Biomedical subjects

Ingvar Andersson

Publications and source records attributed to Ingvar Andersson.

5 recordsLinked to original sources

PubMed2006

Rate of over-diagnosis of breast cancer 15 years after end of Malmö mammographic screening trial: follow-up study.

OBJECTIVE: To evaluate the rate of over-diagnosis of breast cancer 15 years after the end of the Malmö mammographic screening trial. DESIGN: Follow-up study. SETTING: Malmö, Sweden. SUBJECTS: 42 283 women aged 45-69 years at randomisation. INTERVENTIONS: Screening for breast cancer with mammography or not (controls). Screening was offered at the end of the randomisation design to both groups aged 45-54 at randomisation but not to groups aged 55-69 at randomisation. MAIN OUTCOME MEASURES: Rate of over-diagnosis of breast cancer (in situ and invasive), calculated as incidence in the invited and control groups, during period of randomised design (period 1), during period after randomised design ended (period 2), and at end of follow-up. RESULTS: In women aged 55-69 years at randomisation the relative rates of over-diagnosis of breast cancer (95% confidence intervals) were 1.32 (1.14 to 1.53) for period 1, 0.92 (0.79 to 1.06) for period 2, and 1.10 (0.99 to 1.22) at the end of follow-up. CONCLUSION: Conclusions on over-diagnosis of breast cancer in the Malmö mammographic screening trial can be drawn mainly for women aged 55-69 years at randomisation whose control groups were never screened. Fifteen years after the trial ended the rate of over-diagnosis of breast cancer was 10% in this age group.

Age Factors↗

PubMed2005

Average glandular dose in routine mammography screening using a Sectra MicroDose Mammography unit.

The Sectra MicroDose Mammography system is based on direct photon counting (with a solid-state detector), and a substantially lower dose to the breast than when using conventional systems can be expected. In this work absorbed dose measurements have been performed for the first unit used in routine mammography screening (at the Hospital of Helsingborg, Sweden). Two European protocols on dosimetry in mammography have been followed. Measurement of half value layer (HVL) cannot be performed as prescribed, but this study has demonstrated that non-invasive measurements of HVL can be performed accurately with a sensitive and well collimated solid-state detector with simultaneous correction for the energy dependence. The average glandular dose for a 50 mm standard breast with 50% glandularity, simulated by 45 mm polymethylmethacrylate, was found to be 0.21 and 0.28 mGy in March and December 2004, respectively. These values are much lower than for any other mammography system on the market today. It has to be stressed that the measurements were made using the current clinical settings and that no systematic optimisation of the relationship between absorbed dose and diagnostic image quality has been performed within the present study. In order to further increase the accuracy of absorbed dose measurements for this unit, the existing dose protocols should be revised to account also for the tungsten/aluminium anode/filter combination, the multi-slit pre-collimator device and the occurrence of a dose profile in the scanning direction.

Air↗

PubMed2004

Non-attendance in breast cancer screening is associated with unfavourable socio-economic circumstances and advanced carcinoma.

Our first objective was to assess changes in non-attendance, proportion of advanced breast cancer and survival in Malmö Mammographic Service Screening Program, MMSSP, compared to a former trial, Malmö Mammographic Screening Trial, MMST. Our second objective was to describe non-attenders in MMSSP in socio-economic terms and risk for advanced breast cancer compared to attenders. Information from hospital and national registers was used to identify 33,800 women invited to service screening in MMSSP 1990-93. Attendance rates at first screening, the proportion of advanced breast cancers (Stage II-IV) and survival among non-attenders in MMSSP were compared to the non-attenders and with the control group of the former trial, MMST. Various socio-economic factors were assessed as potential predictors of non-attendance in MMSSP. Odds ratios (OR) and 95% confidence interval (CI) were computed. Incidence of breast cancer during a 10-year-period, relative risks and 95% CI among non-attenders compared to attenders in MMSSP were computed. Attendance rates were significantly lower in MMSSP but a lower proportion of advanced breast cancers and a somewhat better survival among breast cancer cases (not significant) was seen in non-attenders in MMSSP compared to MMST. In MMSSP non-attendance was associated with being unmarried, being born abroad, being not currently employed, crowded housing conditions and low income. Incidence of advanced breast cancer was significantly higher among non-attenders than among attenders. Attendance has decreased over time and potential reasons are discussed. Stage distribution and survival among non-attenders seem to have improved. Several socio-economic factors predict non-attendance and non-attenders are at higher risk for advanced breast cancer.

Aged↗

PubMed2002

Long-term effects of mammography screening: updated overview of the Swedish randomised trials.

BACKGROUND: There has been much debate about the value of screening mammography. Here we update the overview of the Swedish randomised controlled trials on mammography screening up to and including 1996. The Kopparberg part of the Two-County trial was not available for the overview, but the continuation of the Malmö trial (MMST II) has been added. The article also contains basic data from the trials that have not been presented before. Methods The trials (n=247010, invited group 129750, control group 117260) have been followed up by record linkage to the Swedish Cancer and Cause of Death Registers. The relative risks (RR) for breast cancer death and mortality were calculated for the invited and the control groups. The trial-specific as well as the age-specific effects were analysed. RRs were calculated by the density method, with total person-time experience of the cohort by time interval of follow-up as a basis for estimating mortality rates. We calculated weighted RRs and 95% CI with the Mantel-Haenszel procedure. FINDINGS: The median trial time-the time from randomisation until the first round was completed for the control group or if the control group was not invited, until end of follow-up-was 6.5 years (range 3.0-18.1). The median follow-up time, the time from randomisation, to the end of follow-up, was 15.8 years (5.8-20.2). There were 511 breast cancer deaths in 1864770 women-years in the invited groups and 584 breast cancer deaths in 1688440 women-years in the control groups, a significant 21% reduction in breast cancer mortality (RR=0.79, 95% CI 0.70-0.89). The reduction was greatest in the age group 60-69 years at entry (33%). Looking at 5-year age groups, there were statistically significant effects in the age groups 55-59, 60-64, and 65-69 years (RR=0.76, 0.68, and 0.69, respectively). There was a small effect in women 50-54 years at randomisation (RR=0.95). The benefit in terms of cumulative breast cancer mortality started to emerge at about 4 years after randomisation and continued to increase to about 10 years. Thereafter the benefit in absolute terms was maintained throughout the period of observation. The age-adjusted relative risk for the total mortality was 0.98 (0.96-1.00). INTERPRETATION: The advantageous effect of breast screening on breast cancer mortality persists after long-term follow-up. The recent criticism against the Swedish randomised controlled trials is misleading and scientifically unfounded.

Adult↗

PubMed2002

Decreasing rate of fatty involution at screening mammography.

RATIONALE AND OBJECTIVES: This study was performed to document the perceived decrease in fatty involution at screening mammography during the past decade and evaluate the influence of hormone replacement therapy (HRT). MATERIALS AND METHODS: In December 1996, the mammograms of 261 consecutive screening patients with a comparison study obtained 5 years earlier were evaluated, and their breasts were categorized according to Breast Imaging Reporting and Data System categories for breast density. The women, aged 50-59 years, included 119 who had been receiving HRT for 0.25-15 years (mean, 3 years). From the files, 261 age-matched screening mammograms from 1986 were obtained; these patients also had comparison mammograms from 1981. Analysis of variance was used to determine differences between the 1980s group, the 1990s group receiving HRT, and the 1990s group not receiving HRT. Scheffé tests were used for post hoc comparisons. Stepwise regression analysis was used to evaluate the relative influence of age, decade, score of the first mammogram, and HRT. RESULTS: Breast density for the 1991 mammograms did not differ significantly from that in 1981 (P < .05). Initial breast density was the best predictor of final breast density in both decades (P < .001), regardless of HRT status. The change in breast density (toward fatty) over the 5-year interval in the 1980s (mean, 0.48) was significantly greater than that in both 1990s groups (mean for HRT group, 0.11; no HRT, 0.30; P < .05). CONCLUSION: These results confirm that breast density at screening mammography in the 1990s did not decrease with age at the same rate as in the 1980s, even in patients not receiving HRT.

Adipose Tissue↗