7 and gall bladder 3.6%; ASR 5.5.

CONCLUSION

The present data has been calculated with an estimated 15-20% probable under ascertainment. Tobacco-associated cancers in Karachi were responsible for 38.3% of the tumours diagnosed amongst the males. Two principal cancers, breast and oral cavity were responsible for 40.1% of the cancers in females. A rare finding was the high incidence of gall bladder cancer in the females. At present it is difficult to determine whether this indicates a genuine high risk or a selection bias. A continuous process of cancer registration to study the trends in the incidence and an adequate cancer control program are possible and essential for Pakistan and can be based on the pattern being practiced in Karachi.

Recognition of DNA-arginine photoadduct by anti-DNA autoantibodies in systemic lupus erythematosus

BACKGROUND & OBJECTIVES

Studies have been carried out to synthesize and characterize the photoconjugate between positively charged amino acid, arginine and DNA fragments and their role in the induction of anti-DNA antibodies.

METHODS

Calf thymus DNA fragments of about 200 base pairs (bp) were covalently crosslinked with arginine under UV light. The amino acid was found to be covalently photoconjugated to DNA and resulted in the formation of a crosslink. The photoadduct was characterized by various physicochemical methods.

RESULTS

Photoaddition of arginine to 200 bp DNA rendered the nucleic acid conformer thermodynamically more stable than the native form. After systematic characterization of the photoadduct, it was used as an antigen for the generation of antibodies in experimental animals. The photoadducts were found to be immunogenic in rabbits, inducing high titre antibodies. The DNA-arginine photoadduct showed higher binding with SLE sera known to have high level of anti-DNA antibodies.

INTERPRETATION & CONCLUSION

Naturally occurring anti-DNA autoantibodies were found to recognize DNA-arginine photoadduct. The recognition of DNA-arginine photoadduct by anti-DNA autoantibodies points to the role of modified DNA in the induction of anti-DNA antibodies in autoimmune disorders.

Associations of plasma aflatoxin B1-albumin adduct level with plasma selenium level and genetic polymorphisms of glutathione S-transferase M1 and T1

Mortality from hepatocellular carcinoma (HCC) is extraordinarily high in Matzu, an island off the coast of Southeastern China. To investigate factors associated with plasma aflatoxin B1 (AFB1)-albumin adduct level, we studied 304 healthy adult residents from Matzu. AFB1-albumin adducts were determined by competitive enzyme-linked immunosorbent assay, hepatitis B surface antigen status by enzyme immunoassay, genotypes of glutathione S-transferase (GST) M1 and T1 by polymerase chain reaction, plasma selenium by atomic absorption spectrometry, and plasma retinol, alpha-tocopherol, alpha-carotene, and beta-carotene levels by high-performance liquid chromatography. Men had higher AFB1-albumin adduct levels than women. GSTM1-nonnull and GSTT1-null genotypes and low plasma selenium level were significantly associated with an increased level of AFB1-albumin adducts among men, whereas age was significantly correlated with adduct level among women. High intake of fermented beans was associated with an increased adduct level among men and women. The inverse associations between plasma selenium level and AFB1-albumin adducts were statistically significant among those with null genotypes of GSTM1 and GSTT1, but not among the nonnull genotypes. This study provides insight into the dietary and genetic factors influencing AFB1-albumin adduct formation in an isolated population with high liver cancer mortality.

Association of aflatoxin B(1)-albumin adduct levels with hepatitis B surface antigen status among adolescents in Taiwan

Chronic hepatitis B virus (HBV) infection and aflatoxin B(1) (AFB(1)) exposure interact synergetically to induce hepatocellular carcinoma. One suggested mechanism for this interaction is the enhanced activation of AFB(1) in chronically HBV-infected individuals. Whereas no associations between chronic HBV infection and AFB(1)-albumin adducts were observed in several studies in adults, hepatitis B surface antigen (HbsAg)-positive children were found to have elevated adducts in Gambia. To assess the association between chronic HBV infection and AFB(1)-albumin adduct level in Taiwan, 200 junior high school adolescents from 20 townships were assayed for HBsAg and AFB(1)-albumin adducts. The mean AFB(1)-albumin adduct level was higher in HBsAg-positive compared with HBsAg-negative subjects. The association between HBsAg status and AFB(1)-albumin adducts remained after multivariate adjustment. This finding additionally supports the synergetic interaction between HBV and AFB(1), but the mechanism remains to be elucidated.

Nutrient intake and risk of subtypes of esophageal and gastric cancer

Incidence rates for adenocarcinoma of the esophagus and gastric cardia have been rising rapidly. We examined nutrient intake as a risk factor for esophageal and gastric cancers in a population-based case-control study in Connecticut, New Jersey, and western Washington state. Interviews were completed for cases with histologically confirmed esophageal adenocarcinoma (n = 282), adenocarcinoma of the gastric cardia (n = 255), esophageal squamous cell carcinoma (n = 206), and noncardia gastric adenocarcinoma (n = 352), along with population controls (n = 687). Associations between nutrient intake and risk of cancer were estimated by adjusted odds ratios (ORs), comparing the 75th versus the 25th percentile of intake. The following nutrients were significantly inversely associated with risk of all four tumor types: fiber, beta-carotene, folate, and vitamins C and B6. In contrast, dietary cholesterol, animal protein, and vitamin B12 were significantly positively associated with risk of all four tumor types. Dietary fat [OR, 2.18; 95% confidence interval (CI), 1.27-3.76] was significantly associated with risk of esophageal adenocarcinoma only. Dietary nitrite (OR, 1.65; 95% CI, 1.26-2.16) was associated with noncardia gastric cancer only. Vitamin C supplement use was associated with a significantly lower risk for noncardia gastric cancer (OR, 0.60; 95% CI, 0.41-0.88). Higher intake of nutrients found primarily in plant-based foods was associated with a reduced risk of adenocarcinomas of the esophagus and gastric cardia, whereas higher intake of nutrients found primarily in foods of animal origin was associated with an increased risk.

Variability in aflatoxin-albumin adduct levels and effects of hepatitis B and C virus infection and glutathione S-transferase M1 and T1 genotype

Exposure to aflatoxin B1 (AFB1), an important cofactor in the etiology of hepatocellular carcinoma in Taiwan, is influenced by dietary and other factors. The present study examined the intraindividual variability in AFB1-albumin adducts, the most reliable long-term biomarker of AFB1 exposure, and whether the baseline or follow-up adduct levels and the intraindividual variability in adduct levels are modified by endogenous and environmental factors. The study measured AFB1-albumin adduct levels among 264 healthy male residents of three townships (Hu-Hsi, Ma-Kung, and Pai-Hsa) of Penghu Islets, Taiwan, at two different time points with a median interval of 1.68 years (range 1.00-3.17 years). There was a generalized reduction in the adduct levels, with the median values being 22.1 pmol/mg (range 5.0-355.8 pmol/mg) at time 1 and 14.3 pmol/mg (range 5.0-205.2 pmol/mg) at time 2. This intraindividual variability in adduct levels was inversely associated with the age of subjects and the time interval between the two blood draws. The variability in adduct levels was lower among subjects in Hu-Hsi and Pai-Hsa townships as compared to those in Ma-Kung. No significant association was observed for the intraindividual variability in AFB1-albumin adducts with regard to the season when blood was drawn. There was also no significant association between intraindividual variability and hepatitis B surface antigen, anti-hepatitis C virus (anti-HCV), glutathione S-transferase (GST) M1, or GSTT1 status. In conclusion, we found substantial intraindividual variability in the AFB1 exposure (as determined by AFB1-albumin adducts) in Taiwan, which was probably more likely related to dietary or other environmental influences rather than to endogenous factors (e.g., hepatitis B/C viral infection or GST M1/T1 genetic status).

Family history of cancer and risk of esophageal and gastric cancers in the United States

The worldwide rates for histology- and subsite-specific types of esophageal and gastric cancer reveal strikingly divergent patterns. The contribution of environmental and genetic factors has been explored in several high-incidence areas, but data on genetic influences are scarce for Western countries. Using data from a multicenter, population-based, case-control study on 1,143 cases and 695 controls in the United States, we evaluated whether a family history of digestive or other cancers was associated with an increased risk of esophageal adenocarcinoma (n = 293), esophageal squamous cell carcinoma (n = 221), gastric cardia adenocarcinoma (n = 261) or non-cardia gastric adenocarcinoma (n = 368). After adjusting for other risk factors, individuals reporting a family history of digestive cancers experienced no increased risk of either type of esophageal cancer but they were prone to adenocarcinomas of the gastric cardia [odds ratio (OR) = 1.34, 95% confidence interval (CI) 0.91-1.97] and non-cardia segments (OR =1.46, 95% CI 1.03-2.08). This familial tendency, particularly for non-cardia gastric tumors, was largely explained by an association with family history of stomach cancer (OR = 2.52, 95% CI 1.50-4.23). In addition, family history of breast cancer was associated with increased risks of esophageal adenocarcinoma (OR = 1.74, 95% CI 1.07-2.83) and non-cardia gastric adenocarcinoma (OR = 1.76, 95% CI 1.09-2.82). Also seen were non-significant familial associations of esophageal squamous-cell cancer with prostate cancer as well as non-cardia gastric cancer with leukemia and brain tumors, though these relationships must be interpreted with caution. Our data point to the role of familial susceptibility to gastric cancer, but not to any form of esophageal cancer, in the United States.

Variations in the use of adjuvant chemotherapy for node-positive colon cancer in the elderly: a population-based study

BACKGROUND

Since 1990, the recommended adjuvant therapy for patients with surgically resected node-positive colon cancer has been 5-fluorouracil (5-FU), usually in combination with leucovorin or levamisole. The purpose of this study is to assess the distribution of adjuvant 5-FU treatment in the elderly.

METHODS

The Surveillance, Epidemiology and End Results-Medicare database provides population-based information on cancer patients, representing approximately 14% of the United States population, along with health care utilization data from Medicare claims files. We studied patients with node-positive colon cancer diagnosed between 1992 and 1996 who survived at least 120 days beyond diagnosis (N = 4998).

RESULTS

About 50% of elderly patients received 5-FU within 4 months of diagnosis. The proportion of patients treated with 5-FU increased by about 10% from 1992 to 1996. In a multiple logistic regression model, 5-FU treatment was less likely to be given to older patients (compared with those aged 65-69 years, the odds ratio (OR) [95% CI] was 0.82 [0.67-1.00] for ages 70 to 74 years, 0.47 [0.39-0.57] for ages 75 to 79, 0.17 [0.13-0.20] for ages 80 to 84, and 0.04 [0.03-0.05] for ages 85 to 88 years. Non-Hispanic black patients were less likely to be treated than non-Hispanic white patients (OR 0.46 [0.36-0.59]); patients with more than three positive lymph nodes were more likely to be treated than those with three or less, and those with comorbid conditions were less likely to be treated than those without such conditions.

CONCLUSIONS

Despite its proven efficacy in reducing colon cancer mortality, 5-FU-based chemotherapy is not widely used among apparently eligible patients over age 65. Efforts are needed to ensure that elderly and non-Hispanic black patients receive appropriate treatment.

Associations between drinking water and urinary arsenic levels and skin lesions in Bangladesh

The present study examined the associations between drinking water and urinary arsenic levels and skin lesions among 167 residents of three contiguous villages in Bangladesh. Thirty-six (21.6%) had skin lesions (melanosis, hyperkeratosis, or both), of which 13 (36.1%) occurred in subjects who were currently drinking water containing concentrations of arsenic < 50 micrograms/L. The risk for skin lesions in relation to the exposure estimates based on urinary arsenic was elevated more than 3-fold, with the odds ratios for the highest versus the lowest quartiles being 3.6 (95% confidence interval, 1.2 to 12.1) for urinary total arsenic and 3.2 (95% confidence interval, 1.1 to 10.0) for urinary creatinine-adjusted total arsenic. The risks for skin lesions in relation to the exposure estimates based on arsenic in drinking water were less strongly elevated, with the odds ratios for the highest versus the lowest quartiles of exposure being 1.7 (95% confidence interval, 0.6 to 5.1) for drinking-water arsenic and 2.3 for cumulative arsenic index. The study suggests that arsenic exposure is associated with skin lesions in the Bangladesh population and that urinary arsenic may be a stronger predictor of skin lesions than arsenic in drinking water in this population.

The metropolitan new york registry & cfrbcs. Unique resources for breast cancer research

PURPOSE: The goal of the Metropolitan NY Registry, and five other international collaborating sites of the Cooperative Family Registry for Breast Cancer Studies [CFRBCS], has been the development of a comprehensive resource for interdisciplinary genetic epidemiology studies addressing breast cancer risk and prognostic factors.METHODS: Family recruitment has been conducted in clinical and community settings by a multidisciplinary team of collaborators affiliated at six major metropolitan NY medical centers. Families meeting one of the following criteria were invited to join: a male with breast cancer; a female with breast or ovarian cancer diagnosed at age </=45; a female with breast and ovarian cancer; or two or more first and second degree relatives diagnosed at any ages. Participants are asked to complete an epidemiology questionnaire, dietary history form, extensive family history, and donate biospecimens including blood and urine. Pathology reports and tissue samples are obtained for breast and ovarian cancer cases; pathology reports are requested to confirm the history of other cancers.RESULTS: Of the 1102 families (3,252 participants), 28 males and 1,304 females had been treated for breast cancer. More than 2,400 blood samples are banked and >3,000 epidemiology questionnaires completed. Ethnic/racial data indicates 14% are of African American or Hispanic heritage and 509 families (46%) are of Ashkenazi descent. One or more DNA samples from 400 Ashkenazi families have been tested for the three BRCA1/2 founder mutations. Of 331 Ashkenazi participants with a history of breast and/or ovarian cancer, 19% were found to be mutation carriers. Thirty-six (7 men/29 women) mutation carriers are free of cancer.CONCLUSIONS: The families participating in the NY Registry reflect a spectrum of breast cancer risk. The extensive NY and CFRBCS databases and banked biospecimens provide a unique resource for multidisciplinary genetic epidemiologic studies that may identify avenues for prevention.

Cancer education among primary care physicians in an underserved community

INTRODUCTION

Urban minority groups, such as those living in north Manhattan, are generally underserved with regard to cancer prevention and screening practices. Primary care physicians are in a critical position to counsel their patients on these subjects and to order screening tests for their patients.

METHODS

Eighty-four primary care physicians in two intervention communities who received educational visits about cancer screening and prevention were compared with 38 physicians in a nearby community who received no intervention. With pre- and post-test interviews over an 18-month period, the physicians were asked about their attitudes toward, knowledge of (relative to American Cancer Society guidelines), and likelihood of counseling and screening for breast, cervical, colorectal, and prostate cancers.

RESULTS

Comparison of the two surveys of physicians indicated no statistically significant differences in knowledge of cancer prevention or screening. At post-test, however, intervention group physicians identified significantly fewer barriers to practice than control physicians (p<0.05). While overall, the educational visits to inner-city primary care physicians did not appear to significantly alter cancer prevention practices, there was a positive dose-response relationship among the subgroup of participants who received three or more project contacts.

CONCLUSIONS

We uncovered significant changes in attitude due to academic detailing among urban primary care physicians practicing in north Manhattan. A significant pre-test sensitization effect and small numbers may have masked overall changes in cancer prevention and screening behaviors among physicians due to the intervention.

Cancer screening and prevention practices of inner-city physicians

INTRODUCTION

Effective preventive services are needed most in underserved, inner-city settings that suffer disproportionately from morbidity and mortality. Primary care physicians can play an important role in the provision of efficacious cancer prevention and screening services to patients in these communities.

METHOD

We surveyed 122 primary care physicians about their cancer prevention and screening knowledge, attitudes, and practices.

RESULTS

Relative to the findings from national and local surveys, sample physicians were not as knowledgeable about national guidelines for preventive care, were less likely to counsel on smoking cessation, and were less likely to advise diet modification. Although physician practices reflected national cancer prevention and screening guidelines in general, a significant proportion of physicians suggested lung and prostate cancer screening tests that were inconsistent with national recommendations.

CONCLUSIONS

Systematic efforts are needed to increase the knowledge and practices of inner-city physicians concerning cancer prevention and screening.

Gastroesophageal reflux disease, use of H2 receptor antagonists, and risk of esophageal and gastric cancer

OBJECTIVE

The incidence of esophageal adenocarcinoma has risen rapidly in the past two decades, for unknown reasons. The goal of this analysis was to determine whether gastroesophageal reflux disease (GERD) or the medications used to treat it are associated with an increased risk of esophageal or gastric cancer, using data from a large population-based case-control study.

METHODS

Cases were aged 30-79 years, newly diagnosed with esophageal adenocarcinoma (n = 293), esophageal squamous cell carcinoma (n = 221), gastric cardia adenocarcinoma (n = 261), or non-cardia gastric adenocarcinoma (n = 368) in three areas with population-based tumor registries. Controls (n = 695) were chosen by random digit dialing and from Health Care Financing Administration rosters. Data were collected using an in-person structured interview.

RESULTS

History of gastric ulcer was associated with an increased risk of non-cardia gastric adenocarcinoma (OR 2.1, 95% CI 1.4-3.2). Risk of esophageal adenocarcinoma increased with frequency of GERD symptoms; the odds ratio in those reporting daily symptoms was 5.5 (95% CI 3.2-9.3). Ever having used H2 blockers was unassociated with esophageal adenocarcinoma risk (OR 0.9, 95% CI 0.5-1.5). The odds ratio was 1.3 (95% CI 0.6-2.8) in long-term (4 or more years) users, but increased to 2.1 (95% CI 0.8-5.6) when use in the 5 years prior to the interview was disregarded. Risk was also modestly increased among users of antacids. Neither GERD symptoms nor use of H2 blockers or antacids was associated with risk of the other three tumor types.

CONCLUSIONS

Individuals with long-standing GERD are at increased risk of esophageal adenocarcinoma, whether or not the symptoms are treated with H2 blockers or antacids.

Carcinogenic effects of radiotherapy for breast cancer

As increasing numbers of women with breast cancer survive their illness, it is critical to ascertain the long-term consequences of breast cancer treatment. One important effect is the occurrence of second malignancies, particularly in women treated with radiation therapy. Methodologic considerations raised in studying this issue include the effects of postmastectomy radiotherapy vs whole-breast irradiation, as currently employed following breast-conserving surgery; particularly germane are differences in the fields irradiated and the relative dosages to which various organs are exposed. Breast cancer radiotherapy does not appear to be a major factor in the occurrence of subsequent contralateral breast cancer. Such therapy may raise the risk of leukemia, particularly in association with certain types of adjuvant chemotherapy. Lung cancer risk is also increased, especially in cigarette smokers, and there are some indications that the risks of esophageal cancer and sarcomas may be elevated as well. Clinicians should be aware of these risks when trying to distinguish breast cancer recurrences from new primary malignancies. However, it should also be remembered that a high relative risk may represent only a slight increase in absolute risk. The benefits of breast cancer radiotherapy in improving survival or quality of life remain the principal factors to be weighed when deciding whether to treat patients with radiation.

The association between biliary tract cancers and cancers of other sites

OBJECTIVE

Cancers of the biliary tract, including cancers of the gallbladder and bile duct, generally carry a very poor prognosis. Little is known about their etiology. The pattern of co-occurrence of two cancers may give clues to shared etiological risk factors. We therefore investigated the association of biliary tract cancer with other cancers, especially with estrogen- and tobacco-related cancers.

METHODS

We used data from the Surveillance, Epidemiology, and End Results Program of the National Cancer Institute. Associations between biliary tract cancer and other cancers were evaluated using the standardized incidence ratio as an estimate of the relative risk of a second primary malignancy.

RESULTS

Estrogen-related cancers of the breast and uterine corpus and smoking-related upper aerodigestive tract cancers were not associated with biliary tract cancer. The risk of gallbladder cancer was inversely related to the risk of prostate cancer in men, but positively related to the risk of cervical cancer in women.

CONCLUSIONS

This study suggests that smoking and estrogen exposure have minimal roles in the pathogenesis of biliary tract cancer. Our finding of an inverse relationship between prostate cancer and gallbladder cancer requires confirmation by further studies.

Pro-oxidant, anti-oxidant and cleavage activities on DNA of curcumin and its derivatives demethoxycurcumin and bisdemethoxycurcumin

Curcumin, a naturally occurring phytochemical responsible for the colour of turmeric shows a wide range of pharmacological properties including antioxidant, anti-inflammatory and anti-cancer effects. We have earlier shown that curcumin in the presence of Cu(II) causes strand cleavage in DNA through generation of reactive oxygen species, particularly the hydroxyl radical. Thus, curcumin shows both antioxidant as well as pro-oxidant effects. In order to understand the chemical basis of various biological properties of curcumin, we have studied the structure-activity relationship between curcumin and its two naturally occurring derivatives namely demethoxycurcumin (dmC) and bisdemethoxycurcumin (bdmC). Curcumin was found to be the most effective in the DNA cleavage reaction and a reducer of Cu(II) followed by dmC and bdmC. The rate of formation of hydroxyl radicals by the three curcuminoids also showed a similar pattern. The relative antioxidant activity was examined by studying the effect of these curcuminoids on cleavage of plasmid DNA by Fe(II)-EDTA system (hydroxyl radicals) and the generation of singlet oxygen by riboflavin. The results indicate that curcumin is considerably more active both as an antioxidant as well as an oxidative DNA cleaving agent. The DNA cleavage activity is the consequence of binding of Cu(II) to various sites on the curcumin molecule. Based on the present results, we propose three binding sites for Cu(II). Two of the sites are provided by the phenolic and methoxy groups on the two benzene rings and the third site is due to the presence of 1,3-diketone system between the rings. Furthermore, both the antioxidant as well as pro-oxidant effects of curcuminoids are determined by the same structural moieties.

PTEN/MMAC1 mutations in hepatocellular carcinomas

Mutations in the PTEN/MMAC1 gene have been identified in several types of human cancers and cancer cell lines, including brain, endometrial, prostate, breast, thyroid, and melanoma. In this study, we screened a total of 96 hepatocellular carcinoma (HCC) samples from Taiwan, where HCC is the leading cancer in males and third leading cancer in females, for mutations in the PTEN/MMAC1 gene. Complete sequence analysis of these samples demonstrated a missense mutation in exon 5 (K144I) and exon 7 (V255A) from HCC samples B6-21 and B6-2, respectively. A putative splice site mutation was also detected in intron 3 from sample B6-2. Both B6-21 and B6-2 were previously shown to contain missense mutations in the coding sequences of the p53 gene. Functional studies with the two missense mutations demonstrated that while mutation V255A in exon 7 resulted in a loss of phosphatase activity, mutation K144I in exon 5 retained its phosphatase activity. Additionally, we identified a silent mutation (P96P) in exon 5 of the PTEN/MMAC1 gene from HCC sample B6-22. These data provide the first evidence that the PTEN/MMAC1 gene is mutated in a subset of HCC samples.

Risk factors for biliary tract cancers

OBJECTIVE

Little is known regarding risk factors for biliary tract cancer, i.e., gallbladder carcinoma and extrahepatic bile duct carcinoma. This is the first case-control study conducted in the U.S. regarding risk factors for these cancers.

METHODS

In this hospital-based case-control study, we reviewed the medical records of 69 patients with primary biliary tract cancer who were admitted to Columbia-Presbyterian Medical Center for surgery between January 1, 1980, and April 4, 1994, and of 138 controls, consisting of patients admitted for surgery for benign conditions.

RESULTS

We found a significant association between cholelithiasis and biliary tract cancers (odds ratio, 19.5; 95% confidence interval, 6.4-59.4). Risk factors associated with gallbladder cancer included female gender, age, cigarette smoking, and postmenopausal status in women. Risk factors associated with extrahepatic bile duct cancer included history of cholecystectomy and hysterectomy in women.

CONCLUSION

The risk factors for biliary tract cancers that have been identified in our study delineate a high-risk population, which in the future may be targeted for preventive measures.

Serum cholesterol and the risk of ductal carcinoma in situ: a case-control study

While multiple studies have investigated the association between serum cholesterol level and breast cancer, the results have generally been conflicting. No prior study has investigated its association with ductal carcinoma in situ (DCIS) of the breast. In this hospital-based case-control study, 152 DCIS cases were compared to 242 controls (patients with benign surgical conditions). Unconditional logistic regression was used to compare the serum cholesterol levels, adjusting for relevant covariates. No statistically significant difference was observed for different quartiles of the serum cholesterol level as compared to the lowest quartile. Incidentally observed was an elevated risk for DCIS in postmenopausal versus premenopausal women, and in peri-menopausal versus premenopausal women. There is no apparent association between the serum cholesterol level and breast DCIS.

Association between coronary heart disease and cancers of the breast, prostate, and colon

Coronary heart disease (CHD) and cancers of the breast, prostate, and colon are more common in industrialized countries than in the developing world, and to some degree, these conditions appear to share risk factors. To investigate whether there is an association between these cancers and a prior history of CHD, a hospital-based case-control study was conducted at Columbia-Presbyterian Medical Center in New York. The study was based on 252 breast cancer cases, 256 colorectal cancer cases, and 322 benign surgical controls, all of whom underwent biopsy or surgery between January 1989 and December 1992, and on 319 prostate cancer cases and 189 benign prostatic hypertrophy controls diagnosed between January 1984 and December 1986 (prior to widespread use of prostate-specific antigen screening). Medical records were reviewed on each, focusing on the preoperative anesthesia and surgical clearances. No association was found between a history of CHD and breast or colorectal cancer, but an elevated risk was found for prostate cancer (odds ratio, 2.00; 95% confidence interval, 1.18-3.39), using unconditional logistic regression with adjustment for appropriate confounders. No association was found between cigarette smoking and any of the three cancers. Aspirin use was protective for colorectal cancer (odds ratio, 0.35; 95% confidence interval, 0.17-0.73) but had no association with breast or prostate cancer. The study suggests that individuals with CHD are at elevated risk for prostate cancer but not breast or colorectal cancer. Etiological risk factors associated with CHD should be investigated with regard to prostate cancer. Patients with CHD may represent a high-risk group for prostate cancer and potential future targets for prostate cancer screening interventions.

Risk of esophageal and gastric adenocarcinomas in relation to use of calcium channel blockers, asthma drugs, and other medications that promote gastroesophageal reflux

Incidence of adenocarcinomas of the esophagus and gastric cardia has risen dramatically over the past 2 decades in the U. S., for reasons that are not yet clear. A number of common medications (e.g., calcium channel blockers, tricyclic antidepressants, and certain asthma medications) promote gastroesophageal reflux by relaxing the lower esophageal sphincter (LES). Reflux is thought to increase cancer risk by promoting cellular proliferation, and by exposing the esophageal epithelium to potentially genotoxic gastric and intestinal contents. Recent studies have suggested that calcium channel blockers may also increase cancer risk by inhibiting apoptosis. Using personal interview data from a multicenter, population-based case-control study conducted between 1993 and 1995 in three areas of the U. S., we evaluated whether the use of LES-relaxing drugs was associated with increased risk of adenocarcinomas of the esophagus and gastric cardia. Cases of esophageal adenocarcinoma (n = 293) and gastric cardia adenocarcinoma (n = 261) were compared with general population controls (n = 695). Information on additional case groups of esophageal squamous cell carcinoma (n = 221) and noncardia gastric cancer (n = 368) were also available for comparison. Overall, 27.4% of controls had used one or more of these drugs for at least 6 months, compared with 30.2% of esophageal adenocarcinoma and 23.8% of gastric cardia adenocarcinoma cases. The adjusted odds ratios (ORs) for ever use were 1.0 [95% confidence interval (CI) = 0.7-1.5] and 0.8 (95% CI = 0.5-1.1), respectively. There was little evidence of increasing risk with increasing duration of use of all LES-relaxing drugs together. We found an increased risk of esophageal adenocarcinoma among persons reporting use of asthma drugs containing theophylline (OR = 2.5; 95% CI = 1.1-5.6) or beta agonists (OR = 1.7; 95% CI = 0.8-3.8). Risks were higher among long-term users (>5 years) of these drugs (OR = 3.1; 95% CI = 0.9-10.3 and OR = 2.3; 95% CI = 0.8-7.0, respectively). In contrast, there was no evidence that the use of calcium channel blockers or other specific groups of drugs increased the risk of any of the cancers studied. These results provide reassuring evidence that the increases in incidence of adenocarcinomas of the esophagus and gastric cardia are not likely to be related to the use of LES-relaxing drugs as a group, or calcium channel blockers in particular, but they do suggest that persons treated for long-standing asthma may be at increased risk of esophageal adenocarcinoma.

Family history of colorectal adenomatous polyps and increased risk for colorectal cancer

BACKGROUND

The risk for colorectal cancer among family members of patients with colorectal cancer is well established, but the risk among family members of patients with colorectal adenomas is less well established.

OBJECTIVE

To examine the risk for colorectal cancer among first-degree relatives of patients with adenoma compared with that among first-degree relatives of controls without adenoma.

DESIGN

Reconstructed cohort study.

SETTING

Three university-based colonoscopy practices in New York City.

PATIENTS

1554 first-degree relatives of 244 patients with newly diagnosed adenomas and 2173 first-degree relatives of 362 endoscopically normal controls.

MEASUREMENTS

Structured interviews were used to obtain family history. Adjusted relative risks (RR) were estimated from Cox proportional hazards regression models.

RESULTS

The risk for colorectal cancer was elevated (RR, 1.74 [95% CI, 1.24 to 2.45]) among first-degree relatives of patients with newly diagnosed adenomas compared with the risk among first-degree relatives of controls. This increased risk was the same for parents (RR, 1.58 [CI, 1.07 to 2.34]) and siblings (RR, 1.58 [CI, 0.81 to 3.08]). First-degree relatives of patients with adenomas did not have elevated risk for other cancers. The risk for colorectal cancer among family members increased with decreasing age at diagnosis of adenoma in probands. Among first-degree relatives of patients who were 50 years of age or younger when the adenoma was diagnosed, the risk was more than four times greater (RR, 4.36 [CI, 2.24 to 8.51]) than that among first-degree relatives of patients who were older than 60 years of age when the adenoma was diagnosed.

CONCLUSIONS

First-degree relatives of patients with newly diagnosed adenomas, particularly of patients who are 50 years of age or younger at diagnosis, are at increased risk for colorectal cancer and should undergo screening similar to that recommended for relatives of patients with colorectal cancer.

Strand scission in DNA induced by curcumin in the presence of Cu(II)

Curcumin, a naturally occurring phytochemical responsible for the colour of turmeric, has shown a wide range of pharmacological properties including anti-inflammatory, anti-tumour promoter and anti-oxidant effects. In this paper we show that in the presence of Cu(II), curcumin caused breakage of calf thymus and supercoiled plasmid pBR322 DNA. The products were relaxed circles with no detectable linear forms. Other metal ions tested (Mg(II), Ca(II), Fe(II) and Ni(II)) were ineffective or less effective in the DNA breakage reaction. Cu(I) was shown to be an essential intermediate by using the Cu(I)-specific sequestering reagent neocuproine. The involvement of active oxygen species, such as H2O2 and (1)O2 was established by the inhibition of DNA breakage by catalase and azide. Curcumin is also able to directly produce O2- and H2O2 and in the presence of Cu(II), OH is generated. Absorption spectra of curcumin in the presence of DNA indicated that a complex is formed between the two. The results are discussed in relation to the established pro-oxidant activities of other known anti-oxidants.

Use of aspirin and other nonsteroidal anti-inflammatory drugs and risk of esophageal and gastric cancer

Regular users of aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) are at reduced risk of colon cancer, but the evidence for protective effects of NSAIDs elsewhere in the digestive tract is scant. We investigated the association between the use of NSAIDs and risk of esophageal and gastric cancer, using data from a large population-based, case-control study. Cases were individuals, ages 30-79 years, diagnosed with esophageal adenocarcinoma (n = 293), esophageal squamous cell carcinoma (n = 221), gastric cardia adenocarcinoma (n = 261), or noncardia gastric adenocarcinoma (n = 368) in three areas with population-based tumor registries. Controls (n = 695) were selected by random digit dialing and through the rosters of the Health Care Financing Administration. After controlling for the major risk factors, we found that current users of aspirin were at decreased risk of esophageal adenocarcinoma [odds ratio (OR), 0.37; 95% confidence interval (CI), 0.24-0.58], esophageal squamous cell carcinoma (OR, 0.49; 95% CI, 0.28-0.87), and noncardia gastric adenocarcinoma (OR, 0.46; 95% CI, 0.31-0.68), but not of gastric cardia adenocarcinoma (OR, 0.80; 95% CI, 0.54-1.19), when compared to never users. Risk was similarly reduced among current users of nonaspirin NSAIDs. The associations with current NSAID use persisted when we excluded use within 2 or 5 years of reference date, which might have been affected by preclinical disease in cases, and when we restricted analyses to subjects reporting no history of chronic gastrointestinal symptoms. Our findings add to the growing evidence that the risk of cancers of the esophagus and stomach is reduced in users of NSAIDs, although whether the association is causal in nature is not clear.

Body mass index and risk of adenocarcinomas of the esophagus and gastric cardia

BACKGROUND

Incidence rates have risen rapidly for esophageal adenocarcinoma and moderately for gastric cardia adenocarcinoma, while rates have remained stable for esophageal squamous cell carcinoma and have declined steadily for noncardia gastric adenocarcinoma. We examined anthropometric risk factors in a population-based case-control study of esophageal and gastric cancers in Connecticut, New Jersey, and western Washington.

METHODS

Healthy control subjects (n = 695) and case patients with esophageal squamous cell carcinoma or noncardia gastric adenocarcinoma (n = 589) were frequency-matched to case patients with adenocarcinomas of esophagus or gastric cardia (n = 554) by 5-year age groups, sex, and race (New Jersey only). Classification of cases by tumor site of origin and histology was determined by review of pathology materials and hospital records. Data were collected using in-person structured interviews. Associations with obesity, measured by body mass index (BMI), were estimated by odds ratios (ORs). All ORs were adjusted for geographic location, age, sex, race, cigarette smoking, and proxy response status.

RESULTS

The ORs for esophageal adenocarcinoma rose with increasing adult BMI. The magnitude of association with BMI was greater among the younger age groups and among nonsmokers. The ORs for gastric cardia adenocarcinoma rose moderately with increasing BMI. Adult BMI was not associated with risk of esophageal squamous cell carcinoma or noncardia gastric adenocarcinoma.

CONCLUSIONS

Increasing prevalence of obesity in the United States population may have contributed to the upward trends in esophageal and gastric cardia adenocarcinomas.

Radiation therapy for breast cancer and increased risk for esophageal carcinoma

BACKGROUND

Several case reports have suggested an association between radiation therapy for breast cancer and the subsequent occurrence of esophageal carcinomas.

OBJECTIVE

To examine the association between radiation therapy for breast cancer and subsequent esophageal squamous-cell carcinomas and adenocarcinomas.

DESIGN

Population-based retrospective cohort study.

SETTING

Population-based U.S. cancer registries.

PATIENTS

220,806 women in whom breast cancer was diagnosed between 1 January 1973 and 31 December 1993; 1,216,853 person-years of follow-up.

MEASUREMENTS

Age- and period-adjusted standardized incidence ratio as a measure of relative risk for the second primary cancer.

RESULTS

In women who had received radiation therapy for breast cancer, the relative risk for esophageal squamous-cell carcinoma increased to 5.42 (95% CI, 2.33 to 10.68) and the relative risk for esophageal adenocarcinoma increased to 4.22 (CI, 0.47 to 15.25) 10 or more years after radiation therapy. No increased risk was seen for either type of carcinoma among patients with breast cancer who did not receive radiation therapy.

CONCLUSION

The risk for esophageal carcinoma is increased in women who receive radiation therapy for breast cancer.

Smoking among male teenagers in Dhaka, Bangladesh

BACKGROUND

Smoking is now recognized as a major public health problem in the developing world. Despite this, there is a dearth of relevant data on smoking prevalence and on the characteristics and attitudes of smokers: in particular, studies are lacking among teenagers and young adults, the group in which the habit frequently begins. The present study addresses this issue by examining the smoking patterns of a sample of teenagers in Dhaka, Bangladesh, during 1991.

METHODS

The study investigated smoking behavior and attitudes among two groups of male teenagers: the first consisted of 555 students, age 12-20 years, selected from two metropolitan high schools; the second, chosen to provide a broad comparison group from a different socioeconomic stratum, contained 112 males of similar age residing in an urban slum. Data were collected largely by interview supplemented by some direct observation and relevant secondary data.

RESULTS

The results showed that 29% of the students and 68% of the slum dwellers said they were regular smokers. In addition, the slum youths smoked substantially more and had smoked for longer than the students. While the study suggests both groups of smokers had been influenced to take up smoking by the smoking behavior of peers and parents, peers were more important for the students. Advertising may also have been a important influence on students since smokers in this group could better identify tobacco advertisements compared with their nonsmoking peers. No significant association was found between respondents' knowledge of the health risks of smoking and their actual smoking behavior.

CONCLUSIONS

This study demonstrates that in Bangladesh, smoking is very common among middle-class male teenagers and even more prevalent among youths from nearby slums. Clearly, local and national programs that draw on relevant knowledge from other countries, but are appropriate to Bangladesh, need to be developed to tackle a major epidemic.