Effect of start age of breast cancer screening mammography on the risk of false-positive results

Cumulative risks of false positive recall and screen-detected breast cancer after multiple screening examinations

Women tend to make a decision about participation in breast cancer screening and adhere to this for future invitations. Therefore, our study aimed to provide high-quality information on cumulative risks of false-positive (FP) recall and screen-detected breast cancer over multiple screening examinations. Individual Dutch screening registry data (2005-2018) were gathered on subsequent screening examinations of 92 902 women age 49 to 51 years in 2005. Survival analyses were used to calculate cumulative risks of a FP and a true-positive (TP) result after seven examinations. Data from 66 472 women age 58 to 59 years were used to extrapolate to 11 examinations. Participation, detection and additional FP rates were calculated for women who previously received FP results compared to women with true negative (TN) results. After 7 examinations, the cumulative risk of a TP result was 3.7% and the cumulative risk of a FP result was 9.1%. After 11 examinations, this increased to 7.1% and 13.5%, respectively. Following a FP result, participation was lower (71%-81%) than following a TN result (>90%). In women with a FP result, more TP results (factor 1.59 [95% CI: 1.44-1.72]), more interval cancers (factor 1.66 [95% CI: 1.41-1.91]) and more FP results (factor 1.96 [95% CI: 1.87-2.05]) were found than in women with TN results. In conclusion, due to a low recall rate in the Netherlands, the cumulative risk of a FP recall is relatively low, while the cumulative risk of a TP result is comparable. Breast cancer diagnoses and FP results were more common in women with FP results than in women with TN results, while participation was lower.

Benefits and harms of breast cancer mammography screening for women at average risk of breast cancer: A systematic review for the European Commission Initiative on Breast Cancer

OBJECTIVES

Mammography screening is generally accepted in women aged 50-69, but the balance between benefits and harms remains controversial in other age groups. This study systematically reviews these effects to inform the European Breast Cancer Guidelines.

METHODS

We searched PubMed, EMBASE and Cochrane Library for randomised clinical trials (RCTs) or systematic reviews of observational studies in the absence of RCTs comparing invitation to mammography screening to no invitation in women at average breast cancer (BC) risk. We extracted data for mortality, BC stage, mastectomy rate, chemotherapy provision, overdiagnosis and false-positive-related adverse effects. We performed a pooled analysis of relative risks, applying an inverse-variance random-effects model for three age groups (<50, 50-69 and 70-74). GRADE (Grading of Recommendations Assessment, Development and Evaluation) was used to assess the certainty of evidence.

RESULTS

We identified 10 RCTs including 616,641 women aged 38-75. Mammography reduced BC mortality in women aged 50-69 (relative risk (RR) 0.77, 95%CI (confidence interval) 0.66-0.90, high certainty) and 70-74 (RR 0.77, 95%CI 0.54-1.09, high certainty), with smaller reductions in under 50s (RR 0.88, 95%CI 0.76-1.02, moderate certainty). Mammography reduced stage IIA+ in women 50-69 (RR 0.80, 95%CI 0.64-1.00, very low certainty) but resulted in an overdiagnosis probability of 23% (95%CI 18-27%) and 17% (95%CI 15-20%) in under 50s and 50-69, respectively (moderate certainty). Mammography was associated with 2.9% increased risk of invasive procedures with benign outcomes (low certainty).

CONCLUSIONS

For women 50-69, high certainty evidence that mammography screening reduces BC mortality risk would support policymakers formulating strong recommendations. In other age groups, where the net balance of effects is less clear, conditional recommendations will be more likely, together with shared decision-making.

Towards personalized screening: Cumulative risk of breast cancer screening outcomes in women with and without a first-degree relative with a history of breast cancer

Several reviews have estimated the balance of benefits and harms of mammographic screening in the general population. The balance may, however, differ between individuals with and without family history. Therefore, our aim is to assess the cumulative risk of screening outcomes; screen-detected breast cancer, interval cancer, and false-positive results, in women screenees aged 50-75 and 40-75, with and without a first-degree relative with a history of breast cancer at the start of screening. Data on screening attendance, recall and breast cancer detection were collected for each woman living in Nijmegen (The Netherlands) since 1975. We used a discrete time survival model to calculate the cumulative probability of each major screening outcome over 19 screening rounds. Women with a family history of breast cancer had a higher risk of all screening outcomes. For women screened from age 50-75, the cumulative risk of screen-detected breast cancer, interval cancer and false-positive results were 9.0, 4.4 and 11.1% for women with a family history and 6.3, 2.7 and 7.3% for women without a family history, respectively. The results for women 40-75 followed the same pattern for women screened 50-75 for cancer outcomes, but were almost doubled for false-positive results. To conclude, women with a first-degree relative with a history of breast cancer are more likely to experience benefits and harms of screening than women without a family history. To complete the balance and provide risk-based screening recommendations, the breast cancer mortality reduction and overdiagnosis should be estimated for family history subgroups.

Mammography screening in less developed countries

Less developed countries (LDCs) are struggling with an increasing burden of breast cancer. It is important to identify what interventions might be most effective and feasible in reducing overall breast cancer mortality in a resource constrained settings. Mammography screening (MS) utilized in developed countries cannot be equally applied to LDCs. We provide a summary of the status of existing and past MS program attempts in LDCs, and try to determine the prerequisites under which any developing country is ready to benefit from a MS program. We make the case for a “mixed” portfolio of tools to reduce breast cancer mortality with MS reserved only for those sub-populations that meet the criteria. We hope our review will provide a background for policy makers to apply rigorous criteria before attempting to implement costly MS program and before judiciously evaluating additional competed programs in their countries.

Comparison of cumulative false-positive risk of screening mammography in the United States and Denmark

INTRODUCTION

In the United States (US), about one-half of women screened with annual mammography have at least one false-positive test after ten screens. The estimate for European women screened ten times biennially is much lower. We evaluate to what extent screening interval, mammogram type, and statistical methods, can explain the reported differences.

METHODS

We included all screens from women first screened at age 50-69 years in the US Breast Cancer Surveillance Consortium (BCSC) (n=99,455) between 1996-2010, and from two population-based mammography screening programs in Denmark (n=230,452 and n=400,204), between 1991-2012 and 1993-2013, respectively. Model-based cumulative false-positive risks were computed for the entire sample, using two statistical methods (Hubbard Njor) previously used to estimate false-positive risks in the US and Europe.

RESULTS

Empirical cumulative risk of at least one false-positive test after eight (annual or biennial) screens was 41.9% in BCSC, 16.1% in Copenhagen, and 7.4% in Funen. Variation in screening interval and mammogram type did not explain the differences by country. Using the Hubbard method, the model-based cumulative risks after eight screens was 45.1% in BCSC, 9.6% in Copenhagen, and 8.8% in Funen. Using the Njor method, these risks were estimated to be 43.6, 10.9 and 8.0%.

CONCLUSION

Choice of statistical method, screening interval and mammogram type does not explain the substantial differences in cumulative false-positive risk between the US and Europe.

Comparison of Screened and Nonscreened Breast Cancer Patients in Relation to Age: A 2-Institution Study

INTRODUCTION

Screening programs for breast cancer aim to allow early diagnosis, and thus reduce mortality. The aim of this study was to assess the effect of a population screening program in a sample of women aged between 50 and 69 years in terms of recurrence, metastasis, biological profiles, and survival, and to compare their results with those of women of a wider age range who did not participate on the screening program.

PATIENTS AND METHODS

A prospective multicenter study in which 1821 patients with 1873 breast tumors who received surgery between 1999 and 2014 at MútuaTerrassa University Hospital and the Hospital of Terrassa in Barcelona were analyzed. A comparison was performed in the 50- to 69-year-old age group between those who participated on the screening program and those who did not.

RESULTS

The mean age of patients was 58 years. The mean follow-up was 72 months, and median follow-up 59 months. The screened group showed significantly better results in all prognostic factors and in specific mortality than all nonscreened groups. The specific mortality rate in the screened patients was 2.4% (12/496), local recurrence 2.8% (14/496), and metastasis at 10 years 3.6% (18/496). In the nonscreened group, younger women presented a higher rate of metastasis (16.4% [81/493]) and a shorter disease-free period (77.1% [380/493]). The age group older than 70 years had the highest number of T4 tumors (7.5% [30/403]) and the highest proportion of radical surgery (50.4% [203/403]).

CONCLUSION

Patients in the screening program presented improved survival. We speculate that extending breast cancer screening programs to women younger than 50 and older than 70 years could bring about mortality benefits.

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.