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

Understanding recent trends in incidence of invasive breast cancer in Norway: age-period-cohort analysis based on registry data on mammography screening and hormone treatment use

Objective To quantify the separate contributions of menopausal hormone treatment and mammography screening activities on trends in incidence of invasive breast cancer between 1987 and 2008

Breast cancer tumor growth estimated through mammography screening data

Introduction Knowledge of tumor growth is important in the planning and evaluation of screening programs, clinical trials, and epidemiological studies. Studies of tumor growth rates in humans are usually based on small and selected samples. In the present study based on the Norwegian Breast Cancer Screening Program, tumor growth was estimated from a large population using a new estimating procedure/model. Methods A likelihood-based estimating procedure was used, where both tumor growth and the screen test sensitivity were modeled as continuously increasing functions of tumor size. The method was applied to cancer incidence and tumor measurement data from 395,188 women aged 50 to 69 years. Results Tumor growth varied considerably between subjects, with 5% of tumors taking less than 1.2 months to grow from 10 mm to 20 mm in diameter, and another 5% taking more than 6.3 years. The mean time a tumor needed to grow from 10 mm to 20 mm in diameter was estimated as 1.7 years, increasing with age. The screen test sensitivity was estimated to increase sharply with tumor size, rising from 26% at 5 mm to 91% at 10 mm. Compared with previously used Markov models for tumor progression, the applied model gave considerably higher model fit (85% increased predictive power) and provided estimates directly linked to tumor size. Conclusion Screening data with tumor measurements can provide population-based estimates of tumor growth and screen test sensitivity directly linked to tumor size. There is a large variation in breast cancer tumor growth, with faster growth among younger women

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

Birth length and weight as predictors of breast cancer prognosis

Background Birth size, and particularly birth length, is positively associated with breast cancer risk in adulthood. The objective of this study was to examine whether birth size is associated with survival among breast cancer patients. Methods Information on birth size (weight, length and ponderal index (kg/length (m3)) was collected from birth archives for 331 breast cancer patients who were diagnosed at two university hospitals in Norway (Bergen and Trondheim). The patients were followed from the time of diagnosis until death from breast cancer, death from another cause, or to the end of follow-up, and birth size was related to survival, using Cox regression analysis. Results Breast cancer patients with birth length ≥ 52 cm had nearly twice the risk of dying (hazard ratio, 1.92, 95% confidence interval, 1.09-3.41) from breast cancer compared to women with birth length less than 48 cm, after adjustment for place of birth and year of diagnosis. Similar analyses related to birth weight and ponderal index showed no clear association with breast cancer survival. Conclusions Poorer outcome of breast cancer patients with high birth length may reflect effects of factors that stimulate longitudinal growth and simultaneously increase the risk of metastases and fatal outcome. It is possible that the insulin-like growth factor (IGF) system is involved in the underlying mechanisms

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

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

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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

17β-Estradiol Levels During An Entire Menstrual Cycle In Response To Adult Stature and Insulin, Of Possible Importance For Breast Cancer Risk: The EBBA-I study.

Background: The normal breast cells develop into malignant cells as a result of a complex interplay between genetic, environmental, nutritional and hormonal factors. Attained adult stature and insulin levels, risk factors for breast cancer, may also vary in response to the same factors. Thus, we hypothesize that 17β-estradiol, a key factor in the carcinogenesis of the breast, may vary in response to adult height in combination with insulin levels of possible importance of breast cancer risk. Methods: Among 204 healthy women, aged 25-35 years who participated in the Norwegian EBBA-I study, 17β-estradiol concentrations were measured in daily saliva samples throughout one entire menstrual cycle using radioimmunoassay (RIA). Attained height (cm) was measured, and serum concentrations of insulin were determined in fasting blood samples. The associations between adult height, insulin and 17β-estradiol levels throughout a menstrual cycle were studied using multivariate linear regression analyses and linear mixed models for repeated measures. Adjustments for potential confounding factors were performed. Results: A 37.2 % increase in 17β-estradiol levels was observed during the entire menstrual cycle among women with an adult height ≥170 cm (upper tertile) and insulin levels ≥ 90 pmol/L (upper tertile) compared to women with the same attained adult height, and insulin levels < 90pmol/L. The association was even more pronounced when we looked into those women with attained adult height ≥170 cm (upper tertile) and serum insulin ≥ 101 pmol/L (upper quartile) (Fig. 1). Adjustments for potential confounding factors were performed. 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 throughout the entire menstrual cycle when their insulin levels rise, of possible importance for breast cancer risk.AnthropologyHuman Evolutionary Biolog