Effect of hormone replacement therapy on cancer detection by mammography

[Assessment of the dense breast within the French screening program: the role of ultrasonography]

Mammographic density is associated with an increased risk of breast cancer. It also reduces the reliability of screening mammography. Among the population targeted by the French screening program, about 28% have dense breasts and 3% have very dense breasts. Breast density varies with age, HRT and mammographic technique. Ultrasonography for dense but otherwise clinically and mammographically normal breasts allows detection of cancers not visible on mammograms. The French program protocol allows the evaluation of results from breast US in this context with regards to the number of detected cancers and false positive rate.

Influence of Patterns of Hormone Replacement Therapy Use and Mammographic Density on Breast Cancer Detection

BACKGROUND

There is evidence that factors such as current hormone replacement therapy (HRT) use and mammographic density may each lower the sensitivity of mammography and are associated with a greater risk of developing an interval cancer. This study explores this relationship further by examining the influence of patterns of HRT use and the percentage of mammographic density on the detection of breast cancer by classification of interval cancer.

METHODS

This study uses a case-case design nested within a cohort of women screened by the Ontario Breast Screening Program between 1994 and 2002. Interval cancers, both those missed at screening but seen on retrospective review (n = 87) or true intervals without visible tumor signs at screening (n = 288) were matched to 450 screen-detected cancers. The association between the percentage of mammographic density, measured by radiologists and a computer-assisted method, and HRT use, ascertained from a mailed questionnaire, and the risk of being diagnosed with an interval cancer was estimated using conditional logistic regression.

RESULTS

A monotonic gradient of increasing risk for interval cancers was found for each 25% increase in mammographic density [odds ratio (OR), 1.77; 95% confidence intervals (95% CI), 1.07-2.95 for missed intervals and OR, 2.16; 95% CI, 1.59-2.94 for true intervals]. After adjusting for mammographic density, a significantly increased risk for true-interval cancers remained for women taking estrogen alone (OR, 1.75; 95% CI, 1.11-2.83) as well as for missed- (OR, 2.84; 95% CI, 1.32-6.13) and true-interval cancers (OR, 1.79; 95% CI, 1.10-2.90) for women taking combined HRT.

CONCLUSIONS

Information on mammographic density and HRT use should routinely be collected at the time of screening. Women at risk should be made aware of the lower sensitivity of mammography and offered alternative procedures for screening.

The effect of low dose hormone therapy on mammographic breast density

OBJECTIVES

To evaluate the effect of two standard and one low dose continuous hormone therapy regimens on mammography.

METHODS

One hundred and thirty-two non-hysterectomized postmenopausal women were randomly allocated either to conjugated equine estrogens 0.625 mg plus medroxyprogesterone acetate 5 mg (CEE/MPA, n=38), 17beta-estradiol 2 mg plus norethisterone acetate 1 mg (E2/NETA, n=44) or 17beta-estradiol 1 mg plus norethisterone acetate 0.5 mg (low E2/NETA, n=50). Treatment was continuous and the study period lasted 12 months. Main outcome measures were the changes according to Wolfe classification between baseline and 12-month mammograms.

RESULTS

Five (13.2%) women in the CEE/MPA group showed an increase in breast density. Fourteen (31.8%) women on E2/NETA and 6 (12.2%) on low E2/NETA treatment revealed an increase in breast density. No woman exhibited an involution of fibroglandular tissue.

CONCLUSIONS

Different hormone therapy regimens have a variable impact on breast density probably depending on the steroid used. Low dose hormone therapy associates with significantly lesser increase in breast density.

Postmenopausal hormone therapy and mammographic breast density

OBJECTIVE

The aim of this study was to evaluate the effects of different types of hormone replacement therapy (HRT) on mammographic density.

MATERIALS AND METHODS

In a prospective 1-year study, 103 postmenopausal women were randomized to receive tibolone 2.5 mg/die, continuous conjugated equine estrogens 0.625 mg/die plus medroxyprogesterone acetate (MPA) 5mg/die or placebo. Mammograms were performed at baseline and after 12 months of treatment. Mammographic density was quantified according to the Wolfe classification.

RESULTS

After 12 months of HRT 16 of the 35 patients (45.1%) receiving continuous combined hormonal therapy showed an increase of breast density change in the Wolfe classification. After treatment with tibolone, an up grading in breast density, according to Wolfe's classification, was found in 2 of the 43 patients (2.3%). No changes were recorded in the 25 patients of the control group. The difference between the group treated with continuous combined hormonal therapy and the control group was highly significant (p<0.001). The difference in breast density between patients in treatment with tibolone and the control group was not statistically significant (p=0.34).

DISCUSSION

Continuous combination HRT may be more commonly associated with an increase of mammography density than tibolone treatment.

Use of hormone therapy and risk of breast cancer detected at screening and between mammographic screens

Postmenopausal hormone therapy (HT) is associated with increased risk of breast cancer, but in women undergoing breast cancer screening it is not clear whether use of HT is associated with increased risk of breast cancer detected at screening or between screens (interval cancer). Further, it is unclear whether the use of the HTs that have been common in Scandinavia is associated with higher risk of breast cancer than the HTs used in other countries. Our study was based on data from 296,651 women aged 50-69 years, who participated in the Norwegian Breast Cancer Screening Program during 1995-2004. After a mean enrollment time of 3.8 years, 1,512 women were diagnosed with invasive screen detected breast cancer, and 814 with invasive interval breast cancer. Cox regression models were used to estimate hazard ratios (HRs) of breast cancer associated with HT use, after adjusting for confounders. Ever users of HT had a 58% increased risk of breast cancer, compared to never users. The HRs associated with HT use were 1.45 (95% confidence interval (CI) = 1.29-1.63) for screen detected and 1.89 (95% CI = 1.61-2.23) for interval cancer. The difference between screen detected and interval cancer was statistically significant (p = 0.011). The HR of breast cancer increased with duration of HT use, but significantly more so for interval than for screen detected cancer (use of HT for 5 or more years compared to never use; HR = 2.91, 95% CI = 2.10-4.04 and HR = 1.94, 95% CI = 1.51-2.50, respectively; p = 0.002). The population attributable fraction of breast cancer due to HT use was 19.8% overall. Ever users of HT tended to develop a cancer of lower grade. No other differences in histological tumor characteristics were observed between ever and never users of HT among screen detected or interval cancers. The estimated risks of either breast cancer overall with HT use are higher in Norway than reported in similar studies from the U.S. HT-use is a stronger risk factor for interval cancer than for screen detected cancer. The increased risk of interval cancer, which may partly be due to decreased sensitivity of mammograms in HT users, remains a challenge in breast cancer screening programs.

Hormone replacement therapy and false positive recall in the Million Women Study: patterns of use, hormonal constituents and consistency of effect

INTRODUCTION

Current and recent users of hormone replacement therapy (HRT) have an increased risk of being recalled to assessment at mammography without breast cancer being diagnosed ('false positive recall'), but there is limited information on the effects of different patterns of HRT use on this. The aim of this study is to investigate in detail the relationship between patterns of use of HRT and false positive recall.

METHODS

A total of 87,967 postmenopausal women aged 50 to 64 years attending routine breast cancer screening at 10 UK National Health Service Breast Screening Units from 1996 to 1998 joined the Million Women Study by completing a questionnaire before screening and were followed for their screening outcome.

RESULTS

Overall, 399 (0.5%) participants were diagnosed with breast cancer and 2,629 (3.0%) had false positive recall. Compared to never users of HRT, the adjusted relative risk (95% CI) of false positive recall was: 1.62 (1.43-1.83), 1.80 (1.62-2.01) and 0.76 (0.52-1.10) in current users of oestrogen-only HRT, oestrogen-progestagen HRT and tibolone, respectively (p (heterogeneity) < 0.0001); 1.65 (1.43-1.91), 1.49 (1.22-1.81) and 2.11 (1.45-3.07) for current HRT used orally, transdermally or via an implant, respectively (p (heterogeneity) = 0.2); and 1.84 (1.67-2.04) and 1.75 (1.49-2.06) for sequential and continuous oestrogen-progestagen HRT, respectively (p (heterogeneity) = 0.6). The relative risk of false positive recall among current users appeared to increase with increasing time since menopause, but did not vary significantly according to any other factors examined, including duration of use, hormonal constituents, dose, whether single- or two-view screening was used, or the woman's personal characteristics.

CONCLUSION

Current use of oestrogen-only and oestrogen-progestagen HRT, but not tibolone, increases the risk of false positive recall at screening.

Hormone replacement therapy, percent mammographic density, and sensitivity of mammography

OBJECTIVE

We examine to what extent the lower mammographic sensitivity found in hormone replacement therapy (HRT) users can be explained by any association of HRT use with higher mammographic density and more difficult to detect cancers.

METHODS

We used logistic regression to estimate the odds of a false-negative screen (a breast cancer diagnosed in the 24 months after a negative screening examination) for HRT users and to estimate, and adjust for, mammographic density (measured on a continuous scale, blinded, using a reliable, computer-assisted method), tumor characteristics (size, grade, and morphology), and potential confounders (age, symptom status, family history, and prior screening) among women ages > or =55 years who attended BreastScreen Victoria for first round screening mammography in 1994 and 1995 (1,086 breast cancers) and for subsequent round screening (471 breast cancers) in 1995 and 1996.

RESULTS

After adjusting for confounders, HRT users were more likely to have a false-negative screen [first round: odds ratio (OR), 1.99; 95% confidence interval (95% CI), 1.4-2.9; subsequent round: OR, 2.29; 95% CI, 1.4-3.8]. This effect was modestly attenuated by adjusting for mammographic density (first round: OR, 1.54; 95% CI, 1.0-2.3; subsequent round: OR, 1.97; 95% CI, 1.2-3.3). Adjusting for tumor characteristics resulted in a modest increase in the odds of a false negative at first round but had no effect at subsequent round.

CONCLUSIONS

Mammographic density only partly explains the effect of HRT on sensitivity. Further research needs to clarify whether hyperemic breast tissue changes affect cancer detectability in HRT users as well as the possibility that the quality of mammography may be poor in some HRT users.

The relationship between mammographic density and duration of hormone therapy: effects of estrogen and estrogen–progestin

BACKGROUND

The purpose of this study was to examine the effects of duration of hormone therapy (HT) and treatment regimens on mammographic density.

METHODS

A retrospective study was carried out of of 467 post-menopausal women who received estrogen or estrogen-progestin and had regular mammographic density determination by the Breast Imaging Reporting and Data System between 1994 and 2001.

RESULTS

The fraction of women using HT who had an increase in mammographic density became more important over time. Further analysis of the effects of regimens after 4 years of HT shows that the increase in mean density was much greater in women receiving combined HT than in those receiving estrogen alone. The incidence of increased mammographic density showed significantly progressive increases over the duration of combined HT from 7.5 to 22.4%.

CONCLUSIONS

Although most women using HT maintained breast density at pre-treatment levels, there is a note of caution for women using long-term HT, especially those using combined estrogen-progestin.

Thérapeutiques hormonales de la ménopause : impact sur la densité mammographique

Whether qualitative-classified or quantitative-measured, mammographic density, which changes according to physiological variations, is nowadays commonly recognized as a factor increasing the relative risk of breast cancer. The present review aims at clarifying the impact of menopausal hormonal therapies on mammographic density. Neither Tibolone nor Raloxifene seem to have any negative impact on mammographic density. In some instances, oestrogens-progestin hormonal replacement therapies may increase mammographic density and thus reduce sensitivity and specificity of screening mammograms. Shorter intervals between mammographies combined with additional physical examination and breast ultrasonography appear to be the best way to reduce interval cancers.

Hormones and mammographic breast density

Mammographic density reveals information about the hormonal environment along with the heritability in which breast cancer develops. This is made possible by the widespread use of population screening by mammography. Increasingly this is an important observation not just for population studies, which reveal disease determinants, but also for the individual. Density reveals the effect of the intrinsic hormonal environment and its background genetics, and also the effect of pharmaceuticals--agents used for disease control and prevention and hormone replacement therapy (HRT) used for well-being around the menopause. Increasingly this focus on the individual will need methods of measurement of density that can be monitored with greater accuracy than the widely used BI-RADS 4 categories. For this purpose studies are under way to measure volume of dense tissue as a continuous variable. In due course, measurement of density will be used as a biomarker of risk, employed in risk models and to monitor interventions. Before this can happen more knowledge will be needed of the change occurring naturally through the menopause and the differences between individuals. This will need specific study backed up with detailed information about the patient on large numbers of women and their mammograms. Currently the widespread use of HRT has increased the prevalence of the dense patterns and potentially may adversely affect the effectiveness of mammographic screening programmes. There is a large literature recording this from which we see that combined continuous preparations of oestrogen progestin are more likely to cause increased density than oestrogen alone or tibolone. Breast density, measured more accurately, has the potential to be an important adjunct to risk estimation and to monitor interventions for breast cancer prevention with pharmaceuticals (such as SERMS) and by change in lifestyle behaviours.

Hormone replacement therapy and mammographic screening

The benefits of hormone replacement therapy (HRT) with oestrogen are well known and have led to widespread usage of HRT in post-menopausal women. There is an increased relative risk of breast cancer with prolonged HRT use of 1.7 at worst and this does not warrant more frequent screening. HRT itself makes mammographic screening less effective by adversely affecting both the sensitivity and specificity of screening mammography.A number of large studies have shown a reduction in the sensitivity of screening mammography of between 7% and 21% in current HRT users. This reduction in sensitivity is seen only in women over the age of 50 and is more marked when using single view mammography. The reduction in sensitivity is largely confined to those women who have a dense mammographic background pattern while on HRT. HRT use is also associated with a reduction in specificity of between 12% and almost 50%. This reduction in specificity is mainly found at incident screens. What can be done to minimize the adverse effects of HRT on mammographic screening? The imminent introduction of two views at all screens within the National Health Breast Screening Programme will be helpful. Short-term cessation of HRT use may deter attendance for screening by HRT users and is unproven. Combined oestrogen and progesterone preparations taken continuously appear to be particularly associated with adverse breast screening performance, while tibolone may have little effect on mammographic density. Manipulation of the type of HRT preparations used may allow the adverse effects of HRT on breast screening to be reduced.

Effects of different types of hormone replacement therapy on mammographic density

OBJECTIVES

to evaluate the effects of different types of hormone replacement therapy (HRT) on mammographic density in postmenopausal women.

METHODS

In a prospective 1-year study, 121 healthy postmenopausal women were allocated to one of the following five study groups: twenty-six women were treated with continuous transdermal 17beta-estradiol 50 mcg/die plus acetate nomegestrolo 5 mg/die sequentially added for 12 days per month (Group A); 25 women were treated with continuous transdermal 17beta-estradiol 50 mcg/die plus acetate nomegestrolo 2.5 mg/die added every day (Group B); 23 women were treated with continuous transdermal 17beta-estradiol 50 mcg/die (Group C); 24 women were treated with tibolone 2.5 mg/die (Group D); and 23 women not receiving any medication represented the control group (Group E). At the time of recruitment and after 12 months a two-view mammography was performed to evaluate mammographic density according to a quantitative method: type 1 (less than 25% of mammary gland covered by dense tissue), type 2 (from 25 to 75% of total glandular area covered by dense tissue), type 3 (more than 75% of mammary parenchyma covered by dense tissue).

RESULTS

After 12 months of HRT, seven out of 20 patients (35%) in group A, nine of 21 patients (42.85%) in group B, four out of 19 patients (21%) in group C and two of 20 patients (10%) in group D, showed an increase in mammographic density. No variation of density was observed at the second mammographic test in the control group. The mammographic density increase which occurred in groups A, B and C was statistically significant (P<0.05) when compared with group E; no statistically significant difference (P=0.49) was found in mammographic density increase between group D and group E. When the different treatment types were compared each other, a statistically significant difference (P=0.04) was found only between the mammographic density increase occurring in groups B and D.

CONCLUSIONS

HRT may cause an increase of mammographic density. The frequency of the density increase is related to the type of HRT and a replacement therapy including a progestin, especially in continuous combination with estrogen, leads to more evident mammographic changes. Tibolone does not significantly affect mammographic density.

Effects of a short-term suspension of hormone replacement therapy on mammographic density

OBJECTIVE

To evaluate the effects of hormone replacement therapy (HRT) and of a short-term suspension of HRT on mammographic density.

DESIGN

Prospective clinical study.

SETTING

Outpatient menopausal clinic of the Second University of Naples.

PATIENT(S)

Ninety-seven healthy postmenopausal women.

INTERVENTION(S)

Thirty-nine menopausal women with intact uterus (group A) were treated with continuous transdermal E(2) plus acetate nomegestrolo sequentially added, 37 women in surgical menopause (group B) were treated with transdermal E(2) continuously administered, and 21 menopausal women did not receive any medication (group C). At the entry and after 12 months, a mammography was performed without suspension of HRT (group A1: 19 women; group B1: 19 women) or after a short-term suspension (group A2: 20 women; group B2: 18 women).

MAIN OUTCOME MEASURE(S)

Mammographic density evaluated according to a quantitative method.

RESULT(S)

At the second mammography, seven patients in group A1, four patients in group B1, and one patient in both groups A2 and B2 showed an increase in mammographic density, whereas no mammographic density increase was observed in patients in group C. A statistically significant difference in the mammographic density increase was found between group A1 and group A2; no difference was found between group B1 and B2.

CONCLUSION(S)

Suspension of HRT for about 3 weeks may reverse mammographic density increase associated with its use.

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.

Hormone replacement therapy and accuracy of mammographic screening

BACKGROUND

Hormone replacement therapy (HRT) is commonly used and may affect the accuracy of mammographic screening.

METHODS

We examined the sensitivity, specificity, and small-cancer detection rate according to HRT use in 103,770 women in Victoria, Australia, who attended first-round screening in 1994 and who did not have a personal history of breast cancer or a breast lump or a bloodstained or watery nipple discharge at the time of screening. BreastScreen Victoria provides mammography to women aged 40 years and older every 2 years. Unconditional logistic modelling was used to adjust for age, family history, and symptom status.

FINDINGS

The sensitivity of screening mammography for a 2-year screening interval was lower in HRT users (64.8% [95% CI 58-72]) than non-users (77.3% [74-81]). In the target group (50-69 years), the sensitivity was 64.3% (57-72) in HRT users and 79.8% (76-84) in non-users. Among women who were diagnosed with cancer during the 2-year screening interval, HRT users were more likely to have a false negative result than non-users (odds ratio 1.60 [1.04-2.21]) after adjusting for potential confounding factors. Specificity was 0.6% lower in HRT users compared with non-users. Among women who did not have cancer diagnosed in the interval, HRT users were more likely to have a false positive result (adjusted odds ratio 1.12 [1.05-1.19]).

INTERPRETATION

We show that HRT use reduces the sensitivity of mammographic screening. In countries where HRT use is widespread, the reduction in sensitivity with HRT use may undermine the capacity of population-based mammographic-screening programmes to realise their potential mortality benefit.

Mammographic density changes in perimenopausal and postmenopausal women: is effect of hormone replacement therapy predictable?

BACKGROUND

Mammographic density adversely affects diagnostic accuracy and may be a risk factor for breast cancer. Mammographic density is affected by hormone replacement therapy (HRT).

OBJECTIVE

To assess mammographic density in postmenopausal women with and without HRT.

METHOD

Part I. Mammographic density was determined in 1232 postmenopausal women attending a breast screening clinic. Density was compared between HRT users and nonusers in three age groups. When available, previous mammograms were assessed for interval density change. Part II. Density change in 162 women during transition from premenopause to postmenopause was recorded. HRT effect was assessed.

RESULTS

Part I. There was no density difference between postmenopausal HRT-users and nonusers younger than age 55. Thereafter, the density was significantly less in nonusers. In the majority of HRT-users the density remained at pretreatment levels but density increased in 8% of women after HRT was started. Part II. Of 117 HRT nonusers followed over menopause 38% had a density decrease before age 55. Of those started on HRT, 80% had no density change, 18% decreased density and 2% increased density.

CONCLUSIONS

The density decreases significantly after age 55 with the greatest change occurring between age 55 and 64. This decrease does not occur in the majority of HRT-users. Usually HRT maintains the density present at the time HRT is started. Density decreases after HRT is started in some women suggesting refractoriness to hormones. In fewer than 8% of women density increases commensurate with HRT. Any adverse effect of HRT may depend on the receptivity of the epithelial elements which, in turn, may be reflected by the mammographic density at the time HRT is started.

The effect of hormone replacement therapy on the sensitivity of screening mammograms

AIM

The use of hormone replacement therapy (HRT) can lead to various changes on the mammogram including increasing density. The object of this study was to assess the effect of HRT on the sensitivity of mammographic screening by comparing HRT usage in women with screen detected breast cancers with HRT usage at the time of screening in women presenting with interval cancers.

METHODS

The West of Scotland Breast Screening Programme serves a population of 180,000 women aged 50-64 years old. Between May 1988 and December 1995, 1461 breast cancers were detected by the screening programme in 1441 women over the age of 50 and 372 interval breast cancers presented in 371 women screened between these dates. HRT usage at the time of screening was noted with details of age, postcode and the time between screening and diagnosis in the case of the women with interval cancers.

RESULTS

Among women under 65 years old, screened between 1988-1993, 12.3% of women with screen detected cancers and 22.2% of women with interval cancers were using HRT (P<0.001). Further analysis demonstrates that interval cancer rate is related to age as well as HRT use. After adjusting for age at time of screening, deprivation category and year of screening, the relative risk of a woman using HRT having an interval cancer compared with that of a woman not using HRT is 1.79. The relative risk of an interval cancer arising in the first year after screening for a woman on HRT is 2.27.

CONCLUSION

The use of HRT and being of an age below 60 years are both risk factors for presenting with an interval cancer after mammographic breast screening. Our results indicate that the use of HRT leads to a decrease in the sensitivity of mammographic screening.