Biomedical subjects

H Ahsan

Publications and source records attributed to H Ahsan.

51 records · Page 3Linked to original sources

PubMed1997

Association of adenocarcinoma and squamous cell carcinoma of the esophagus with tobacco-related and other malignancies.

Little is known about the etiology of esophageal and gastric cardia adenocarcinoma (EGA), a cancer with one of the fastest-rising incidences in the developed world. To explore the etiology of this cancer, we conducted a retrospective cohort analysis using data from the Surveillance, Epidemiology and End Results Program of the United States National Cancer Institute to study EGA and esophageal squamous cell carcinoma (ESC), in association with cancers of other sites. Standardized incidence ratios, adjusted for age, sex, and time period, were calculated as a measure of the relative risk (RR) of developing a second primary cancer (EGA or ESC) following a given first primary site. We found a moderately elevated risk of EGA following cancers of the lung (RR = 1.9 in men and RR = 2.0 in women) and of the head and neck (RR = 2.1 in men and RR = 6.3 in women) and a strongly elevated risk of ESC following cancers of the lung (RR = 2.8 in men and RR = 5.1 in women) and of the head and neck (RR = 9.6 in men and RR = 38.8 in women). A significantly elevated risk following breast cancer in women was observed for both EGA (RR = 2.6; 95% confidence interval, 1.8-3.7) and ESC (RR = 1.4; 95% confidence interval, 1.1-1.9). We also found a significantly elevated risk of EGA following bladder (RR = 2.0), colorectal (RR = 1.7), and prostate (RR = 1.4) cancer in men and of ESC following colorectal cancer (RR = 1.7) in women in this study. The strong association with tobacco-related malignancies in this study reinforces the role of tobacco in the etiology of esophageal cancers, which appears stronger for squamous cell carcinoma than for adenocarcinoma and stronger in women than in men. The study also suggests a possible shared etiology between esophageal adenocarcinoma and colorectal cancer in men and provides new evidence about the association of both adenocarcinoma and squamous cell carcinoma of the esophagus with breast cancer in women. Findings of this study provide clues to the etiology of EGA and ESC.

Adenocarcinoma↗

PubMed1996

High risk of Kaposi's sarcoma and central nervous system lymphoma in the same individuals: a finding related to acquired immunodeficiency syndrome.

Kaposi's sarcoma and central nervous system (CNS) lymphoma are the 2 most common malignancies related to HIV infection. To investigate the association between Kaposi's sarcoma and CNS lymphoma, a population-based retrospective cohort study was conducted. Using U.S. Surveillance, Epidemiology and End Results Program data, the gender-specific age- and calendar year-adjusted standardized incidence ratios were calculated for the pre-AIDS (1973-80) and AIDS (1981-1990) eras, as an estimate of the relative risk (RR) of developing one condition following another. For the AIDS era in men, the RR of CNS lymphoma following Kaposi's sarcoma was 979.7 and that of Kaposi's sarcoma following CNS lymphoma was 231.1. There were no instances of the co-occurrence of these malignancies in women in either era or in men for the pre-AIDS era. The extremely high RRs for the co-occurrence of Kaposi's sarcoma and CNA lymphoma in men during the AIDS era suggests that the association of these malignancies occurs within the same HIV-infected individuals.

Acquired Immunodeficiency Syndrome↗

PubMed1996

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.

Adenocarcinoma↗

PubMed1996

Recurrent adenomatous polyps and body mass index.

Interest in risk factors for the recurrence of adenomatous polyps derives from the use of recurrent adenomas as surrogate end points in longitudinal studies of invasive colorectal cancer. In this case-control study, the effect of increased body mass index (BMI) on the risk of recurrent adenomas was investigated. Subjects consisted of patients seen at three colonoscopy practices in New York City, all of whom had a previous history of adenomas. On index colonoscopy, recurrent cases had an adenoma, whereas controls were normal. Men and women were analyzed separately, with different logistic models developed using backward elimination from a full model containing the covariates age at diagnosis, age-at-highest-weight, pack-years of smoking, activity level, energy intake, and fat and fiber intake. Men in the upper quartiles of BMI were found to be at greater risk of recurrent adenomas. In a model which controlled for age at diagnosis, age-at-highest-weight, activity level, pack-years of smoking and kilocalories, the estimated odds ratios were 2.2, 1.9 and 1.9 respectively for the second, third and fourth quartiles compared to the first quartile. Only the estimate for the second quartile was found to be statistically significant. No effect was observed for women, even in a model which controlled for age at diagnosis, age-at-highest-weight, pack-years and total fat. Obesity may play a role in adenoma recurrence. Confirmation of this finding would have important implications for possible prevention strategies in the future.

Adenomatous Polyps↗

PubMed1996

Increased expression of the cyclin D1 gene in Barrett's esophagus.

Previous studies have found a 3-10-fold amplification and overexpression of the cyclin D1 gene in about 32% of human esophageal squamous cell carcinoma. The purpose of this study was to evaluate the prevalence of increased expression of the cyclin D1 protein in Barrett's esophagus. Using 69 formalin-fixed and paraffin-embedded human esophageal specimens, which had been removed endoscopically or obtained at surgery during 1993 and 1994, all immunohistochemical analyses were performed using an avidin-biotin complex immunoperoxidase technique. Increased nuclear expression of the cyclin D1 protein was noted in 32 of 69 samples (46%; 44% of the samples from males and 50% of the samples from females). Positive nuclear staining for the cyclin D1 protein in Barrett's disease with intestinal metaplasia was found in 38% of the male cases and 25% of the female cases, whereas in gastric metaplasia it was positive in 33% of men and 48% of women. Nuclear accumulation of the cyclin D1 protein was also found in both dysplastic and nondysplastic lesions, and it was not associated with sex, age, or cigarette or alcohol consumption. Samples from patients taking proton pump inhibitors tended to be less frequently positive (32%) for cyclin D1 nuclear staining when compared to patients taking H2 antagonists (45%) or antacids (55%). These studies suggest that increased expression of cyclin D1 is an early event in the tumorigenic process of esophageal adenocarcinomas and that the increased expression of this gene might predispose the epithelium to malignant transformation.

Adenocarcinoma↗

PubMed1995

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.

Databases, Factual↗

PubMed1995

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.

Abortion, Spontaneous↗

PubMed1995

Effect of catheter diameter on resting pressures in anal fissure patients.

PURPOSE: Controversy exists as to whether fissure patients have elevated resting pressures when compared with control patients. The diameter of manometry catheters used in past studies varies widely (1.5-25 mm) and may have contributed to differences observed in resting pressures. A prospective study was undertaken to determine the influence of manometry catheter diameter on maximum resting pressure in patients with idiopathic chronic anal fissures. METHODS: A total of 28 fissure patients and 28 control patients had manometry performed with both a 1.8-mm and a 4.8-mm (external diameter) water-perfused catheter. RESULTS: Mean maximum resting pressure (RP) for fissure patients as measured with the 1.8-mm catheter was 86 (range, 65-115) mmHg and 83 (range, 47-117) mmHg with the 4.8-mm catheter (P = 0.65). Mean maximum RP for control patients with the 1.8-mm catheter was 70 (range, 30-108) mmHg and 72 (range, 35-109) mmHg with the 4.8-mm catheter (P = 0.07). When fissure and control patients were compared, a significantly higher mean RP was observed in the fissure group for both the 1.8-mm catheter (86 vs. 70 mmHg, respectively; P = 0.01) and the 4.8-mm catheter (83 vs. 72 mmHg, respectively; P = 0.03). There was no significant difference in length of the high-pressure zone within each group or when the fissure group and controls were compared, regardless of catheter used. For both groups of patients, there was a significantly higher incidence of ultraslow waves (USWs) observed with the 4.8-mm catheter when compared with the 1.8-mm catheter. The USW frequency was not significantly different when fissure and control groups were compared with either catheter type. CONCLUSIONS: Catheter size did not influence measured maximum RP in fissure patients. The maximum RP was significantly greater for fissure patients overall when compared with the control group, regardless of catheter used. There was an increased frequency of USWs noted with the larger catheter size in all patients; however, these USWs only became apparent when catheter was left at each station until a true baseline RP was obtained.

Adult↗

PubMed1995

Coronary artery disease and colorectal neoplasia.

PURPOSE: This study was designed to determine whether patients with coronary artery disease are at elevated risk for colorectal neoplasia. METHODS: A case-control study was conducted among consecutive patients in three colonoscopy practices in New York City from 1986 to 1988. All study participants completed an interview questionnaire covering demographics, diet, environmental and behavioral exposures, family and personal medical history, and other variables. For the present study, 298 newly diagnosed colorectal adenoma cases and 107 incident cancer cases were compared with 507 colonoscoped controls without colorectal neoplasia or other significant findings on colonoscopy. Data on history of coronary artery disease (angina and/or heart attack) were obtained solely from the study participants' questionnaire responses. RESULTS: No association was observed between angina, heart attack, or either and colorectal adenomas in males. However, prior coronary artery disease was found to be associated with colorectal cancer in males more than 60 years of age and with colorectal adenomas in females aged 50 years or younger. CONCLUSION: Men with coronary artery disease may be at elevated risk for subsequent colorectal cancer. Young women with coronary artery disease also may be at elevated risk for colorectal neoplasia.

Adenomatous Polyps↗

PubMed1995

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.

Adenoma↗

PubMed1995

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.

Adult↗

PubMed1995

Association of malignant brain tumors and cancers of other sites.

PURPOSE: We conducted an exploratory study of brain tumors that occurred as a second primary malignancy to identify potential risk factors for brain tumors. METHODS: Using data from the Surveillance, Epidemiology, and End Results (SEER) Program, we calculated the sex-specific standardized incidence ratio (SIR), adjusted to age and time period, as an estimate of the relative risk (RR) of developing a second primary brain tumor following other cancers. RESULTS: We found an elevated RR of brain tumors after bladder cancer in both men (RR, 1.7; 95% confidence interval [CI], 1.2 to 2.3) and women (RR, 1.7; 95% CI, 0.8 to 3.2); this effect was present for both astrocytoma and glioblastoma multiforme. Elevated RRs of brain tumors were also found after sarcoma (RR, 4.4; 95% CI, 1.8 to 9.0) and leukemia (RR, 2.9; 95% CI, 1.6 to 4.8) in men, and after colorectal cancer (RR, 1.8; 95% CI, 1.3 to 2.4) and endometrial cancer (RR, 1.4; 95% CI, 1.0 to 1.9) in women. The highest RR observed in this study was for CNS lymphoma following any first primary malignancy in men (RR, 7.9; 95% CI, 5.5 to 11.0). CONCLUSION: The associations of brain tumors with bladder, colorectal, and endometrial cancers in women, and an increased occurrence of CNS lymphoma as a second malignancy in men, are new findings that have not been described previously.

Adult↗

PubMed1994

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.

Adenomatous Polyps↗

PubMedDate not supplied

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.

Adolescent↗

PubMedDate not supplied

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.

Age Factors↗