Tobacco, alcohol, and socioeconomic status and adenocarcinomas of the esophagus and gastric cardia

BACKGROUND

Incidence rates for adenocarcinomas of the esophagus and gastric cardia have risen steeply over the last few decades. To determine risk factors for these tumors, we conducted a multicenter, population-based, case-control study.

METHODS

The study included 554 subjects newly diagnosed with esophageal or gastric cardia adenocarcinomas, 589 subjects newly diagnosed with esophageal squamous cell carcinoma or other gastric adenocarcinomas, and 695 control subjects. Estimates of risk (odds ratios [ORs] and corresponding 95% confidence intervals [CIs]) were calculated for the four tumor types separately and for esophageal and gastric cardia adenocarcinomas combined.

RESULTS

Risk of esophageal and gastric cardia adenocarcinomas combined was increased among current cigarette smokers (OR = 2.4; 95% = 1.7-3.4), with little reduction observed until 30 years after smoking cessation; this risk rose with increasing intensity and duration of smoking. Risk of these tumors was not related to beer (OR = 0.8; 95% CI = 0.6-1.1) or liquor (OR = 1.1; 95% CI = 0.8-1.4) consumption, but it was reduced for drinking wine (OR = 0.6; 95% CI = 0.5-0.8). Similar ORs were obtained for the development of noncardia gastric adenocarcinomas in relation to tobacco and alcohol use, but higher ORs were obtained for the development of esophageal squamous cell carcinomas. For all four tumor types, risks were higher among those with low income or education.

CONCLUSIONS

Smoking is a major risk factor for esophageal and gastric cardia adenocarcinomas, accounting for approximately 40% of cases.

IMPLICATIONS

Because of the long lag time before risk of these tumors is reduced among ex-smokers, smoking may affect early stage carcinogenesis. The increase in smoking prevalence during the first two thirds of this century may be reflected in the rising incidence of these tumors in the past few decades among older individuals. The recent decrease in smoking may not yet have had an impact.

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.

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.

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.

Bladder carcinoma and other second malignancies after radiotherapy for prostate carcinoma

BACKGROUND

Radiation therapy (RT) to the pelvis has been associated with an increased risk of bladder carcinoma, as well as other malignancies. However, no controlled studies have previously explored the risk of second malignancies after RT for prostate carcinoma.

METHODS

A retrospective cohort study was conducted utilizing data from the Surveillance, Epidemiology, and End Results Program (SEER) of the U. S. National Cancer Institute from 1973-1990. The standardized incidence ratio (SIR), adjusted for age, was calculated as an estimate of the relative risk (RR) of developing a second malignancy after prostate carcinoma for radiated and nonradiated prostate carcinoma patients separately.

RESULTS

The cohort was comprised of 34,889 prostate carcinoma patients who had undergone RT, and 106,872 who had not. After 8 years, the risk of bladder carcinoma was elevated for the RT group (RR 1.5; 95% confidence interval [CI], 1.1-2.0) but not for the non-RT group (RR 1.0; 95% CI, 0.7-1.2). There was an elevated risk of bladder carcinoma for the RT group at 5-8 years as well (RR 1.3; 95% CI, 1.0-1.7). No elevations in risk were observed for rectal carcinoma, acute nonlymphocytic leukemia, or chronic lymphocytic leukemia for either RT patients or non-RT patients.

CONCLUSIONS

The risk of bladder carcinoma is elevated several years after RT for prostate carcinoma, but this elevation is not dramatic. There is no increased risk of rectal carcinoma or leukemia after this type of radiation exposure.

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.

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.

A population-based study of the incidence of malignant small bowel tumours: SEER, 1973-1990

BACKGROUND

Little is known about the incidence of cancers of the small bowel.

METHODS

Data from cancer registries participating in the Surveillance, Epidemiology, and End-Results (SEER) Program from 1973 to 1990 were analysed to determine the incidence of the four major histological types of cancer occurring in the small intestine: adenocarcinomas, malignant carcinoid tumours, lymphomas and sarcomas. In addition, the incidence rate of lymphomas arising from the small intestine and stomach and adenocarcinomas from the small intestine, stomach and colon were compared over time.

RESULTS

Small bowel tumours occurred rarely, with an average annual incidence rate of 9.9 per million people. Carcinoid tumours and adenocarcinomas were the most common histological subtypes, with average annual incidence rates of 3.8 and 3.7 per million people respectively, followed by lymphomas (1.1 per million people) and sarcomas (1.3 per million people). For all histological subtypes, men had higher rates than women. Most tumours occurred in older adults; over 90% of cases occurred in people over the age of 40. During the 18-year study period, the incidence of small bowel tumours has risen slowly. In white men, black men and black women, rises in the incidence of adenocarcinomas, malignant carcinoids and lymphomas contributed to this trend. In white women, the incidence of adenocarcinomas, was stable while malignant carcinoids and lymphomas rose. The incidence of sarcomas was steady for all groups except black women, for which it fell. The histological types were distributed by anatomical subsite: adenocarcinomas were distributed more proximally on average whereas lymphomas were more common distally. In addition, there was an association between the incidence trends of adenocarcinomas occurring in the duodenum and colon suggesting similar risk factors for cancers in these regions. There was no similar correlation for tumours in the jejunum and ileum. The incidence of lymphomas over time rose in all areas of the small intestine, paralleling a similar rise in lymphomas of the stomach.

CONCLUSIONS

Cancers of the small bowel are rare despite a slow increase over the past two decades, especially among lymphomas. Higher rates in males and whites deserve further investigation.

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.

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.

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.

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.

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.

Incidence and recurrence rates of colorectal adenomas: a prospective study

BACKGROUND/AIMS

The frequency of colorectal adenomas, the precursor lesions for most cases of colorectal carcinoma, has been generally measured as prevalence rates of adenomas at autopsy or colonoscopy. The aim of this study was to estimate the incidence rate of adenomas and compare it with the adenoma recurrence rate.

METHODS

Data on colonoscopies performed in three New York City practices were collected prospectively. The cumulative rate of adenoma diagnosis on repeat colonoscopy was calculated for patients with no abnormalities on index colonoscopy ("incidence" rate) and for patients with adenomas on the index colonoscopy ("recurrence" rate).

RESULTS

The cumulative incidence rate of adenomas at 36 months was 16%, and the cumulative recurrence rate at 36 months was 42% (P < 0.004). The recurrence rate was higher in patients with multiple adenomas than in those with a single adenoma on index colonoscopy, although the increase was not statistically significant.

CONCLUSIONS

Although the recurrence rate has always been assumed to be elevated, this study is the first to compare the recurrence rate of adenomas with the incidence rate directly and to show that the recurrence rate is indeed elevated.

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.

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.

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.

Incidence of malignant pleural mesothelioma after thoracic radiotherapy

BACKGROUND

Although usually associated with asbestos exposure, a number of case reports have noted the occurrence of malignant pleural mesothelioma in patients who received radiotherapy (RT) to the thorax.

METHODS

The authors performed a retrospective cohort study utilizing 251,750 women registered with breast carcinoma in the Surveillance, Epidemiology, and End Results Program of the U.S. National Cancer Institute from 1973-1993, 24.8% of whom received RT as part of their initial management, and 13,743 people with Hodgkin's disease, 50.6% of whom received RT as part of their initial management.

RESULTS

Six cases of malignant pleural mesothelioma were found: two in breast carcinoma patients treated with RT and four found in women not treated with RT. No cases occurred in the patients with Hodgkin's disease. The overall estimated relative risk for malignant pleural mesothelioma after RT was 1.56 (95% confidence interval, 0.18-5.63).

CONCLUSIONS

To the authors' knowledge, this is the first controlled study to investigate thoracic radiation exposure and malignant pleural mesothelioma, and no association was found.

Trends in incidence of primary malignant brain tumors in USA, 1981-1990

BACKGROUND

There has been considerable controversy regarding whether a recent observed rise in brain tumor incidence is real and so suggestive of increasing exposure to environmental carcinogens, or whether it is largely explainable by changes in diagnostic technology, particularly the introduction of computerized axial tomography (CT) scans in the 1970s. We analysed data from the US Surveillance, Epidemiology, and End Results (SEER) Program to investigate whether there was a rise of brain tumor incidence during 1981-1990, the period after CT scans became extensively available, and if so, the rates of which specific histologic subtypes have risen.

METHODS

Age- and sex-specific, as well as age-adjusted incidence rates were calculated for each brain tumor histologic subtype. Regression analysis was used to estimate age-adjusted incidence rate ratios (RR) for different periods and to examine time trends.

RESULTS

For all histologic subtypes, the incidence rates increased with age. Regarding time trends, lymphomas in men increased in all age groups during the study period with the age-adjusted rate ratio reaching 5.6 (95% CI: 3.7-8.3) for 1989-1990 as compared to 1981-1982. Lymphoma in women and glioblastoma multiforme in both sexes also appear to have increased, particularly in the elderly. Other histologies did not show any time trends in the age-specific or age-adjusted analyses.

CONCLUSION

Our histology-specific analysis is not suggestive of any significant increase in the incidence of brain tumors during 1980-1990, except for lymphomas in men.

Cigarette smoking and other behavioral risk factors for recurrence of colorectal adenomatous polyps (New York City, NY, USA)

Adenomatous polyps (hereinafter referred to as adenomas) are known precursors of colorectal cancer. Cigarette smoking has been associated with adenomas but not with colorectal cancer, while alcohol and fat intake have been associated with both adenomas and cancer in some studies. Approximately 30 percent of patients with resected adenomas develop another adenoma within three years. This case-control study explores the association of cigarette smoking with adenoma recurrence. Between April 1986 and March 1988, we administered a questionnaire to colonoscoped patients aged 35 to 84 years in three New York City (NY, USA) practices. We compared 186 recurrent polyp cases (130 males, 56 females) and 330 controls (187 males, 143 females) who had a history of polypectomy but normal follow-up colonoscopy, by cigarette-smoking pack-years adjusted for possible confounders. Risk for a metachronous or recurrent adenoma was significantly greater in the highest quartile of smokers than in never-smokers among both men (odds ratio [OR] = 1.8, 95 percent confidence interval [CI] = 1.0-3.4) and women (OR = 3.6, CI = 1.7-7.6). Adjustment for time since smoking cessation reduced risk only slightly, as did adjustment for dietary fat intake, which itself remained significant. No association was found between alcohol intake and risk of recurrence. Cigarette smokers appear to have an elevated risk of adenoma recurrence that is not eliminated entirely by smoking cessation. Intervention trials that use adenoma recurrence as an endpoint should take smoking into account.

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.

Pancreas cancer as a second primary malignancy. A population-based study

BACKGROUND

The study of second primary malignancies may give clues to the etiology of various cancers. Little is known about risk factors for pancreatic carcinoma; therefore, its occurrence as a second primary malignancy was investigated.

METHODS

Data from the Surveillance, Epidemiology, and End-Results (SEER) program were used for the period from January 1, 1973 through December 31, 1990. Person-years of follow-up for various cancer sites were calculated, excluding the initial 6 months after diagnosis, and were multiplied times the age- and sex-specific incidence rates for pancreas cancer to calculate the expected number of second primary pancreas cancer cases. The observed number of cases was divided by the expected number to estimate the relative risk (RR) of pancreas cancer as a second primary cancer, and 95% confidence limits were calculated.

RESULTS

The risk of second primary cancer was elevated after lung cancer for men (RR 1.3, 95% CI 1.0-1.6) and women (RR 2.5, 95% CI 1.9-3.2). An elevation in risk also was found after head and neck cancer in women (RR 1.8, 95% CI 1.2-2.5) and bladder cancer in women (RR 1.5, 95% CI 1.1-2.0), but not in men. Other significant elevations were found after prostate cancer (RR 1.2, 95% CI 1.1-1.3), and a decreased risk was found after lymphoma in men (RR 0.2, 95% CI 0.0-0.8).

CONCLUSIONS

Second primary pancreas cancer is increased after tobacco-related malignancies, particularly in females, supporting the role of cigarette smoking as a risk factor for pancreas cancer and suggesting a stronger effect of cigarette smoking for women. The elevation in risk after prostate cancer and the decreased risk after lymphoma in males need to be confirmed in other data sets.

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.

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.

Reproductive risk factors for colorectal adenomatous polyps (New York City, NY, United States)

Events of reproductive life, such as parity and age at menarche, have been found in some but not all studies to be associated with risk for colorectal cancer in females. Because adenomatous polyps (adenomas) are precursors of colorectal cancer, we investigated whether reproductive variables were associated with colorectal adenomas. We conducted a case-control study among patients examined in three colonoscopy practices in New York City (NY, United States) from 1986 to 1988. Adenoma cases (n = 128) were defined as women who had an adenoma detected at the index colonoscopy with no history of inflammatory bowel disease, adenomas, or cancer. Controls (n = 283) were women with a normal index colonoscopy and no history of inflammatory bowel disease, adenomas, or cancer. The adjusted odds ratio (OR) for the association of early menarche (age less than 13 years) with adenomas was 0.6 (95 percent confidence interval = 0.4-0.9). Parity, history of spontaneous or induced abortion, infertility, type of menopause, age at menopause, use of oral contraceptives, and use of menopausal hormone replacement therapy were not associated statistically significantly with adenoma risk, although some possible trends were observed. Our findings do not implicate reproductive events, nulliparity, or overexposure to estrogens or to menstrual cycles as mechanisms of increased risk for colorectal neoplasia.