Ductal carcinoma in situ of the breast (DCIS) is rare in younger women, accounting for about 4% of all cases of DCIS in France, and tends to be diagnosed by clinical findings or casually, after plastic surgery. After breast conserving treatment, young age ( less than 40) is a predictive factor of relapses in patients with DCIS. Age may serve as one more parameter that should be considered in the complex decision-making process necessary to create a treatment plan for a woman with DCIS. Breast conservative treatment (BCT) could be used if: margins are free and more than 10 mm; if DCIS size is less than 11 mm and DCIS is free of necrosis and comedocarcinoma. Mastectomy ought to be proposed in case of: multifocal DCIS, or DCIS size more than 30 mm; invaded margins after re-excision; radiotherapy contraindicated; small breasts and patient choice. Immediate breast reconstruction should be proposed for patients with all the poor predictive factors. In other cases, treatment procedure will be explained to the patient and the treatment will be chosen by the patient in consultation with the medical team (radiologist, surgeon, pathologist and oncologist). Radiotherapy with boost or hormonotherapy with tamoxifen should not be used routinely but may be proposed individually.