Screen-detected versus interval cancers: Effect of imaging modality and breast density in the Flemish Breast Cancer Screening Programme

OBJECTIVES

To investigate if direct radiography (DR) performs better than screen-film mammography (SF) and computed radiography (CR) in dense breasts in a decentralized organised Breast Cancer Screening Programme. To this end, screen-detected versus interval cancers were studied in different BI-RADS density classes for these imaging modalities.

METHODS

The study cohort consisted of 351,532 women who participated in the Flemish Breast Cancer Screening Programme in 2009 and 2010. Information on screen-detected and interval cancers, breast density scores of radiologist second readers, and imaging modality was obtained by linkage of the databases of the Centre of Cancer Detection and the Belgian Cancer Registry.

RESULTS

Overall, 67% of occurring breast cancers are screen detected and 33% are interval cancers, with DR performing better than SF and CR. The interval cancer rate increases gradually with breast density, regardless of modality. In the high-density class, the interval cancer rate exceeds the cancer detection rate for SF and CR, but not for DR.

CONCLUSIONS

DR is superior to SF and CR with respect to cancer detection rates for high-density breasts. To reduce the high interval cancer rate in dense breasts, use of an additional imaging technique in screening can be taken into consideration.

KEY POINTS

• Interval cancer rate increases gradually with breast density, regardless of modality. • Cancer detection rate in high-density breasts is superior in DR. • IC rate exceeds CDR for SF and CR in high-density breasts. • DR performs better in high-density breasts for third readings and false-positives.

Technical and clinical breast cancer screening performance indicators for computed radiography versus direct digital radiography

OBJECTIVES

To compare technical and clinical screening performance parameters between computed radiography (CR) and direct digital radiography (DR) systems.

METHODS

The number of women screened with CR was 73,008 and with DR 116,945. Technical and patient dose survey data of 25 CR and 37 DR systems were available. Technical performance was expressed by threshold thickness values at the mean glandular dose (MGD) level of routine practice. Clinical indicators included recall rate (RR), cancer detection rate (CDR), percentage of ductal carcinoma in situ (DCIS), percentage of cancers with T-scores smaller than 1 cm and positive predictive value (PPV).

RESULTS

Contrast threshold values for the 0.1-mm gold disk were 1.44 μm (SD 0.13 μm) for CR and 1.20 μm (SD 0.13 μm for DR). MGD was 2.16 mGy (SD 0.36 mGy) and 1.35 mGy (SD 0.32 mGy) for CR and DR respectively. We obtained for CR, respectively DR, the following results: RR in the first round of 5.48 % versus 5.61 %; RR in subsequent rounds of 2.52 % versus 2.65 %; CDR of 0.52 % versus 0.53 %; DCIS of 0.08 % versus 0.11 %; a rate of cancers with T-scores smaller than 1 cm of 0.11 % versus 0.11 %; PPV of 18.45 % versus 18.64 %; none of them was significantly different.

CONCLUSION

Our screening indicators are reassuring for the use of CR and DR, with CR operating at 60 % higher MGD.

KEY POINTS

• Breast cancer screening can employ both computed (CR) and direct digital radiography (DR). • Screening performance parameters for CR and DR technology are not significantly different. • Screening parameters are in accordance with European Guidelines. • Radiation doses employed for CR are generally 60 % greater than for DR.

Age-specific accuracy of initial versus subsequent mammography screening: results from the Ghent breast cancer-screening programme

The aim of this study was to determine whether age-related differences in the accuracy of mammography breast cancer screening decrease with repeated examination. Data from the first 8 years (May 1992 to April 1999) of the Ghent breast cancer-screening programme were used for analysis. In total, 28 944 mammography examinations were included. The referral rate, cancer detection rate, positive predictive value, sensitivity and specificity were chosen as performance indicators. Values were calculated for women aged 40-49, 50-59 and 60-69 years, at initial versus subsequent examinations, respectively. For first examinations, overall, performance was much lower for the women in their forties than for the older age groups. On subsequent screening, the effect of age disappeared, as expected, or was even reversed for the positive predictive value and sensitivity of the examination. In the light of the ongoing debate over the eligible age for mammography screening, these results support a universal recommendation beginning at the age of 40 years.

Diagnostic ability of general practitioners and dermatologists in discriminating pigmented skin lesions

BACKGROUND

Early recognition of melanoma is the key in preventing metastatic disease.

OBJECTIVE

The aim of this study was to evaluate diagnostic ability of general practitioners (GPs) and dermatologists concerning pigmented skin lesions in general and melanoma in particular. We also investigated whether the diagnostic ability of GPs changed after a lecture on melanoma.

METHODS

A test set of 13 pigmented skin lesions on 35-mm color slides was presented to 160 GPs and 60 dermatologists during educational courses.

RESULTS

GPs correctly evaluated biologic behavior of the pigmented skin lesions in 72% of the evaluations. In 71% of these evaluations they correctly identified the lesions. The proportion of lesions correctly identified was positively correlated with the frequency of pigmented skin lesions in everyday practice. Dermatologists made a correct identification of the lesions in 88% of all evaluations, and they correctly evaluated biologic behavior in 94% of these. Recognition of melanoma was proportional to melanoma exposure in everyday practice. Thick melanomas were better recognized than thin melanomas in both physician groups. After a lecture on melanoma, sensitivity of GPs to recognize malignant disease increased from 72% to 84%, without a significant decrease in specificity. The proportion of lesions correctly identified also rose significantly (66% vs 52%).

Time delays and related factors in the diagnosis of cutaneous melanoma

Delay in melanoma diagnosis was investigated in a population-based sample of 130 patients. The median time elapsing from the first notice of the lesion to excision was 110.5 days. There was no linear correlation between total delay time and Breslow-thickness of the diagnosed melanomas (P=0.19). Patient delay, defined as the time from first notice of a (change in a) lesion to the first observation by a physician, exceeded 2 months in half of all patients. Only 41% of the patients consulted a doctor because they were worried about the lesion. Colour change and itch were associated with a longer patient delay. There was no correlation with age, gender, socio-economic factors, localisation of the lesion and the person who first noticed the lesion. In one quarter of all patients, the time from first observation by a physician to excision of the lesion exceeded 2.5 months. This physician delay seemed to be attributed to misdiagnosis and to a delay occurring during referral.

The melanoma burden in Belgium; premature morbidity and mortality make melanoma a considerable health problem

The aim of this study was to investigate the impact of melanoma on public health in Belgium. Melanoma incidence and mortality rates were analysed relative to those of other cancers. These cancers were then evaluated for premature morbidity and mortality by studying age-specific incidence rates, years of potential life lost before 65, and years of potential life lost per death. Melanoma accounts for 1.23% of all incident cancer cases and 0.7% of all cancer deaths in Belgium. It is the seventeenth most common cancer in men and the sixteenth most common cancer in women. Compared with other, more frequent cancers, melanoma seems to affect patients at a younger age; in the 20-39 age group melanoma is the third most common cancer in both sexes. It is the second most important cancer in terms of years of potential life lost per death, preceded only by tumours of the central nervous system. These findings show that melanoma incidence and mortality rates are exceeded by many other cancers. Nevertheless, melanoma poses an important health problem because of its predilection for young and middle-aged people. We suspect that these observations are not specific for Belgium and will also apply to other European countries.

Under-registration of melanoma in Belgium: an analysis

The overall underestimation of incident cancer cases in the Belgian National Cancer Registry is estimated at about 20-25%, with a probable larger under-registration among males. Melanoma incidence is suspected to be underestimated even further because of the hospital-based reporting system of the National Cancer Registry. To investigate the suspected underestimation of melanoma in Belgium, the official data were compared with international data on melanoma incidence and the results of a melanoma registration programme launched in the province of East Flanders. The Eindhoven Cancer Registry, which covers a registration area near the Belgian border, was used as a reference to calculate the expected number of melanomas in East Flanders for 1995. The results indicate an ongoing under-registration of melanoma cases by the National Cancer Registry. Based on the Eindhoven Cancer Registry data, the under-registration in East Flanders is estimated at 43% for males and 36% for females. The East Flanders registration programme apparently obtains a better registration in females. This is mainly due to a higher registration in the younger age groups. In these groups a higher proportion of in situ melanomas and a thinner median Breslow thickness of the invasive melanomas is observed.

Trends in mortality from cutaneous malignant melanoma in Belgium

BACKGROUND AND METHODS

Changes over time of mortality rates from cutaneous malignant melanoma (CMM) in Belgium were analysed, based on people (n = 3695) aged 25-84 years, who died of CMM from 1954 to 1992. All data were collected from the Belgian National Institute of Statistics. For the log-linear analysis and calculation of the average annual change, only the data from 1973 to 1992 were considered.

RESULTS

The age-adjusted mortality rates (per 10(5)) for the age group 25-84 years old increased from 0.5 in 1954 to 3.0 in 1992 in men, and from 0.8 in 1954 to 2.2 in 1992 in women. The average annual percentage change in men (-0.003%) was stable over the period 1973-1982, and increased to 4.4% over the period 1983-1992. In women, the average annual increase was 4.6% over the period 1973-1982, and continued to increase to 6.8% over the period 1983-1992. Log-linear analysis showed that the change in rates for both men and women was mainly due to an age-'drift' effect, contrary to the results of the average annual percentage change in men.

CONCLUSION

The risk of dying from CMM increased in men and women continuously over the whole period, irrespective of birth cohort. In both men and women, there was approximately a 20% increase in CMM mortality per 5-year period.

Screening for breast cancer in Ghent, Belgium: first results of a programme involving the existing health services

In 1992, a population-based breast cancer screening programme was initiated in the municipality of Ghent: all women aged 40-69 years were personally invited to attend a local radiology unit for a mammogram, after being examined by a general practitioner or gynaecologist of their choice. The results of history taking, clinical breast examination, first and second reading, further investigation and primary treatment were registered. In total, 24.3% of the eligible population was screened in the period 1992-1994. The recall and biopsy rates were 2.9% and 1.4%, respectively. The cancer detection rate was 8.1 per 1000 women screened. Of all cancers detected, 88.0% (66/75) were invasive. Of these, 35.9% (23/64) measured 10 mm or less in diameter. The benign to malignant biopsy ratio was 0.7. Apart from the low participation, these results suggest that the programme is effective, compared with reference standards and the results of other studies.