Quality control in the locoregional treatment of
Ductal carcinoma in situ
Ductal carcinoma in situ (DCIS) is defined as a malignant transformation of the ductal lining cells within an intact basal membrane. DCIS is more frequently diagnosed following the increased breast screening. Nowadays, over 15% of the screen-detected malignancies are DCIS
. DCIS may appear in different histological variants with specific cyto-nuclear, architectural and molecular
- pathological features
. As invasive cancer, poorly differentiated DCIS is related to a more aggressive behaviour, particularly with respect to an invasive recurrence and consequent metastatic disease.
The aim of surgical treatment of DCIS is to achieve tumour-free margins
. To reach this goal, all requirements related to the treatment of invasive cancer are applicable to DCIS
Optimal imaging (including magnification views in cases of microcalcifications).
Presurgery diagnosis of microcalcifications or density by histological core (stereotactic or ultrasound-guided) biopsies.
Discussion of the patient in the multidisciplinary team.
Specimen radiography after diagnostic and/or therapeutic excisional surgery.
Guide-wire localisation preceding any surgery of a clinically-occult lesion.
The surgical resection should aim to result in at least 1-cm tumour-free margin.
Marking of the specimen after excision to guide the pathologist.
Diagnostic work-up by the pathologist according to established guidelines.
DCIS should be excised completely. If margins are involved a re-excision (guided by post-operative mammography and if necessary again a guide-wire localisation) should be attempted. When a re-excision will result in poor cosmesis, a mastectomy (with or without reconstruction) should be considered and offered. If on basis of mammographical findings, the DCIS is considered to be too large for breast conservation (usually exceeding a 3 cm area of microcalcifications) immediate mastectomy with or without reconstruction should be discussed. In
"true" DCIS, treatment of the axilla is not recommended
Radiotherapy reduces breast relapse rates by 40% after a complete excision of DCIS, irrespective the histological features of the DCIS
Therefore, the possibility of radiotherapy should always be discussed with the patient who desires to conserve her breast after complete excision of DCIS. There are instances where the risk of invasive local relapse, which may lead to dissemination, is extremely low
Small (<2 cm) foci of DCIS
Low grade of DCIS
Histologically-confirmed wide margins more than 10 mm.
In these situations, the adjuvant value of radiotherapy is very limited.
After BCT for DCIS, patients should be followed carefully with at least annual mammography. It should be kept in mind that DCIS is a potentially curable disease (by mastectomy). Therefore, BCT should carry a very limited risk for the development of invasive cancer.
Recommendation: After complete excision of DCIS, adjuvant radiotherapy of the breast should be discussed with the patient.
OUTCOME MEASURE: The breast relapse rate (invasive cancer) after BCT for DCIS should be less than 10% at 10 years.
OUTCOME MEASURE: The chest wall relapse rate after mastectomy for DCIS should be less than 5% at 10 years.