Effect of screening result on waiting times to assessment and breast cancer diagnosis: results from the Ontario Breast Screening Program.

BACKGROUND The effect of severity of screening result on delays to diagnosis has primarily been examined for mammographic abnormalities. This study will examine delays to assessment and diagnosis for women with an abnormal mammogram compared to women with an abnormal clinical breast examination (CBE) or abnormal CBE and mammogram. METHODS Using data routinely collected by Ontario Breast Screening Program (OBSP), 12,675 women aged 50 to 69 with an abnormal screening result between January 1, 2000 and December 31, 2000 were followed prospectively to the completion of their assessment process. Median waiting times from abnormal screen to first assessment procedure and diagnosis were compared by modality of referral and among women with a breast cancer diagnosis by prognostic features. RESULTS The median waiting time to first assessment and to diagnosis was significantly longer for women with only a clinical abnormality compared to women with a mammographic abnormality. In addition, women diagnosed with cancers of larger size had longer delays when the abnormality was detected only clinically. However, women referred by both modalities had significantly shorter waiting times to first assessment procedure and to diagnosis of poor prognosis cancers compared to women referred by mammography alone. INTERPRETATION Women with an abnormal CBE and mammogram are assessed more promptly and have shorter diagnostic times. However, women with only a CBE abnormality had delays to diagnosis as a result of longer waiting times to first assessment procedure. Integration of the OBSP with assessment centres should improve times to diagnosis irrespective of modality of referral.