Case 1: Ductal carcinoma in situ

Authors: Sarah Gierahn Nielsen, med. student & Hanne Melgaard Nielsen, MD

Step 1: Patophysiology

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]

Step 2: Recommendations for treatment

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.

Step 3: Lumpectomy

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

Step 4: 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

Step 5: Radiotherapy

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

Step 6: Follow-up

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.

Acknowledgements

Illustrators: Caroline Lilja, med. student