Breast Cancer Screening (PDQ®): Screening - Health Professional Information [NCI] - Characteristics of Cancers Detected by Screening Mammography
Several studies have shown that the method of cancer detection is a powerful predictor of patient outcome, which is useful for prognostication and treatment decisions. All of the studies accounted for stage, nodal status, and tumor size.
A 10-year follow-up study of 1,983 Finnish women with invasive breast cancer demonstrated that the method of cancer detection is an independent prognostic variable. When controlled for age, nodal status, and tumor size, screen-detected cancers had a lower risk of relapse and better overall survival. For women whose cancers were detected outside screening, the hazard ratio (HR) for death was 1.90 (95% confidence interval [CI], 1.15–3.11), even though they were more likely to receive adjuvant systemic therapy.
Purpose of This Summary
This PDQ cancer information summary for health professionals provides comprehensive, peer-reviewed, evidence-based information about breast cancer prevention. It is intended as a resource to inform and assist clinicians who care for cancer patients. It does not provide formal guidelines or recommendations for making health care decisions.
Reviewers and Updates
This summary is reviewed regularly and updated as necessary by the PDQ Screening and Prevention Editorial...
Similarly, an examination of the breast cancers found in three randomized screening trials (Health Insurance Plan, National Breast Screening Study [NBSS]-1, and NBSS-2) accounted for stage, nodal status, and tumor size and determined that patients whose cancer was found via screening have a more favorable prognosis. The relative risks for death were 1.53 (95% CI, 1.17–2.00) for interval and incident cancers, compared with screen-detected cancers; and 1.36 (95% CI, 1.10–1.68) for cancers in the control group, compared with screen-detected cancers.
A third study compared the outcomes of 5,604 English women with screen-detected cancers to those with symptomatic breast cancers diagnosed between 1998 and 2003. After controlling for tumor size, nodal status, grade, and patient age, researchers found that the women with screen-detected cancers fared better than their symptomatic counterparts. The HR for survival of the symptomatic women was 0.79 (95% CI, 0.63–0.99). Thus, method of cancer detection is a powerful predictor of patient outcome, which is useful for prognostication and treatment decisions. The findings of this study are also consistent with the evidence that some screen-detected cancers are low risk and represent overdiagnosis.
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Joensuu H, Lehtimäki T, Holli K, et al.: Risk for distant recurrence of breast cancer detected by mammography screening or other methods. JAMA 292 (9): 1064-73, 2004.
Shen Y, Yang Y, Inoue LY, et al.: Role of detection method in predicting breast cancer survival: analysis of randomized screening trials. J Natl Cancer Inst 97 (16): 1195-203, 2005.
Wishart GC, Greenberg DC, Britton PD, et al.: Screen-detected vs symptomatic breast cancer: is improved survival due to stage migration alone? Br J Cancer 98 (11): 1741-4, 2008.