Care pathway of women with interval breast cancer in 2016, based on medico-administrative data

Since 2004, an organised screening programme (OS) for breast cancer has been in place for 50-74 years women who are not at an increased risk. Despite this, 17% of cancers diagnosed within 24 months following an OS mammogram are interval cancers (IC), diagnosed even though the OS had not reported cancer. After identifying IC from the French administrative healthcare database (SNDS), our objective was to describe the care pathways of women with IC in 2016. The IC identification algorithm is based on breast imaging tests conducted in the 24 months prior to diagnosis and on the compatibility of their timeline with ACR3 lesion follow-up (BIRADS guidelines). The care pathways of 3 groups were compared: women with IC, diagnosed through the OS, and diagnosed outside the OS programme (personalised screening or based on clinical signs, PSCS group). Respectively, 12,965 (46%), 3433 (12%), and 11,761 women (42%) were classified in the OS, IC and PSCS groups, i.e. 20.9% IC cases among the women taking part in the OS programme. The women from the IC group presented with more forms with lymph node or metastatic involvement than those of the OS group. Their pathways were more complex than in the OS group: at an equivalent stage, more total mastectomies and more adjuvant or neoadjuvant chemotherapy regimens. The care pathways of women with IC are intermediate with respect to those of the OS or PSCS group.Cases of IC probably include several cancer prognosis profiles. The authors propose an algorithm to identify breast interval cancer (IC) from the French administrative healthcare database (SNDS) and compare them to those of women whose cancer was diagnosed through the organized screening programme or outside the organized screening programme. The care pathways of women with IC are intermediate with respect to those of the other groups.