Mammography utilization: patient characteristics and breast cancer stage at diagnosis.

OBJECTIVE: Missed mammograms represent missed opportunities for earlier breast cancer diagnosis. The purposes of this study were to identify patient characteristics associated with missed mammograms and to examine the association between missed mammograms and breast cancer stage at diagnosis.
MATERIALS AND METHODS: Mammography frequency and cancer stage were retrospectively examined in 1368 cases of primary breast cancer diagnosed at our clinic from 2002 to 2008.
RESULTS: Regardless of age (median, 62.7 years), 1428 women who underwent mammography were more likely to have early-stage (stage 0-II) breast cancer at diagnosis than were those who did not undergo mammography (p < 0.001). Similarly, the number of mammographic examinations in the 5 years before diagnosis was inversely related to stage: 57.3% (94/164) of late-stage cancers were diagnosed in women missing their last five annual mammograms. In a multivariate analysis, family history of breast cancer was most predictive of undergoing mammography (odds ratio, 3.492; 95% CI, 2.616-4.662; p < 0.0001) followed by number of medical encounters (odds ratio, 1.022; 95% CI, 1.017-1.027; p < 0.0001). Time to travel to the nearest mammography center was also predictive of missing mammograms: Each additional minute of travel time decreased the odds of undergoing at least one mammographic examination in the 5 years before cancer diagnosis (odds ratio, 0.990; 95% CI, 0.986-0.993; p < 0.0001).
CONCLUSION: Missing a mammogram, even in the year before a breast cancer diagnosis, increases the chance of a cancer diagnosis at a later stage. Interventions to encourage use of mammography may be of particular benefit to women most likely to miss mammograms, including those with no family history of breast cancer, fewer encounters with the health care system, and greater travel distance to the mammography center.