Influence of annual mammography from age 40 on breast cancer pathology

Misinformation and Facts about Breast Cancer Screening

Quality medical practice is based on science and evidence. For over a half-century, the efficacy of breast cancer screening has been challenged, particularly for women aged 40–49. As each false claim has been raised, it has been addressed and refuted based on science and evidence. Nevertheless, misinformation continues to be promoted, resulting in confusion for women and their physicians. Early detection has been proven to save lives for women aged 40–74 in randomized controlled trials of mammography screening. Observational studies, failure analyses, and incidence of death studies have provided evidence that there is a major benefit when screening is introduced to the general population. In large part due to screening, there has been an over 40% decline in deaths from breast cancer since 1990. Nevertheless, misinformation about screening continues to be promoted, adding to the confusion. Despite claims to the contrary, a careful reading of the guidelines issued by major groups such as the U.S. Preventive Services Task Force and the American College of Physicians shows that they all agree that most lives are saved by screening starting at the age of 40. There is no scientific support for using the age of 50 as a threshold for screening. All women should be provided with the facts and not false information about breast cancer screening so that they can make “informed decisions” for themselves about whether to participate.

Annual mammographic screening to reduce breast cancer mortality in women from age 40 years: long-term follow-up of the UK Age RCT

BACKGROUND

There remains disagreement on the long-term effect of mammographic screening in women aged 40-49 years.

OBJECTIVES

The long-term follow-up of a randomised controlled trial that offered annual mammography to women aged 40-49 years. The estimation of the effect of these mammograms on breast cancer and other-cause mortality, and the effect on incidence, with implications for overdiagnosis.

DESIGN

An individually randomised controlled trial comparing offering annual mammography with offering usual care in those aged 40-48 years, and thus evaluating the effect of annual screening entirely taking place before the age of 50 years. There was follow-up for an average of 23 years for breast cancer incidence, breast cancer death and death from other causes. We analysed the mortality and incidence data by Poisson regression and estimated overdiagnosis formally using Markov process models.

SETTING

Twenty-three screening units in England, Wales and Scotland within the NHS Breast Screening Programme.

PARTICIPANTS

Women aged 39-41 years were recruited between 1990 and 1997. After exclusions, a total of 53,883 women were randomised to undergo screening (the intervention group) and 106,953 women were randomised to have usual care (the control group).

INTERVENTIONS

The intervention group was invited to an annual breast screen with film mammography, two view at first screen and single view thereafter, up to and including the calendar year of their 48th birthday. The control group received no intervention. Both groups were invited to the National Programme from the age of 50 years, when screening is offered to all women in the UK.

MAIN OUTCOME MEASURES

The main outcome measures were mortality from breast cancers diagnosed during the intervention phase of the trial (i.e. before the first National Programme screen at 50 years), mortality from all breast cancers diagnosed after randomisation, all-cause mortality, mortality from causes other than breast cancer, and the incidence of breast cancer.

RESULTS

There was a statistically significant 25% reduction in mortality from breast cancers diagnosed during the intervention phase at 10 years' follow-up (relative rate 0.75, 95% confidence interval 0.58 to 0.97; p = 0.03). No reduction was observed thereafter (relative rate 0.98, 95% confidence interval 0.79 to 1.22). Overall, there was a statistically non-significant 12% reduction (relative rate 0.88, 95% confidence interval 0.74 to 1.03; p = 0.1). The absolute benefit remained approximately constant over time, at one death prevented per 1000 women screened. There was no effect of intervention on other-cause mortality (relative rate 1.02, 95% confidence interval 0.97 to 1.07; p = 0.4). The intervention group had a higher incidence of breast cancer than the control group during the intervention phase of the trial, but incidence equalised immediately on the first National Programme screen at the age of 50-52 years.

LIMITATIONS

There was 31% average non-compliance with screening and three centres had to cease screening for resource and capacity reasons.

CONCLUSIONS

Annual mammographic screening at the age of 40-49 years resulted in a relative reduction in mortality, which was attenuated after 10 years. It is likely that digital mammography with two views at all screens, as practised now, could improve this further. There was no evidence of overdiagnosis in addition to that which already results from the National Programme carried out at later ages.

FUTURE WORK

There is a need for research on the effects of modern mammographic protocols and additional imaging in this age group.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN24647151.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 55. See the NIHR Journals Library website for further project information. Other funding in the past has been received from the Medical Research Council, Cancer Research UK, the Department of Health and Social Care, the US National Cancer Institute and the American Cancer Society.

Effect of Mammography Screening on Mortality by Histological Grade

Background: It has been asserted that mammography screening preferentially benefits those with less aggressive cancers, with lesser or no impact on more rapidly progressing and therefore more life-threatening tumors.Methods: We utilized data from the Swedish Two-County Trial, which randomized 77,080 women ages 40 to 74 to invitation to screening and 55,985 for usual care. We tabulated cancers by histologic grade and then compared mortality from cancers specific to histologic grade between the invited and control group using Poisson regression, with specific interest in the effect on mortality from grade 3 cancers. We used incidence-based mortality from tumors diagnosed within the screening phase of the trial. Finally, we cross-tabulated grade with tumor size and node status, to assess downstaging within tumor grades.Results: There was a major reduction in mortality from grade 3 tumors (RR = 0.65; 95% CI, 0.53-0.80; P < 0.001), and more deaths prevented from grade 3 tumors (n = 95) than grade 1 and 2 tumors combined (n = 48) in the invited group. The proportions of tumors ≥15 mm or larger and node-positive tumors were substantially reduced in the grade 3 tumors in the invited group.Conclusions: The combination of prevention of tumors progressing to grade 3 and detection at smaller sizes and lesser rates of lymph node metastases within grade 3 tumors results in a substantial number of deaths from grade 3 cancers being prevented by invitation to mammographic screening.Impact: Mammography screening prevents deaths from aggressive cancers. Cancer Epidemiol Biomarkers Prev; 27(2); 154-7. ©2017 AACR.

Observed and Predicted Risk of Breast Cancer Death in Randomized Trials on Breast Cancer Screening

BACKGROUND

The role of breast screening in breast cancer mortality declines is debated. Screening impacts cancer mortality through decreasing the number of advanced cancers with poor diagnosis, while cancer treatment works through decreasing the case-fatality rate. Hence, reductions in cancer death rates thanks to screening should directly reflect reductions in advanced cancer rates. We verified whether in breast screening trials, the observed reductions in the risk of breast cancer death could be predicted from reductions of advanced breast cancer rates.

PATIENTS AND METHODS

The Greater New York Health Insurance Plan trial (HIP) is the only breast screening trial that reported stage-specific cancer fatality for the screening and for the control group separately. The Swedish Two-County trial (TCT)) reported size-specific fatalities for cancer patients in both screening and control groups. We computed predicted numbers of breast cancer deaths, from which we calculated predicted relative risks (RR) and (95% confidence intervals). The Age trial in England performed its own calculations of predicted relative risk.

RESULTS

The observed and predicted RR of breast cancer death were 0.72 (0.56-0.94) and 0.98 (0.77-1.24) in the HIP trial, and 0.79 (0.78-1.01) and 0.90 (0.80-1.01) in the Age trial. In the TCT, the observed RR was 0.73 (0.62-0.87), while the predicted RR was 0.89 (0.75-1.05) if overdiagnosis was assumed to be negligible and 0.83 (0.70-0.97) if extra cancers were excluded.

CONCLUSIONS

In breast screening trials, factors other than screening have contributed to reductions in the risk of breast cancer death most probably by reducing the fatality of advanced cancers in screening groups. These factors were the better management of breast cancer patients and the underreporting of breast cancer as the underlying cause of death. Breast screening trials should publish stage-specific fatalities observed in each group.

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.

Clinicopathological differences between interval and screen-detected breast cancers diagnosed within a screening programme in Northern Portugal

Objective

To evaluate clinicopathological differences between screen-detected (SD) and interval (IC) breast cancers diagnosed in women enrolled in an organized breast screening programme in 2000--2007.

Setting

Breast Cancer Screening Programme of the north region of Portugal.

Methods

Using data from the screening programme and from the population-based North Region Cancer Registry, SD and IC were identified. Information on screening history, age, date of diagnosis, tumour size, histological type and grade, lymph node status, tumour stage, biomarkers, and treatment was obtained from the cancer registry and from clinical and pathological reports. Association between mode of detection and these clinicopathological characteristics was estimated by unconditional logistic regression.

Results

A total of 442 SD and 112 IC were identified in women aged 50--69. Compared with SD, IC were diagnosed in younger women (60.0 ± 5.8 years and 58.4 ± 6.0 years, respectively), were larger (tumour size >20 mm: 60.2% versus 25.1%), lobular (6.3% versus 16.1%), with a higher differentiation grade (grade 3: 17.7% versus 38.9%), had more lymph node metastases, more advanced stage, and oestrogen receptor (ER) negative (12.9% versus 29.0%) and progesterone negative, and HER2 positive. After multivariable analysis, compared with SD, IC were more likely to be larger than 20 mm, lobular, of grade 3 and negative for ER.

Conclusion

Our results are consistent with other studies. IC’s have a more aggressive biology than SDs. Our findings did not show any unexpected pattern requiring changes to our screening procedures, but continuous identification and characterization of IC is advisable.

Factors that influence mammography use and breast cancer detection among Mexican-American and African-American women

OBJECTIVE

This study examined factors that influence mammography use and breast cancer detection, including education, health insurance, and acculturation, among Mexican-American (MA) and African-American (AA) women.

METHODS

The study included 670 breast cancer cases (388 MAs and 282 AAs), aged 40-86 years at diagnosis. Data on mammography use, detection, and delay in seeking care were collected via questionnaires and medical records. Using a language-based bidimensional acculturation measure, MAs were classified as English-dominant (n = 67), bilingual (n = 173), and Spanish-dominant (n = 148). Mammography prior to diagnosis was assessed by racial/ethnic acculturation subgroup using logistic regression.

RESULTS

In age-adjusted models, mammography use was non-significantly lower among English-dominant (OR = 0.84; 95% CI: 0.45-1.59) and bilingual (OR = 0.86; 95% CI: 0.55-1.35) MAs and significantly lower among Spanish-dominant MAs (OR = 0.53; 95% CI: 0.34-0.83) than among AA women. After adjustment for education or insurance, there was no difference in mammography use by race/ethnicity and acculturation subgroup. Despite high self-reported mammography use (75%), a large proportion of cases reported self-detection (59%) and delay in seeking care >90 days (17%).

CONCLUSIONS

These findings favor promoting culturally appropriate messaging about the benefits and limitations of mammography, education about breast awareness, and prompt reporting of findings to a health professional.

Pathological and mammographic prognostic factors for screen detected cancers in a multi-centre randomised, controlled trial of mammographic screening in women from age 40 to 48 years

AIM

To assess pathological and radiological prognostic factors for cancers detected by screening within a multi-centre RCT trial of mammographic screening of younger women.

METHOD

The survival of 232 women with screen detected invasive cancer was ascertained. Data on invasive cancer size, histological grade, nodal status, vascular invasion, mammographic spiculation, comedo calcification and mammographic background were assessed. Kaplan-Meier and Cox proportional hazards methods were used to examine survival.

RESULTS

Univariate analysis indicated that women with cancers with the following features had poorer survival; ≥ 30 mm, histologically grade 3, heavily node positive (4 or more positive nodes), vascular invasion positive and displaying mammographic comedo calcification. In a multivariate model survival remained poorer in women with four or more nodes positive (HR 8.36, 95% CI 2.31, 30.17) and in those with comedo calcification (HR 3.00,95% CI 1.13, 7.99).

CONCLUSION

Nodal status and the presence of mammographic comedo calcification have independent prognostic significance in young women with screen detected cancer.

Effectiveness of mammography screening in reducing breast cancer mortality in women aged 39-49 years: a meta-analysis

BACKGROUND

Mammography screening of women >50 years of age significantly reduces breast cancer mortality in randomized controlled trials (RCTs). We sought to evaluate the effectiveness of mammography screening in women aged 39-49 years in reducing breast cancer mortality and to discuss previously published meta-analyses.

METHODS

PubMed/MEDLINE, OVID, COCHRANE, and Educational Resources Information Center (ERIC) databases were searched, and extracted references were reviewed. Dissertation abstracts and clinical trials databases available online were assessed to identify unpublished works. All assessments were independently done by two reviewers. All trials included were RCTs, published in English, included data on women aged 39-49, and reported relative risk (RR)/odds ratio (OR) or frequency data.

RESULTS

Nine studies were identified: the Kopparberg, Ostergotland (The Two-County study), Health Insurance Plan (HIP), Canada, Stockholm, Gothenburg, Edinburgh, Age, and Malmo trials. The individual trials were quality assessed, and the data were extracted using predefined forms. Using the DerSimonian and Laird random effects model, the results from the seven RCTs with the highest quality score were combined, and a significant pooled RR estimate of 0.83 (95% confidence interval [CI] 0.72-0.97) was calculated. Post hoc sensitivity analyses excluding studies with randomization before 1980 caused a loss of statistical significance (RR 0.87, 95% CI: 0.56, 1.13).

CONCLUSIONS

Mammography screenings are effective and generate a 17% reduction in breast cancer mortality in women 39-49 years of age. The quality of the trials varies, and providers should inform women in this age group about the positive and negative aspects of mammography screenings.

Prognosis and pathology of screen-detected carcinomas: how different are they?

BACKGROUND

It has been observed that screen-detected breast cancers have a better prognosis than symptomatic tumors, even after taking pathological tumor attributes into account. This has led to the hypothesis that screen-detected tumors are substantially biologically different from symptomatic cancers.

METHODS

The pathology and survival by detection mode was investigated in 21,382 breast cancers diagnosed in women aged 50-64 years in the West Midlands, United Kingdom, between 1988 and 2004. Tumor attributes were compared using chi-square tests and logistic regression. Survival was analyzed using Cox regression.

RESULTS

Screen-detected cancers were significantly smaller, better differentiated, and less likely to be node-positive than symptomatic cancers (P < .001 in all cases). In addition, a higher proportion of screen-detected cancers were hormone receptor-positive, and a higher proportion were tubular carcinomas (P < .001). Survival was substantially better in screen-detected breast cancers (86% at 10 yearsvs 70% for interval cancers and 58% for cancers in women unexposed to screening). Adjustment for age, tumor size, nodal status, grade, histological type, and year of diagnosis accounted for 64% (interval cancers) and 68% (unexposed women) of these survival differences, respectively. Overall survival improved with time. Approximately half of this improvement was due to the increase over time in the proportion of tumors that were screen-detected.

CONCLUSION

The majority of the difference in prognosis between screen-detected and symptomatic breast cancers is due to the differences in routinely measured pathological features (size, type, grade, and nodal status), leaving a small residual difference to be accounted for by other biological differences.