Impact of Screening Mammography on Treatment in Women Diagnosed with Breast Cancer.

BACKGROUND: Screening mammography reduces breast cancer mortality; however, screening recommendations, ordering, and compliance remain suboptimal and controversies regarding the value of screening persist. We evaluated the influence of screening mammography on the extent of breast cancer treatment.

METHODS: Patients ≥ 40 years of age diagnosed with breast cancer from September 2008 to May 2016 at a single institution were divided into two groups: those with screening 1-24 months prior to diagnosis, and those with screening at 25+ months, including patients with no prior mammography. The association between the two groups and various clinical factors were assessed using logistic regression models. Subgroup analysis was performed based on age groups.

RESULTS: Analysis included 1125 patients, 819 (73%) with screening at 1-24 months, and 306 (27%) with screening at 25+ months, including 65 (6%) who never had mammography. Overall, patients in the 25+ months group were more likely to receive chemotherapy [odds ratio (OR) 1.51, p = 0.0040], undergo mastectomy (OR 1.32, p = 0.0465), and require axillary dissection (AD; OR 1.66, p = 0.0045) than those in 1-24 months group. On subgroup analysis, patients aged 40-49 years with no prior mammography were more likely to have larger tumors (p = 0.0323) and positive nodes (OR 4.52, p = 0.0058), undergo mastectomy (OR 3.44, p = 0.0068), undergo AD (OR 4.64, p = 0.0002), and require chemotherapy (OR 2.52, p = 0.0287) than the 1-24 months group.

CONCLUSIONS: Screening mammography is associated with decreased stage at diagnosis and receipt of less-extensive treatment. This was evident in all groups, including the 40-49 years age group, where controversy exists on whether screening is even necessary.