Mammographic screening in Sami speaking municipalities and a control group. Are early outcome measures influenced by ethnicity?

Female citizens of Sami (the indigenous people of Norway) municipalities in northern Norway have a low risk of breast cancer. The objective of this study was to describe the attendance rate and outcome of the Norwegian Breast Cancer Screening Program (NBCSP) in the Sami-speaking municipalities and a control group.

A retrospective registry-based study.

The 8 municipalities included in the administration area of the Sami language law (Sami) were matched with a control group of 11 municipalities (non-Sami). Population data were accessed from Statistics Norway. Data regarding invitations and outcome in the NBCSP during the period 2001-2010 was derived from the Cancer Registry of Norway (CRN). The NBCSP targets women aged 50-69 years. Rates and percentages were compared using chi-square test with a p-value<0.05 as statistical significant.

The attendance rate in the NBCSP was 78% in the Sami and 75% in the non-Sami population (p< 0.01). The recall rates were 2.4 and 3.3% in the Sami and non-Sami population, respectively (p<0.01). The rate of invasive screen detected cancer was not significantly lower in the Sami group (p=0.14). The percentage of all breast cancers detected in the NBCSP among the Sami (67%) was lower compared with the non-Sami population (86%, p=0.06).

Despite a lower risk of breast cancer, the Sami attended the NBCSP more frequently than the control group. The recall and cancer detection rate was lower among the Sami compared with the non-Sami group.