Biennial Versus Annual Mammography and the Risk of Late-Stage Breast Cancer

Tumor Doubling Time and Screening Interval

The goal of screening is to detect breast cancers when still curable to decrease breast cancer-specific mortality. Breast cancer screening in the United States is routinely performed with digital mammography and digital breast tomosynthesis. This article reviews breast cancer doubling time by tumor subtype and examines the impact of doubling time on breast cancer screening intervals. By the article's end, the reader will be better equipped to have informed discussions with patients and medical professionals regarding the benefits and disadvantages of the currently recommended screening mammography intervals.

Interval Cancers in Understanding Screening Outcomes

Interval breast cancers are not detected at routine screening and are diagnosed in the interval between screening examinations. A variety of factors contribute to interval cancers, including patient and tumor characteristics as well as the screening technique and frequency. The interval cancer rate is an important metric by which the effectiveness of screening may be assessed and may serve as a surrogate for mortality benefit.

Impact of Mammography Screening Frequency on Breast Cancer Mortality Rates

The frequency of mammography screening remains a topic of ongoing debate. This meta-analysis aimed to investigate the impact of annual vs. biennial mammography screenings on breast cancer mortality rates. A comprehensive search of relevant literature published up to 2021 was performed, with the primary outcome being the difference in breast cancer mortality rates between annual and biennial screenings. The extracted data included relative risks and 95% confidence intervals (CIs), with studies selected based on predetermined inclusion and exclusion criteria, emphasizing the quality of methodology and minimization of bias. Of the included studies, thirteen met the criteria, covering diverse demographic cohorts and screening frequencies. The synthesized data revealed a pattern of lower relative risk in annual screenings compared to biennial screenings across all studies. Notably, subgroup analyses indicated that age and racial background might modulate the effectiveness of screening frequency. In conclusion, this meta-analysis offers strong evidence suggesting that annual mammography screenings could be more effective than biennial screenings in reducing breast cancer mortality rates, especially in certain high-risk demographics. The results emphasize the importance of personalized, evidence-based approaches to mammography, with a call for future research to validate these findings and delve deeper into optimizing breast cancer screening strategies.

Impact of Breast Cancer Screening on 10-Year Net Survival in Canadian Women Age 40-49 Years

PURPOSE

In Canada, some provincial/territorial mammography screening programs include women age 40-49 years, whereas others do not. This study examines the impact of this dichotomy on the 10-year breast cancer (BC) net survival (NS) among women age 40-49 years and 50-59 years at diagnosis.

METHODS

Using the Canadian Cancer Registry data record linked to death information, we evaluated the cohort of Canadian women age 40-49 years and 50-59 years diagnosed with BC from 2002 to 2007. We compared 10-year NS estimates in the jurisdictions with organized screening programs that included women age 40-49 years, designated as screeners (Northwest Territories, British Columbia, Alberta, Nova Scotia, and Prince Edward Island), with comparator programs that did not (Yukon, Manitoba, Saskatchewan, Ontario, Quebec, New Brunswick, and Newfoundland and Labrador).

RESULTS

BC was the primary cause of 10-year mortality in women age 40-49 years diagnosed with BC (90.7% of deaths). Among these women, the 10-year NS for screeners (84.8%; 95% CI, 83.8 to 85.8) was 1.9 percentage points (pp) higher than that for comparators (82.9%; 95% CI, 82.3 to 83.5; P = .001). The difference in favor of screeners was significant among women age 45-49 years (2.6 pp; P = .001) but not among women age 40-44 years (0.9 pp; P = .328). Similarly, the incidence-based BC mortality rate was significantly lower in screener jurisdictions among women age 40-49 years and 45-49 years, but not for 40-44 years. Provincial/territorial NS increased significantly with higher mammography screening participation (P = .003). The BC incidence rate was virtually identical in screener and comparator jurisdictions among women age 40-49 years (P = .976) but was significantly higher for comparators among women age 50-59 years (P < .001).

CONCLUSION

Screening programs that included women in their 40s were associated with a significantly higher BC 10-year NS in women age 40-49 years, but not an increased rate of BC diagnosis. These results may inform screening guidelines for women age 40-49 years.

Benefits and harms of annual, biennial, or triennial breast cancer mammography screening for women at average risk of breast cancer: a systematic review for the European Commission Initiative on Breast Cancer (ECIBC)

BACKGROUND

Although mammography screening is recommended in most European countries, the balance between the benefits and harms of different screening intervals is still a matter of debate. This review informed the European Commission Initiative on Breast Cancer (BC) recommendations.

METHODS

We searched PubMed, EMBASE, and the Cochrane Library to identify RCTs, observational or modelling studies, comparing desirable (BC deaths averted, QALYs, BC stage, interval cancer) and undesirable (overdiagnosis, false positive related, radiation related) effects from annual, biennial, or triennial mammography screening in women of average risk for BC. We assessed the certainty of the evidence using the GRADE approach.

RESULTS

We included one RCT, 13 observational, and 11 modelling studies. In women 50-69, annual compared to biennial screening may have small additional benefits but an important increase in false positive results; triennial compared to biennial screening may have smaller benefits while avoiding some harms. In younger women (aged 45-49), annual compared to biennial screening had a smaller gain in benefits and larger harms, showing a less favourable balance in this age group than in women 50-69. In women 70-74, there were fewer additional harms and similar benefits with shorter screening intervals. The overall certainty of the evidence for each of these comparisons was very low.

CONCLUSIONS

In women of average BC risk, screening intervals have different trade-offs for each age group. The balance probably favours biennial screening in women 50-69. In younger women, annual screening may have a less favourable balance, while in women aged 70-74 years longer screening intervals may be more favourable.

Annual Mammographic Screening Reduces the Risk of Interval or Higher Stage Invasive Breast Cancers Among Postmenopausal Women in the Ontario Breast Screening Program

Purpose: In the Ontario Breast Screening Program (OBSP) annual screening improved breast cancer detection for women 50–74 years with a family/personal history compared to biennial, while detection was equivalent for women screened annually for mammographic density ≥75%. This study compares the risk of interval or higher stage invasive cancers among postmenopausal women screened annually vs biennially by age and estrogen use. Methods: A retrospective design identified 4247 invasive breast cancers diagnosed among concurrent cohorts of women 50–74 screened in the OBSP with digital mammography between 2011 and 2014, followed until 2016. Polytomous logistic regression estimated the risk of interval or higher stage breast cancers by age and estrogen use between women screened annually because of first-degree relative with breast or ovarian cancer or personal history of ovarian cancer, or mammographic density ≥75%, and those screened biennially. Results: The risk of interval vs screen-detected cancers was significantly reduced in women screened annually for family/personal history (OR=.64; 95%CI:0.51–.80), particularly those 60–74 years (OR=.59; 95%CI:0.45–.77) or not currently using estrogen (OR=.66; 95%CI:0.52–.83) compared to those screened biennially. The risk of stage II–IV vs stage I tumors was also lower in women 60–74 years screened annually for family/personal history (OR=.79; 95%CI:0.64–.97) and in those screened annually for mammographic density ≥75% currently using estrogen (OR=.51; 95%CI:0.26–1.01) compared to women screened biennially. Conclusion: Postmenopausal women at increased risk screened annually had equivalent or reduced risks of interval or higher stage invasive breast cancers than those screened biennially, further supporting risk-based screening in this population.

Benefits and Risks of Mammography Screening in Women Ages 40 to 49 Years

Breast cancer screening in the United States is complicated by conflicting recommendations from professional and governmental organizations. The benefits and risks of breast cancer screening differ though by age which should influence shared decision-making discussions. Compared to older women, women ages 40 to 49 years have a lower risk of breast cancer, but the types of breast cancer that develop are often more aggressive with a poorer prognosis. Furthermore, younger women have a longer life expectancy and fewer comorbidities. The primary benefits of screening for women in their 40s are a reduction in breast cancer mortality, years of life lost to breast cancer, and morbidity of breast cancer treatment by detecting cancers at an earlier stage. Compared to older women, the risks of breast cancer screening in women ages 40 to 49 years includes more false positive recalls and biopsies as well as transient anxiety. Concerns regarding radiation induced malignancy and overdiagnosis are minimal in this age group. The shorter lead time of breast cancer in women ages 40 to 49 years also favors shorter screening intervals. This information should help inform providers in their shared decision-making discussions with patients.

Annual Screening Mammography Associated With Lower Stage Breast Cancer Compared With Biennial Screening

OBJECTIVE. The purpose of this study was to compare breast cancer characteristics and treatment regimens among women undergoing annual versus nonannual screening mammography. MATERIALS AND METHODS. In this retrospective, institutional review board-approved, HIPAA-compliant cohort study, a breast cancer database was queried for patients who received a mammographic or clinical diagnosis of breast cancer during 2016-2017. Annual versus biennial and annual versus nonannual (biennial and triennial) mammography screening cohorts were compared using t tests or Wilcoxon rank sum tests for continuous variables and chi-square or Fisher exact tests for categoric variables. RESULTS. A total of 490 patients were diagnosed with breast cancer during 2016-2017. Among these women, 245 had an assignable screening frequency and were 40-84 years old (mean, 61.8 ± 9.9 [SD] years; median, 62 years). Screening frequency was annual for 200 of these 245 patients (81.6%), biennial for 32 (13.1%), and triennial for 13 (5.3%). Annual screening resulted in fewer late-stage presentations (AJCC stage II, III, or IV in 48 of 200 patients undergoing annual [24.0%] vs 14 of 32 undergoing biennial [43.8%; p = .02] and vs 20 of 45 undergoing nonannual screening [44.4%; p = .006]), fewer interval cancers (21 of 200 for annual [10.5%] vs 12 of 32 for biennial [37.5%; p < .001] and vs 15 of 45 for nonannual [33.3%; p < .001]), and smaller mean tumor diameter (1.4 ± 1.2 cm for annual vs 1.8 ± 1.6 cm for biennial [p = .04] and vs 1.8 ± 1.5 cm nonannual [p = .03]). Lower AJCC stage, fewer interval cancers, and smaller tumor diameter also persisted among postmenopausal women undergoing annual screening. Patients undergoing biennial and nonannual screening showed nonsignificant greater use of axillary lymph node dissection (annual, 24 of 200 [12.0%]; biennial, 6 of 32 [18.8%]; nonannual, 7 of 45 [15.6%]) and chemotherapy (annual, 55 of 200 [27.5%]; biennial, 12 of 32 [37.5%]; nonannual, 16 of 45 [35.6%]). CONCLUSION. Annual mammographic screening was associated with lower breast cancer stage and fewer interval cancers than biennial or nonannual screening.

Annual vs Biennial Screening: Diagnostic Accuracy Among Concurrent Cohorts Within the Ontario Breast Screening Program

BACKGROUND

The Ontario Breast Screening Program recommends annual mammography to women age 50-74 years at increased risk because of family history of breast or ovarian cancer or personal history of ovarian cancer or mammographic density 75% or greater. Few studies have examined the diagnostic accuracy of recommendations based on risk factors and included screen film as well as digital mammography.

METHODS

A retrospective design identified concurrent cohorts of women age 50-74 years screened annually or biennially with digital mammography only between 2011 and 2014 and followed until 2016 or breast cancer diagnosis. Diagnostic accuracy measures were compared between women screened annually because of first-degree relative of breast or ovarian cancer or personal history of ovarian cancer (n = 67 795 women), mammographic density 75% or greater (n = 51 956), or both (n = 3758) and those screened biennially (n = 526 815). The association between recommendation and sensitivity and specificity was assessed using generalized estimating equation models. All P values are two-sided.

RESULTS

For annual screening because of family or personal history vs biennial, sensitivity was statistically significantly higher (81.7% vs 70.6%; OR = 1.86, 95% CI = 1.48 to 2.34), particularly for invasive cancers and postmenopausal women. Although there was no statistically significant difference in sensitivity for annual screening for mammographic density 75% or greater, specificity was statistically significantly lower (91.3%; OR = 0.87, 95% CI = 0.80 to 0.96) vs biennial (92.3%), particularly for women age 50-59 years.

CONCLUSION

Compared with biennial screening, annual screening improved detection for women with a family or personal history of breast and/or ovarian cancer, supporting screening that is more frequent. The benefit for annual screening for women with higher mammographic density must be weighed against possible harms of increased false positives.

Incidence of interval breast cancer among women aged 45-49 in an organised mammography screening setting

OBJECTIVE

To estimate the proportional incidence (PI) of first- and second-year interval breast cancer among women aged 45-49.

METHODS

In the Emilia-Romagna Region (northern Italy), women aged 45-49 are invited to mammography screening annually, and women aged 50-74 biennially. For younger ones, the proportional incidence of interval cancer in the first and unique interval year was calculated using standard methods. For the second, hypothetical year, it was estimated using two different estimates of the ratio between the second- and the first-year proportional incidence observed among women aged 50-54. Overall, 567,151 negative mammography records were used.

RESULTS

In the first interval year, the observed proportional incidence of interval cancer among women aged 45-49 was 0.27 (95% confidence interval (CI), 0.22-0.33), within the European limit considered desirable for women aged 50-69 (<0.30). In the second, hypothetical interval year, the estimated proportional incidence ranged from 0.61 (95% CI, 0.43-0.86) to 0.48 (95% CI, 0.31-0.76) depending on whether the estimate was based on data from the pre-digital or digital era, respectively.

CONCLUSION

The more up-to-date estimate of 0.48, slightly below the maximum limit considered acceptable for women aged 50-69 (<0.50), suggests that a screening interval of two years may also be an acceptable option for women aged 45-49.

Breast cancer screening with mammography in women aged 40-49 years: Impact of length of screening interval on effectiveness of the program

Objectives

To estimate the impact on the effectiveness of Swedish breast cancer screening program in women aged 40–49 years of shortening the screening interval from 21 months to 18 or 12 months.

Methods

The reduction in breast cancer mortality among participants in screening with mammography was previously estimated in the Swedish SCReening of Young women (SCRY) study to be 29%. The expected increased effectiveness with a hypothetical shorter screening interval than the average of 21 months in SCRY was calculated using data about the women who died from breast cancer even though they participated in the SCRY program.

Results

During the study period, 547 women who participated in the index screening round died from breast cancer. Shortening the screening interval to 18 months led to an improved effectiveness of 0.7–3.9% considering interval cancers only and of 1.3–7.6% considering screening-detected cancers only, and for both interval and screening-detected cancers the improvement was 1.9–11.5% when the assumed mortality reduction for the deceased cases varied from 5% to 30%. Shortening the screening interval to 12 months increased the effectiveness by 1.6–9.8% for interval cancers and by 2.9–17.4% for both interval and screening-detected cancers.

Conclusion

Shortening the screening interval for women aged 40–49 years to 18 or 12 months might further reduce the breast cancer mortality rate.

Identifying the Social Determinants of Breast Health Behavior: a Qualitative Content Analysis

Background: Prevention, early diagnosis and reduction of mortality caused by breast cancer are the priorities of the world health systems. The aim of this study was to identify the social factors that affect the women’s breast health behavior based on the social determinants model of the World Health Organization (WHO). Materials and Method: This qualitative study was conducted and analyzed using content analysis approach. The data were collected from 32 participants by semi-structured interviews and focused group discussion. The participants comprised of breast surgeons, radiologists, health care providers and women over 35 years of age in Tehran who were selected through purposeful sampling. The interviews continued until data saturation was reached. Results: Based on the experiences of the participants, three themes were obtained from the data that shaped the women’s breast health behavior, including 1) the context of health policy, 2) socioeconomic status, and 3) cultural, psychological, and behavioral factors. Conclusion: A better understanding of social determinants related to breast health behavior can be effective in designing and applying of appropriate theories and models of education and intervention, so that, by early diagnosis of breast cancer and timely treatment of patients, the disease complications and mortality would be reduced.

Lifetime utilization of mammography among Maltese women: a cross-sectional survey

BACKGROUND

The knowledge of Maltese women not attending the Maltese Breast Screening Programme (MBSP) for mammography screening is scarce. Previous research has identified two distinct groups of non-attendees: those who do not attend because a mammogram was taken elsewhere and those who never attended for mammography anywhere. It is however unknown which determinants are predictive of lifetime attendance 'anywhere' and 'real' non-attendance. The present study examines the relationship between ever-using (Lifetime attendees) or never using mammography (Lifetime non-attendees) and psychosocial - as well as sociodemographic factors, with the aim to identify predictors that can inform practice.

METHODS

Women's characteristics, knowledge, health beliefs and illness perceptions were compared, based on prior data of 404 women, aged 50-60 years at the time of their first MBSP invitation. The main variable of interest described women's attendance to mammography (LIFETIME ATTENDEES) and no mammography (LIFETIME NON-ATTENDEES). Data were analyzed using descriptive statistics, chi-square tests, Mann Whitney test, Independent Samples t-test, Shapiro Wilk test and logistic regression.

RESULTS

During their lifetime, 86.1% of Maltese women (n = 348) were attendees, while 13.9% (n = 56) were non-attendees. Non-attendees were more likely to be women with a lower family income (χ2 = 13.1, p = 0.011), widowers (χ2 = 9.0, p = 0.030), non-drivers (χ2 = 7.7, p = 0.006), without a breast condition (χ2 = 14.2, p <  0.001), who had no relatives or close friends with cancer (χ2 = 8.3, p = 0.016), and who were less encouraged by a physician (χ2 = 4.9, p = 0.027), unsure of the screening frequency (χ2 = 28.5, p <  0.001), more anxious (p = 0.040) and fearful (p = 0.039). Perceived benefits, barriers, cues to action, self-efficacy and emotional representations were the most significant variables to describe the differences between lifetime attendees and non-attendees. Perceived barriers and cues to action were the strongest predictors for lifetime non-attendance (p <  0.05 respectively).

CONCLUSIONS

The health beliefs of women who have never attended for mammography during their lifetime should be targeted, particularly perceived barriers and cues to action. Further research should focus on understanding knowledge gaps, attitudinal barriers and emotional factors among 'real' non-attendees who require a more targeted approach.

The impact of false positive breast cancer screening mammograms on screening retention: A retrospective population cohort study in Alberta, Canada

OBJECTIVES

The impact of false positives on breast cancer screening retention is inconsistent across international studies. We investigate factors associated with screening retention, including false positive screening results, invasiveness of diagnostic procedures, and geographic variation in Alberta, Canada.

METHODS

A total of 213 867 women aged 50-67 years who had an index screen mammogram between July 2006 and June 2008 were evaluated at 30 months post index screen to determine the screening retention rate. The association of screening retention with invasiveness of the diagnostic procedure, time to diagnostic resolution, and region of residence were investigated using multivariable log binomial regression, adjusting for women's age.

RESULTS

Women with false positive screening results were less likely to return for their next recommended screening than those with a true negative result (62.0% vs. 68.7%). Compared to women with normal screening results, the adjusted risk ratios of fail-to-rescreen for women with imaging-only follow-up, needle sampling, and open biopsy were 1.08 (95% CI: 1.05-1.12), 1.72 (95% CI: 1.44-2.07) and 2.29 (95% CI: 2.09-2.50) respectively. Screening retention rates were slightly higher for rural residents than urban residents. Time to diagnostic resolution was not associated with screening retention. Screening retention peaked at one year from the index date of the previous screening.

CONCLUSION

Higher awareness of the strong negative impact that biopsies in the case of a false positive screening have on screening retention is needed. Such awareness can inform intervention strategies to mitigate the impact and improve screening retention rate.

Patterns and determinants of mammography screening in Lebanese women

The associations of ever using and/or repeating a mammography test with psychosocial and socio-demographic factors were surveyed in 2014 among Lebanese women ≥ 40. A sample of 2400 women was selected across Lebanon. Variables with significant bivariate associations with various types of behaviors were entered in multivariate analysis. Of the total, 105 women (4·4%) had never heard of mammography as a tool for early breast cancer detection. Among the remaining 2295, 45% had ever used it, of whom 10% had obtained it for the first time within the 12 months preceding the survey. Repeaters were 67% of 926 women who had the time opportunity to do so (median lifetime frequency: 2). Older age, higher socio-economic status (SES) and living within the Greater Beirut (GB) area were significantly associated with ever-use. Within GB, psychosocial factors such as perceived susceptibility and benefits were most strongly associated with ever-use. Outside GB, socio-economic advantage seemed to mostly affect ever-use. Only 4% reported opposition from husbands to their mammography, and husband's support was significant for adherence to mammography guidelines mostly outside GB. Higher education emerged also as a significant socio-demographic determinant for ever-repeating in all regions. Perceived comfort of the previous test strongly affected the likelihood of repeating it. Providing mammography free-of-charge may alleviate some obstacles among women with socio-economic disadvantage. Stressing that good results one year do not make the cancer less likely or repeating the test less important, as well as improving the comfort of mammography testing could ensure test repeating.

Relationship between the method of detection and prognostic factors for breast cancer in a community with a screening programme

Objectives

To analyse and compare the prognostic factors of breast cancer in the target population of our community-screening programme as a function of the method of detection and to analyse the differences in the prognostic factors as a function of the patient's age and the screening episode.

Setting

A Breast Cancer-Screening Programme (BCSP) in Northeast Spain.

Methods

Observational study of all primary malignant breast lesions diagnosed in a woman between 50 and 69 years of age between 18 October 1995 and 31 December 2002. The 16 centres that women from the target population might have attended were contacted.

Results

A total of 225 (37.2%) of the lesions included were diagnosed through the BCSP, 59 (9.7%) interval cancers were detected, and 321 (53.1%) were detected through other circuits. Node involvement was significantly lower in the lesions detected at screening (32%) in comparison to the interval cancers (41.8%) and those detected through other circuits (47.5%). A significantly larger percentage of the interval tumours (28.6%) and the lesions diagnosed outside the BCSP (22.1%) scored 5.4 on the Nottingham Prognostic Index (NPI) than those diagnosed within the programme (10.9%). The relation between the NPI and the detection method was only statistically significant in the 65-69-year-old age group. The NPI score of the tumours detected by the BCSP showed a statistically significant association with age.

Conclusion

This analysis has shown notable differences in some prognostic factors for breast cancer according to the method of detection. Association between age and the a priori prognosis of the malignant lesions arises.

Number and characteristics of breast cancer cases diagnosed in four periods in the screening interval of a biennial population-based screening programme

Objective

To describe the distribution and prognostic tumour characteristics of interval breast cancers diagnosed in four periods after index screen (1-6, 7-12, 13-18 and 19+ months) in a population-based screening programme inviting women aged 50–69 years to biennial screening.

Setting

The Norwegian Breast Cancer Screening Programme (NBCSP)

Methods

In all, 848 interval breast cancer cases were diagnosed in 437,235 screening examinations. The distribution and prognostic tumour characteristics of the interval cancers diagnosed in four periods in the screening interval will be described. Proportions and rates will be compared by χ2-test.

Results

A total of 70% of the interval cancers in the NBCSP were diagnosed in the second year of the interval. Except for tumour size (P = 0.027), we found no evidence of adverse prognostic breast characteristics (grade, lymph node involvement, oestrogen and progesterone receptor positive) in invasive tumours diagnosed during the second versus the first year of the screening interval (Chi square P 0.05 for all). The prognostic characteristics of the tumours did not differ by age groups. It was a decreasing interval cancer rate per 10,000 women-years by age.

Conclusion

The risk of interval cancer increases by time after index screen, and 70% of the interval cancers in the NBCSP were diagnosed in the second year of the interval. Prognostic histological tumour characteristics did not differ by time after index screen, thus mean sojourn time (tumour growth rate) seems important for stating an optimal screening interval in a population-based screening programme.

Is the false-positive rate in mammography in North America too high?

The practice of investigating pathological abnormalities in the breasts of females who are asymptomatic is primarily employed using X-ray mammography. The importance of breast screening is reflected in the mortality-based benefits observed among females who are found to possess invasive breast carcinoma prior to the manifestation of clinical symptoms. It is estimated that population-based screening constitutes a 17% reduction in the breast cancer mortality rate among females affected by invasive breast carcinoma. In spite of the significant utility that screening confers in those affected by invasive cancer, limitations associated with screening manifest as potential harms affecting individuals who are free of invasive disease. Disease-free and benign tumour-bearing individuals who are subjected to diagnostic work-up following a screening examination constitute a population of cases referred to as false positives (FPs). This article discusses factors contributing to the FP rate in mammography and extends the discussion to an assessment of the consequences associated with FP reporting. We conclude that the mammography FP rate in North America is in excess based upon the observation of overtreatment of in situ lesions and the disproportionate distribution of detriment and benefit among the population of individuals recalled for diagnostic work-up subsequent to screening. To address the excessive incidence of FPs in mammography, we investigate solutions that may be employed to remediate the current status of the FP rate. Subsequently, it can be suggested that improvements in the breast-screening protocol, medical litigation risk, image interpretation software and the implementation of image acquisition modalities that overcome superimposition effects are promising solutions.

Breast Tumor Prognostic Characteristics and Biennial vs Annual Mammography, Age, and Menopausal Status

IMPORTANCE

Screening mammography intervals remain under debate in the United States.

OBJECTIVE

To compare the proportion of breast cancers with less vs more favorable prognostic characteristics in women screening annually vs biennially by age, menopausal status, and postmenopausal hormone therapy (HT) use.

DESIGN, SETTING, AND PARTICIPANTS

This was a study of a prospective cohort from 1996 to 2012 at Breast Cancer Surveillance Consortium facilities. A total of 15,440 women ages 40 to 85 years with breast cancer diagnosed within 1 year of an annual or within 2 years of a biennial screening mammogram.

EXPOSURES

We updated previous analyses by using narrower intervals for defining annual (11-14 months) and biennial (23-26 months) screening.

MAIN OUTCOMES AND MEASURES

We defined less favorable prognostic characteristics as tumors that were stage IIB or higher, size greater than 15 mm, positive nodes, and any 1 or more of these characteristics. We used log-binomial regression to model the proportion of breast cancers with less favorable characteristics following a biennial vs annual screen by 10-year age groups and by menopausal status and current postmenopausal HT use.

RESULTS

Among 15,440 women with breast cancer, most were 50 years or older (13,182 [85.4%]), white (12,063 [78.1%]), and postmenopausal (9823 [63.6%]). Among 2027 premenopausal women (13.1%), biennial screeners had higher proportions of tumors that were stage IIB or higher (relative risk [RR], 1.28 [95% CI, 1.01-1.63]; P=.04), size greater than 15 mm (RR, 1.21 [95% CI, 1.07-1.37]; P=.002), and with any less favorable prognostic characteristic (RR, 1.11 [95% CI, 1.00-1.22]; P=.047) compared with annual screeners. Among women currently taking postmenopausal HT, biennial screeners tended to have tumors with less favorable prognostic characteristics compared with annual screeners; however, 95% CIs were wide, and differences were not statistically significant (for stage 2B+, RR, 1.14 [95% CI, 0.89-1.47], P=.29; size>15 mm, RR, 1.13 [95% CI, 0.98-1.31], P=.09; node positive, RR, 1.18 [95% CI, 0.98-1.42], P=.09; any less favorable characteristic, RR, 1.12 [95% CI, 1.00-1.25], P=.053). The proportions of tumors with less favorable prognostic characteristics were not significantly larger for biennial vs annual screeners among postmenopausal women not taking HT (eg, any characteristic: RR, 1.03 [95% CI, 0.95-1.12]; P=.45), postmenopausal HT users after subdividing by type of hormone use (eg, any characteristic: estrogen+progestogen users, RR, 1.16 [95% CI, 0.91-1.47]; P=.22; estrogen-only users, RR, 1.14 [95% CI, 0.94-1.37]; P=.18), or any 10-year age group (eg, any characteristic: ages 40-49 years, RR, .1.04 [95% CI, 0.94-1.14]; P=.48; ages 50-59 years, RR, 1.03 [95% CI, 0.94-1.12]; P=.58; ages 60-69 years, RR, 1.07 [95% CI, 0.97-1.19]; P=.18; ages 70-85 years, RR, 1.05 [95% CI, 0.94-1.18]; P=.35).

CONCLUSIONS AND RELEVANCE

Premenopausal women diagnosed as having breast cancer following biennial vs annual screening mammography are more likely to have tumors with less favorable prognostic characteristics. Postmenopausal women not using HT who are diagnosed as having breast cancer following a biennial or annual screen have similar proportions of tumors with less favorable prognostic characteristics.

Cancer screening in the United States, 2016: A review of current American Cancer Society guidelines and current issues in cancer screening

Each year the American Cancer Society (ACS) publishes a summary of its guidelines for early cancer detection, data and trends in cancer screening rates, and select issues related to cancer screening. In this issue of the journal, we summarize current ACS cancer screening guidelines, including the update of the breast cancer screening guideline, discuss quality issues in colorectal cancer screening and new developments in lung cancer screening, and provide the latest data on utilization of cancer screening from the National Health Interview Survey.

The impact of mammographic screening on the surgical management of breast cancer

BACKGROUND AND OBJECTIVES

Mammographic screening has been shown to result in downward stage migration, reflected by smaller tumor sizes and less extensive nodal involvement. National guidelines restrict screening recommendations in women age 40-49. The purpose of this study is to evaluate the specific impact of mammographic screening patterns on the surgical management of breast cancer in women aged 40-49.

METHODS

The study is a population-based retrospective review of the Vermont Breast Cancer Surveillance System of women aged 40-49 with a diagnosis of breast cancer. Tumor stage and related characteristics at the time of diagnosis, as well as the type of surgical intervention performed were recorded for women presenting with screen-detected versus non-screen-detected breast cancer.

RESULTS

Screen-detected breast cancers in women aged 40-49 were associated with a greater incidence of DCIS, smaller invasive tumor size, fewer cases of positive nodes, and higher rates of breast conservation compared to non-screened women presenting with symptomatic disease.

CONCLUSIONS

Mammographic screening is associated with less aggressive surgical treatment of breast cancer including higher rates of breast conservation. The observed changes in surgical management should factor into individual decision-making regarding screening mammography. J. Surg. Oncol. 2016;113:496-500. © 2016 Wiley Periodicals, Inc.

Breast Cancer Screening for Women at Average Risk: 2015 Guideline Update From the American Cancer Society

IMPORTANCE

Breast cancer is a leading cause of premature mortality among US women. Early detection has been shown to be associated with reduced breast cancer morbidity and mortality.

OBJECTIVE

To update the American Cancer Society (ACS) 2003 breast cancer screening guideline for women at average risk for breast cancer.

PROCESS

The ACS commissioned a systematic evidence review of the breast cancer screening literature to inform the update and a supplemental analysis of mammography registry data to address questions related to the screening interval. Formulation of recommendations was based on the quality of the evidence and judgment (incorporating values and preferences) about the balance of benefits and harms.

EVIDENCE SYNTHESIS

Screening mammography in women aged 40 to 69 years is associated with a reduction in breast cancer deaths across a range of study designs, and inferential evidence supports breast cancer screening for women 70 years and older who are in good health. Estimates of the cumulative lifetime risk of false-positive examination results are greater if screening begins at younger ages because of the greater number of mammograms, as well as the higher recall rate in younger women. The quality of the evidence for overdiagnosis is not sufficient to estimate a lifetime risk with confidence. Analysis examining the screening interval demonstrates more favorable tumor characteristics when premenopausal women are screened annually vs biennially. Evidence does not support routine clinical breast examination as a screening method for women at average risk.

RECOMMENDATIONS

The ACS recommends that women with an average risk of breast cancer should undergo regular screening mammography starting at age 45 years (strong recommendation). Women aged 45 to 54 years should be screened annually (qualified recommendation). Women 55 years and older should transition to biennial screening or have the opportunity to continue screening annually (qualified recommendation). Women should have the opportunity to begin annual screening between the ages of 40 and 44 years (qualified recommendation). Women should continue screening mammography as long as their overall health is good and they have a life expectancy of 10 years or longer (qualified recommendation). The ACS does not recommend clinical breast examination for breast cancer screening among average-risk women at any age (qualified recommendation).

CONCLUSIONS AND RELEVANCE

These updated ACS guidelines provide evidence-based recommendations for breast cancer screening for women at average risk of breast cancer. These recommendations should be considered by physicians and women in discussions about breast cancer screening.

[Cost-effectiveness of an organized breast cancer screening program in Southern Brazil]

The aim of this study was to evaluate the cost-effectiveness of an organized breast cancer mammographic screening program implemented in Porto Alegre (Núcleo Mama Porto Alegre - NMPOA), Rio Grande do Sul State, Brazil. A Markov model was constructed to estimate the incremental cost-effectiveness ratio of NMPOA compared to current BC diagnosis and care in the Brazilian public health system, in a hypothetical cohort of women aged 40-69 years at risk of developing breast cancer. Model parameters were collected from NMPOA and the national literature. In the NMPOA strategy, effectiveness was modeled taking into account the actual observed screening adherence. Effectiveness was measured in quality-adjusted life years (QALYs). Incremental cost-effectiveness ratio in the base case was R$ 13,426 per QALY. This result was not sensitive to variation in the main model parameters in sensitivity analyses. Considering the threshold usually suggested as highly attractive in Brazil, breast cancer screening as performed in NMPOA is cost-effective in cities with high incidence of breast cancer.

An analysis of mass screening strategies using a mathematical model: comparison of breast cancer screening in Japan and the United States

BACKGROUND

Although the United States Preventive Services Task Force (USPSTF) downgraded their recommendation for breast cancer screening for women aged 40-49 years in 2009, Japanese women in their 40s have been encouraged to attend breast cancer screenings since 2004. The aim of this study is to examine whether these different mass-screening strategies are justifiable by the different situations of these countries and to provide evidence for suitable judgment.

METHODS

Performance of screening strategies (annual/biennial intervals; initiating/terminating ages) was evaluated using a mathematical model based on the natural history of breast cancer and the transition between its stages. Benefits (reduced number of deaths and extended average life expectancy) and harm (false-positives) associated with these strategies were calculated.

RESULTS

Additional average life expectancy by including women in their 40s as participants were 13 days (26%) and 25 days (22%) in Japan and the United States, respectively, under the biennial screening condition; however, the respective increases in numbers of false-positive cases were 65% and 53% in Japan and the United States. Moreover, the number of screenings needed to detect one diagnosis or to avert one death was smaller when participants were limited to women of age 50 or over than when women in their 40s were included. The validity of including women in their 40s in Japan could not be determined without specifying the weight of harms compared to benefits.

CONCLUSIONS

Whether screening of women in their 40s in Japan is justifiable must be carefully determined based the quantitative balance of benefits and harms.

Implications of CISNET modeling on number needed to screen and mortality reduction with digital mammography in women 40-49 years old

OBJECTIVE

In this article, we evaluate the implications of recent Cancer Intervention and Surveillance Modeling Network (CISNET) modeling of benefits and harms of screening to women 40-49 years old using annual digital mammography.

CONCLUSION

We show that adding annual digital mammography of women 40-49 years old to biennial screening of women 50-74 years old increases lives saved by 27% and life-years gained by 47%. Annual digital mammography in women 40-49 years old saves 42% more lives and life-years than biennial digital mammography. The number needed to screen to save one life (NNS) with annual digital mammography in women 40-49 years old is 588.

A reality check for overdiagnosis estimates associated with breast cancer screening

The frequency of overdiagnosis associated with breast cancer screening is a topic of controversy. Published estimates vary widely, but identifying which estimates are reliable is challenging. In this article we present an approach that provides a check on these estimates. Our approach leverages the close link between overdiagnosis and lead time by identifying the average lead time most consistent with a given overdiagnosis frequency. We consider a high-profile study that suggested that 31% of breast cancers diagnosed in the United States in 2008 were overdiagnosed and show that this corresponds to an average lead time of about nine years among localized cases. Comparing this estimate with the average lead time for invasive, screen-detected breast cancers of 40 months, around which there is a relative consensus, suggests the published estimate of overdiagnosis is excessive. This approach provides a novel way to appraise estimates of overdiagnosis given knowledge of disease natural history.

Cost-effectiveness of annual versus biennial screening mammography for women with high mammographic breast density

OBJECTIVES

The sensitivity of screening mammography is much lower among women who have dense breast tissue, compared with women who have largely fatty breasts, and they are also at much higher risk of developing the disease. Increasing mammography screening frequency from biennially to annually has been suggested as a policy option to address the elevated risk in this population. The purpose of this study was to assess the cost-effectiveness of annual versus biennial screening mammography among women aged 50-79 with dense breast tissue.

METHODS

A Markov model was constructed based on screening, diagnostic, and treatment pathways for the population-based screening and cancer care programme in British Columbia, Canada. Model probabilities and screening costs were calculated from screening programme data. Costs for breast cancer treatment were calculated from treatment data, and utility values were obtained from the literature. Incremental cost-effectiveness was expressed as cost per quality adjusted life year (QALY), and probabilistic sensitivity analysis was conducted.

RESULTS

Compared with biennial screening, annual screening generated an additional 0.0014 QALYs (95% CI: -0.0480-0.0359) at a cost of $819 ($ = Canadian dollars) per patient (95% CI: 506-1185), resulting in an incremental cost effectiveness ratio of $565,912/QALY. Annual screening had a 37.5% probability of being cost-effective at a willingness-to-pay threshold of $100,000/QALY.

CONCLUSION

There is considerable uncertainty about the incremental cost-effectiveness of annual mammography. Further research on the comparative effectiveness of screening strategies for women with high mammographic breast density is warranted, particularly as digital mammography and density measurement become more widespread, before cost-effectiveness can be reevaluated.

Screening mammography benefit controversies: sorting the evidence

Numerous clinical studies have confirmed that screening women age 40 years and older reduces breast cancer mortality by 30% to 50%. Several factors including faster breast cancer growth rates and lower breast cancer incidence among younger women, as well as shorter life expectancy and more comorbid conditions among older women, should also be considered in screening guidelines. Annual screening beginning at age 40 years and continuing with no upper age limit, as long as a woman has a life expectancy of at least 5 years and no significant comorbid conditions, is currently recommended.

Impact of mammography screening interval on breast cancer diagnosis by menopausal status and BMI

BACKGROUND

Controversy remains regarding the frequency of screening mammography. Women with different risks for developing breast cancer because of body mass index (BMI) may benefit from tailored recommendations.

OBJECTIVE

To determine the impact of mammography screening interval for women who are normal weight (BMI < 25), overweight (BMI 25-29.9), or obese (BMI ≥ 30), stratified by menopausal status.

DESIGN

Two cohorts selected from the Breast Cancer Surveillance Consortium. Patient and mammography data were linked to pathology databases and tumor registries.

PARTICIPANTS

The cohort included 4,432 women aged 40-74 with breast cancer; the false-positive analysis included a cohort of 553,343 women aged 40-74 without breast cancer.

MAIN MEASURES

Stage, tumor size and lymph node status by BMI and screening interval (biennial vs. annual). Cumulative probability of false-positive recall or biopsy by BMI and screening interval. Analyses were stratified by menopausal status.

KEY RESULTS

Premenopausal obese women undergoing biennial screening had a non-significantly increased odds of a tumor size > 20 mm relative to annual screeners (odds ratio [OR] = 2.07; 95 % confidence interval [CI] 0.997 to 4.30). Across all BMI categories from normal to obese, postmenopausal women with breast cancer did not present with higher stage, larger tumor size or node positive tumors if they received biennial rather than annual screening. False-positive recall and biopsy recommendations were more common among annually screened women.

CONCLUSION

The only negative outcome identified for biennial vs. annual screening was a larger tumor size (> 20 mm) among obese premenopausal women. Since annual mammography does not improve stage at diagnosis compared to biennial screening and false-positive recall/biopsy rates are higher with annual screening, women and their primary care providers should weigh the harms and benefits when deciding on annual versus biennial screening.

Program-specific cost-effectiveness analysis: breast cancer screening policies for a safety-net program

BACKGROUND

Every Woman Counts (EWC), a California breast cancer screening program, faced challenging budget cutbacks and policy choices.

METHODS

A microsimulation model evaluated costs, outcomes, and cost-effectiveness of EWC program mammography policy options on coverage for digital mammography (which has a higher cost than film mammography but recent legislation allowed reimbursement at the lower film rate); screening eligibility age; and screening frequency. Model inputs were based on analyses of program claims data linked to California Cancer Registry data, Surveillance, Epidemiology, and End Results data, and the Medi-Cal literature. Outcomes included number of procedures, cancers, cancer deaths, costs, and incremental cost per life-year.

RESULTS

Projected model outcomes matched program data closely. With restrictions on the number of clients screened, strategies starting screening at age 40 years were dominated (not cost-effective). This finding was highly robust in sensitivity analyses. Compared with no screening, biennial film mammography for women aged 50 to 64 years was projected to reduce 15-year breast cancer mortality by nearly 7.8% at $18,999 per additional life-year, annual film mammography was $106,428 per additional life-year, and digital mammography $180,333 per additional life-year. This more effective, more expensive strategy was projected to reduce breast cancer mortality by 8.6%. Under equal mammography reimbursement, biennial digital mammography beginning at age 50 years was projected to decrease 15-year breast cancer mortality by 8.6% at an incremental cost per additional life-year of $17,050.

CONCLUSIONS

For the EWC program, biennial screening mammography starting at age 50 years was the most cost-effective strategy. The impact of digital mammography on life expectancy was small. Program-specific cost-effectiveness analysis can be completed in a policy-relevant time frame to assist policymakers faced with difficult program choices.

Mammographic screening interval in relation to tumor characteristics and false-positive risk by race/ethnicity and age

BACKGROUND

Biennial screening mammography retains most of the benefits of annual breast cancer screening with reduced harms. Whether screening guidelines based on race/ethnicity and age would be more effective than age-based guidelines is unknown.

METHODS

Mammography data from the Breast Cancer Surveillance Consortium were linked to pathology and tumor databases. The authors identified women aged 40 to 74 years who underwent annual, biennial, or triennial screening mammography between 1994 and 2008. Logistic regression was used to estimate adjusted odds ratios (OR) and 95% confidence intervals (95% CI) of adverse tumor characteristics among 14,396 incident breast cancer cases and 10-year cumulative risks of false-positive recall and biopsy recommendation among 1,276,312 noncases.

RESULTS

No increased risk of adverse tumor characteristics associated with biennial versus annual screening were noted in white women, black women, Hispanic women aged 40 to 49 years, or Asian women aged 50 to 74 years. Hispanic women aged 50 to 74 years who screened biennially versus annually were found to have an increased risk of late-stage disease (OR, 1.6; 95% CI, 1.0-2.5) and large tumors (OR, 1.6; 95% CI, 1.1-2.4). Asian women aged 40 to 49 years who underwent biennial screening had an elevated risk of positive lymph nodes (OR, 3.1; 95% CI, 1.3-7.1). No elevated risks were associated with triennial versus biennial screening. Cumulative false-positive risks decreased markedly with a longer screening interval.

CONCLUSIONS

The authors found limited evidence of elevated risks of adverse tumor characteristics with biennial versus annual screening, whereas cumulative false-positive risks were lower. However, elevated risks of late-stage disease in Hispanic women and lymph node-positive disease in younger Asian women who screened less often than annually warrant consideration and replication.

Outcomes of screening mammography by frequency, breast density, and postmenopausal hormone therapy

IMPORTANCE

Controversy exists about the frequency women should undergo screening mammography and whether screening interval should vary according to risk factors beyond age.

OBJECTIVE

To compare the benefits and harms of screening mammography frequencies according to age, breast density, and postmenopausal hormone therapy (HT) use.

DESIGN

Prospective cohort.

SETTING

Data collected January 1994 to December 2008 from mammography facilities in community practice that participate in the Breast Cancer Surveillance Consortium (BCSC) mammography registries.

PARTICIPANTS

Data were collected prospectively on 11,474 women with breast cancer and 922,624 without breast cancer who underwent mammography at facilities that participate in the BCSC.

MAIN OUTCOMES AND MEASURES

We used logistic regression to calculate the odds of advanced stage (IIb, III, or IV) and large tumors (>20 mm in diameter) and 10-year cumulative probability of a false-positive mammography result by screening frequency, age, breast density, and HT use. The main predictor was screening mammography interval.

RESULTS

Mammography biennially vs annually for women aged 50 to 74 years does not increase risk of tumors with advanced stage or large size regardless of women's breast density or HT use. Among women aged 40 to 49 years with extremely dense breasts, biennial mammography vs annual is associated with increased risk of advanced-stage cancer (odds ratio [OR], 1.89; 95% CI, 1.06-3.39) and large tumors (OR, 2.39; 95% CI, 1.37-4.18). Cumulative probability of a false-positive mammography result was high among women undergoing annual mammography with extremely dense breasts who were either aged 40 to 49 years (65.5%) or used estrogen plus progestogen (65.8%) and was lower among women aged 50 to 74 years who underwent biennial or triennial mammography with scattered fibroglandular densities (30.7% and 21.9%, respectively) or fatty breasts (17.4% and 12.1%, respectively).

CONCLUSIONS AND RELEVANCE

Women aged 50 to 74 years, even those with high breast density or HT use, who undergo biennial screening mammography have similar risk of advanced-stage disease and lower cumulative risk of false-positive results than those who undergo annual mammography. When deciding whether to undergo mammography, women aged 40 to 49 years who have extremely dense breasts should be informed that annual mammography may minimize their risk of advanced-stage disease but the cumulative risk of false-positive results is high.

Breast cancer screening: review of benefits and harms, and recommendations for developing and low-income countries

Breast cancer is the most common cancer in women worldwide. The disease remains a public health concern as recent evidence indicates that the breast cancer burden has increased mainly in developing and low-income countries (DLICs). Despite the demonstrated benefits, the debate about the real benefits and harms of breast cancer screening is ongoing. Many experts believe that the benefits of screening, in terms of reduced breast cancer mortality, outweigh the harms, whereas others think the opposite. In this review, we assess the clinical utility of available screening modalities, present evidence, overdiagnosis, cost-effectiveness, and other pertinent issues. We also examine relevant data from DLICs to underscore the barriers and challenges that impede implementation of screening strategies in those populations. We also provide recommendations concerning rational preventive strategies for breast cancer control for women in DLICs.

Screening outcomes in older US women undergoing multiple mammograms in community practice: does interval, age, or comorbidity score affect tumor characteristics or false positive rates?

Background Uncertainty exists about the appropriate use of screening mammography among older women because comorbid illnesses may diminish the benefit of screening. We examined the risk of adverse tumor characteristics and false positive rates according to screening interval, age, and comorbidity. Methods From January 1999 to December 2006, data were collected prospectively on 2993 older women with breast cancer and 137 949 older women without breast cancer who underwent mammography at facilities that participated in a data linkage between the Breast Cancer Surveillance Consortium and Medicare claims. Women were aged 66 to 89 years at study entry to allow for measurement of 1 year of preexisting illnesses. We used logistic regression analyses to calculate the odds of advanced (IIb, III, IV) stage, large (>20 millimeters) tumors, and 10-year cumulative probability of false-positive mammography by screening frequency (1 vs 2 years), age, and comorbidity score. The comorbidity score was derived using the Klabunde approximation of the Charlson score. All statistical tests were two-sided. Results Adverse tumor characteristics did not differ statistically significantly by comorbidity, age, or interval. Cumulative probability of a false-positive mammography result was higher among annual screeners than biennial screeners irrespective of comorbidity: 48.0% (95% confidence interval [CI] = 46.1% to 49.9%) of annual screeners aged 66 to 74 years had a false-positive result compared with 29.0% (95% CI = 28.1% to 29.9%) of biennial screeners. Conclusion Women aged 66 to 89 years who undergo biennial screening mammography have similar risk of advanced-stage disease and lower cumulative risk of a false-positive recommendation than annual screeners, regardless of comorbidity.

Racial differences in breast cancer stage at diagnosis in the mammography era

OBJECTIVES

We assessed racial differences in breast cancer mortality by stage at diagnosis, since mammography became available.

METHODS

We calculated adjusted odds of distant (versus local or regional) tumors for 143,249 White and 13,571 Black women aged 50 to 69 years, diagnosed with breast cancer between 1982 and 2007 and living in a Surveillance, Epidemiology, and End Results region. We compared linear trends in stage at diagnosis before and after 1998.

RESULTS

Distant-stage cancer was diagnosed in 5.8% of White and 10.2% of Black participants. The Black-White disparity in distant tumors narrowed until 1998 (1998 adjusted difference = 0.65%), before increasing. Between 1982 and 1997, the proportion of distant tumors decreased for Blacks (adjusted odds ratio [AOR]/y = 0.973; 95% confidence interval [CI] = 0.960, 0.987) and Whites (AOR/y = 0.978; 95% CI = 0.973, 0.983), with no racial differences (P = .47). From 1998 to 2007, the odds of distant versus local or regional tumors increased for Blacks (AOR/y = 1.036; 95% CI = 1.013, 1.060) and Whites (AOR/y = 1.011; 95% CI = 1.002, 1.021); the rate of increase was greater for Blacks than Whites (P = .04).

CONCLUSIONS

In the mammography era, racial disparities remain in stage at diagnosis.

Sensitivity and specificity of mammographic screening as practised in Vermont and Norway

OBJECTIVE

The aim of this study was to examine the sensitivity and specificity of screening mammography as performed in Vermont, USA, and Norway.

METHODS

Incident screening data from 1997 to 2003 for female patients aged 50-69 years from the Vermont Breast Cancer Surveillance System (116 996 subsequent screening examinations) and the Norwegian Breast Cancer Screening Program (360 872 subsequent screening examinations) were compared. Sensitivity and specificity estimates for the initial (based on screening mammogram only) and final (screening mammogram plus any further diagnostic imaging) interpretations were directly adjusted for age using 5-year age intervals for the combined Vermont and Norway population, and computed for 1 and 2 years of follow-up, which ended at the time of the next screening mammogram.

RESULTS

For the 1-year follow-up, sensitivities for initial assessments were 82.0%, 88.2% and 92.5% for 1-, 2- and >2-year screening intervals, respectively, in Vermont (p=0.022). For final assessments, the values were 73.6%, 83.3% and 81.2% (p=0.047), respectively. For Norway, sensitivities for initial assessments were 91.0% and 91.3% (p=0.529) for 2- and >2-year intervals, and 90.7% and 91.3%, respectively, for final assessments (p=0.630). Specificity was lower in Vermont than in Norway for each screening interval and for all screening intervals combined, for both initial (90.6% vs 97.8% for all intervals; p<0.001) and final (98.8% vs 99.5% for all intervals; p<0.001) assessments.

CONCLUSION

Our study showed higher sensitivity and specificity in a biennial screening programme with an independent double reading than in a predominantly annual screening program with a single reading.

ADVANCES IN KNOWLEDGE

This study demonstrates that higher recall rates and lower specificity are not always associated with higher sensitivity of screening mammography. Differences in the screening processes in Norway and Vermont suggest potential areas for improvement in the latter.

Safety and cost-effectiveness of shortening hospital follow-up after breast cancer treatment

BACKGROUND

In the Netherlands, the first 5 years of follow-up after treatment for breast cancer are carried out in hospital with yearly mammography. After this, for patients aged over 60 years who have undergone mastectomy, there is a shift of care to the National Screening Programme (NSP) for mammography every 2 years. After breast-conserving therapy follow-up is perfomed by the general practitioner (GP), with mammography every second year and physical examination annually. The aim of this study was to evaluate the clinical effects and costs of four different strategies for follow-up after breast cancer treatment.

METHODS

An extended and validated simulation model for breast cancer follow-up was used. The current guidelines for follow-up (baseline strategy) and three less intensive follow-up strategies were evaluated. The main outcome measure was the detection rate of small tumours (2 cm or smaller) and associated costs for each strategy.

RESULTS

Shortening the follow-up time in hospital by shifting care to the NSP or GP after 2 years instead of 5 years of hospital follow-up, lowering the age of referral to the NSP or GP from 60 to 50 years, and termination of annual physical examination by the GP after hospital follow-up did not decrease the detection of small tumours. In addition, a substantial decrease in costs was observed with simplified follow-up.

CONCLUSION

Decreasing hospital follow-up time, lowering the age of referral to the NSP or GP, and termination of annual physical examinations would lead to a substantial reduction in costs while maintaining the possibility of detecting small breast cancers.

Tipping the balance of benefits and harms to favor screening mammography starting at age 40 years: a comparative modeling study of risk

BACKGROUND

Timing of initiation of screening for breast cancer is controversial in the United States.

OBJECTIVE

To determine the threshold relative risk (RR) at which the harm-benefit ratio of screening women aged 40 to 49 years equals that of biennial screening for women aged 50 to 74 years.

DESIGN

Comparative modeling study.

DATA SOURCES

Surveillance, Epidemiology, and End Results program, Breast Cancer Surveillance Consortium, and medical literature.

TARGET POPULATION

A contemporary cohort of women eligible for routine screening.

TIME HORIZON

Lifetime.

PERSPECTIVE

Societal.

INTERVENTION

Mammography screening starting at age 40 versus 50 years with different screening methods (film, digital) and screening intervals (annual, biennial).

BENEFITS

life-years gained, breast cancer deaths averted; harms: false-positive mammography findings; harm-benefit ratios: false-positive findings/life-years gained, false-positive findings/deaths averted.

RESULTS OF BASE-CASE ANALYSIS

Screening average-risk women aged 50 to 74 years biennially yields the same false-positive findings/life-years gained as biennial screening with digital mammography starting at age 40 years for women with a 2-fold increased risk above average (median threshold RR, 1.9 [range across models, 1.5 to 4.4]). The threshold RRs are higher for annual screening with digital mammography (median, 4.3 [range, 3.3 to 10]) and when false-positive findings/deaths averted is used as an outcome measure instead of false-positive findings/life-years gained. The harm-benefit ratio for film mammography is more favorable than for digital mammography because film has a lower false-positive rate.

RESULTS OF SENSITIVITY ANALYSIS

The threshold RRs changed slightly when a more comprehensive measure of harm was used and were relatively insensitive to lower adherence assumptions.

LIMITATION

Risk was assumed to influence onset of disease without influencing screening performance.

CONCLUSION

Women aged 40 to 49 years with a 2-fold increased risk have similar harm-benefit ratios for biennial screening mammography as average-risk women aged 50 to 74 years. Threshold RRs required for favorable harm-benefit ratios vary by screening method, interval, and outcome measure.

PRIMARY FUNDING SOURCE

National Cancer Institute.

Trends in incidence and detection of advanced breast cancer at biennial screening mammography in The Netherlands: a population based study

Introduction

The aims of this study were to determine trends in the incidence of advanced breast cancer at screening mammography and the potential of screening to reduce it.

Methods

We included a consecutive series of 351,009 screening mammograms of 85,274 women aged 50-75 years, who underwent biennial screening at a Dutch breast screening region in the period 1997-2008. Two screening radiologists reviewed the screening mammograms of all advanced screen detected and advanced interval cancers and determined whether the advanced cancer (tumor > 20 mm and/or lymph node positive tumor) had been visible at a previous screen. Interval cancers were breast cancers diagnosed in women after a negative screening examination (defined as no recommendation for referral) and before any subsequent screen. Patient and tumor characteristics were compared between women with advanced cancer and women with non-advanced cancer, including ductal carcinoma in situ.

Results

A total of 1,771 screen detected cancers and 669 interval cancers were diagnosed in 2,440 women. Rates of advanced cancer remained stable over the 12-year period; the incidence of advanced screen-detected cancers fluctuated between 1.5 - 1.9 per 1,000 screened women (mean 1.6 per 1,000) and of advanced interval cancers between 0.8 - 1.6 per 1,000 screened women (mean 1.2 per 1,000). Of the 570 advanced screen-detected cancers, 106 (18.6%) were detected at initial screening; 265 (46.5%) cancers detected at subsequent screening had been radiologically occult at the previous screening mammogram, 88 (15.4%) had shown a minimal sign, and 111 (19.5%) had been missed. Corresponding figures for advanced interval cancers were 50.9% (216/424), 24.3% (103/424) and 25.1% (105/424), respectively. At multivariate analysis, women with a ≥ 30 months interval between the latest two screens had an increased risk of screen-detected advanced breast cancer (OR 1.63, 95%CI: 1.07-2.48) and hormone replacement therapy increased the risk of advanced disease among interval cancers (OR 3.04, 95%CI: 1.22-7.53).

Conclusion

We observed no decline in the risk of advanced breast cancer during 12 years of biennial screening mammography. The majority of these cancers could not have been prevented through earlier detection at screening.

Annual Mammography Screening: Is it Necessary?

Recent recommendations from the U.S. Preventative Services Task Force suggest that screening mammography for women should be biennial starting at age 50 years and continue to age 74 years. With these recommendations in mind, we proposed a study to evaluate women at our institution in whom breast cancer is diagnosed within 1 year of a previously benign mammogram. A retrospective chart review was performed over a 4-year period. Only patients who had both diagnostic mammograms and previous mammograms performed at our institution and a pathologic diagnosis of breast cancer were included. Benign mammograms were defined as either Breast Imaging Reporting And Data System 1 or 2. Analysis of the time elapse between benign mammogram and subsequent mammogram indicative of the diagnosis of breast cancer was performed. A total of 205 patients were included. The average age was 64 years. From our results, 48 patients, 23 per cent of the total, had a documented benign mammogram at 12 months or less before a breast cancer diagnosis. One hundred forty-three (70%) patients had a benign mammogram at 18 months or less prior. This study raises concern that 2 years between screening mammograms may delay diagnosis and possible treatment options for many women.