Breast cancer mortality in participants of the Norwegian Breast Cancer Screening Program

BACKGROUND The Norwegian Breast Cancer Screening Program started in 1996. To the authors' knowledge, this is the first report using individual-based data on invitation and participation to analyze breast cancer mortality among screened and nonscreened women in the program. METHODS Information on dates of invitation, attendance, breast cancer diagnosis, emigration, death, and cause of death was linked by using unique 11-digit personal identification numbers assigned all inhabitants of Norway at birth or immigration. In total, 699,628 women ages 50 to 69 years without prior a diagnosis of breast cancer were invited to the program from 1996 to 2009 and were followed for breast cancer through 2009 and death through 2010. Incidence-based breast cancer mortality rate ratios (MRRs) were compared between the screened and nonscreened cohorts using a Poisson regression model. The MRRs were adjusted for calendar period, attained age, years since inclusion in the cohorts, and self-selection bias. RESULTS The crude breast cancer mortality rate was 20.7 per 100,000 women-years for the screened cohort compared with 39.7 per 100,000 women-years for the nonscreened cohort, resulting in an MRR of 0.52 (95% confidence interval, 0.47-0.59). The mortality reduction associated with attendance in the program was 43% (MRR, 0.57; 95% confidence interval, 0.51-0.64) after adjusting for calendar period, attained age, years after inclusion in the cohort, and self-selection bias. CONCLUSIONS After 15 years of follow-up, a 43% reduction in mortality was observed among women who attended the national mammographic screening program in Norway

Parity, hormones and breast cancer subtypes - results from a large nested case-control study in a national screening program.

BACKGROUND: Breast cancer comprises several molecular subtypes with different prognoses and possibly different etiology. Reproductive and hormonal factors are associated with breast cancer overall, and with luminal subtypes, but the associations with other subtypes are unclear. We used data from a national screening program to conduct a large nested case-control study. METHODS: We conducted a nested case-control study on participants in the Norwegian Breast Cancer Screening Program in 2006 - 2014. There was information on estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2) for 4748 cases of breast cancer. Breast cancer subtypes were defined as luminal A-like (ER+ PR+ HER2-), luminal B-like (ER+ PR- HER2- or ER+ PR+/PR-HER2+), HER2-positive (ER- PR- HER2+) and triple-negative (ER- PR- HER2-). Conditional logistic regression was used to estimate odds ratios (ORs) of breast cancer associated with age at first birth, number of pregnancies, oral contraceptive use, intrauterine devices and menopausal hormone therapy. Analyses were adjusted for age, body mass index, education, age at menarche, number of pregnancies and menopausal status. RESULTS: Number of pregnancies was inversely associated with relative risk of luminal-like breast cancers (p-trend ≤0.02), and although not statistically significant, with HER2-positive (OR = 0.60, 95% CI 0.31-1.19) and triple-negative cancer (OR = 0.70, 95% CI 0.41-1.21). Women who had ≥4 pregnancies were at >40% lower risk of luminal-like and HER2-positive cancers than women who had never been pregnant. However, there was a larger discrepancy between tumor subtypes with menopausal hormone use. Women who used estrogen and progesterone therapy (EPT) had almost threefold increased risk of luminal A-like cancer (OR = 2.92, 95% CI 2.36-3.62) compared to never-users, but were not at elevated risk of HER2-positive (OR = 0.88, 95% CI 0.33-2.30) or triple-negative (OR = 0.92, 95% CI 0.43 - 1.98) subtypes. CONCLUSIONS: Reproductive factors were to some extent associated with all subtypes; the strongest trends were with luminal-like subtypes. Hormone therapy use was strongly associated with risk of luminal-like breast cancer, and less so with risk of HER2-positive or triple-negative cancer. There are clearly some, but possibly limited, etiologic differences between subtypes, with the greatest contrast between luminal A-like and triple-negative subtypes. TRIAL REGISTRATION: Not applicable

Adult Height, Insulin Levels and 17β-Estradiol in Young Women

Background: Adult height and insulin levels have independently been associated with breast cancer risk. However, little is known about whether these factors influence estradiol levels. Thus, we hypothesize that adult height in combination with insulin levels may influence premenopausal 17β-estradiol throughout the entire menstrual cycle of possible importance of breast cancer risk. Methods: Among 204 healthy women, aged 25-35 years who participated in the Norwegian EBBA I study, birth weight and age at menarche were assessed by questionnaire, personal health record and interview. 17β-estradiol concentrations were estimated by daily saliva samples throughout one entire menstrual cycle using radioimmunoassay (RIA). Measures of height (cm) were taken as well as waist circumference (cm), body mass index (BMI kg/m2) and total fat percentage (DEXA % fat). Fasting blood samples were drawn, and serum concentrations of insulin were determined. Results: The women reported a mean height of 166.5 cm, birth weight of 3389 g and age at menarche 13.1 years. Mean BMI was 24.4 kg/m2, mean waist circumference 79.5 cm and mean total fat percentage 34.1%. Women with an adult height of more than 170 cm and insulin levels higher than 90 pmol/L experienced on average an 37.2 % increase in 17β- estradiol during an entire menstrual cycle compared to those with the same height, and insulin levels below 90 pmol/L. Moreover, this was also observed throughout the entire menstrual cycle. Conclusion: Our findings support that premenopausal levels of 17β-estradiol vary in response to adult height and insulin levels, suggesting that women who become taller are put at risk for higher estradiol levels when their insulin levels rise of possible importance for breast cancer risk.Anthropolog

Screening for colorectal cancer. Collaboration among politicians and scientists is necessary

Hægt er að lesa greinina í heild sinni með því að smella á hlekkinn View/OpenColorectal cancer is one of the most common cancers in the western world. It is especially common in the Nordic countries. In many of the European countries and in the United States colonoscopy is recommended as a screening procedure for CRC. However, there are no randomized studies of the effects of the method on incidence, mortality, possible complications or negative effects on the population. Public pressure to have screening for CRC with colonoscopy will probably increase heavily in the next years to come. We fear that colonoscopy will be introduced as a screening method without proper scientific support. Therefore we want to argue for a common Nordic randomized study on population screening with colonoscopy.Krabbamein í ristli og endaþarmi er eitt af algengustu krabbameinum í hinum vestræna heimi, og sérstaklega er það algengt á Norðurlöndum. Í mörgum Evrópulöndum og Bandaríkjunum er ristilspeglun ráðlögð sem skimunaraðferð fyrir þessu krabbameini. Það hafa samt ekki verið gerðar slembirannsóknir á áhrifum aðferðarinnar á nýgengi, dánartíðni, mögulega fylgikvilla eða neikvæð áhrif á almenning. Þrýstingur almennings á að fá skimun fyrir meininu með ristilspeglun mun líklega aukast mikið á næstu árum. Það er hætta á því að ristilspeglun sem skimunaraðferð verði innleidd án nægilegrar vísindalegrar undirstöðu. Þess vegna viljum við færa rök fyrir mikilvægi þess að gerð verði samnorræn slembirannsókn á skimun með ristilspeglun meðal almennings

Colorectal cancer - Demand for a joint Nordic study on the value of colonoscopic screening

To access publisher full text version of this article. Please click on the hyperlink in Additional Links fieldNo abstract availabl

Trends for invasive squamous cell neoplasia of the skin in Norway

Over the period 1966–1995, based on 11 662 patients, the incidence of squamous cell carcinoma of the skin increased three to four times in Norway mainly as a result of an increased number of localized tumours. In men, cancer of the auricle was the second most common site; in women the incidence was low. © 1999 Cancer Research Campaig

An epidemiological study of cancer in adult twins born in Norway 1905–1945

We have identified 23 334 individuals (40%) of twins born in Norway 1905–45 where both twins were alive in 1960 without malignant disease. These were linked to the Cancer Registry of Norway. A reduced risk of malignant disease was demonstrated among twins for all tumour sites combined; standardized incidence rate (SIR): 0.90 (95% CI 0.85–0.94) in females and 0.95 (95% Cl 0.90–0.99) in males. In both sexes, we observed a significant reduced incidence of malignant melanomas of the skin. The incidence of colorectal cancer tended to be reduced for both sexes. In females, the incidence of tumours of the central nervous system and lungs were reduced. We consider our findings are real, but cannot explain them. © 2001 Cancer Research Campaign http://www.bjcancer.co

Circulating vitamin D, vitamin D-related genetic variation, and risk of fatal prostate cancer in the National Cancer Institute Breast and Prostate Cancer Cohort Consortium

BACKGROUND: Evidence from experimental animal and cell line studies supports a beneficial role for vitamin D in prostate cancer (PCa). Although the results from human studies have been mainly null for overall PCa risk, there may be a benefit for survival. This study assessed the associations of circulating 25-hydroxyvitamin D (25(OH)D) and common variations in key vitamin D-related genes with fatal PCa. METHODS: In a large cohort consortium, 518 fatal cases and 2986 controls with 25(OH)D data were identified. Genotyping information for 91 single-nucleotide polymorphisms (SNPs) in 7 vitamin D-related genes (vitamin D receptor, group-specific component, cytochrome P450 27A1 [CYP27A1], CYP27B1, CYP24A1, CYP2R1, and retinoid X receptor α) was available for 496 fatal cases and 3577 controls. Unconditional logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for the associations of 25(OH)D and SNPs with fatal PCa. The study also tested for 25(OH)D-SNP interactions among 264 fatal cases and 1169 controls. RESULTS: No statistically significant relationship was observed between 25(OH)D and fatal PCa (OR for extreme quartiles, 0.86; 95% CI, 0.65-1.14; P for trend = .22) or the main effects of the SNPs and fatal PCa. There was evidence suggesting that associations of several SNPs, including 5 related to circulating 25(OH)D, with fatal PCa were modified by 25(OH)D. Individually, these associations did not remain significant after multiple testing; however, the P value for the set-based test for CYP2R1 was .002. CONCLUSIONS: Statistically significant associations were not observed for either 25(OH)D or vitamin D-related SNPs with fatal PCa. The effect modification of 25(OH)D associations by biologically plausible genetic variation may deserve further exploration