Chiarelli Anna M, Kirsh Victoria A, Klar Neil S, Shumak Rene, Jong Roberta, Fishell Eve, Yaffe Martin J, Boyd Norman F
Division of Preventive Oncology, Cancer Care Ontario, 620 University Avenue, Toronto, Ontario, Canada M5G 2L7.
Cancer Epidemiol Biomarkers Prev. 2006 Oct;15(10):1856-62. doi: 10.1158/1055-9965.EPI-06-0290.
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.
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.
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.
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.
有证据表明，当前激素替代疗法（HRT）的使用和乳腺X线密度等因素可能会降低乳腺X线摄影的敏感性，并与发生间期癌的风险增加有关。本研究通过检查HRT使用模式和乳腺X线密度百分比对间期癌分类检测乳腺癌的影响，进一步探讨这种关系。
本研究采用病例对照设计，嵌套于1994年至2002年期间由安大略省乳腺筛查项目筛查的一组女性中。将筛查时漏诊但回顾性检查发现的间期癌（n = 87）或筛查时无可见肿瘤体征的真正间期癌（n = 288）与450例筛查发现的癌症进行匹配。通过放射科医生和计算机辅助方法测量的乳腺X线密度百分比与通过邮寄问卷确定的HRT使用之间的关联，以及被诊断为间期癌的风险，使用条件逻辑回归进行估计。
乳腺X线密度每增加25%，间期癌风险呈单调递增梯度[漏诊间期癌的优势比（OR）为1.77；95%置信区间（95%CI）为1.07 - 2.95，真正间期癌的OR为2.16；95%CI为1.59 - 2.94]。在调整乳腺X线密度后，单独服用雌激素的女性发生真正间期癌（OR为1.75；95%CI为1.11 - 2.83）以及服用联合HRT的女性发生漏诊（OR为2.84；95%CI为1.32 - 6.13）和真正间期癌（OR为1.79；95%CI为1.10 - 2.90）的风险仍显著增加。
筛查时应常规收集乳腺X线密度和HRT使用情况的信息。应让有风险的女性了解乳腺X线摄影敏感性较低的情况，并提供其他筛查方法。
