Minimizing misclassification of hormone users at mammography screening

Consequences of a false-positive mammography result: drug consumption before and after screening

Background Previous research showed women experiencing false-positive mammograms to have greater anxiety about breast cancer than women with normal mammograms. To elucidate psychological effects of false-positive mammograms, we studied impact on drug intake. Methods We calculated the ratio of drug use for women with false-positive versus women with normal mammograms, before and after the event, using population-based registers, 1997-2006. The ratio of the ratios (RRR) assessed the impact. Results Before the test, 40.3% of women from the false-positive group versus 36.2% from the normal group used anxiolytic and antidepressant drugs. There was no difference in use of beta blockers. Hormone therapy was used more frequently by the false-positive, 36.6% versus 28.7%. The proportion of women using anxiolytic and antidepressant drugs increased with 19% from the before to the after period in the false-positive group, and with 16% in the normal group, resulting in an RRR of 1.02 (95% CI 0.92-1.14). RRR was 1.03 for beta blockers, 0.97 for hormone therapy. Conclusion(s) Drugs used to mitigate mood disorders were used more frequently by women with false-positive than by women with normal mammograms already before the screening event, while the changes from before to after screening were similar for both groups. The results point to the importance of control for potential selection in studies of screening effects.

Risk of breast cancer after false-positive test results in screening mammography

BACKGROUND

Screening for disease in healthy people inevitably leads to some false-positive tests in disease-free individuals. Normally, women with false-positive screening tests for breast cancer are referred back to routine screening. However, the long-term outcome for women with false-positive tests is unknown.

METHODS

We used data from a long-standing population-based screening mammography program in Copenhagen, Denmark, to determine the long-term risk of breast cancer in women with false-positive tests. The age-adjusted relative risk (RR) of breast cancer for women with a false-positive test compared with women with only negative tests was estimated with Poisson regression, adjusted for age, and stratified by screening round and technology period. All statistical tests were two-sided.

RESULTS

A total of 58 003 women, aged 50-69 years, were included in the analysis. Women with negative tests had an absolute cancer rate of 339/100 000 person-years at risk, whereas women with a false-positive test had an absolute rate of 583/100 000 person-years at risk. The adjusted relative risk of breast cancer after a false-positive test was 1.67 (95% confidence interval [CI] 1.45 to 1.88). The relative risk remained statistically significantly increased 6 or more years after the false-positive test, with point estimates varying between 1.58 and 2.30. When stratified by assessment technology phase and using equal follow-up time, the false-positive group from the mid 1990s had a statistically significantly higher risk of breast cancer (RR = 1.65, 95% CI = 1.22 to 2.24) than the group with negative tests, whereas the false-positive group from the early 2000s was not statistically significantly different from the group testing negative.

CONCLUSIONS

The implementation of new assessment technology coincided with a decrease in the size of excess risk of breast cancer for women with false-positive screening results. However, it may be beneficial to actively encourage women with false-positive tests to continue to attend regular screening.

Type of hormone therapy and risk of misclassification at mammography screening

OBJECTIVE

Current users of hormone therapy (HT) are known to have a lower accuracy of mammography screening than do never users. We studied whether the risk of misclassification depends on type of hormone, administration, regimen, and dose of the therapy.

METHODS

We linked data from mammography screening registers with drug prescription registers from Fyn, Denmark to identify current and never HT users among screening participants. We compared false-positive risks and interval cancer proportions between current users of different HT preparations, taking women's age, breast density, screen number, and age of comparison mammogram into account.

RESULTS

Estrogen therapy users had a significantly higher false-positive risk when the administration was by injection instead of oral (relative risk [RR], 2.37; 95% CI, 1.37-4.09). Women using sequential estrogen plus progestogen therapy had a significantly higher false-positive risk (RR, 1.94; 95% CI, 1.16-3.26) and a nonsignificantly higher interval cancer proportion (RR, 4.29; 95% CI, 0.69-26.53) when the administration of both hormones was transdermal instead of oral. Using tibolone instead of comparable hormones gave a nonsignificantly lower false-positive risk and a nonsignificantly higher interval cancer proportion.

CONCLUSIONS

Our data showed increased risks of misclassification at mammography screening among women using estrogen injections or transdermal, sequential estrogen plus progestogen. Tibolone seems to offer no advantage regarding accuracy of screening mammography.

Hormonal exposures and the risk of uveal melanoma

OBJECTIVES

Several studies suggest that hormonal mechanisms may be associated with the development of uveal melanoma. Therefore, the association between the risk of uveal melanoma and exposure to hormonal exposures was investigated in a case-control study from nine European countries.

METHODS

Incident cases of uveal melanoma were frequency-matched to population and hospital controls by country, age, and sex. Female subjects were asked about their reproductive history, use of menopausal hormone replacement therapy and oral contraceptives. Among men, occupational handling of oils while working with transformers or capacitors which contain polychlorinated biphenyls (PCB) was solicited. Unconditional logistic regression analyses were calculated, adjusting for several potential confounders. Analyses were stratified by sex.

RESULTS

Two hundred and ninety-three cases (165 men, 128 women) and 3,198 control subjects (2,121 men, 1,077 women) were interviewed. Among women, no associations were observed with hormonal status variables, intake of hormonal therapy or intake of oral contraceptives. Men showed an increased risk with occupational exposure to transformer/capacitor oils (OR = 2.74; Bonferroni-corrected 99.3% CI 1.07-7.02). However, these results were based on few exposed subjects only.

CONCLUSION

The results of this study do not support the hypothesis of a hormonal influence in the carcinogenesis of uveal melanoma. Our finding of a potentially increased risk with PCB-containing oils requires further research.