Is Breast MRI Better at Finding Second Breast Cancers than Mammograms Alone for Breast Cancer Survivors? [Internet]

Excerpt

Background: Annually, more than 250 000 US women are diagnosed with breast cancer and are recommended for yearly surveillance mammography for second cancers after treatment completion. Many also receive breast magnetic resonance imaging (MRI), without evidence of effectiveness.

Objectives: (1) Assess patient and provider perspectives on surveillance breast imaging; (2) compare effectiveness of breast MRI with or without mammography to mammography only; (3) develop patient decision aids with education on breast imaging and results from imaging tests.

Methods: The research was based within 5 breast imaging registries in the US Breast Cancer Surveillance Consortium. Using a structured interview guide we conducted 6 focus groups with 41 women who had a personal history of breast cancer. We conducted a systematic literature review, following all relevant standards. We identified 33 938 surveillance mammograms and 2506 breast MRIs from 13 266 women following treatment for stage 0 to III breast cancer diagnosed in 2003-2012; second cancer events were ascertained within 1 year after imaging. We estimated performance measures using end-of-day radiologic assessment and compared them using multivariable logistic regression to adjust for potential confounders. Finally, we developed a prototype, web-based surveillance decision tool with information about breast imaging and results, incorporating women’s personal characteristics.

Results: Women reported anxiety when anticipating surveillance results and discomfort but high trust in imaging. Our systematic review indicated need for robust analyses, including comparative studies in breast imaging. We observed 397 second breast cancers within 1 year of mammogram (286 invasive, 108 ductal carcinoma in situ [DCIS], 3 unknown) and 44 cancers within 1 year of breast MRI (30 invasive cancers, 13 DCIS, 1 unknown). Unadjusted performance measures comparing breast MRI to mammography only (respectively, per 1000 examinations), were cancer detection rates (within 1 year of exam): 10.8 (95% confidence interval [CI], 9.6-12.0) vs 8.2 (95% CI, 7.98.5); and interval cancer rates: 6.8 (95% CI, 5.8-7.8) vs 3.5 (95% CI, 3.3-3.7). Sensitivity was 61.4% (95% CI, 46.5-76.2) vs 70.3% (95% CI, 65.8-74.8); specificity was 88.2% (95% CI, 86.9-89.5) vs 88.5% (95% CI, 88.1-88.8); and positive predictive value of cancer among biopsied women was 19.5% (95% CI, 12.3-26.7) vs 30.5% (95% CI, 27.0-34.0). By multivariable logistic regression, breast MRI was associated with improved cancer detection rate (OR = 1.68; 95% CI, 1.04-2.69; p = 0.03) and specificity (OR = 1.20; 95% CI, 1.03-1.40; p = 0.02), with no statistically significant difference in sensitivity (OR = 1.10; 95% CI, 0.45-2.72) and a 2.23-fold increased biopsy rate (95% CI, 1.86-2.66).

Conclusions: Women are challenged to understand surveillance breast imaging. Surveillance breast MRI compared with mammography in community practice had 2-fold higher biopsy rates with improved cancer detection, without improvement in sensitivity or a decrease in interval cancer rates. Our promising prototype decision aid provides women and clinicians with information about surveillance imaging. In sum, our results fill a gap about breast imaging for women with a personal history of breast cancer and can facilitate survivorship care planning after a breast cancer diagnosis.