This is a companion study of the other Italian studies on tomosyntesis as primary screening test for breast cancer: RETomo (NCT02698202), PROTEUS (NCT02590315), IMPETO (NCT03587259). The investigators conduct a randomized trial in three centres with a protocol that is similar to that of the other three studies. As for IMPETO and differently from the RETomo and PROTEUS studies, the intervention will be tomosynthesis + synthetic 2D.

In the three centres about 8000 women will be recruited (4000 in the experimental arm and 4000 in the control arm).

The study will compare the performance of tomosynthesis plus synthetic 2D vs digital mammography in respect to incidence of advanced cancers (interval and following round) and interval cancers. Women 50 to 65 years old will be screened once according to randomization arm for one round, then all will be screened with digital mammography after two years.

The investigators also will measure detection rates, specificity, interval cancers, advanced cancers occurring as interval cancers or at subsequent screens and allowing to estimate excess overdiagnosis comparing overall cumulative incidence after two or three rounds of screening.

Women will be asked for informed consent when they attend the mammography. If they accept they will be randomised to one of the two arms.

All examinations will be read by two independent radiologists, in case of discordance a third reading is asked.