Ductal carcinoma in situ (DCIS) is a preinvasive lesion originating within normal breast tissue with histologic progression from atypical hyperplasia to invasive breast cancer.

• Characterized by the presence of clonal proliferation of neoplastic epithelial cells
• Without sufficient surgical treatment, 30-50% of DCIS patient will develop invasive carcinomas – most within a 10-year period. [1] Danish and European guidelines suggest, that DCIS, constitute between 10% and 20% of screening-detected suspicious lesions.[2][3]

Surgical and radiotherapy

• Golden standard for treatment of DCIS is lumpectomy.
• Mastectomy is only performed in case of widespread lesions.
• Postoperative radiotherapy is given after lumpectomy for DCIS as a standard.

Indications

• Non-widespread diffuse or multifocal DCIS
• Expected cosmetically outcome, that is satisfying
• Patient acceptance of post-control and possibly radiation treatment
• Patient acceptance of increased recurrence risk compared with mastectomy
  

Indications

• Large, diffuse and / or multifocal DCIS lesions
• The expected cosmetically outcome won’t be satisfying
• Patients not accepting post-checks and possibly radiation treatment
• Patients not accepting increased recurrence risk associated with lumpectomy
• Known risk of BRCA1 or BRC2 mutation

Postoperative radiotherapy is recommended in a dose, that is sufficient enough to control any microscopic disease left after surgery

• 40.05Gy in 15 fractions over three weeks
• Either one of the following tumour bed boost should be considered:
• 50 Gy/ 25 fr. + 10 Gy/ 5 fr.: 57 Gy / 50 Gy / 25 fr.
• 50 Gy/ 25 fr. + 16 Gy/ 8 fr.: 63 Gy / 51,52 Gy / 28 fr.
• 40 Gy/ 15 fr. + 10 Gy/ 5 fr.: 45,75 Gy / 40 Gy / 15 fr.
• 40 Gy/ 15 fr. + 16 Gy/ 8 fr.: 52,2 Gy / 42,3 Gy / 18 fr

In Denmark, it is recommended, that patients treated for DCIS should be monitored for 3 years in order to detect early, local recurrence or contralateral neoplasia.

• Patients ≤ 50 years: Patients are offered an annual, clinical mammography until screening age
• Follow up for patient patients >/= 50 years is determined by whether the patient has had:
• Mastectomized: Screening mammography of the contralateral breast every second year
• Lumpectomized: Clinical mammography 18 months after surgery. After this, a decision to transit to regular screening mammography program.