Socioeconomic inequalities in attending the mass screening for breast cancer in the south of the Netherlands--associations with stage at diagnosis and survival.

The associations of socioeconomic status (SES) and participation in the breast cancer screening program, as well as consequences for stage of disease and prognosis were studied in the Netherlands, where no financial barriers for participating or health care use exist. From 1998 to 2005, 1,067,952 invitations for biennial mammography were sent to women aged 50-75 in the region covered by the Eindhoven Cancer Registry. Screening attendance rates according to SES were calculated. Tumor stage and survival were studied according to SES group for patients diagnosed with breast cancer between 1998 and 2006, whether screen-detected, interval carcinoma or not attended screening at all. Attendance rates were rather high: 79, 85 and 87% in women with low, intermediate and high SES (p < 0.001), respectively. Compared to the low SES group, odds ratios for attendance were 1.5 (95%CI:1.5-1.6) for the intermediate SES group and 1.8 (95%CI:1.7-1.8) for the high SES group. Moreover, women with low SES had an unfavorable tumor-node-metastasis stage compared to those with high SES. This was seen in non-attendees, among women with interval cancers and with screen-detected cancers. Among non-attendees and interval cancers, the socioeconomic survival disparities were largely explained by stage distribution (48 and 35%) and to a lesser degree by therapy (16 and 16%). Comorbidity explained most survival inequalities among screen-detected patients (23%). Despite the absence of financial barriers for participation in the Dutch mass-screening program, socioeconomic inequalities in attendance rates exist, and women with low SES had a significantly worse tumor stage and lower survival rate.