The predictive value of positive test results in screening for breast cancer by mammography in the Nijmegen programme

Breast Cancer Screening in Women over Age 50

Breast cancer screening with mammography is strongly advocated by some and rejected by others. Discussions in the medical literature focus on the beneficial and unfavourable effects of breast cancer screening. Among the latter are the suggested excess mortality rate of screen-detected breast cancer patients, the high number of unnecessary biopsies, the possibility of overdiagnosis and subsequent unnecessary treatment, and the occurrence of interval breast cancer cases. It is concluded that screening can to a certain extent prevent women from dying of breast cancer but some negative effects are unavoidable. However, adequate training of the screening team can minimize the number of unnecessary biopsies and the occurrence of interval cancers. Research is needed to evaluate the natural course of so-called ‘minimal’ lesions, and to optimize screening tests. The search for new (imaging) techniques is needed to detect lobular cancers in dense breasts.

Mammography screening in African American women: evaluating the research

BACKGROUND

Notwithstanding some controversy regarding the benefits of screening mammography, it is generally assumed that the effects are the same for women of all race/ethnic groups. Yet evidence for its efficacy from clinical trial studies comes primarily from the study of white women. It is likely that mammography is equally efficacious in white and African American women when applied under relatively optimal clinical trial conditions, but in actual practice African Americans may not be receiving equal benefit, as reflected in their later stage at diagnosis and greater mortality.

METHODS

Initial searches of Medline using search terms related to screening mammography, race, and other selected topics were supplemented with national data that are routinely published for cancer surveillance. Factors that potentially compromise the benefits of mammography as it is delivered in the current health care system to African American women were examined.

RESULTS

While there have been significant improvements in mammography screening utilization, observational data suggest that African American women may still not be receiving the full benefit. Potential explanatory factors include low use of repeat screening, inadequate followup for abnormal exams, higher prevalence of obesity and, possibly, breast density, and other biologic factors that contribute to younger age at diagnosis.

CONCLUSIONS

Further study of biologic factors that may contribute to limited mammography efficacy and poorer breast cancer outcomes in African American women is needed. In addition, strategies to increase repeat mammography screening and to ensure that women obtain needed followup of abnormal mammograms may increase early detection and improve survival among African Americans. Notwithstanding earlier age at diagnosis for African American women, mammography screening before age 40 years is not recommended, but screening of women aged 40-49 years is particularly critical.

Mammographic breast density and risk of breast cancer: masking bias or causality?

Masking bias is hypothesized to explain associations between breast density and breast cancer risk. Tumours in dense breasts may be concealed at the initial examination, but manifest themselves in later years, suggesting an increase in breast cancer incidence. We studied the association between breast density and breast cancer risk in 0, 1-2, 3-4 and 5-6 year periods between initial examination and diagnosis. We studied 359 cases and 922 referents, identified in a breast cancer screening programme in Nijmegen, The Netherlands. Breast density was assessed at the initial examination and classified as 'dense' (if > 25% of the breast was composed of density) or 'lucent' (< or = 25% density). In women examined with mid-1970s film screen mammography, we found that at time 0 the odds ratio (OR) for women with dense breasts compared to those with lucent breasts was 1.4 (95% confidence interval (CI): 0.7-6.2). After a 3-4 year period the risk was increased to 3.3 (95% CI: 1.5-7.1). Then, the risk decreased again (OR: 1.2, 95% CI: 0.6-2.7). This rise and decline in risk are in accordance with the masking hypothesis. The observation, however, that the risk at time 0 does not appear to be lower for women with dense breasts than for those with lucent breasts, seems to be inconsistent with the masking hypothesis and may be indicative of causality. The same analysis were performed in women whose initial screening examination was done with current high-quality mammography. Due to the small size of this study group no firm conclusions could be drawn, but it seems as if masking bias could still play a role with high-quality mammography.

Effect of mammographic breast density on breast cancer screening performance: a study in Nijmegen, The Netherlands

STUDY OBJECTIVE

To study the implications of breast density on mammographic screening performance.

DESIGN

Screening outcomes of women with dense breast patterns were compared with those of women with lucent breast patterns (dense > 25% densities, lucent < or = 25% densities); the women were screened in different periods (before/after improvement of the mammographic technique in 1982).

SETTING

Nijmegen, the Netherlands, 1977-1994.

PARTICIPANTS

Between 1977 and 1994, 73,525 repeat screenings were performed in 19,152 participants (aged 50-69 years) in the Nijmegen breast cancer screening programme (repeat screenings were defined as mammographic examinations that were preceded by an examination in the previous screening round). Participants were screened biennially with mammography. There were 258 screen detected and 145 interval cancers.

MAIN RESULTS

Before 1982 (rounds 2-4) the predictive value of a positive screening test (PV+) was lower in women with dense breasts than in those with lucent breasts (dense 29% v lucent 52%, p = 0.003). Also, the ratio of screen detected cancers to the total number of screen detected plus interval cancers (as a proxy for sensitivity) was lower in this group (based on a one year interval: dense 63% v lucent 92%, p = 0.001 and based on a two year interval: dense 41% v lucent 68%, p = 0.002). Moreover, the survival rate was less favourable for those with dense breasts (p = 0.07). In rounds 5-10, there were no important differences with respect to PV+ (dense 66% v lucent 62%, p = 0.57) or survival (p = 0.48). Moreover, sensitivity based on a one year interval was nearly as high in women with dense breasts as in those with lucent breasts (85% v 86%, p = 0.75). However, based on a two year interval sensitivity was lower (dense 59% v lucent 72%, p = 0.04).

CONCLUSIONS

In the early screening years (rounds 2-4) high breast density had an unfavourable effect on screening performance. Nowadays, the situation has improved with respect to PV+, survival and detecting tumours in dense breasts with a lead time of up to one year, but little improvement has occurred in the detection of tumours with a lead time greater than one year.

The effectiveness of mailed patient reminders on mammography screening: a meta-analysis

BACKGROUND

Researchers have tried to increase mammography screening rates by using patient-oriented reminders. This paper compares the effectiveness of mailed patient reminders at increasing mammography screening.

METHODS

Sixteen published articles met the inclusion criteria and were included in the meta-analysis. To assess the association between reminders and mammography screening, the Mantel-Haenszel odds ratio (OR) was calculated.

RESULTS

Among U.S. studies in which controls did not receive any type of reminder, women who received reminders were approximately 50% more likely to get a mammogram (OR 1.48; chi(2)MH(1) = 38.27, P < .001). In addition, tailored letters were found to be more effective than generic reminders (OR 1.87; chi(2)MH(1) = 4.70, P < .05). Combining cost and effectiveness data allowed for estimates of cost per woman screened, which ranged from $0.96 to $5.88.

CONCLUSIONS

Patient reminders are effective at increasing mammography screening. More research is needed to assess (1) the cost-effectiveness of patient reminders and (2) their effectiveness across race, education, income, and type of insurance.

Breast cancer surveillance: ambulatory care focus in residency may influence practice patterns

Breast cancer causes significant morbidity and mortality in the United States. Early detection of malignant lesions may increase survival rates. Recommended surveillance techniques include breast self-examination, breast examination by a clinician, and mammography. However, results of research suggest that physicians adhere inconsistently to screening guidelines. Residency training has the potential to impact significantly on future practice patterns. This study evaluated the breast cancer screening patterns in women 50 years of age and older by internal medicine resident physicians in a traditional and a primary care residency program from 1988-1994. A retrospective chart review revealed that resident physicians in the primary care residency performed more breast cancer surveillance than residents in the traditional residency for the following techniques: instructions for breast self-examinations, 10.9% vs. 3.6% (P < 0.0007); breast examinations, 81.3% vs. 39.1% (P < 0.00001); mammographies, 93.8% vs. 37.3% (P < 0.00001). This study suggests that the frequency of breast cancer screening by resident physicians may improve with increased ambulatory care experience. Additional study is necessary to identify other factors that could influence preventive care practices.

Diagnostic outcome of repeated mammography screening

Mammographic screening for breast cancer within health service routines was evaluated for the years 1987-1992, with special focus on repeated screening during 1989-1992. The overall attendance rate by women aged 40 to 74 years was 82.8%. During 1989-1992 malignancy was found in 2.6/1000 screened women, giving a 87.4% positive predictive rate at surgery and 95.9% efficiency. Among women aged > or = 45 years, the positive predictive rate was > 94%. Fine-needle aspiration (FNA) biopsy showed invasive cancers in 84% and highly suspected cancer in another 15%; 60% of the lesions were nonpalpable. For first-time (prevalence) screening (1987-1988) the positive predictive rate was 86% and the malignancy yield 6.4/1000. In women aged 40-44 years there were few surgical referrals (1.6%), but the positive predictive rate at surgery was only 48.3%, indicating diagnostic difficulties in young women. The median size of all invasive cancers was 12 mm: 84% were classified as pT1, and 23% had lymph node involvement. Stage II disease was found in 27% of all malignancies. The use of FNA in the diagnostic workup for breast cancer screening is of crucial importance to the maintenance of high positive predictive rates at surgery. Moreover, regular analysis is important even when mammographic screening is incorporated into the routine work of health services.

Can mammography screening explain the race difference in stage at diagnosis of breast cancer?

BACKGROUND

A race difference in the stage at diagnosis of breast cancer is well established: African American women are less likely than white women to be diagnosed at a localized stage. The purpose of this study was to determine the extent to which the observed race (black/white) difference in stage at diagnosis of breast cancer could be accounted for by race differences in the mammography screening history.

METHODS

This was a population-based, retrospective study of 145 African American and 177 white women with newly diagnosed breast cancer in Connecticut, between January, 1987 and March, 1989. Cases were ascertained through active surveillance of 22 Connecticut hospitals.

RESULTS

Black women were diagnosed more commonly with later stage cancer (TNM stage > or = II) (age-adjusted odds ratio [OR] = 2.01, 95% confidence interval [CI] 1.24-3.24) than were white women. Blacks were also more likely than whites to report that they had not received a mammogram in the 3 years before development of symptoms or diagnosis (OR = 2.05, 95% CI 1.26-3.35); this association was not altered substantially with adjustment for socioeconomic status. In race-specific analyses, mammography was protective against later stage diagnosis in white women, but not in black women. With adjustment for mammography screening, the OR for the race-stage association was reduced only minimally, and race remained a significant predictor of stage at diagnosis.

CONCLUSIONS

In these population-based data, history of mammography screening was not an important explanatory variable in the race-stage association. Specifically, history of mammographic screening accounted for less than 10% of the observed black/white difference in stage at diagnosis of breast cancer.

Physicians' recommendations for mammography: do tailored messages make a difference?

OBJECTIVES

Message tailoring, based on individual needs and circumstances, is commonly used to enhance face-to-face patient counseling. Only recently has individual tailoring become feasible for printed messages. This study sought to determine whether printed tailored recommendations addressing women's specific screening and risk status and perceptions about breast cancer and mammography are more effective than standardized printed recommendations.

METHODS

Computer-assisted telephone interviews were conducted with 435 women, aged 40 to 65 years, who had visited family practice groups within the previous 2 years. Subjects were randomly allocated to receive individually tailored or standardized mammography recommendation letters mailed from physicians to patients' homes. Follow-up interviews were conducted 8 months later.

RESULTS

Tailored letter recipients were more likely to remember and to have read more of their letters than standardized version recipients. After controlling for baseline status, tailored letter receipt was associated with more favorable follow-up mammography status for women with incomes below $26,000 and for Black women.

CONCLUSIONS

Tailored messages are a more effective medium for physicians' mammography recommendations; tailoring may be especially important for women of low socioeconomic status.

Double reading of mammography screening films--one radiologist or two?

The effect of double reading on the number of breast cancers detected and the number of women recalled was examined in 15,457 women aged 50-59 years attending for mammographic breast screening. All the screening mammograms were interpreted independently by two radiologists without knowledge of each other's findings. All the cases selected by either radiologist were then reviewed by both radiologists and a consensus decision made on whom to recall for further studies. This method of double reading increased the number of breast cancers detected by 9% (P < 0.05) and decreased the number of women recalled by 45% (P < 0.001). Double reading of mammography screening films together with consensus decisions on the selected cases is recommended.

The role of the surgical pathologist in the examination of the non-palpable breast lesion

The specimen excised for the mammographically detected lesion is somewhat unique and requires special consideration by the surgical pathologist. The biopsy, in most instances, contains no grossly visible lesion and is relatively large so that blocking in its entirety is not practical. The pathologist needs to establish that the radiological abnormality is contained in the biopsy and to this end specimen radiography is required. Established prognostic parameters for breast carcinoma, such as tumor size, histological type, grade and hormone receptor status are equally applicable in the non-palpable breast lesion but consideration should also be given to the identification of epithelial proliferations which have increased risk for subsequent carcinoma. In addition, the recognition of ductal carcinoma in situ in the biopsy indicates potential for widespread disease, and lobular carcinoma in situ, a less commonly detected lesion in mammography, is associated with multifocality and disease in the contra-lateral breast. Both lesions are also associated with increased risk of recurrence in the remaining breast tissue. Failure to observe the corresponding quantity of calcium seen in radiographs relates to the fact that calcium may occur, not only as calcium phosphate, but also as calcium oxalate, the latter not being stained by hematoxylin and eosin but readily detected by its birefringent nature in polarized light. Detailed correlation of serial thin slices of the specimen with radiographic features is largely an educational exercise but is the most time-consuming step in the examination of the non-palpable breast lesion.(ABSTRACT TRUNCATED AT 250 WORDS)

Breast cancer diagnosis by screening mammography: early results of the Central Sydney Area Health Service Breast X-ray Programme

The Central Sydney Area Health Service (CSAHS) Breast X-ray Programme is a pilot mammography screening project for breast cancer detection funded by the NSW Government. Screening by two-view mammography is carried out in a mobile van and is offered free to women aged over 45 years living in the CSAHS region, the inner western suburbs of Sydney. In the first 18 months of operation from March 1988, 7193 women were screened: 99 women underwent excision biopsy and 53 cancers were diagnosed. This is an overall detection rate of seven cancers per thousand women screened. Sixty per cent of the cancers were impalpable to the examining surgeon; 19% of all cancers were shown to have axillary node metastasis at the time of diagnosis. These results compare well with those of the major European screening studies.

Mammography screening--reasons for recall and the influence of experience on recall in the Finnish system

The reasons for recall and the influence of experience on recall were studied in 579 women (3.21%) recalled from mammography screening. The proportion of recalls for further studies was the greatest (6.30%) at the onset of screening. With increased experience, the proportion decreased by stages and in the second screening round it was only 2.04%. The proportion of cases referred for surgical biopsy in the first screening round was 0.7% and the proportion of screening-detected breast cancers was 0.52%. These change little with increasing experience. In the second screening round, however, the proportion of referrals for surgical biopsy (0.43% of those screened) and of screening-detected breast cancers, (0.30%) were both low. A tumour-like density was the commonest finding resulting in recall for further studies, and the number caused by superimposition of normal parenchymal structures decreased with experience, while the proportion of breast cancers and benign tumours increased. The proportion of cases with parenchymal distortion resulting in recall for further studies was similar in both screening rounds but the number of those referred for biopsy fell dramatically in the second screening round. The number of recalls for microcalcification also fell with experience and the proportion of breast cancers in this group increased over the two screening rounds. A high ratio of malignancies in surgical biopsies can be expected when the radiologists undertaking primary screening also perform all further studies.

Referral policy and positive predictive value of call for surgical biopsy in the Florence Breast Cancer Screening Program

The authors evaluate the referral rates and the predictive value (PV) of call for diagnostic work up or biopsy in a population based breast cancer screening program in the 1979-1986 period. The presence of mammographic abnormalities either benign or suspicious proved to be the only reliable referral criterion (recall rate = 7.9%, recall PV = 3.8%, biopsy call PV = 39%). When mammography was normal the presence of breast complaints other than pain or of a radiologically dense breast were aspecific referral criteria, and since the latter was abandoned, (a) referral rates dropped especially in younger women, (b) referral or biopsy PV improved, whereas (c) cancer detection rate was almost unaffected. Younger age was associated with higher referral rates and with lower PV of both referral or biopsy. Whenever comparison with previous examination was possible, mammography accuracy was higher; this explains the decrease in referral rates and the increased predictivity observed at further rounds with respect to first screening round.

Screening for breast cancer in Nijmegen. Report of 6 screening rounds, 1975-1986

A population-based screening programme for breast cancer was initiated in Nijmegen in 1975 with mammography as the only screening procedure. Up to January 1987, 6 screening rounds were carried out with a 2-year screening interval. Rates of attendance, referral, biopsy and detection were calculated and numbers of interval cancers are presented in order to give a clear view of what repeated screening can accomplish in a population. At the first screening round the attendance rate was 87% for women under age 50 and 83% for women aged 50-64. For women aged 65 or over the initial attendance rate was 40%. Rates of attendance declined in subsequent years. Detection rates were highest for elderly women at their first examination: 9.5 per 1,000 screened women. Corresponding rates were 5.6 and 2.3 per 1,000 for women aged 50-64 and below 50 respectively. The positive predictive value for referral was, on average, 20% for women under age 50 and 50% for elderly women, although a sharp increase was seen in the last 2 screening examinations for all age-groups. Predictive values for biopsy were higher: 30% on average for women aged under 50 and 60%-70% for elderly women, again with a sharp increase in the last 2 screening rounds. Interval cancer rates, calculated as the number of cancers occurring within 2 years among negatively screened women at risk, showed no particular trend and varied between 0.9-1.3 per 1,000 woman-years after each screening round. Compared to screen-detected cancers, interval cancers occurred more frequently in younger women. In women under age 50, the ratio between screen-detected and interval cancer was about 1:1, while it was about 2:1 for elderly women.