Cancer Epidemiology Unit

About: Cancer Epidemiology Unit is a based out in . It is known for research contribution in the topics: Population & Cancer. The organization has 669 authors who have published 1725 publications receiving 93979 citations.

Familial breast cancer: Characteristics and outcome of BRCA 1-2 positive and negative cases

Abstract: The clinical and pathological characteristics and the clinical course of patients with breast cancer and BRCA 1–2 mutation are poorly known. From 1997, patients with breast cancer and a family history of breast or ovarian cancer were offered BRCA testing. The clinical and pathological features of patients with known BRCA status were retrospectively assessed and comparisons were made between cancers arising in BRCA positive and BRCA wild type (WT) patients respectively. Type of treatment, pattern of relapse, event (local relapse, contralateral breast cancer, metastases) free and overall survival were also compared in the two groups. Out of the 210 patients tested, 125 had been treated and followed-up at our Institution and were evaluated in this study. BRCA positive patients tended to be more often premenopausal (79% vs 65%) and to have positive lymphnodes (63% vs 49%), poorly differentiated tumours (76% vs 40% – p = 0.002 at univariate analysis, not significant at multivariate analysis) and negative estrogen receptors (43% vs 29%). Treatment was not different in the two groups. In the 86 BRCA-WT patients, the first event was a local relapse in 3 (3%), metachronous contralateral breast cancer in 7 (8%) and distant metastases in 16 (19%). In the 39 BRCA positive patients, the corresponding figures were 3 (8%), 8 (21%) and 3 (8%). There was no difference in event free survival, with a median of 180 months in both groups of patients. At 20 years, projected survival was 85% for BRCA positive patients and 55% for BRCA-WT, but this difference was not statistically significant. Although BRCA positive patients have more frequently negative prognostic factors, their prognosis appears to be equal to or better than in patients with BRCA-WT.

Sample selection and validity of exposure–disease association estimates in cohort studies

Abstract: Background Participants in cohort studies are frequently selected from restricted source populations. It has been recognised that such restriction may affect the study validity. Objectives To assess the bias that may arise when analyses involve data from cohorts based on restricted source populations, an area little studied in quantitative terms. Methods Monte Carlo simulations were used, based on a setting where the exposure and one risk factor for the outcome, which are not associated in the general population, influence selection into the cohort. All the parameters involved in the simulations (ie, prevalence and effects of exposure and risk factor on both the selection and outcome process, selection prevalence, baseline outcome incidence rate, and sample size) were allowed to vary to reflect real life settings. Results The simulations show that when the exposure and risk factor are strongly associated with selection (ORs of 4 or 0.25) and the unmeasured risk factor is associated with a disease HR of 4, the bias in the estimated log HR for the exposure–disease association is ±0.15. When these associations decrease to values more commonly seen in epidemiological studies (eg, ORs and HRs of 2 or 0.5), the bias in the log HR drops to just ±0.02. Conclusions Using a restricted source population for a cohort study will, under a range of sensible scenarios, produce only relatively weak bias in estimates of the exposure–disease associations.

Age-specific Differences in the Relationship Between Oral Contraceptive Use and Breast Cancer

Abstract: Background Nearly all studies have suggested that the use of oral contraceptives (OC) is not associated with the aggregate risk of breast cancer diagnosed in women aged 20-54 years. Because of age-specific differences in the breast cancer-parity relationship and because of age-specific differences in other breast cancer risk factors, the Centers for Disease Control reexamined data from the Cancer and Steroid Hormone Study (CASH) to assess whether OC use has different effects on the risk of breast cancer at different ages of diagnosis. Methods This population-based case-control study was designed to examine the relationship between the use of OC and the risk of breast, ovarian, and endometrial cancer. CASH was conducted in eight geographic areas in the United States during 1980-1982. All participants were interviewed at home with a pretested standardized questionnaire including a calendar of life events and a photograph book of all pills marketed in the United States. Results We found that the relationship between the risk of breast cancer and OC use appeared to vary by the age at diagnosis. Among women aged 20-34 years at diagnosis or interview, those who had ever used OC had a slightly increased risk of breast cancer (odds ratio [OR], 1.4; 95% confidence interval [CI], 1.0-2.1) compared with women of the same ages who had never used OC. Among these women, there were no trends of increasing or decreasing risk with any measure of OC use. Among women aged 35-44 years, there was no association between OC use and breast cancer. Among women aged 45-54 years, those who used OC had a slightly decreased risk of breast cancer (OR, 0.9; 95% CI, 0.8-1.0). Among these women, risk estimates decreased significantly with increasing time since first and last use. Conclusions Although the slightly increased risk estimates for the youngest women were compatible with findings by other investigators, the decreased risk estimates for the oldest women have not been described in as many studies. Available data provide no reasons to change prescribing practices or the use of OC that are related to the breast cancer risk.

The acceptability of repeat Internet-based hybrid diet assessment of previous 24-h dietary intake: administration of the Oxford WebQ in UK Biobank

Abstract: Although dietary intake over a single 24-h period may be atypical of an individual's habitual pattern, multiple 24-h dietary assessments can be representative of habitual intake and help in assessing seasonal variation. Web-based questionnaires are convenient for the participant and result in automatic data capture for study investigators. This study reports on the acceptability of repeated web-based administration of the Oxford WebQ--a 24-h recall of frequency from a set food list suitable for self-completion from which energy and nutrient values can be automatically generated. As part of the UK Biobank study, four invitations to complete the Oxford WebQ were sent by email over a 16-month period. Overall, 176 012 (53% of those invited) participants completed the online version of the Oxford WebQ at least once and 66% completed it more than once, although only 16% completed it on all four occasions. The response rate for any one round of invitations varied between 34 and 26%. On most occasions, the Oxford WebQ was completed on the same day that they received the invitation, although this was less likely if sent on a weekend. Participants who completed the Oxford WebQ tended to be white, female, slightly older, less deprived and more educated, which is typical of health-conscious volunteer-based studies. These findings provide preliminary evidence to suggest that repeated 24-h dietary assessment via the Internet is acceptable to the public and a feasible strategy for large population-based studies.

Serum concentrations of cholesterol, apolipoprotein A-I and apolipoprotein B in a total of 1694 meat-eaters, fish-eaters, vegetarians and vegans

Abstract: Serum concentrations of cholesterol, apolipoprotein A-I and apolipoprotein B in a total of 1694 meat-eaters, fish-eaters, vegetarians and vegans