Offered Screening Mammography Research Articles

Common breast cancer risk alleles and risk assessment: a study on 35 441 individuals from the Danish general population

We hypothesized that common breast cancer risk alleles are associated with incidences of breast cancer and other cancers in the general population, and identify low risk women among those invited for screening mammography. About 35 441 individuals from the Danish general population were followed in Danish health registries for up to 21 years after blood sampling. After genotyping 72 breast cancer risk loci, each with 0–2 alleles, the sum for each individual was calculated. We used the simple allele sum instead of the conventional polygenic risk score, as it is likely more sensitive in detecting associations with risks of other endpoints than breast cancer. Breast cancer incidence in the 19 010 women was increased across allele sum quintiles (log-rank trend test; P = 1×10 − 12), but not incidence of other cancers (P = 0.41). Age- and study-adjusted hazard ratio for the fifth versus the first allele sum quintile was 1.82 (95% confidence interval; 1.53–2.18). Corresponding hazard ratios per allele were 1.04 (1.03–1.05) and 1.05 (1.02–1.08) for breast cancer incidence and mortality, similar across risk factors. In 50-year-old women, the starting age for screening mammography in Denmark, the average 5-year breast cancer risk was 1.5%, overall and 1.1%, 1.4%, 1.6%, 1.7%, 2.1%, for the first through fifth quintile, respectively. Based on age, nulliparity, familial history, and allele sum, 25% of women aged 50–69 years, and 94% of women aged 40–49 years, had absolute 5-year breast cancer risks ≤ 1.5%. Using polygenic risk score led to similar results. Common breast cancer risk alleles are associated with incidence and mortality of breast cancer in the general population, but not with other cancers. After including breast cancer allele sum in risk assessment, 25% of women currently being offered screening mammography had an absolute 5-year risk below the cutoff of average risk for a 50-year-old woman.

Le dépistage organisé du cancer du sein

Breast screening programs are increasingly controversial, especially regarding two points: the number of breast cancer deaths they avoid, and the problem of over-diagnosis and over-treatment. The French national breast cancer screening program was extended to cover the whole country in 2004. Ten years later it is time to examine the risk/benefit ratio of this program and to discuss the need for change. Like all forms of cancer management, screening must be regularly updated, taking into account the state of the art, new evidence, and uncertainties. All screening providers should keep themselves informed of the latest findings. In the French program, women aged 50-74 with no major individual or familial risk factors for breast cancer are offered screening mammography and clinical breast examination every two years. Images considered non suspicious of malignancy by a first reader are re-examined by a second reader. The devices and procedures are subjected to quality controls. Participating radiologists (both public and private) are required to read at least 500 mammographies per year. The program's national participation rate was 52.7 % in 2012. When individual screening outside of the national program is taken into account (nearly 15 % of women), coverage appears close to the European recommendation of 65 %. Breast cancer mortality has been falling in France by 0.6 % per year for over 30 years, starting before mass screening was implemented, and by 1.5 % since 2005. This decline can be attributed in part to earlier diagnosis and better treatment, so that the specific impact of screening cannot easily be measured. Over-treatment, defined as the detection and treatment of low-malignancy tumors that would otherwise not have been detected in a person's lifetime, is a major negative effect of screening, but its frequency is not precisely known (reported to range from 1 % to 30 %). In view of these uncertainties, it would be advisable to modify the program in order to increase its efficiency, by targeting populations at a higher risk than the women currently included, and to reduce the number of mammograms done outside the program, as they are not subject to the same quality controls. Risks could be reduced by increasing the sensitivity of mammography and the specificity of the readings. Moreover, it is mandatory to inform women of both the benefits and risks of screening, in compliance with the principle of enabling patients to make a free and informed choice.

Breast cancer screening implementation and reassurance

Women not offered screening mammography reported higher levels of negative psychosocial aspects than women offered screening. This was demonstrated in a questionnaire survey where 1000 women were included: 500 women living in areas where the public authorities had never offered screening mammography and 500 women living in areas where women had been invited to screening mammography for >10 years. After this baseline survey, nationwide screening mammography was implemented. The aim of this follow-up study was to resurvey the 1000 women and to investigate if the identified difference in reported psychosocial aspects had disappeared or been reduced because of the nationwide screening implementation. The 1000 women included in the previous survey were posted part I of the questionnaire Consequences of Screening in Breast Cancer (COS-BC1) in August 2011, nearly 5 years after they received the COS-BC1 the first time. A total of 677 women returned the questionnaire. There was no statistically significant difference between the two groups in reported psychosocial aspects. Women new to screening reported less negative psychosocial aspects compared with the previous survey. An implementation of a screening mammography programme provides reassurance for those women invited to the screening. This reassurance is in contrast to the unbalanced proportion between the intended benefits and the unintended harms of the screening programme.

Integrating Tools for Breast Cancer Risk Assessment, Risk Reduction, and Early Detection

Commentary on Graubard et al., [p. 2430][1] In 2010, it is projected that there will be 207,090 diagnoses and 39,840 deaths from breast cancer among women in the United States. Approximately 10,300 will be diagnosed before the age of 40 ([1][2]), the age when the American Cancer Society ([2][3])

Effect of Screening Mammography on Breast-Cancer Mortality in Norway

A challenge in quantifying the effect of screening mammography on breast-cancer mortality is to provide valid comparison groups. The use of historical control subjects does not take into account chronologic trends associated with advances in breast-cancer awareness and treatment. The Norwegian breast-cancer screening program was started in 1996 and expanded geographically during the subsequent 9 years. Women between the ages of 50 and 69 years were offered screening mammography every 2 years. We compared the incidence-based rates of death from breast cancer in four groups: two groups of women who from 1996 through 2005 were living in counties with screening (screening group) or without screening (nonscreening group); and two historical-comparison groups that from 1986 through 1995 mirrored the current groups. We analyzed data from 40,075 women with breast cancer. The rate of death was reduced by 7.2 deaths per 100,000 person-years in the screening group as compared with the historical screening group (rate ratio, 0.72; 95% confidence interval [CI], 0.63 to 0.81) and by 4.8 deaths per 100,000 person-years in the nonscreening group as compared with the historical nonscreening group (rate ratio, 0.82; 95% CI, 0.71 to 0.93; P<0.001 for both comparisons), for a relative reduction in mortality of 10% in the screening group (P=0.13). Thus, the difference in the reduction in mortality between the current and historical groups that could be attributed to screening alone was 2.4 deaths per 100,000 person-years, or a third of the total reduction of 7.2 deaths. The availability of screening mammography was associated with a reduction in the rate of death from breast cancer, but the screening itself accounted for only about a third of the total reduction. (Funded by the Cancer Registry of Norway and the Research Council of Norway.)

Prognosis of screen-detected breast cancers: results of a population based study

BackgroundThe reduced mortality rate from breast carcinoma among women offered screening mammography is demonstrated after 15–20 years of follow-up. However, the assessment of 5-year overall and event-free survival could represent an earlier measure of the efficacy of mammography screening program (MSP).MethodsAll cases of breast cancer diagnosed in the Province of Modena between years 1996 and 2000 in women aged 50 to 69 years, were identified through the Modena Cancer Registry (MCR). Stage of disease and treatment information were obtained from clinical records. All the events occurring up to June 30, 2003 were retrieved by experienced monitors. Five-year overall and event-free survival were the principal end-points of the study.ResultsDuring a 5-year period, 587 primary breast cancers were detected by the MSP and 471 primary breast cancers were diagnosed out of the MSP. The screen-detected breast cancers were smaller, more likely node negative, with low histological grade, low proliferative activity and positive receptors status. Furthermore, the breast cancer diagnosed through the MSP more frequently received a conservative surgery. The 5-year survival rate was 94% in the screen-detected group, versus 84% in the other group (p = 0.0001). The rate of 5-year event-free survival was 89% and 75% for the MSP participants and not participants, respectively (p = 0.0001).ConclusionsOur data confirm a favourable outcome of screen-detected breast cancers in terms of five-year overall and event-free survival, which reflect the good quality assurance parameters of the MSP. Finally, a cancer registry should be implemented in every area covered by screening programs.

Early assessment of a population-based breast cancer screening program

1018 Background: The reduced mortality rate from breast carcinoma among women offered screening mammography is usually observed after 10 years of follow-up. However, the assessment of 5-year overall and event-free survival could represent an earlier measure of the efficacy of mammography screening. Methods: All cases of breast cancer diagnosed in the Province of Modena between years 1996 and 2000 in women aged from 50 to 69 years, identified through the Modena Cancer Registry were linked to the data-base of the screening mammographic program (SMP), allowing the identification of cases with invasive or in situ breast cancer diagnosed in women attending or not the SMP. Stage of disease and treatment information were obtained from clinical records. All the events occurred up to June 30, 2003 were retrieved by experienced monitors. Five-year overall and event-free survival were the principal end-points of the study. Results: Between January 1,1996 and December 31, 2000, 1058 new breast cancer were detected among women aged 50–69 residents in the Province of Modena. 55% of cases were detected through the screening program. The screen-detected tumors had smaller size (13 vs 19 mm, p<0.0001) were more likely to have a pathologically confirmed negative nodal status (81% vs 62%, p<0.0001), a low histologic grade (25% vs 21%, p< 0.0001), a low proliferative activity (74% vs 61%, p<0.0001), and a positive hormonal status (84% vs 73%, p=0.02). In addition, breast conservative surgery was performed in 75% of SMP participants and in only 54% of non participants. The 5-year estimated survival rate was 94% for women with screen-detected breast cancer and 84% for those with not screen-detected breast cancer (p=0.0001). The rate of 5-year event free survival was 89% and 75% for the SMP attenders and non attenders, respectively (p=0.0001). Conclusions: Our data demonstrate a better prognosis of screen-detected breast cancers in terms of five-year overall and event-free survival, which represent an earlier measure of the efficacy of a population based breast cancer screening program. Finally, a population-based cancer registry is a relevant tool in the evaluation of the program itself. No significant financial relationships to disclose.

Screening Mammography Controversies: Resolved, Partly Resolved, and Unresolved

Since the 1960s, multiple randomized clinical trials have measured differences in breast cancer mortality between women 40 and 70 years of age who were offered screening mammography and control group women. This article describes briefly these trials, which nearly universally documented statistically significant reductions in breast cancer deaths. These trials also underestimated the benefit, regardless of age, due to screening parameters that were not optimized. In recent years, published articles analyzing studies of Swedish women have claimed that there is no reduction in overall mortality from breast cancer and other causes among women offered screening. Critical assessment of these articles noted that breast cancer deaths were less than 5% of all deaths and that no statistically significant reduction in overall mortality rates should be expected within the population that had been analyzed. The latest screening mammography controversies involve potential adverse consequences and risks, such as X-ray exposure, detection of ductal carcinoma in situ (DCIS), and "excessive" callback rates for additional imaging studies. Despite these controversies, the preponderance of scientific evidence continues to strongly support annual screening mammography for women 40 years of age and older.

Screening mammography: a missed opportunity

By age 80, 1/10 women will be diagnosed with breast cancer. Both positive and negative associations have been reported between alcohol consumption and breast cancer. Minority women are less likely to undergo breast cancer screening. All women admitted for alcohol detoxification in an urban setting with a high minority population were offered screening mammography, using American Cancer guidelines. Women with previously diagnosed breast cancer were excluded from the study. The mammograms were performed by standard technique in the hospital radiology department. The subjects with positive mammograms were referred for further diagnostic studies, as determined by the internist managing the patient’s care. Of the 117 women admitted, 28 were excluded due to age. Only one woman, previously treated for breast cancer, was also excluded. Of the 88 women screened, abnormalities were detected in 32. The women with normal mammograms did not differ from those with abnormal studies in: (1) age; (2) years of alcohol consumption; (3) age at menarche; (4) parity; (5) age at first full term pregnancy; and (6) personal history of benign breast disease or family history of breast cancer. The alcohol detoxification unit provides a unique opportunity to screen women for breast cancer. Compliance with initial screening is high but resistance is encountered if further diagnostic studies are required to evaluate suspicious lesions. Surprisingly, in this study, the number of suspicious lesions detected was not higher than expected.

Factors associated with the use of screening mammography in a primary care setting.

Despite consensus recommendations the use of screening mammography remains low. We examined physician and patient related variables associated with requests to undergo screening mammography in a primary care setting, in order to assess current barriers to screening mammography at the level of the physician-patient interaction. A sample of 261 women over the age of 50, whose primary care was provided by resident physicians in a large, urban, academic medical center were examined. Data concerning patients and physicians demographic and clinical characteristics were abstracted. The data were analyzed by Chi-square and stepwise logistic regression. Forty-five percent of the patients were offered screening mammography within the study year and 53% were offered mammography over the preceding two years. Variables significantly associated with a request for screening included a previous history of breast disease (p < .001) and the severity of the patient's overall medical condition. Patients with an overall medical condition rated as mild were more likely to be requested to undergo screening than patients rated as moderately or severely ill (p < .01). Patients with higher educational levels were also more likely to be offered screening (P = .06). First year postgraduate (PGY 1) physicians requested more mammograms than PGY 2 or PGY 3 physicians (P < .05). A multivariable model utilizing logistic regression confirmed the association of the significant variables above with screening requests. Physicians were more likely to request mammography in patients at higher risk for developing breast cancer and less likely to request it in patients who had co-morbid illness. Increasing physician understanding of the importance and benefits of mammography and further investigation of strategies to ensure physician compliance with mammography recommendations are necessary to increase utilization.

The Use of Mammography for Screening-Reply

In Reply. —Dr Kopans suggests that the conclusions of our article on the PPV of screening mammography are biased and more sweeping than the data justify, and that we have targeted women younger than 50 years. In fact, we did not make a recommendation for or against screening average-risk women younger than 50 years. We concluded that efforts to promote screening mammography should focus on women 50 years of age or older and on women 40 years of age or older with a family history, in whom the majority of breast cancers occur (78% in our study) and in whom screening mammography has the highest PPV. We also recommended that all asymptomatic women who request or are offered screening mammography should be told the likely outcomes of screening. In addition, our article provides data about the performance of screening mammography that clinicians may use to inform women of likely outcomes