Implementation of service screening with mammography in Sweden: from pilot study to nationwide programme

Prevalence of women with breast implants in Sweden: a study based on the population-based mammography screening programme

BACKGROUND

Knowledge about the prevalence of women with breast implants is paramount in calculations of risks and in estimations of effects on screening and breast cancer treatment. Most of the estimations of prevalence made to date are rough and often based on sales data. The main aim of this study was to  calculate the prevalence of breast implants in Swedish women. The secondary aim was to investigate if it is feasible to establish the occurrence of breast implants with the help of the public mammography screening programme, in a country with a publicly funded welfare-type healthcare system and with a clear documentation of screening.

METHODS

Information on implants was prospectively collected from all screening attendants from 1st of February 2022 to 1st of August 2022 based on a question from the radiographer to the woman and later verified on the mammogram.

RESULTS

During the study period 4,639 women were screened, of which 182 had implants (3.9%). The  frequency varies between 1.6 and 6.4% in different age groups.

CONCLUSION

The prevalence of breast implants in Swedish women is estimated to be around 4%. The population-based mammography screening programme in countries with a publicly funded welfare-type healthcare system and a clear documentation of mammography screening attendance, seems to be a feasible way to establish the prevalence of breast implants in the population. The large number of women with breast implants warrants further studies regarding the best diagnostic and treatment alternatives for this group. Pre-registration: ClinicalTrials.Gov identifier NCT05222100.

Influence of mammographic density and compressed breast thickness on true mammographic sensitivity: a cohort study

Understanding the detectability of breast cancer using mammography is important when considering nation-wide screening programmes. Although the role of imaging settings on image quality has been studied extensively, their role in detectability of cancer at a population level is less well studied. We wish to quantify the association between mammographic screening sensitivity and various imaging parameters. Using a novel approach applied to a population-based breast cancer screening cohort, we specifically focus on sensitivity as defined in the classical diagnostic testing literature, as opposed to the screen-detected cancer rate, which is often used as a measure of sensitivity for monitoring and evaluating breast cancer screening. We use a natural history approach to model the presence and size of latent tumors at risk of detection at mammography screening, and the screening sensitivity is modeled as a logistic function of tumor size. With this approach we study the influence of compressed breast thickness, x-ray exposure, and compression pressure, in addition to (percent) breast density, on the screening test sensitivity. When adjusting for all screening parameters in addition to latent tumor size, we find that percent breast density and compressed breast thickness are statistically significant factors for the detectability of breast cancer. A change in breast density from 6.6 to 33.5% (the inter-quartile range) reduced the odds of detection by 61% (95% CI 48-71). Similarly, a change in compressed breast thickness from 46 to 66 mm reduced the odds by 42% (95% CI 21-57). The true sensitivity of mammography, defined as the probability that an examination leads to a positive result if a tumour is present in the breast, is associated with compressed breast thickness after accounting for mammographic density and tumour size. This can be used to guide studies of setups aimed at improving lesion detection. Compressed breast thickness-in addition to breast density-should be considered when assigning complementary screening modalities and personalized screening intervals.

Factors Associated With False-Positive Recalls in Mammography Screening

BACKGROUND

We aimed to identify factors associated with false-positive recalls in mammography screening compared with women who were not recalled and those who received true-positive recalls.

METHODS

We included 29,129 women, aged 40 to 74 years, who participated in the Karolinska Mammography Project for Risk Prediction of Breast Cancer (KARMA) between 2011 and 2013 with follow-up until the end of 2017. Nonmammographic factors were collected from questionnaires, mammographic factors were generated from mammograms, and genotypes were determined using the OncoArray or an Illumina custom array. By the use of conditional and regular logistic regression models, we investigated the association between breast cancer risk factors and risk models and false-positive recalls.

RESULTS

Women with a history of benign breast disease, high breast density, masses, microcalcifications, high Tyrer-Cuzick 10-year risk scores, KARMA 2-year risk scores, and polygenic risk scores were more likely to have mammography recalls, including both false-positive and true-positive recalls. Further analyses restricted to women who were recalled found that women with a history of benign breast disease and dense breasts had a similar risk of having false-positive and true-positive recalls, whereas women with masses, microcalcifications, high Tyrer-Cuzick 10-year risk scores, KARMA 2-year risk scores, and polygenic risk scores were more likely to have true-positive recalls than false-positive recalls.

CONCLUSIONS

We found that risk factors associated with false-positive recalls were also likely, or even more likely, to be associated with true-positive recalls in mammography screening.

Tumour Growth Models of Breast Cancer for Evaluating Early Detection-A Summary and a Simulation Study

With the advent of nationwide mammography screening programmes, a number of natural history models of breast cancers have been developed and used to assess the effects of screening. The first half of this article provides an overview of a class of these models and describes how they can be used to study latent processes of tumour progression from observational data. The second half of the article describes a simulation study which applies a continuous growth model to illustrate how effects of extending the maximum age of the current Swedish screening programme from 74 to 80 can be evaluated. Compared to no screening, the current and extended programmes reduced breast cancer mortality by 18.5% and 21.7%, respectively. The proportion of screen-detected invasive cancers which were overdiagnosed was estimated to be 1.9% in the current programme and 2.9% in the extended programme. With the help of these breast cancer natural history models, we can better understand the latent processes, and better study the effects of breast cancer screening.

Change in mammography screening attendance after removing the out-of-pocket fee: a population-based study in Sweden (2014-2018)

Purpose

To assess the change in mammography screening attendance in Sweden—overall and in sociodemographic groups at risk of low attendance—after removal of the out-of-pocket fee in 2016.

Methods

Individual-level data on all screening invitations and attendance between 2014 and 2018 were linked to sociodemographic data from Statistics Sweden. Odds ratios and 95% confidence intervals (CIs) for attendance by time period and sociodemographic factor were computed using mixed logistic regression to account for repeated measures within women. The study sample included 1.4 million women, aged 40–75, who had a mammography screening appointment in 2014–2015 and/or 2017–2018 in 14 of Sweden’s 21 health care regions.

Results

Overall screening attendance was 83.8% in 2014–2015 and 84.1% in 2017–2018 (+ 0.3 percentage points, 95% CI 0.2–0.4). The greatest increase in attendance was observed in non-Nordic women with the lowest income, where attendance rose from 62.9 to 65.8% (+ 2.9 points, 95% CI 2.3–3.6), and among women with four or more risk factors for low attendance, where attendance rose from 59.2 to 62.0% (+ 2.8 points, 95% CI 2.2–3.4).

Conclusion

Screening attendance did not undergo any important increase after implementing free screening, although attendance among some sociodemographic groups increased by almost three percentage points after the policy change.

Population-based mammography screening attendance in Sweden 2017-2018: A cross-sectional register study to assess the impact of sociodemographic factors

Sweden has a population-based mammography screening programme for women aged 40–74. The objective of this study was to examine the association between mammography screening attendance and sociodemographic factors in 15 of Sweden's 21 health care regions. Register-based information was collected on all mammography screening invitations and attendance during 2017 and 2018, and linked to individual-level sociodemographic data from Statistics Sweden. Odds ratios (ORs) and 95% confidence intervals (CIs) for attendance were computed by sociodemographic factor. The study sample included 1.5 million women, aged 40–75, with an overall screening attendance of 81.3%. The lowest odds of attending were found for women living without a partner (OR = 0.52, 95% CI: 0.52–0.53), low-income women (OR = 0.57, 95% CI: 0.56–0.57), and non-Nordic women born in Europe (OR = 0.60, 95% CI: 0.59–0.61). Other groups with lower odds of attending were women whose main source of income was social assistance or benefits (OR = 0.62, 95% CI: 0.62–0.63), those not owning their home (OR = 0.66, 95% CI: 0.66–0.67), and those with low level of education (OR = 0.72, 95% CI: 0.71–0.73). Having multiple of these sociodemographic characteristics further lowered the odds of attending. Although overall mammography screening attendance in Sweden is high, sociodemographic inequalities exist, and efforts should be made to address these. Particular attention should be given to low-income women who live without a partner.

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Mammography screening attendance in Sweden was 81% in 2017–2018.

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Sociodemographic inequalities were found for screening attendance.

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Having multiple low attendance risk factors further decreased the odds of attending.

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Lowest attendance among low-income women who live without a partner.

The politicians' perspectives on participation in mammographic screening: an interview-based study from a region in Sweden

Background

Breast cancer is the most common cancer type among women globally. To facilitate early detection, all 40–74-year-old female residents of Sweden are invited to participate in a population-based mammographic screening programme. Approximately 20% of all invited women decline the offer, and if this is due to systematic differences that can be adjusted, it can indicate inequity in healthcare. Assessment of and being updated about the health and healthcare of the residents are largely the responsibilities of the self-governed regions in Sweden. The understanding of the residents’ health serves as a basis for decision making and priority setting. This study aims to describe how politicians representing a region in Sweden perceive women’s participation in mammographic screening and the politicians’ own possibility to promote such participation.

Methods

Qualitative thematic analysis was conducted on the data obtained from individual semi-structured interviews held in 2019. The interviewees comprised ten politicians (six women and four men, 38–71 years old) representing a sub-committee focusing on public health and healthcare issues.

Results

Two main themes have been identified: 1) expected actions and 2) expected conditions for acting, including a total of four sub-themes. According to the politicians, the expected actions, such as obtaining information and being updated about matters regarding mammographic screening, concern both the women invited to the screening and the politicians themselves. Additionally, for both the individual and the healthcare organisation, here represented by the politicians, expected actions entail a shared commitment to maintain health. The expected conditions for acting refer to the politician’s awareness of the factors influencing the women’s decision to undergo or refuse the screening and having the resources to enable taking actions to facilitate participation.

Conclusions

Expected actions and expected conditions for acting are tightly connected and entail some form of prioritisation by the politicians. Setting the priorities can be based on information about the purpose of the screening and an understanding of social determinants’ impacts on women’s decision to refrain from mammographic screening, as well as available resources.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13690-021-00576-6.

Risk of invasive breast cancer in relatives of patients with breast carcinoma in situ: a prospective cohort study

BACKGROUND

Wide implementation of mammography screening has resulted in increased numbers of women diagnosed with breast carcinoma in situ. We aimed to determine the risk of invasive breast cancer in relatives of patients with breast carcinoma in situ in comparison to the risk in relatives of patients with invasive breast cancer.

METHODS

We analyzed the occurrence of cancer in a nationwide cohort including all 5,099,172 Swedish women born after 1931 with at least one known first-degree relative. This was a record linkage study of Swedish family cancer datasets, including cancer registry data collected from January 1, 1958, to December 31, 2015. We calculated standardized incidence ratios (SIRs) and 10-year cumulative risk of breast cancer diagnosis for women with a family history of in situ and invasive breast cancer.

RESULTS

Having one first-degree relative with breast carcinoma in situ was associated with 50% increased risk of invasive breast cancer (SIR = 1.5, 95% CI 1.4-1.7) when compared to those who had no family history of invasive breast cancer or breast carcinoma in situ in either first- or second-degree relatives. Similarly, having one first-degree relative with invasive breast cancer was associated with 70% (1.7, 1.7-1.8) increased risk. The 10-year cumulative risk for women at age 50 with a relative with breast carcinoma in situ was 3.5% (2.9-3.9%) and was not significantly different from 3.7% (3.6-3.8%) risk for 50-year-old women with a relative with invasive breast cancer (95% confidence intervals overlapped).

CONCLUSIONS

The risk of invasive breast cancer for women with a family history of breast carcinoma in situ was comparable to that for women with a family history of invasive breast cancer. Therefore, family history of breast carcinoma in situ should not be overlooked in recommendations for breast cancer prevention for women with a family history of breast cancer.

Mammography screening reduces rates of advanced and fatal breast cancers: Results in 549,091 women

BACKGROUND

It is of paramount importance to evaluate the impact of participation in organized mammography service screening independently from changes in breast cancer treatment. This can be done by measuring the incidence of fatal breast cancer, which is based on the date of diagnosis and not on the date of death.

METHODS

Among 549,091 women, covering approximately 30% of the Swedish screening-eligible population, the authors calculated the incidence rates of 2473 breast cancers that were fatal within 10 years after diagnosis and the incidence rates of 9737 advanced breast cancers. Data regarding each breast cancer diagnosis and the cause and date of death of each breast cancer case were gathered from national Swedish registries. Tumor characteristics were collected from regional cancer centers. Aggregated data concerning invitation and participation were provided by Sectra Medical Systems AB. Incidence rates were analyzed using Poisson regression.

RESULTS

Women who participated in mammography screening had a statistically significant 41% reduction in their risk of dying of breast cancer within 10 years (relative risk, 0.59; 95% CI, 0.51-0.68 [P < .001]) and a 25% reduction in the rate of advanced breast cancers (relative risk, 0.75; 95% CI, 0.66-0.84 [P < .001]).

CONCLUSIONS

Substantial reductions in the incidence rate of breast cancers that were fatal within 10 years after diagnosis and in the advanced breast cancer rate were found in this contemporaneous comparison of women participating versus those not participating in screening. These benefits appeared to be independent of recent changes in treatment regimens.

Pattern of Mammography Utilization by Women Attending Asokoro District Hospital, Abuja, Nigeria

Introduction:

Mammography is a major tool for the screening and diagnosis of breast cancer globally. Poor funding and lack of good public health education for mammography in resource-limited countries limit access to mammographic services. In these settings, patients bear the cost of breast cancer screening from out-of-pocket expenses. The aim of this study was to interrogate the pattern of utilization of mammography by women of childbearing age, who attended Asokoro District Hospital (ADH) for Healthcare, with the view to increase uptake.

Materials and Methods:

This was a 4-year retrospective, cross-sectional study of 534 women who attended ADH from July 2015 to June 2019 for screening or diagnostic mammography. Data were extracted from completed questionnaire by women who had mammography during the period under review. The data were entered into Statistical Package for the Social Sciences version 27 by IBM for analysis.

Results:

The mean age of the women was 47.8 years ± 7.7 with a range of 30–82 years. Most of the women, 525 (94.9%), were referred for mammography by health workers; only nine (5.1%) had mammography on self-referral. In all, 71% of the women paid for their mammography from their pockets, whereas 28.1% made payments through the National Health Insurance Scheme (NHIS). A total of 100% of women who reported for mammography on self-referral paid for the services from their pockets. The association between the funding options and mode of referral was statistically significant, P = 0.049.

Conclusion:

This study showed that referral for mammography by health workers was responsible for not only most of the mammograms conducted but also all the women who utilized NHIS to pay for this service. Resources should therefore be directed towards creating awareness among health workers, especially with the present level of NHIS coverage in the population, in order to increase the uptake of screening mammography in the population.

Different menopausal hormone regimens and risk of breast cancer

Background

There are considerable knowledge gaps concerning different estrogen and progestin formulations, regimens, and modes of administration of menopausal hormone therapy (HT) and the risk of breast cancer. Our objective was to assess the different treatment options for menopausal HT and the risk of breast cancer.

Patients and methods

This Swedish prospective nationwide cohort study included all women who received ≥1 HT prescription during the study period 2005-2012 (290 186 ever-users), group-level matched (1 : 3) to 870 165 never-users; respectively, 6376 (2.2%) and 18 754 (2.2%) developed breast cancer. HT, ascertained from the Swedish Prescribed Drug Register, was subdivided by estrogen and progestogen formulation types, regimens (continuous versus sequential) and modes of administration (oral versus transdermal). The risk of invasive breast cancer was presented as adjusted odds ratios (OR) and 95% confidence intervals.

Results

Current use of estrogen-only therapy was associated with a slight excess breast cancer risk [odds ratio (OR) = 1.08 (1.02-1.14)]. The risk for current estrogen plus progestogen therapy was higher [OR = 1.77 (1.69-1.85)] and increased with higher age at initiation [OR = 3.59 (3.30-3.91) in women 70+ years]. In contrast, past use was associated with reduced breast cancer risk. Current continuous estrogen/progestin use was associated with higher risk [OR = 2.18 (1.99-2.40) for progesterone-derived; OR = 2.66 (2.49-2.84) for testosterone-derived] than sequential use [OR = 1.37 (0.97-1.92) for progesterone-derived; OR = 1.12 (0.96-1.30) for testosterone-derived]. The OR for current use was 1.12 (1.04-1.20) for estradiol, 0.76 (0.69-0.84) for estriol, 4.47 (2.67-7.48) for conjugated estrogens, and 1.68 (1.51-1.87) for tibolone. Oral and cutaneous HT showed similar associations.

Conclusion

Different HT regimens have profoundly different effects on breast cancer risk. Because of registry limitations some confounders could not be assessed. This knowledge may guide clinical decision-making when HT is considered.

Risk-tailored starting age of breast cancer screening based on women's reproductive profile: A nationwide cohort study

BACKGROUND

Although reproductive history is recognised to affect the risk of breast cancer, current breast cancer screening guidelines do not consider risk differences by this important factor. As there is a need for an earlier screening in women at increased risk of breast cancer, we provided evidence-based risk-adapted starting age of screening based on different reproductive profiles.

MATERIAL AND METHODS

We conducted a nationwide cohort study including 5,099,172 Swedish women born after 1931. Records of study participants in Swedish Cancer Registry, Multi-generation Register, Cause of Death Register, and national censuses (follow-up, 1958-2015) have been linked. We used 10-year cumulative risk of breast cancer curves to determine the age at which women with different reproductive factors attained the risk level at which breast screening is usually recommended.

RESULTS

The 10-year cumulative risk of breast cancer at age 40, 45 and 50 years in the general population, at which current screening guidelines recommend screening was calculated. We found that women with various reproductive factors (defined by parity and age at first birth) obtained this level of risk at different ages. The difference was between nine years later and three years earlier.

CONCLUSIONS

This study provides the age at which women with particular reproductive profile could start risk-adapted breast cancer screening. This supplies novel information for clinicians and women about when to start breast cancer screening and is an important step towards a personalised screening.

Joint models of tumour size and lymph node spread for incident breast cancer cases in the presence of screening

Continuous growth models show great potential for analysing cancer screening data. We recently described such a model for studying breast cancer tumour growth based on modelling tumour size at diagnosis, as a function of screening history, detection mode, and relevant patient characteristics. In this article, we describe how the approach can be extended to jointly model tumour size and number of lymph node metastases at diagnosis. We propose a new class of lymph node spread models which are biologically motivated and describe how they can be extended to incorporate random effects to allow for heterogeneity in underlying rates of spread. Our final model provides a dramatically better fit to empirical data on 1860 incident breast cancer cases than models in current use. We validate our lymph node spread model on an independent data set consisting of 3961 women diagnosed with invasive breast cancer.

Overdiagnosis in the population-based organized breast cancer screening program estimated by a non-homogeneous multi-state model: a cohort study using individual data with long-term follow-up

Background

Overdiagnosis, defined as the detection of a cancer that would not become clinically apparent in a woman’s lifetime without screening, has become a growing concern. Similar underlying risk of breast cancer in the screened and control groups is a prerequisite for unbiased estimates of overdiagnosis, but a contemporary control group is usually not available in organized screening programs.

Methods

We estimated the frequency of overdiagnosis of breast cancer due to screening in women 50–69 years old by using individual screening data from the population-based organized screening program in Stockholm County 1989–2014. A hidden Markov model with four latent states and three observed states was constructed to estimate the natural progression of breast cancer and the test sensitivity. Piecewise transition rates were used to consider the time-varying transition rates. The expected number of detected non-progressive breast cancer cases was calculated.

Results

During the study period, 2,333,153 invitations were sent out; on average, the participation rate in the screening program was 72.7% and the average recall rate was 2.48%. In total, 14,648 invasive breast cancer cases were diagnosed; among the 8305 screen-detected cases, the expected number of non-progressive breast cancer cases was 35.9, which is equivalent to 0.43% (95% confidence interval (CI) 0.10%–2.2%) overdiagnosis. The corresponding estimates for the prevalent and subsequent rounds were 15.6 (0.87%, 95% CI 0.20%–4.3%) and 20.3 (0.31%, 95% CI 0.07%–1.6%), respectively. The likelihood ratio test showed that the non-homogeneous model fitted the data better than an age-homogeneous model (P <0.001).

Conclusions

Our findings suggest that overdiagnosis in the organized biennial mammographic screening for women 50–69 in Stockholm County is a minor phenomenon. The frequency of overdiagnosis in the prevalent screening round was higher than that in subsequent rounds. The non-homogeneous model performed better than the simpler, traditional homogeneous model.

Electronic supplementary material

The online version of this article (10.1186/s13058-018-1082-z) contains supplementary material, which is available to authorized users.

Organized screening programmes for breast and cervical cancer in 17 EU countries: trajectories of attendance rates

BACKGROUND

The aim was to analyse participation trajectories in organised breast and cervical cancer screening programmes and the association between socioeconomic variables and participation.

METHODS

A pooled, cross-sectional, time series analysis was used to evaluate secondary data from 17 European countries in 2004-2014.

RESULTS

The results show that the mammographic screening trend decreases after an initial increase (coefficient for the linear term = 0.40; p = 0.210; 95% CI = - 0.25, 1.06; coefficient for the quadratic term = - 0.07; p = 0.027; 95% CI = - 0.14, - 0.01), while the cervical screening trend is essentially stable (coefficient for the linear term = 0.39, p = 0.312, 95% CI = - 0.42, 1.20; coefficient for the quadratic term = 0.02, p = 0.689, 95% CI = - 0.07, 0.10). There is a significant difference among the country-specific slopes for breast and cervical cancer screening (SD = 16.7, p < 0.001; SD = 14.4, p < 0.001, respectively). No association is found between participation rate and educational level, income, type of employment, unemployment and preventive expenditure. However, participation in cervical cancer screening is significantly associated with a higher proportion of younger women (≤ 49 years) and a higher Gini index (that is, higher income inequality).

CONCLUSIONS

In conclusion three messages: organized cancer screening programmes may reduce the socioeconomic inequalities in younger people's use of preventive services over time; socioeconomic variables are not related to participation rates; these rates do not reach a level of stability in several countries. Therefore, without effective recruitment strategies and tailored organizations, screening participation may not achieve additional gains.

Decision aid on breast cancer screening reduces attendance rate: results of a large-scale, randomized, controlled study by the DECIDEO group

Controversies regarding the benefits of breast cancer screening programs have led to the promotion of new strategies taking into account individual preferences, such as decision aid. The aim of this study was to assess the impact of a decision aid leaflet on the participation of women invited to participate in a national breast cancer screening program. This Randomized, multicentre, controlled trial. Women aged 50 to 74 years, were randomly assigned to receive either a decision aid or the usual invitation letter. Primary outcome was the participation rate 12 months after the invitation. 16 000 women were randomized and 15 844 included in the modified intention-to-treat analysis. The participation rate in the intervention group was 40.25% (3174/7885 women) compared with 42.13% (3353/7959) in the control group (p = 0.02). Previous attendance for screening (RR = 6.24; [95%IC: 5.75-6.77]; p < 0.0001) and medium household income (RR = 1.05; [95%IC: 1.01-1.09]; p = 0.0074) were independently associated with attendance for screening. This large-scale study demonstrates that the decision aid reduced the participation rate. The decision aid activate the decision making process of women toward non-attendance to screening. These results show the importance of promoting informed patient choices, especially when those choices cannot be anticipated.

Classification of normal screening mammograms is strongly influenced by perceived mammographic breast density

INTRODUCTION

To investigate how breast screen readers classify normal screening cases using descriptors of normal mammographic features and to assess test cases for suitability for a single reading strategy.

METHODS

Fifteen breast screen readers interpreted a test set of 29 normal screening cases and classified them by firstly rating their perceived difficulty to reach a 'normal' decision, secondly identifying the cases' salient normal mammographic features and thirdly assessing the cases' suitability for a single reading strategy.

RESULTS

The relationship between the perceived difficulty in making 'normal' decisions and the normal mammographic features was investigated. Regular ductal pattern (T_b  = -0.439, P = 0.001), uniform density (T_b  = -0.527, P < 0.001), non-dense breasts (T_b  = -0.736, P < 0.001), symmetrical mammographic features (T_b  = -0.474, P = 0.001) and overlapped density (T_b  = 0.630, P < 0.001) had a moderate to strong correlation with the difficulty to make 'normal' decisions. Cases with regular ductal pattern (T_b  = 0.447, P = 0.002), uniform density (T_b  = 0.550, P < 0.001), non-dense breasts (T_b  = 0.748, P < 0.001) and symmetrical mammographic features (T_b  = 0.460, P = 0.001) were considered to be more suitable for single reading, whereas cases with overlapped density were not (T_b  = -0.679, P < 0.001).

CONCLUSION

The findings suggest that perceived mammographic breast density has a major influence on the difficulty for readers to classify cases as normal and hence their suitability for single reading.

A validation of DCIS registration in a population-based breast cancer quality register and a study of treatment and prognosis for DCIS during 20 years

AIMS

Sweden has a long history of population-based cancer registration. The aim of our study was to assess the validity of DCIS registration in a regional Breast Cancer Quality Register (BCQR) and to analyze trends in incidence, treatment and outcome of DCIS, over a 20-year period.

MATERIAL AND METHODS

All patients with a diagnosis of primary DCIS reported in the BCQR of the Uppsala-Örebro healthcare region in Sweden 1992-2012 were included. Three hundred women were randomly selected and their medical records were compared to register data. The study period was divided into four time periods.

RESULTS

A total of 2952 women were registered with a DCIS diagnosis. In the final validation cohort of 295 patients, 23 were found to have either recurrent DCIS or invasive breast cancer and eight had LCIS. The completeness and validity of key variables were 91-99%. Twenty of 31 local recurrences were registered (65%).The proportion of DCIS to all breast cancers was 9.5%. Tumor size increased over time. The frequency of mastectomy increased from 23.0% to 39.0%. The proportion of patients receiving radiotherapy after breast conserving surgery increased from 30.1% to 67.6%. The reported local recurrence rate was 9.7% after 10 years. Reported recurrences after BCS and mastectomy were 12.0 and 7.0%, respectively. The recurrence rate did not differ between women undergoing BCS with or without radiotherapy.

CONCLUSION

Only 89.5% of reported DCIS was a primary pure DCIS. The completeness of primary treatment and tumor data was high. The proportion of reported local recurrences was disappointingly low, 65%. The proportion of DCIS was stable over time with a trend towards more intensified treatment. The reported recurrence rate was low independent of treatment and can reflect adequate patient selection, but also over treatment. Our results address the necessity to validate register data on a regular basis.

The impact of in situ breast cancer and family history on risk of subsequent breast cancer events and mortality - a population-based study from Sweden

Background

The clinical behavior of in situ breast cancer is incompletely understood and several factors have been associated with invasive recurrence. The purpose of this study was to evaluate long-term risk of subsequent breast cancer and mortality among women diagnosed with in situ breast cancer, in relation to family history

Methods

Using the population-based Swedish Multi-Generation and Cancer Registers we identified 8111 women diagnosed with in situ breast cancer between 1980 and 2004. We used standardized incidence ratios (SIRs) to measure the relative risk of subsequent invasive or contralateral in situ breast cancer and standardized mortality ratios (SMRs) for relative risks of death.

Results

Among women diagnosed with in situ breast cancer, the cumulative 10-year and 20-year risk for subsequent contralateral or ipsilateral invasive cancer was approximately 10 % and 18 %, respectively. The risk of subsequent invasive breast cancer was increased more than 4-fold (SIR 4.6 (95 % CI 4.2 − 4.9)) among women with in situ breast cancer as compared to women in the general population and the risk of contralateral in situ breast cancer was increased almost 16-fold (SIR 16.0 (95 % CI 13.2–19.1)). Having a family history of breast cancer increased the risk of contralateral invasive breast cancer by almost 50 % (incidence rate ratio 1.5 (95 % CI 1.0–2.0)). Women under forty years old at diagnosis, without family history, had a 7-fold increased risk, and those with a family history had a 14-fold increased risk for subsequent invasive breast cancer with SIRs of 7.2 (95 % CI 4.8–10.5) and 14.3 (95 % CI 7.4–25.0), respectively. The overall risk of death in women with in situ breast cancer was significantly increased by 30 % compared to the general population but was highly dependent on the occurrence of a second invasive cancer event (SMR 1.3 (95 % CI 1.2–1.4)).

Conclusions

Among women with in situ breast cancer, a positive family history increases the risk of contralateral invasive breast cancer by almost 50 %. The risk of subsequent invasive breast cancer and mortality is substantially higher in younger women, which should be taken into account when planning their treatment and follow up.

Electronic supplementary material

The online version of this article (doi:10.1186/s13058-016-0764-7) contains supplementary material, which is available to authorized users.

Worse quality of life in young and recently diagnosed breast cancer survivors compared with female survivors of other cancers: A cross-sectional study

Literature focusing on health-related quality of life (HRQoL) by cancer site among women only is scarce. This study examines HRQoL of breast cancer (BC) survivors compared with female survivors of other cancers, and to understand which subgroups of BC survivors were particularly at risk of reduced HRQoL. We placed emphasis on young (<50 years) and recently diagnosed (≤5 years) survivors, where the deficits in HRQoL were most pronounced. The cross-sectional study consisted of 2,224 BC survivors, 8,504 non-cancer controls and 2,205 other cancer survivors in the Karma study. We examined HRQoL differences using linear regression analyses in the whole cohort and in a subset of young and recently diagnosed BC survivors (n = 242) and female survivors of other cancers (n = 140) with comparable ages at diagnosis (43.6 vs 43.6, p = 0.917) and time since diagnosis (2.3 vs 2.8 years, p < 0.001). HRQoL was assessed using the EORTC QLQ-C30 questionnaire. While only cognitive functioning was significantly compromised in BC survivors compared with survivors of other cancers when women of all ages were included, young BC survivors reported significantly lower HRQoL on multiple functional scales (global quality of life, emotional, role, social and cognitive functioning) and experienced more fatigue and insomnia. BC survivors with any prior medical history of mental disorders reported poorer HRQoL than those without such a history. We also observed a close-knit relationship between tumor and treatment characteristics. BC survivors perform poorly in HRQoL in comparison with female survivors of other cancers. Our results emphasize the importance of age- and gender-appropriate comparison groups.

Integrating Self-Referral for Mammography into Organised Screening: Results from an Italian Experience

OBJECTIVE

To compare self-referred screenees with respondents to invitation for main performance indicators of mammography screening.

SETTING

First round of an organised, population-based screening programme in six districts of northern Italy.

METHODS

The screening test was a two-view mammography. Eligible women aged 50-69 years were invited. Self-referred attendees were accepted if they were eligible for screening and had not yet been invited or had been invited >6 months before presentation. Age-specific performance indicators were compared with the calculation of their ratio and 95% confidence intervals (CIs). Total ratios were age standardised. In situ carcinomas were excluded.

RESULTS

The eligible population was 183 542 women. There were 112 188 respondents to invitation and 20 280 self-referred attendees. Self-referral rate was inversely related to age. Performance indicators were as follows: recall rate, 5.6% for self-referred attendees vs 5.5% for respondents (ratio 1.02, 95% CI 0.96 to 1.08); total aspiration cytology rate, 37.3% vs 28.3% (1.37, 1.24 to 1.51); biopsy rate, 17.0 vs 12.6 x 1000 (1.51, 1.35 to 1.67); total detection rate, 10.7 vs 7.5 x 1000 (1.70, 1.48 to 1.94); detection rate of pT1 carcinoma, 7.0 vs 6.1 x 1000 (1.35, 1.14 to 1.59); detection rate of pT2-4 carcinoma, 3.5 vs 1.2 x 1000 (3.51, 2.75 to 4.43); false-positive rate, 4.5% vs 4.7% (0.93, 0.87 to 0.99); positive predictive value (PPV) of mammography, 19.1% vs 13.5% (1.59, 1.39 to 1.82); PPV of biopsy, 63.7% vs 60.6% (1.13, 0.98 to 1.29); detected:expected ratio, 5.02 vs 3.37 (1.49, 1.28 to 1.74). All differences were more pronounced among or restricted to women aged 50-54 years.

CONCLUSIONS

Self-referred screenees were similar to respondents to invitation in main indicators of screening feasibility such as recall rate and PPV of biopsy, while showing important increases in detection rates and detected:expected ratios, especially among women aged 50-54 years.

Does the Neighborhood Area of Residence Influence Non-Attendance in an Urban Mammography Screening Program? A Multilevel Study in a Swedish City

BACKGROUND AND AIM

The public health impact of population-based mammography screening programs depends on high participation rates. Thus, monitoring participation rates, as well as understanding and considering the factors influencing attendance, is important. With the goal to acquire information on the appropriate level of intervention for increasing screening participation our study aimed to (1) examine whether, over and above individual factors, the neighborhood of residence influences a woman's mammography non-attendance, and (2) evaluate, whether knowing a woman's neighborhood of residence would be sufficient to predict non-attendance.

METHODS

We analyze all women invited to mammography screening in 2005-09, residing in the city of Malmö, Sweden. Information regarding mammography screening attendance was linked to data on area of residence, demographic and socioeconomic characteristics available from Statistics Sweden. The influence of individual and neighborhood factors was assessed by multilevel logistic regression analysis with 29,901 women nested within 212 neighborhoods.

RESULTS

The prevalence of non-attendance among women was 18.3%. After adjusting for individual characteristics, the prevalence in the 212 neighborhoods was 3.6%. Neighborhood of residence had little influence on non-attendance. The multilevel analysis indicates that 8.4% of the total individual differences in the propensity of non-attendance were at the neighborhood level. However, when adjusting for specific individual characteristics this general contextual effect decreased to 1.8%. This minor effect was explained by the sociodemographic characteristic of the neighborhoods. The discriminatory accuracy of classifying women according to their non-attendance was 0.747 when considering only individual level variables, and 0.760 after including neighborhood level as a random effect.

CONCLUSION

Our results suggest that neighborhoods of residence in Malmö, Sweden (as defined by small-area market statistics (SAMS) areas) do not condition women's participation in population based mammography screening. Thus, interventions should be directed to the whole city and target women with a higher risk of non-attendance.

The impact of co-morbidity on health-related quality of life in breast cancer survivors and controls

BACKGROUND

The objective of this study was: 1) to compare health-related quality of life (HRQoL) scores of breast cancer survivors to matched controls; and 2) to examine the relative impact (explained variance) of the type and number of co-morbidities on HRQoL.

MATERIAL AND METHODS

Data from the KARMA project was used in this cross-sectional study. For each woman diagnosed with breast cancer (n = 2552) there were two healthy age- and geographically matched females (n = 5104). Breast cancer survivors were categorized according to time since diagnosis: recently diagnosed (0-1 year), short- (2-5 years), mid- (6-10 years), and long-term survivors (> 10 years). Women completed a questionnaire addressing demographics (age, educational level, and geographical location), lifestyle factors (body mass index (BMI) and smoking), co-morbidities, and HRQoL. The difference in explained variance in six HRQoL-domains between demographics, lifestyle factors, and co-morbidity in women with breast cancer and matched controls was examined by hierarchical regression analyses.

RESULTS AND CONCLUSION

Women recently diagnosed (n = 63), reported the worst HRQoL followed by short-term survivors (2-5 years, n = 863). Thereafter, HRQoL scores further improved (6-10 years, n = 726), and were comparable to healthy females after 10 years (n = 893). Co-morbidity has a negative impact on HRQoL, which increased with time after diagnosis. Cardiovascular disease and depression were the strongest associates. Breast cancer survivors report clinically significant improvement in HRQoL scores six years after diagnosis. Co-morbidity has a negative impact on HRQoL, which increases with time after diagnosis, even though the number of co-morbidities remains stable. In long-term survivors there should be increasing awareness of co-morbidity and its impact on HRQoL.

Patterns of changing cancer risks with time since diagnosis of a sibling

Family history is a well-known risk factor for many cancers. However, it is important to know if/how the familial risk of cancer changes over time. For each of four major cancers (colorectal, breast, prostate and melanoma), we identified siblings of cancer patients (case siblings) and siblings of matched cancer-free controls sampled from Swedish population-based registers. Effects of age and time since diagnosis on sibling risks were examined using Poisson regression and presented graphically as smoothed hazard ratios (HRs). Screening effects were investigated by comparing hazards before/after the introduction of mammography for breast cancer and prostate-specific antigen (PSA) testing for prostate cancer. Case siblings had higher cancer incidence than control siblings for all cancers at all ages, with overall incidence rate ratios (IRRs) of 2.41 (95% confidence interval 2.14-2.71) for colorectal cancer, 2.37 (2.24-2.52) for breast cancer, 3.69 (3.46-3.93) for prostate cancer and 3.20 (2.72-3.76) for melanoma. Risks were highest in siblings who were young when the first cancer was diagnosed in the family, with siblings aged 30-40 having IRR 9.05 (3.03-27.00) for colorectal cancer and 4.30 (2.87-6.45) for breast cancer. Smoothed HRs remained fairly constant for up to 20 years except for prostate cancer, where the HR decreased steeply during the first few years. After introduction of PSA testing, men had higher incidence of prostate cancer shortly after diagnosis in a brother, but no such screening effect was found for breast cancer. Our findings can help inform the screening and counseling of family members of cancer patients.

Psychometric properties of a Swedish version of the Consequences of Screening--Breast Cancer questionnaire

AIM

To evaluate the psychometric properties of a questionnaire addressing psychosocial consequences of false-positive mammographic screening.

BACKGROUND

The Consequences of Screening--Breast Cancer and Lung Cancer questionnaires target psychosocial consequences of false-positive cancer screening. The Consequences of Screening--Breast Cancer questionnaire and ten items not considered lung cancer specific from the Lung Cancer questionnaire have been adapted for use in mammographic screening in Sweden, but remain psychometrically untested.

DESIGN

Instrument development paper with psychometric cross-sectional and test-retest design.

METHODS

Twelve scales of a Swedish questionnaire version were tested by the Rasch model and traditional psychometric methods. Women with false-positive (Group I, n = 640) and negative (Group II, n = 802) screening mammography responded to the study questionnaire and the Nottingham Health Profile during 2009-2011.

RESULTS

Iterative analyses resulted in nine scales demonstrating Rasch model fit, but all scales exhibited poor targeting with relatively large floor effects. Corrected item-total correlations exceeded the recommended criterion. Score differences between Groups I and II and correlations with Nottingham Health Profile sections followed an expected pattern. Cronbach's α and test-retest reliability was acceptable for group-level assessments for ten and seven scales, respectively.

CONCLUSIONS

Five scales (Sense of dejection, Anxiety, Behavioural, Sleep and Existential values) of the Swedish questionnaire version demonstrated the best psychometric properties. Other scales should be used more cautiously. Although filling an important gap, causes of concern were identified across scales. The questionnaire should therefore be considered for group-level assessments rather than for measurement of individual degrees of psychosocial consequences.

Reasons for non-participation in population-based abdominal aortic aneurysm screening

Background

A population-based screening programme for abdominal aortic aneurysm (AAA) started in 2010 in Stockholm County, Sweden. This present study used individual data from Sweden's extensive healthcare registries to identify the reasons for non-participation in the AAA screening programme.

Methods

All 65-year-old men in Stockholm are invited to screening for AAA; this study included all men invited from July 2010 to July 2012. Participants and non-participants were compared for socioeconomic factors, travel distance to the examination centre and healthcare use. The influence of these factors on participation was analysed using univariable and multivariable logistic regression models.

Results

The participation rate for AAA screening was 77·6 per cent (18 876 of 24 319 men invited). The prevalence of AAA (aortic diameter more than 2·9 cm) among participants was 1·4 per cent. The most important reasons for non-participation in the multivariable regression analyses were: recent immigration (within 5 years) (odds ratio (OR) 3·25, 95 per cent confidence interval 1·94 to 5·47), low income (OR 2·76, 2·46 to 3·10), marital status single or divorced (OR 2·23, 2·08 to 2·39), low level of education (OR 1·28, 1·16 to 1·40) and long travel distance (OR 1·23, 1·10 to 1·37). Non-participants had a higher incidence of stroke (4·5 versus 2·8 per cent; P &lt; 0·001) and chronic pulmonary disease (2·9 versus 1·3 per cent; P &lt; 0·001). Daily smoking was more common in residential areas where the participation rate for AAA screening was low.

Conclusion

Efforts to improve participation in AAA screening should target the groups with low income, a low level of education and immigrants. The higher morbidity in the non-participant group, together with a higher rate of smoking, make it probable that this group also has a high risk of AAA.

Psychosocial factors and attendance at a population-based mammography screening program in a cohort of Swedish women

Background

A better understanding of the factors that influence mammography screening attendance is needed to improve the effectiveness of these screening programs. The objective of the study was to examine whether psychosocial factors predicted attendance at a population-based invitational mammography screening program.

Methods

Data on cohabitation, social network/support, sense of control, and stress were obtained from the Malmö Diet and Cancer Cohort Study and linked to the Malmö mammography register in Sweden. We analyzed 11,409 women (age 44 to 72) who were free of breast cancer at study entry (1992 to 1996). Mammography attendance was followed from cohort entry to December 31, 2009. Generalized Estimating Equations were used to account for repeated measures within subjects. Adjusted odds ratios (OR) and 95% confidence intervals (CI) are reported.

Results

Among 69,746 screening opportunities there were 5,552 (8%) cases of non-attendance. Higher odds of non-attendance were found among women who lived alone (OR = 1.47 (1.33-1.63)) or with children only (OR = 1.52 (1.29-1.81)), had one childbirth (OR = 1.12 (1.01-1.24)) or three or more childbirths (OR = 1.34 (1.21-1.48)), had low social participation (OR= 1.21 (1.10-1.31)), low sense of control (OR = 1.12 (1.02-1.23)), and experienced greater stress (OR = 1.24 (1.13-1.36)).

Conclusions

Public health campaigns designed to optimize mammography screening attendance may benefit from giving more consideration of how to engage with women who are less socially involved.

Invasive lobular carcinoma of the breast: long-term prognostic value of Ki67 and histological grade, alone and in combination with estrogen receptor

Background

The aim of the present study was to investigate the long-term impact of prognostic factors in invasive lobular carcinoma (ILC) of the breast, with a primary focus on Ki67 and histological grade, alone and in combination with estrogen receptor (ER).

Material and methods

One hundred and ninety two well-characterised patients with ILC were included in the study. Ki67, histological grade and ER were evaluated and combined into a prognostic index (KiGE). All grade 1 tumours and ER-positive (ER+) grade 2 tumours with Ki67 ≤ 30% were classified as low-KiGE and all the others as high-KiGE.

Results

Overall, 31% of the patients have died from breast cancer. The median follow-up of the patients still alive was 21 years. Age, tumour size, axillary lymph node status (nodal status), histological grade, Ki67 and KiGE were significant prognostic factors for breast cancer mortality (BCM) in univariable analysis. In a multivariable model, adjusted for adjuvant treatment, age and progesterone receptor (PgR), the strongest prognostic factors for BCM were: Nodal status (hazard ratio (HR) = 2.9, 95% confidence interval (95% CI): 1.4-6.1), KiGE (HR = 2.0, 95% CI: 1.1-3.6), and tumour size (HR = 1.9, 95% CI: 0.98-3.8). By combining these three factors, 37% of the ILC’s could be further divided into a low-risk group, consisting of node negative small (≤ 20 mm) low-KiGE tumours, with a BCM of 5% (95% CI: 1-13%) at 10 years and 12% (95% CI: 5-22%) at 20 years follow-up. None of these patients recieved chemotherapy and only 2 recieved endocrine treatment with tamoxifen.

Conclusions

The combination of Ki67, histological grade and ER into KiGE, together with tumour size and nodal status make it possible to identify a large group of ILC patients with such a good long-term prognosis that chemotherapy can be safely avoided and exclusion of endocrine therapy considered.

A roller coaster of emotions and sense--coping with the perceived psychosocial consequences of a false-positive screening mammography

AIMS AND OBJECTIVES

To explore coping with the perceived psychosocial consequences of a false-positive screening mammography.

BACKGROUND

Mammographic screening has been found effective to decrease breast cancer (BC) mortality, yet there are adverse effects. Psychosocial consequences of false-positive mammographic screening have mainly been investigated from a population-based perspective. A call for qualitative studies to further explore these consequences has thus been postulated. To date, qualitative studies have elucidated women's experiences following their recall breast examinations, but their coping with perceived psychosocial consequences of a false-positive screening mammography has not yet been explored.

DESIGN

An explorative qualitative study.

METHODS

Face-to-face interviews were held with a purposive heterogeneous sample of 13 Swedish-speaking women with a false-positive screening mammography. The transcripts were analysed by the use of an inductive content analysis.

RESULTS

Coping with the perceived psychosocial consequences of a false-positive screening mammography implied a roller coaster of emotion and sense. Women described how they imagined the worst and were in a state of uncertainty feeling threatened by a fatal disease. Conversely, they felt protected, surrounded by their families and being professionally taken care of, which together with perceived sisterhood and self-empowerment evoked strength and hope. Being aware of family responsibility became a crucial matter. Experiencing false-positive screening raised thoughts of thankfulness and reappraisal of life, although an ounce of BC anxiety remained. Consequently, gained awareness about BC screening and values in life surfaced.

CONCLUSIONS

Experiencing a false-positive screening mammography triggers agonising experiences evoking a variety of coping strategies. Provision of screening raises the issue of responsibility for an impact on psychosocial well-being among healthy women.

RELEVANCE TO CLINICAL PRACTICE

Gained knowledge might provide a basis for interventions to prevent psychosocial consequences of false-positive mammographic screening and provide support for women with a potentially compromised ability to overcome such consequences.

Ethnic differences in breast cancer risk and survival: a study on immigrants in Sweden

BACKGROUND

There are large geographic differences in breast cancer risk but whether survival differs between low- and high-risk groups is less well-established. As the survival of cancer depends on the level of healthcare and awareness of disease risks, subtle differences in cancer biology cannot be revealed in international comparisons. Instead, comparison of diverse immigrant groups in a country of uniformly accessible healthcare system should enable conclusions to be made about ethnic determinants of cancer risk and survival.

MATERIAL AND METHODS

The Swedish Family-Cancer Database was used to calculate standardized incidence (SIRs) and hazard ratios (HRs) of death from female breast cancer in 12 505 and 137 547 patients diagnosed with breast cancer among immigrants and Swedes, respectively. The ratios were adjusted for age, period, region, parity, and age at first childbirth. Ordinal logistic regression analysis was used to estimate odds ratios (ORs) for the clinical TNM classes. The analyses were stratified by menopausal status and histology. Results. Turks, Southeast Asians, and Chileans had the lowest breast cancer risk (SIR = 0.44; 95% CI 0.37-0.51) and Iraqis the highest risk (1.19; 1.05-1.35), mainly due to premenopausal cancer (1.51; 1.27-1.78). The HRs for all breast cancers were between 0.98 (0.81-1.18) (low-risk Europeans) and 1.24 (0.94-1.63) (lowest-risk non-Europeans), but were not significant. No differences in survival of ductal carcinoma between immigrants and Swedes were found, while low-risk non-Europeans had a HR of 2.88 (1.37-6.08) for lobular carcinoma. Low-risk non-Europeans were diagnosed in a higher T-class (OR = 1.87; 1.21-2.87) than Swedes.

CONCLUSION

We did not find any evidence that ethnic differences in breast cancer risk substantially affect the survival. The observed poor survival of some low-risk immigrants in lobular carcinoma may be related to treatment. The tendency of low-risk immigrants to present with higher T-class compared to Swedes may depend on their lower participation in the mammography screening program.

Trends of breast cancer and its management in the last twenty years in Aden and adjacent governorates, Yemen

BACKGROUND

Breast cancer is the most common cancer of women and the principal cause of death in middle aged women. The objective of this study was to describe the trend of breast cancer and its management in Aden and adjacent south-eastern governorates of Yemen during the last 20 years.

PATIENTS AND METHODS

This is a retrospective analysis of previous studies on patients with breast cancer in Aden and adjacent south-eastern governorates, Yemen (January 1989 through December 2007). The studied variables were: sex, age, time and type of presentation, disease stage, pathological types and the performed surgical treatment. The sources of information were the treatment registry of Aden health office, archives of Al-Gamhouria teaching hospital; major referral and other public and private hospitals in Aden and Aden Cancer Registry.

RESULTS

The total number of patients was 476, 99% being females. The age range was 19-88 years. The most affected age was 30-50 years (60.5%), 95% presenting after one month of having breast symptoms. Forty-five percent presented with signs of advanced local disease, while 59.2% had palpable axillary lymph nodes on presentation. Early breast cancer (stages I-II) occurred in 47%, and late breast cancer (stages III-IV) in 51.5%. Invasive ductal carcinoma was the commonest pathology (89.3%). The main surgical treatment was mastectomy (modified radical mastectomy (50%).

CONCLUSION

Breast cancer is predominantly a disease of young with late presentation and advanced disease. Improving health awareness and earlier diagnosis of the disease by health education, encouraging breast self-examination, and providing the mammography equipment and mammary clinics in hospitals are recommended. Establishment of oncology and radiotherapy centers in Aden is a necessity.

Do reproductive factors influence T, N, and M classes of ductal and lobular breast cancers? A nation-wide follow-up study

BACKGROUNDS

The clinical tumor-node-metastasis (T, N and M) classes of breast cancers provide important prognostic information. However, the possible association of TNM classes with reproductive factors has remained largely unexplored. Because every woman has a reproductive history, implications to outcome prediction are potentially significant.

METHODS

During the study period from 2002 through 2008, 5,614 pre- and 27,310 postmenopausal patients were identified in the Swedish Family-Cancer Database. Ordinal logistic regression analysis was used to estimate odds ratios (ORs) for TNM classes of breast cancers by histology. The reproductive variables were parity, age at first and last childbirth and time interval between first and last childbirth.

RESULTS

Among postmenopausal patients, the ORs for high-T class (T2-T4) (tumor size ≥2 cm) and metastasis were decreased by parity. A late age at first and last childbirth associated with high-T class and the effects were higher for lobular (OR for late age at first childbirth  = 2.85) than ductal carcinoma. Overall, long time interval between first and last childbirth was related to high-T class and metastasis. However, a short time interval between first and last childbirth in patients with late age at first or last childbirth increased the risk of metastasis. Late age at last childbirth was associated with increased occurrence of lobular carcinoma in situ. Among premenopausal ductal carcinoma patients, nulliparity and early age at first childbirth were associated with high-T class.

CONCLUSIONS

Increasing parity was protective against high-T class and metastasis; late ages at first and last childbirth were risk factors for high-T class in postmenopausal breast cancers. The current decline in parity and delayed age at first childbirth in many countries may negatively influence prognosis of breast cancer.

Patterns of breast cancer mortality trends in Europe

OBJECTIVES

To identify patterns of variation in breast cancer mortality in Europe (1980-2010), using a model-based approach.

METHODS

Mortality data were obtained from the World Health Organization database and mixed models were used to describe the time trends in the age-standardized mortality rates (ASMR). Model-based clustering was used to identify clusters of countries with homogeneous variation in ASMR.

RESULTS

Three patterns were identified. Patterns 1 and 2 are characterized by stable or slightly increasing trends in ASMR in the first half of the period analysed, and a clear decline is observed thereafter; in pattern 1 the median of the ASMR is higher, and the highest rates were achieved sooner. Pattern 3 is characterised by a rapid increase in mortality until 1999, declining slowly thereafter.

CONCLUSION

This study provides a general model for the description and interpretation of the variation in breast cancer mortality in Europe, based in three main patterns.

Breast cancer screening: evidence of benefit depends on the method used

In this article, we discuss the most common epidemiological methods used for evaluating the ability of mammography screening to decrease the risk of breast cancer death in general populations (effectiveness). Case-control studies usually find substantial effectiveness. However when breast cancer mortality decreases for reasons unrelated to screening, the case-control design may attribute to screening mortality reductions due to other causes. Studies based on incidence-based mortality have obtained contrasted results compatible with modest to considerable effectiveness, probably because of differences in study design and statistical analysis. In areas where screening has been widespread for a long time, the incidence of advanced breast cancer should be decreasing, which in turn would translate into reduced mortality. However, no or modest declines in the incidence of advanced breast cancer has been observed in these areas. Breast cancer mortality should decrease more rapidly in areas with early introduction of screening than in areas with late introduction of screening. Nonetheless, no difference in breast mortality trends has been observed between areas with early or late screening start. When effectiveness is assessed using incidence-based mortality studies, or the monitoring of advanced cancer incidence, or trends in mortality, the ecological bias is an inherent limitation that is not easy to control. Minimization of this bias requires data over long periods of time, careful selection of populations being compared and availability of data on major confounding factors. If case-control studies seem apparently more adequate for evaluating screening effectiveness, this design has its own limitations and results must be viewed with caution.See related Opinion article: http://www.biomedcentral.com/1741-7015/10/106 and Commentary http://www.biomedcentral.com/1741-7015/10/164.

Breast cancer incidence and case fatality among 4.7 million women in relation to social and ethnic background: a population-based cohort study

INTRODUCTION

Incidence of breast cancer is increasing around the world and it is still the leading cause of cancer mortality in low- and middle-income countries. We utilized Swedish nationwide registers to study breast cancer incidence and case fatality to disentangle the effect of socioeconomic position (SEP) and immigration from the trends in native Swedes.

METHODS

A nation-wide cohort of women in Sweden was followed between 1961 and 2007 and incidence rate ratio (IRR) and hazard ratio (HR) with 95% confidence intervals (CIs) were estimated using Poisson and Cox proportional regression models, respectively.

RESULTS

Incidence continued to increase; however, it remained lower among immigrants (IRR = 0.88, 95% CI = 0.86 to 0.90) but not among immigrants' daughters (IRR = 0.97, 95% CI = 0.94 to 1.01) compared to native Swedes. Case fatality decreased over the last decades and was similar in native Swedes and immigrants. However, case fatality was significantly 14% higher if cancer was diagnosed after age 50 and 20% higher if cancer was diagnosed in the most recent years among immigrants compared with native Swedes. Women with the highest SEP had significantly 20% to 30% higher incidence but had 30% to 40% lower case fatality compared with women with the lowest SEP irrespective of country of birth. Age at immigration and duration of residence significantly modified the incidence and case fatality.

CONCLUSIONS

Disparities found in case fatality among immigrants by age, duration of residence, age at immigration and country of birth emphasize the importance of targeting interventions on women that are not likely to attend screenings or are not likely to adhere to the therapy suggested by physicians. The lower risk of breast cancer among immigrant women calls for more knowledge about how the lifestyle factors in these women differ from those with high risk, so that preventative measures may be implemented.

Natural history of breast cancers detected in the Swedish mammography screening programme: a cohort study

BACKGROUND

The natural history of screen-detected breast cancers is not well understood. A previous analysis of the incidence change during the introduction of the Norwegian screening programme in the late 1990s suggested that the natural history of many screen-detected invasive breast cancers is to regress spontaneously but the study was possibly confounded by use of hormone replacement therapy in the population. We did a similar analysis of data collected during an earlier period when few women were exposed to hormone replacement therapy.

METHODS

We compared cumulative breast cancer incidence in age-matched cohorts of women living in seven Swedish counties before and after the initiation of public mammography screening between 1986 and 1990. Women aged 40-49 years were invited to screening every year and women aged 50-74 years were invited every 2 years. A screened group including all women aged 40-69 years (n=328,927) was followed-up for 6 years after the first invitation to the programme. A control group including all women in the same age range (n=317,404) was also followed-up for 6 years--4 years without screening and 2 years when they entered the screening programme. Screening attendance was much the same in both groups (close to 80%). Counts of incident invasive breast cancers were obtained from the Swedish Cancer Registry (in-situ cancers were excluded).

FINDINGS

Before the age-matched controls were invited to be screened at the end of their follow-up period, the 4-year cumulative incidence of invasive breast cancer was significantly higher in the screened group (982 per 100,000) than it was in the control group (658 per 100,000) (relative risk [RR] 1·49, 95% CI 1·41-1·58). Even after prevalence screening in the control group, the screened group had higher 6-year cumulative incidence of invasive breast cancer (1443 per 100,000 vs 1269 per 100,000; RR 1·14, 1·10-1·18).

INTERPRETATION

Because the cumulative incidence among controls did not reach that of the screened group, we believe that many invasive breast cancers detected by repeated mammography screening do not persist to be detected by screening at the end of 6 years, suggesting that the natural course of many of the screen-detected invasive breast cancers is to spontaneously regress.

FUNDING

None.

Breast cancer mortality in neighbouring European countries with different levels of screening but similar access to treatment: trend analysis of WHO mortality database

OBJECTIVE

To compare trends in breast cancer mortality within three pairs of neighbouring European countries in relation to implementation of screening.

DESIGN

Retrospective trend analysis.

SETTING

Three country pairs (Northern Ireland (United Kingdom) v Republic of Ireland, the Netherlands v Belgium and Flanders (Belgian region south of the Netherlands), and Sweden v Norway).

DATA SOURCES

WHO mortality database on cause of death and data sources on mammography screening, cancer treatment, and risk factors for breast cancer mortality.

MAIN OUTCOME MEASURES

Changes in breast cancer mortality calculated from linear regressions of log transformed, age adjusted death rates. Joinpoint analysis was used to identify the year when trends in mortality for all ages began to change.

RESULTS

From 1989 to 2006, deaths from breast cancer decreased by 29% in Northern Ireland and by 26% in the Republic of Ireland; by 25% in the Netherlands and by 20% in Belgium and 25% in Flanders; and by 16% in Sweden and by 24% in Norway. The time trend and year of downward inflexion were similar between Northern Ireland and the Republic of Ireland and between the Netherlands and Flanders. In Sweden, mortality rates have steadily decreased since 1972, with no downward inflexion until 2006. Countries of each pair had similar healthcare services and prevalence of risk factors for breast cancer mortality but differing implementation of mammography screening, with a gap of about 10-15 years.

CONCLUSIONS

The contrast between the time differences in implementation of mammography screening and the similarity in reductions in mortality between the country pairs suggest that screening did not play a direct part in the reductions in breast cancer mortality.

Prognosis of early-stage synchronous bilateral invasive breast cancer

BACKGROUND

Contradictory data exists concerning the prognosis of patients with synchronous bilateral breast cancer (SBBC). Most authors report a worse prognosis for SBBC patients compared to unilateral breast cancer (UBC) patients. There are a few studies that did not support these findings. This study gives a comprehensive picture of SBBC and tests the hypothesis that outcome of this entity is based on the tumor with the worse prognosis (reference lesion).

PATIENTS & METHODS

The data of two prospective Swiss breast cancer databases covering a 20-year period (1990-2009) was reviewed. Forty-six cases of SBBC were identified. In 34 patients with early-stage SBBC, the reference lesions (defined as the tumor with the more advanced stage or, in cases where both tumors had the same stage, the larger tumor) were compared in a case-control approach with 100 patients having UBC (SBBC/UBC ratio = 1/3). The controls were matched for age, time of diagnosis, tumor size, axillary node status, histological grade and estrogen-receptor status. Differences in terms of survival curves were analyzed using the log rank test; the possible correlation between matched groups was evaluated by a frailty Cox model.

RESULTS

There were no significant differences in disease-specific survival between SBBC and its unilateral controls (HR, 0.932; 95% CI, 0.322-1.07; p = 0.90).

CONCLUSIONS

The prognosis of SBBC was determined by the reference lesion; the contralateral second tumor had no additional impact on outcome.

The role of mammography screening attendance and detection mode in predicting breast cancer survival-is there added prognostic value?

INTRODUCTION

The aim of this study was to examine whether screening exposure status, defined as detection mode (screening, interval or symptomatic) combined with breast cancer screening attendance prior to diagnosis, had any additional value over detection mode in predicting breast cancer survival. We also assessed the effect of hormone replacement therapy (HRT) on the association of detection mode with breast cancer survival.

METHODS

We analysed and compared the associations of both screening exposure status and detection mode with 5-year breast cancer survival on a cohort of 3013 breast cancer patients, aged 50-74 years in Sweden. We used Cox proportional hazards modelling with adjustments for tumour size, grade, estrogen receptor (ER) and progesterone receptor (PR) status and lymph node involvement. We repeated the analyses after stratification for HRT use.

RESULTS

Multivariate hazard ratios (HR) for cancers detected in patients at subsequent screens, interval cancers and symptomatic cancers in patients with and without previous screening attendance were 1.3 (95%CI 0.7-2.3), 1.8 (95%CI 1.0-3.2), 1.8 (95%CI 0.9-3.6) and 2.2 (95%CI 1.2-4.1) respectively, compared with cancers detected at the first screen. The regression model including screening exposure status had no additional prognostic value over the model including detection mode (P=0.63). HRT users showed a more favourable survival than non-users; this was not influenced by detection mode.

CONCLUSION

The number of routine screening examinations attended in the 5-year period prior to diagnosis had no additional prognostic value over detection mode in predicting breast cancer survival.

Breast cancer, sickness absence, income and marital status. A study on life situation 1 year prior diagnosis compared to 3 and 5 years after diagnosis

BACKGROUND

Improved cancer survival poses important questions about future life conditions of the survivor. We examined the possible influence of a breast cancer diagnosis on subsequent working and marital status, sickness absence and income.

MATERIALS

We conducted a matched cohort study including 4,761 women 40-59 years of age and registered with primary breast cancer in a Swedish population-based clinical register during 1993-2003, and 2,3805 women without breast cancer. Information on socioeconomic standing was obtained from a social database 1 year prior and 3 and 5 years following the diagnosis. In Conditional Poisson Regression models, risk ratios (RRs) and 95% confidence intervals (CIs) were estimated to assess the impact of a breast cancer diagnosis.

FINDINGS

Three years after diagnosis, women who had had breast cancer more often had received sickness benefits (RR = 1.49, 95% CI 1.40-1.58) or disability pension (RR = 1.47, 95% CI 1.37-1.58) than had women without breast cancer. We found no effect on income (RR = 0.99), welfare payments (RR = 0.98), or marital status (RR = 1.02). A higher use of sickness benefits and disability pension was evident in all stages of the disease, although the difference in use of sickness benefits decreased after 5 years, whereas the difference in disability pension increased. For woman with early stage breast cancer, the sickness absence was higher following diagnosis among those with low education, who had undergone mastectomy, and had received chemo- or hormonal therapy. Neither tumour size nor presence of lymph nodes metastasis was associated with sickness absence after adjustment for treatment.

INTERPRETATION

Even in early stage breast cancer, a diagnosis negatively influences working capacity both 3 and 5 years after diagnosis, and it seems that the type of treatment received had the largest impact. A greater focus needs to be put on rehabilitation of breast cancer patients, work-place adaptations and research on long-term sequelae of treatment.

Randomized controlled trial of mammographic screening from age 40 ('Age' trial): patterns of screening attendance

BACKGROUND

The Age trial was a randomized controlled trial to study the effect on breast cancer mortality of invitation to annual mammography from age 40 to 41. Uptake of invitation to screening mammography in UK women aged below 50 is of interest, particularly in the light of the recent announcement that the national breast screening programme will begin inviting women from age 47.

METHODS

The trial took place in 23 National Health Service breast screening units in England, Wales and Scotland between 1991 and 2004. Data on invitation and attendance during 13 years of trial fieldwork were analysed. The participants were 53,884 women in the intervention arm of the Age trial who were randomized to receive annual invitation to mammography from age 40 or 41 up to age 48. The trial is registered as an International Standard Randomised Controlled Trial, number ISRCTN24647151.

RESULTS

Uptake of invitation to routine screening was 68% at first round and 69% at subsequent rounds. A total of 43,709 women in the intervention arm (81%) attended at least one routine screen and 23,262 (43%) attended at least seven screens; 31,392 women attended 75% or more of all routine invitations they were offered. Previous trial attendance was a predictor of subsequent uptake; attendance was inversely related to Townsend deprivation score.

CONCLUSION

Uptake in this trial was comparable with that in the UK screening programme for women aged over 50. There was an inverse relationship between deprivation level and the number of screens attended.