Breast cancer screening represents a major public health challenge. In France, no evidence has been furnished that women with breast cancer diagnosed following a mammogram carried out within the framework of the screening programme (SP) underwent less aggressive treatment than women diagnosed by other means. The aggressiveness of treatment represents a supplementary indicator for studying the impact of SP.
To study this indicator, data from the "Cancer Cohort" were used. This consists of a unique cohort including all subjects suffering from cancer since 2010 in France, resulting in care at a hospital or medical practice. All women aged from 50 to 74 years at average risk and treated in 2014 for incident breast cancer were included. Women having undergone a mammogram within the framework of the SP (SP group) were compared to women having undergone a bilateral mammogram outside the SP, because of an opportunistic screening or a clinical symptom (NSP group).
In 2014, 23,788 women aged from 50 to 74 years at average risk treated for incident breast cancer were identified: 13,530 (57%) in the SP group, and 10,258 (43%) in the NSP group. Women in the SP group had a higher rate of in situ or localised invasive breast cancer than in the NSP group. They had a higher rate of breast-conserving surgery (82% vs 70%), and a lower rate of chemotherapy (34% vs 53%). These findings were observed whatever the stage as defined in the study was. Women in the SP group had a higher rate of pathways involving breast-conserving surgery followed by radiotherapy. Finally, among women with metastatic cancer, those in the SP group had a lower proportion of liver, lung, brain and bone metastases, and a higher proportion of lymph node metastases (other than axillary), regardless of the time to onset of metastases.
The women whom cancer was diagnosed following a mammogram carried out within the framework of the SP had less advanced cancer and less aggressive treatments. This study on observational data contributes to illustrate the benefit of the SP in France using another approach than mortality or overall survival.
Clinical trial identification
Legal entity responsible for the study
French National Cancer Institute.
Has not received any funding.
All authors have declared no conflicts of interest.