Recent results from the Swedish Two-County Trial: the effects of age, histologic type, and mode of detection on the efficacy of breast cancer screening

Realisation of mammography screening in Khanty-Mansiysk Autonomous State – Yugra

Objective: to perform a retrospective analysis of the quality of mammography screening in Khanty-Mansiysk State Region – Yugra from its beginning to 2018 inclusive.

Materials and methods. During this investigation a throughout analysis of epidemiological indicators (breast cancer mortality and morbidity), quality indicators (coverage of the target population, cancer detection in general and early detection, sensitivity and morbidity) and mammographic screening performance indicators (projected and observed morbidity and mortality) was carried out.

Results and conclusions. During this period, 572,348 women were screened, 9.7 % of whom were recommended for further screening. The coverage of the target population for one round was 33 %. Screening test sensitivity for the specified period was 80 %. The observed number of women with newly detected breast cancer cases of stage I in 2018 made 42 % (53 cases) higher in comparison with expected numbers, and in stage T2+ it made 21 % (62 cases) less. The observed number of deaths in 2018 was 23.7 % lower than expected. The above-mentioned demonstrates once again that mammography screening in Khanty-Mansiysk State Region – Yugra has led to the improvement of early diagnosis of breast cancer. This, in turn, leads to a steady decline in breast cancer mortality among women over 40 years of age.

Effect of mammographic screening from age 40 years on breast cancer mortality (UK Age trial): final results of a randomised, controlled trial

BACKGROUND

The appropriate age range for breast cancer screening remains a matter of debate. We aimed to estimate the effect of mammographic screening at ages 40-48 years on breast cancer mortality.

METHODS

We did a randomised, controlled trial involving 23 breast screening units across Great Britain. We randomly assigned women aged 39-41 years, using individual randomisation, stratified by general practice, in a 1:2 ratio, to yearly mammographic screening from the year of inclusion in the trial up to and including the calendar year that they reached age 48 years (intervention group), or to standard care of no screening until the invitation to their first National Health Service Breast Screening Programme (NHSBSP) screen at approximately age 50 years (control group). Women in the intervention group were recruited by postal invitation. Women in the control group were unaware of the study. The primary endpoint was mortality from breast cancers (with breast cancer coded as the underlying cause of death) diagnosed during the intervention period, before the participant's first NHSBSP screen. To study the timing of the mortality effect, we analysed the results in different follow-up periods. Women were included in the primary comparison regardless of compliance with randomisation status (intention-to-treat analysis). This Article reports on long-term follow-up analysis. The trial is registered with the ISRCTN registry, ISRCTN24647151.

FINDINGS

160 921 women were recruited between Oct 14, 1990, and Sept 24, 1997. 53 883 women (33·5%) were randomly assigned to the intervention group and 106 953 (66·5%) to the control group. Between randomisation and Feb 28, 2017, women were followed up for a median of 22·8 years (IQR 21·8-24·0). We observed a significant reduction in breast cancer mortality at 10 years of follow-up, with 83 breast cancer deaths in the intervention group versus 219 in the control group (relative rate [RR] 0·75 [95% CI 0·58-0·97]; p=0·029). No significant reduction was observed thereafter, with 126 deaths versus 255 deaths occurring after more than 10 years of follow-up (RR 0·98 [0·79-1·22]; p=0·86).

INTERPRETATION

Yearly mammography before age 50 years, commencing at age 40 or 41 years, was associated with a relative reduction in breast cancer mortality, which was attenuated after 10 years, although the absolute reduction remained constant. Reducing the lower age limit for screening from 50 to 40 years could potentially reduce breast cancer mortality.

FUNDING

National Institute for Health Research Health Technology Assessment programme.

Precision Science on Incidence and Progression of Early-Detected Small Breast Invasive Cancers by Mammographic Features

The aim was to evaluate how the inter-screening interval affected the performance of screening by mammographic appearances. This was a Swedish retrospective screening cohort study with information on screening history and mammography features in two periods (1977–1985 and 1996–2010). The pre-clinical incidence and the mean sojourn time (MST) for small breast cancer allowing for sensitivity by mammographic appearances were estimated. The percentage of interval cancer against background incidence (I/E ratio) was used to assess the performance of mammography screening by different inter-screening intervals. The sensitivity-adjusted MSTs (in years) were heterogeneous with mammographic features, being longer for powdery and crushed stone-like calcifications (4.26, (95% CI, 3.50–5.26)) and stellate masses (3.76, (95% CI, 3.15–4.53)) but shorter for circular masses (2.65, (95% CI, 2.06–3.55)) in 1996–2010. The similar trends, albeit longer MSTs, were also noted in 1977–1985. The I/E ratios for the stellate type were 23% and 32% for biennial and triennial screening, respectively. The corresponding figures were 32% and 43% for the circular type and 21% and 29% for powdery and crushed stone-like calcifications, respectively. Mammography-featured progressions of small invasive breast cancer provides a new insight into personalized quality assurance, surveillance, treatment and therapy of early-detected breast cancer.

Digital Mammography and Digital Breast Tomosynthesis

Breast imaging technology has advanced significantly from the 1930s until the present. American women have a 1 in 8 chance of developing breast cancer. Mammography has been proven in multiple clinical trials to reduce breast cancer mortality. Although a mainstay of breast imaging and improved from film-screen mammography, digital mammography is not a perfect examination. Overlapping obscuring breast tissue limits mammographic interpretation. Breast digital tomosynthesis reduces and/or eliminates overlapping obscuring breast tissue. Although there are some disadvantages with digital breast tomosynthesis, this relatively lost-cost technology may be used effectively in the screening and diagnostic settings.

Effect of mammographic screening from age 40 years on breast cancer mortality in the UK Age trial at 17 years' follow-up: a randomised controlled trial

BACKGROUND

Age-specific effects of mammographic screening, and the timing of such effects, are a matter of debate. The results of the UK Age trial, which compared the effect of invitation to annual mammographic screening from age 40 years with commencement of screening at age 50 years on breast cancer mortality, have been reported at 10 years of follow-up and showed no significant difference in mortality between the trial groups. Here, we report the results of the UK Age trial after 17 years of follow-up.

METHODS

Women aged 39-41 from 23 UK NHS Breast Screening Programme units years were randomly assigned by individual randomisation (1:2) to either an intervention group offered annual screening by mammography up to and including the calendar year of their 48th birthday or to a control group receiving usual medical care (invited for screening at age 50 years and every 3 years thereafter). Both groups were stratified by general practice. We compared breast cancer incidence and mortality by time since randomisation. Analyses included all women randomly assigned who could be traced with the National Health Service Central Register and who had not died or emigrated before entry. The primary outcome measures were mortality from breast cancer (defined as deaths with breast cancer coded as the underlying cause of death) and breast cancer incidence, including in-situ, invasive, and total incidence. Because there is an interest in the timing of the mortality effect, we analysed the results in different follow-up periods. This trial is registered, number ISRCTN24647151.

FINDINGS

Between Oct 14, 1990, and Sept 25, 1997, 160 921 participants were randomly assigned; 53 883 women in the intervention group and 106 953 assigned to usual medical care were included in this analysis. After a median follow-up of 17 years (IQR 16·8-18·8), the rate ratio (RR) for breast cancer mortality was 0·88 (95% CI 0·74-1·04) from tumours diagnosed during the intervention phase. A significant reduction in breast cancer mortality was noted in the intervention group compared with the control group in the first 10 years after diagnosis (RR 0·75, 0·58-0·97) but not thereafter (RR 1·02, 0·80-1·30) from tumours diagnosed during the intervention phase. The overall breast cancer incidence during 17 year follow-up was similar between the intervention group and the control group (RR 0·98, 0·93-1·04).

INTERPRETATION

Our results support an early reduction in mortality from breast cancer with annual mammography screening in women aged 40-49 years. Further data are needed to fully understand long-term effects. Cumulative incidence figures suggest at worst a small amount of overdiagnosis.

FUNDING

National Institute for Health Research Health Technology Assessment programme and the American Cancer Society. Past funding was received from the Medical Research Council, Cancer Research UK, the UK Department of Health, and the US National Cancer Institute.

The value of modern mammography screening in the control of breast cancer: understanding the underpinnings of the current debates

Since the introduction of mammography screening, debates about the value of screening have endured and been contentious. Recent reviews of the randomized controlled trials reach different conclusions about the absolute benefit of screening, as do evaluations of population trends in breast cancer mortality and the evaluations of service screening. Conclusions about the value of screening commonly are expressed in terms of the balance of benefits and harms, which can differ greatly even when derived seemingly from the same data. It can be shown when different estimates are adjusted to a common screening and follow-up scenario, differences in balance sheet estimates diminish substantially. The strong evidence of benefit associated with exposure to modern mammography screening suggests that it is time to move beyond the randomized controlled trial estimates of benefit and consider policy decisions on the basis of benefits and harms estimated from the evaluation of current screening programs.

Screening for breast cancer with mammography

BACKGROUND

A variety of estimates of the benefits and harms of mammographic screening for breast cancer have been published and national policies vary.

OBJECTIVES

To assess the effect of screening for breast cancer with mammography on mortality and morbidity.

SEARCH METHODS

We searched PubMed (22 November 2012) and the World Health Organization's International Clinical Trials Registry Platform (22 November 2012).

SELECTION CRITERIA

Randomised trials comparing mammographic screening with no mammographic screening.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data. Study authors were contacted for additional information.

MAIN RESULTS

Eight eligible trials were identified. We excluded a trial because the randomisation had failed to produce comparable groups.The eligible trials included 600,000 women in the analyses in the age range 39 to 74 years. Three trials with adequate randomisation did not show a statistically significant reduction in breast cancer mortality at 13 years (relative risk (RR) 0.90, 95% confidence interval (CI) 0.79 to 1.02); four trials with suboptimal randomisation showed a significant reduction in breast cancer mortality with an RR of 0.75 (95% CI 0.67 to 0.83). The RR for all seven trials combined was 0.81 (95% CI 0.74 to 0.87). We found that breast cancer mortality was an unreliable outcome that was biased in favour of screening, mainly because of differential misclassification of cause of death. The trials with adequate randomisation did not find an effect of screening on total cancer mortality, including breast cancer, after 10 years (RR 1.02, 95% CI 0.95 to 1.10) or on all-cause mortality after 13 years (RR 0.99, 95% CI 0.95 to 1.03).Total numbers of lumpectomies and mastectomies were significantly larger in the screened groups (RR 1.31, 95% CI 1.22 to 1.42), as were number of mastectomies (RR 1.20, 95% CI 1.08 to 1.32). The use of radiotherapy was similarly increased whereas there was no difference in the use of chemotherapy (data available in only two trials).

AUTHORS' CONCLUSIONS

If we assume that screening reduces breast cancer mortality by 15% and that overdiagnosis and overtreatment is at 30%, it means that for every 2000 women invited for screening throughout 10 years, one will avoid dying of breast cancer and 10 healthy women, who would not have been diagnosed if there had not been screening, will be treated unnecessarily. Furthermore, more than 200 women will experience important psychological distress including anxiety and uncertainty for years because of false positive findings. To help ensure that the women are fully informed before they decide whether or not to attend screening, we have written an evidence-based leaflet for lay people that is available in several languages on www.cochrane.dk. Because of substantial advances in treatment and greater breast cancer awareness since the trials were carried out, it is likely that the absolute effect of screening today is smaller than in the trials. Recent observational studies show more overdiagnosis than in the trials and very little or no reduction in the incidence of advanced cancers with screening.

Mammography screening and breast cancer mortality in Australia: an aggregate cohort study

BACKGROUND

Evidence that mammography screening reduces breast cancer mortality derives from trials, with observational studies broadly supporting trial findings. The purpose of this study was to evaluate the national mammographic screening programme, BreastScreen Australia, using aggregate screening and breast cancer mortality data.

METHODS

Breast cancer mortality from 1990 to 2004 in the whole Australian population was assessed in relation to screening exposure in the target of women aged 50-69 years. Population cohorts were defined by year of screening (and diagnosis), five-year age group at screening (and diagnosis), and local area of residence at screening (and diagnosis). Biennial screening data for BreastScreen Australia were related to cumulated mortality from breast cancer in an event analysis using Poisson regression, and in a time-to-event analysis using Cox proportional hazards regression. Results were adjusted for repeated measures and the potential effects of mammography outside BreastScreen Australia, regionality, and area socio-economic status.

RESULTS

From the adjusted Poisson regression model, a 22% (95% CI:12-31%) reduction in six-year cumulated mortality from breast cancer was predicted for screening participation of approximately 60%, compared with no screening; 21% (95% CI:11-30%) for the most recently reported screening participation of 56%; and 25% (95% CI:15-35%) for the programme target of 70% biennial screening participation. Corresponding estimates from the Cox proportional hazard regression model were 30% (95% CI:17-41%), 28% (95% CI:16-38%) and 34% (95% CI:20-46%).

CONCLUSIONS

Despite data limitations, the results of this nationwide study are consistent with the trial evidence, and with results of other service studies of mammography screening. With sufficient participation, mammography screening substantially reduces mortality from breast cancer.

Consensus recommendations for advancing breast cancer: risk identification and screening in ethnically diverse younger women

A need exists for a breast cancer risk identification paradigm that utilizes relevant demographic, clinical, and other readily obtainable patient-specific data in order to provide individualized cancer risk assessment, direct screening efforts, and detect breast cancer at an early disease stage in historically underserved populations, such as younger women (under age 40) and minority populations, who represent a disproportionate number of military beneficiaries. Recognizing this unique need for military beneficiaries, a consensus panel was convened by the USA TATRC to review available evidence for individualized breast cancer risk assessment and screening in young (< 40), ethnically diverse women with an overall goal of improving care for military beneficiaries. In the process of review and discussion, it was determined to publish our findings as the panel believes that our recommendations have the potential to reduce health disparities in risk assessment, health promotion, disease prevention, and early cancer detection within and in other underserved populations outside of the military. This paper aims to provide clinicians with an overview of the clinical factors, evidence and recommendations that are being used to advance risk assessment and screening for breast cancer in the military.

Screening for breast cancer with mammography

BACKGROUND

A variety of estimates of the benefits and harms of mammographic screening for breast cancer have been published and national policies vary.

OBJECTIVES

To assess the effect of screening for breast cancer with mammography on mortality and morbidity.

SEARCH STRATEGY

We searched PubMed (November 2008).

SELECTION CRITERIA

Randomised trials comparing mammographic screening with no mammographic screening.

DATA COLLECTION AND ANALYSIS

Both authors independently extracted data. Study authors were contacted for additional information.

MAIN RESULTS

Eight eligible trials were identified. We excluded a biased trial and included 600,000 women in the analyses. Three trials with adequate randomisation did not show a significant reduction in breast cancer mortality at 13 years (relative risk (RR) 0.90, 95% confidence interval (CI) 0.79 to 1.02); four trials with suboptimal randomisation showed a significant reduction in breast cancer mortality with an RR of 0.75 (95% CI 0.67 to 0.83). The RR for all seven trials combined was 0.81 (95% CI 0.74 to 0.87). We found that breast cancer mortality was an unreliable outcome that was biased in favour of screening, mainly because of differential misclassification of cause of death. The trials with adequate randomisation did not find an effect of screening on cancer mortality, including breast cancer, after 10 years (RR 1.02, 95% CI 0.95 to 1.10) or on all-cause mortality after 13 years (RR 0.99, 95% CI 0.95 to 1.03).Numbers of lumpectomies and mastectomies were significantly larger in the screened groups (RR 1.31, 95% CI 1.22 to 1.42) for the two adequately randomised trials that measured this outcome; the use of radiotherapy was similarly increased.

AUTHORS' CONCLUSIONS

Screening is likely to reduce breast cancer mortality. As the effect was lowest in the adequately randomised trials, a reasonable estimate is a 15% reduction corresponding to an absolute risk reduction of 0.05%. Screening led to 30% overdiagnosis and overtreatment, or an absolute risk increase of 0.5%. This means that for every 2000 women invited for screening throughout 10 years, one will have her life prolonged and 10 healthy women, who would not have been diagnosed if there had not been screening, will be treated unnecessarily. Furthermore, more than 200 women will experience important psychological distress for many months because of false positive findings. It is thus not clear whether screening does more good than harm. To help ensure that the women are fully informed of both benefits and harms before they decide whether or not to attend screening, we have written an evidence-based leaflet for lay people that is available in several languages on www.cochrane.dk.

Rational and irrational issues in breast cancer screening

Evidence on the efficacy of breast screening from randomized controlled trials conducted in the last decades of the 1900s is reviewed. For decades, controversy about their results has centered on the magnitude of benefit in terms of breast cancer mortality reduction that can be achieved. However more recently, several expert bodies have estimated the benefits to be smaller than initially expected and concerns have been raised about screening consequences such as over-diagnosis and unnecessary treatment. Trials with substantial mortality reduction have been lauded and others with null effects have been critiqued. Critiques of the Canadian National Breast Screening Study are refuted. Extreme responses by screening advocates to the United States Preventive Services Task Force 2009 guidelines are described. The role vested interests play in determining health policy is clearly revealed in the response to the guidelines and should be more generally known. A general reluctance to explore unexpected results or to accept new paradigms is briefly discussed.

Complementary approaches to assessing risk factors for interval breast cancer

OBJECTIVE

To examine risk factors for interval breast cancer among women screened in a population-based mammography program.

METHODS

Risk for interval cancer was assessed in terms of both the incidence per 10,000 negative screens and the proportion of all breast cancers diagnosed among screened women. Interval (N = 557) and screen-detected cancers (N = 1,545) were identified among 208,667 women receiving mammography in Colorado (1994-2001). Logistic regression was used to assess independent effects of multiple factors.

RESULTS

Overall risk of interval cancer was 29.5/10,000 women screened. Incidence was higher in women >50 years (OR: 2.28, 1.86-2.80), with family history (OR: 2.23, 1.85-2.70), with dense breasts (OR: 3.84, 2.76-5.35), and using hormones (OR: 1.54, 1.20-1.97). Hispanics had lower incidence than Whites (OR: 0.52, 0.34-0.81). Interval cancers represented 26% of all cancers diagnosed. This proportion was higher in women <50 (OR: 1.41, 1.09-1.82) and in women with dense breasts (OR: 2.95, 1.94-4.48).

CONCLUSIONS

Incidence of interval cancer increases with age, breast density, hormone use, and family history. Attempts to reduce occurrence of these cancers through more sensitive and/or intensive screening should focus on these subgroups. The disproportionate number of interval cancers associated with young age and dense breasts suggests these cancers result from both rapid growth and difficulties in detection.

Screening for breast cancer with mammography

BACKGROUND

A variety of estimates of the benefits and harms of mammographic screening for breast cancer have been published and national policies vary.

OBJECTIVES

To assess the effect of screening for breast cancer with mammography on mortality and morbidity.

SEARCH STRATEGY

We searched PubMed (November 2008).

SELECTION CRITERIA

Randomised trials comparing mammographic screening with no mammographic screening.

DATA COLLECTION AND ANALYSIS

Both authors independently extracted data. Study authors were contacted for additional information.

MAIN RESULTS

Eight eligible trials were identified. We excluded a biased trial and included 600,000 women in the analyses. Three trials with adequate randomisation did not show a significant reduction in breast cancer mortality at 13 years (relative risk (RR) 0.90, 95% confidence interval (CI) 0.79 to 1.02); four trials with suboptimal randomisation showed a significant reduction in breast cancer mortality with an RR of 0.75 (95% CI 0.67 to 0.83). The RR for all seven trials combined was 0.81 (95% CI 0.74 to 0.87). We found that breast cancer mortality was an unreliable outcome that was biased in favour of screening, mainly because of differential misclassification of cause of death. The trials with adequate randomisation did not find an effect of screening on cancer mortality, including breast cancer, after 10 years (RR 1.02, 95% CI 0.95 to 1.10) or on all-cause mortality after 13 years (RR 0.99, 95% CI 0.95 to 1.03).Numbers of lumpectomies and mastectomies were significantly larger in the screened groups (RR 1.31, 95% CI 1.22 to 1.42) for the two adequately randomised trials that measured this outcome; the use of radiotherapy was similarly increased.

AUTHORS' CONCLUSIONS

Screening is likely to reduce breast cancer mortality. As the effect was lowest in the adequately randomised trials, a reasonable estimate is a 15% reduction corresponding to an absolute risk reduction of 0.05%. Screening led to 30% overdiagnosis and overtreatment, or an absolute risk increase of 0.5%. This means that for every 2000 women invited for screening throughout 10 years, one will have her life prolonged and 10 healthy women, who would not have been diagnosed if there had not been screening, will be treated unnecessarily. Furthermore, more than 200 women will experience important psychological distress for many months because of false positive findings. It is thus not clear whether screening does more good than harm. To help ensure that the women are fully informed of both benefits and harms before they decide whether or not to attend screening, we have written an evidence-based leaflet for lay people that is available in several languages on www.cochrane.dk.

Young age is not associated with increased local recurrence for DCIS treated by breast-conserving surgery and radiation

BACKGROUND

We report local recurrence (LR) after breast-conserving surgery and radiation (BCS + RT) for ductal carcinoma in situ (DCIS) to determine outcomes for patients aged <or=40 years compared with older women.

METHODS

The study included 440 women with DCIS treated from 1978 to 2007. All patients received whole-breast radiotherapy with a boost in 95% of cases. Demographics, characteristics, surgical, and adjuvant treatments were analyzed for an effect on LR.

RESULTS

Median age was 56.5 years with 24 patients aged <or=40. Median DCIS size was 0.8 cm. Re-excision was required in 62% of patients, and in 75% of those aged <or=40. Tamoxifen was used in 22%, but only one patient aged <or=40. Median follow-up was 6.8 years. Actuarial LR was 7% (95% confidence interval of 4-11%) at 10 years and 8% (5-14%) at 15 years. There was no difference in LR by age (P = 0.76).

CONCLUSIONS

The long-term risk of LR after BCS + RT for DCIS is low, even in patients <or=40 years. This may be due to patient selection for small size, high utilization of re-excision, and radiation boost. Young age may be a smaller contributor to LR risk in DCIS than previously suggested.

Classification of breast computed tomography data

Differences in breast tissue composition are important determinants in assessing risk, identifying disease in images and following changes over time. This paper presents an algorithm for tissue classification that separates breast tissue into its three primary constituents of skin, fat and glandular tissue. We have designed and built a dedicated breast CT scanner. Fifty-five normal volunteers and patients with mammographically identified breast lesions were scanned. Breast CT voxel data were filtered using a 5 pt median filter and the image histogram was computed. A two compartment Gaussian fit of histogram data was used to provide an initial estimate of tissue compartments. After histogram analysis, data were input to region-growing algorithms and classified as to belonging to skin, fat or gland based on their value and architectural features. Once tissues were classified, a more detailed analysis of glandular tissue patterns and a more quantitative analysis of breast composition was made. Algorithm performance assessment demonstrated very good or excellent agreement between algorithm and radiologist observers in 97.7% of the segmented data. We observed that even in dense breasts the fraction of glandular tissue seldom exceeded 50%. For most individuals the composition is better characterized as being a 70% (fat)-30% (gland) composition than a 50% (fat)-50% (gland) composition.

Screening for breast cancer with mammography

BACKGROUND

A variety of estimates of the benefits and harms of mammographic screening for breast cancer have been published and national policies vary.

OBJECTIVES

To assess the effect of screening for breast cancer with mammography on mortality and morbidity.

SEARCH STRATEGY

We searched PubMed (June 2005).

SELECTION CRITERIA

Randomised trials comparing mammographic screening with no mammographic screening.

DATA COLLECTION AND ANALYSIS

Both authors independently extracted data. Study authors were contacted for additional information.

MAIN RESULTS

Seven completed and eligible trials involving half a million women were identified. We excluded a biased trial from analysis. Two trials with adequate randomisation did not show a significant reduction in breast cancer mortality, relative risk (RR) 0.93 (95% confidence interval 0.80 to 1.09) at 13 years; four trials with suboptimal randomisation showed a significant reduction in breast cancer mortality, RR 0.75 (0.67 to 0.83) (P = 0.02 for difference between the two estimates). RR for all six trials combined was 0.80 (0.73 to 0.88). The two trials with adequate randomisation did not find an effect of screening on cancer mortality, including breast cancer, RR 1.02 (0.95 to 1.10) after 10 years, or on all-cause mortality, RR 1.00 (0.96 to 1.04) after 13 years. We found that breast cancer mortality was an unreliable outcome that was biased in favour of screening, mainly because of differential misclassification of cause of death. Numbers of lumpectomies and mastectomies were significantly larger in the screened groups, RR 1.31 (1.22 to 1.42) for the two adequately randomised trials; the use of radiotherapy was similarly increased.

AUTHORS' CONCLUSIONS

Screening likely reduces breast cancer mortality. Based on all trials, the reduction is 20%, but as the effect is lower in the highest quality trials, a more reasonable estimate is a 15% relative risk reduction. Based on the risk level of women in these trials, the absolute risk reduction was 0.05%. Screening also leads to overdiagnosis and overtreatment, with an estimated 30% increase, or an absolute risk increase of 0.5%. This means that for every 2000 women invited for screening throughout 10 years, one will have her life prolonged. In addition, 10 healthy women, who would not have been diagnosed if there had not been screening, will be diagnosed as breast cancer patients and will be treated unnecessarily. It is thus not clear whether screening does more good than harm. Women invited to screening should be fully informed of both benefits and harms.

Screening for Breast Cancer

Strong evidence supports the value of breast cancer screening with mammography, and high-quality mammography screening can be considered a major public health achievement. As noted earlier in the discussion about the evaluation of service screening, the group of women who did not participate in mammographic screening in the decades after screening had been introduced had essentially unchanged or only minor improvements in mortality compared with the pattern before the introduction of screening, despite widespread use of adjuvant chemotherapy or hormonal therapy. Breast cancer should be treated in its preclinical phase if we are to save the lives of women with this disease, and a considerable body of evidence outlines best practices that, with broader adherence, would result in greater breast cancer mortality reductions than have been observed to date.

Does surgery induce angiogenesis in breast cancer? Indirect evidence from relapse pattern and mammography paradox

A significant bimodal relapse hazard pattern has been observed in two independent databases for patients untreated with adjuvant chemotherapy. This implies there is more than one mode of relapse. The earliest and most closely grouped relapses occur 8-10 months after surgery for young women with node-positive disease. Analysis of these data using computer simulation suggested that surgery probably instigated angiogenesis in dormant distant disease in approximately 20% of cases for premenopausal node-positive patients. We explore if this could explain the mammography paradox for women aged 40-49: an unexplained temporary excess in mortality for the screened population compared to controls. Calculations based on our data predict surgery-induced angiogenesis would accelerate disease by a median of two years and produce 0.11 early deaths per 1000 screened young women in the third year of screening. The predicted timing as well as the magnitude of excess mortality agree with trial data. Surgery-induced angiogenesis could account for the mammography paradox for women aged 40-49 and the bimodal relapse hazard pattern. According to the proposed biology, removing tumors could remove the source of inhibitors of angiogenesis or growth factors could appear in response to surgical wounding. While this needs confirmation, this could be considered when designing treatment protocols particularly for young women with positive nodes. It reinforces the need for close coordination between surgical resection and ensuing medical intervention. Women need to be advised of risk of accelerated tumor growth and early relapse before giving informed consent for mammography.

Role of Detection Method in Predicting Breast Cancer Survival: Analysis of Randomized Screening Trials

BACKGROUND

Screening mammography detects breast cancers earlier than those detected symptomatically, and so mammographically detected breast cancers tend to have better prognoses. The so-called stage shift that results from screen detection is subject to lead-time and length biases, and so earlier detection may not translate into longer survival. We used data from three large breast cancer screening trials--Health Insurance Plan (HIP) of New York and two Canadian National Breast Cancer Screening Studies (CNBSS)--to investigate survival benefits of breast cancer screening beyond stage shift. We also address whether method of detection is an independent prognostic factor in breast cancer.

METHODS

The HIP trial randomly assigned approximately 62,000 women to screening and control groups. The two CNBSS trial cohorts CNBSS-1 and CNBSS-2 included a total of 44,970 women in the screening group and 44,961 in the control group. After adjusting for stage and other tumor characteristics in a Cox proportional hazards model, survival distributions were compared by method of breast cancer detection with both univariate and multivariable analyses. All P values are two-sided.

RESULTS

Breast cancers detected by screening mammography had a shift in stage distribution to earlier stages (for HIP, P < .001; for CNBSS-1, P = .03; and for CNBSS-2, P < .001). After adjusting for tumor size, lymph node status, and disease stage in a Cox proportional hazards model, method of detection was a statistically significant independent predictor of disease-specific survival. Patients with interval cancers had a 53% (95% confidence interval [CI] = 17% to 100%) greater hazard of death from breast cancer than patients with screen-detected cancers, and patients with cancer in the control groups had a 36% (95% CI = 10% to 68%) greater hazard of death than patients with screen-detected cancer.

CONCLUSION

There was an apparent survival benefit beyond stage shift for patients with screen-detected breast cancers compared with patients with breast cancers detected otherwise. Method of detection appears to be an important prognostic factor, even after adjusting for known tumor characteristics. This finding suggests that clinical trialists should routinely collect information about method of detection.

The randomized trials of breast cancer screening: what have we learned?

Eight randomized controlled trials of mammography screening have been conducted to date. In addition to evaluating the efficacy of screening with an experimental design, the trials provided investigators with access to information about breast cancers much earlier in their development than had previously been available. The trials of mammographic screening provide conclusive evidence that the policy of offering screening is associated with a significant and substantial reduction in breast cancer mortality.

Do physicians tailor their recommendations for breast cancer risk reduction based on patient's risk?

OBJECTIVE

To investigate how physicians tailor their recommendations for breast cancer prevention and risk reduction.

DESIGN

Cross-sectional, mail survey.

PARTICIPANTS

Random sample of primary care physicians in California (N = 822).

MEASUREMENTS AND MAIN RESULTS

Six standardized patient scenarios were used to assess how women's breast cancer risk factors influence physicians' recommendations for screening mammography, counseling about lifestyle behaviors, genetic testing, the use of tamoxifen, prophylactic surgery, and referral to a breast specialist. Over 90% of physicians endorsed mammography for all of the scenarios. Similarly, approximately 80% of physicians endorsed counseling about lifestyle factors for all of the scenarios. Five-year risk of developing breast cancer and family history were both strongly associated with each of the 6 recommendations. Importantly, however, physicians were more likely to endorse the discussion of genetic testing, the use of tamoxifen, and prophylactic surgery for women with a family history of breast cancer compared with women at a higher risk of developing breast cancer but without a family history. Obstetrician-gynecologists were more likely to endorse most of these practices compared with internists.

CONCLUSIONS

Mammography and counseling about lifestyle behaviors are widely endorsed by physicians for breast cancer prevention and risk reduction. Whereas physicians are generally able to tailor their recommendations for prevention and risk reduction based on risk, they may perhaps underutilize genetic evaluation and newer therapeutic options for primary prevention for women who are at high risk of developing breast cancer but do not have a family history.

T1 stage breast cancer: adjuvant hypofractionated conformal radiation therapy to tumor bed in selected postmenopausal breast cancer patients--pilot feasibility study

PURPOSE

To explore the feasibility of a short course of hypofractionated conformal radiation therapy to the tumor bed as part of a breast preservation protocol in postmenopausal patients with nonpalpable pT1N0 stage breast cancer.

MATERIALS AND METHODS

The tumor bed was imaged at computed tomography (CT) in the prone position on a dedicated table. The same table and position were used for treatment with a 4-MV linear accelerator. The planning target volume was the tumor bed plus a 1-2-cm margin defined at postmastectomy CT. A regimen of five fractions was tested in this pilot dose study. Cosmesis was assessed by patients and physicians before treatment and 36 months after treatment.

RESULTS

Ten consecutive patients who were eligible for the study were assigned to one of three dose-per-fraction regimens; nine were treatable with the proposed technique on the basis of CT findings. Patients received five fractions over 10 days (total dose range, 25-30 Gy): Three received 5.0 Gy per fraction; four, 5.5 Gy; and two, 6.0 Gy. At minimum follow-up of 36 months (range, 36-53 months), all patients were alive and disease free with good to excellent cosmesis.

CONCLUSION

Hypofractionated conformal breast radiation therapy is feasible. Further studies are warranted.

Dedicated breast CT: radiation dose and image quality evaluation

PURPOSE

To evaluate the feasibility of breast computed tomography (CT) in terms of radiation dose and image quality.

MATERIALS AND METHODS

Validated Monte Carlo simulation techniques were used to estimate the average glandular dose (AGD). The calculated photon fluence at the detector for high-quality abdominal CT (120 kVp, 300 mAs, 5-mm section thickness) was the benchmark for assessing the milliampere seconds and corresponding radiation dose necessary for breast CT. Image noise was measured by using a 10-cm-diameter cylinder imaged with a clinical CT scanner at 10-300 mAs for 80, 100, and 120 kVp. A cadaveric breast was imaged in the coronal plane to approximate the acquisition geometry of a proposed breast CT scanner.

RESULTS

The AGD for 80-kVp breast CT was comparable to that for two-view mammography of 5-cm breasts (compressed breast thickness). For thicker breasts, the breast CT dose was about one-third less than that for two-view mammography. The maximum dose at mammography assessed in 1-mm(3) voxels was far higher (20.0 mGy) than that at breast CT (5.4 mGy) for a typical 5-cm 50% glandular breast. CT images of an 8-cm cadaveric breast (AGD, 6.3 mGy) were subjectively superior to digital mammograms (AGD, 10.1 mGy) of the same specimen.

CONCLUSION

The potential of high signal-to-noise ratio images with low anatomic noise, which are obtainable at dose levels comparable to those for mammography, suggests that dedicated breast CT should be studied further for its potential in breast cancer screening and diagnosis.

Screening women at high risk of breast cancer on the basis of evidence

Geneticists are able to identify the risk of breast cancer. Strategies on offer include prevention, early diagnosis by screening, and prophylactic surgery. This paper analyses the evidence for offering screening. The radiation dose of mammography has been measured, but the risk is not fully known. Mammography screening of women of 40-50 years in the normal population has known effect. Little evidence is available for women under 40 years or for women with genetic susceptibility to breast cancer. Dense parenchymal pattern is associated with high grade cancers, and is both a risk factor and a reason for impaired screening sensitivity. Whether this applies to younger women or women at high risk is speculative. The pathological features of the cancers in gene carriers show differences from those occurring in normal women. This work should be correlated with imaging features. There is no literature to support the use of newer imaging methods in these women. Ultrasound and MRI avoid radiation and may be useful in dense breasts. SestaMIBI and PET scanning are not yet mature enough for screening, and may never have such a role. Any newer modality must be subjected to a formal randomised trial before being offered to screen women at high risk.

Premenopausal status accelerates relapse in node positive breast cancer: hypothesis links angiogenesis, screening controversy

Much attention has been given to determining the benefit of mammographic screening to reduce breast cancer mortality. Eight randomized clinical trials have been conducted in four countries: the US, Canada, Scotland and Sweden. Trials report an early and stable 30% reduction in breast cancer mortality for women aged 50-59. For women under 50, unexpectedly, the early years of screening produce a disadvantage to the screened population. Only in later years does an advantage appear. To help understand this, we studied relapse patterns using a breast cancer database of 1,173 pre- and postmenopausal, node negative and positive patients treated with surgery only and having 16-20 years of follow-up. This approach is relevant since at least five of the eight screening trials began before the widespread use of adjuvant chemotherapy in the 1980s. Surgical cure rates were independent of menopausal status. However, a major difference in early relapse rate was found. In premenopausal and node positive patients, 27% of all distant relapses occurred within the first 10 months following resection. This is twice the early relapse frequency of any other clinical group. Using computer simulation, we interpret that these early relapses probably result from a disadvantage induced at surgery. A disinhibition or surgery/wounding induced angiogenic surge might be responsible. Disinhibition is known to occur in animal models such as Lewis lung where lung metastases are avascular and dormant until the primary is removed. Sudden outgrowth of tumor after wounding has been observed for a century. According to the simulation, in breast cancer this induction apparently accelerates inevitable relapses by a median of two years. This is offset in later years with a balancing reduction in relapses. These data suggest that the angiogenic switch may be upregulated more frequently among premenopausal women, perhaps depending upon the sex hormones. The acceleration would cause 0.11 deaths per 1,000 screened aged 40-49 subjects in years 2-3, a value comparable to the early year excess mortality in trials of a significant 0.15 deaths per 1,000 subjects. Equal screening advantage is predicted for node negative (but not node positive) pre- and postmenopausal patients. The acceleration of relapse after surgery may explain the paradoxical effect of mammographic screening for women under 50.

Breast cancer screening

Breast cancer is the most common malignancy among women in the United States; however, recent data demonstrates a decline in the mortality rate, which may be attributed to early detection from screening programs combined with effective therapies for early stage disease. As a result of the prevalence of breast cancer and its association with highly emotional issues, screening recommendations have aroused debate in the scientific, public, and legislative domains. A general consensus supports breast cancer screening among women between the ages of 50 and 70; however, much controversy exists regarding screening for women age 40 to 49 or above age 70. This article explores the issues involved in determining breast cancer screening recommendations among asymptomatic women with average risk in the United States.

Breast cancer screening

Randomized controlled trials involving nearly 500,000 women on two continents have confirmed the early promise that screening mammography can reduce breast cancer mortality. The observed benefits of mammographic screening, however, are not the same in all women. The mortality reduction in women over age 70 is unknown, and women aged 40 to 49 do not appear to benefit from mammographic screening to the same extent as those over age 50. The reasons for this disparity are incompletely understood, but it depends in part upon differing tumor biology and mammographic test characteristics in younger women. Even if relative survival benefits were equal for women under and over age 50, absolute reduction in risk would remain considerably lower for younger women, a disparity that would not be corrected by improved screening technology or adjustment of interscreening intervals. The authors' review of the evidence leads them to strongly support mammographic screening of women aged 50 to 69 at an interval not longer than 2 years. The authors also feel it is reasonable to screen women over age 70 who have a favorable life expectancy. They conclude, however, that the evidence does not support a blanket recommendation in favor of screening women aged 40 to 49. Instead, they advocate a well-informed conversation between physician and patient regarding the present knowledge and the risks and benefits of screening for each individual woman. Definitive answers await the results of ongoing RCTs designed to study the survival benefit conferred by screening women aged 40 to 49. Disagreement will undoubtedly persist regarding which recommendations should determine private practice and public policy.

14 years of follow-up from the Edinburgh randomised trial of breast-cancer screening

BACKGROUND

The Edinburgh randomised trial of breast-cancer screening recruited women aged 45-64 years from 1978 to 1981 (cohort 1), and those aged 45-49 years during 1982-85 (cohorts 2 and 3). Results based on 14 years of follow-up and 270,000 woman-years of observation are reported.

METHODS

Breast-cancer mortality rates in the intervention group (28,628 women offered screening) were compared with those in the control group (26,026) with adjustment for socioeconomic status (SES) of general medical practices. Rate ratios were derived by means of logistic regression for the total trial population and for women first offered screening while younger than 50 years. Analyses were by intention to treat.

FINDINGS

Initial unadjusted results showed a difference of just 13% in breast-cancer mortality rates between the intervention and control groups (156 deaths [5.18 per 10,000] vs 167 [6.04 per 10,000]; rate ratio 0.87 [95% CI 0.70-1.06]), but the results were influenced by differences in SES by trial group. After adjustment for SES, the rate ratio was 0.79 (95% CI 0.60-1.02). When deaths after diagnosis more than 3 years after the end of the study were censored the rate ratio became 0.71 (0.53-0.95). There was no evidence of heterogeneity by age at entry and no evidence that younger entrants had smaller or delayed benefit (rate ratio 0.70 [0.41-1.20]). No breast-cancer mortality benefit was observed for women whose breast cancers were diagnosed when they were younger than 50 years. Other-cause mortality rates did not differ by trial group when adjusted for SES.

INTERPRETATION

Our findings confirm results from randomised trials in Sweden and the USA that screening for breast cancer lowers breast-cancer mortality. Similar results are reported by the UK geographical comparison, UK Trial of Early Detection of Breast Cancer. The results for younger women suggest benefit from introduction of screening before 50 years of age.