19 Breast Cancer

436 Breast Cancer

when EIDC+ versus 2% when EIDC- (24). They are therefor more frequently associated with positive section margins after tumour excision and have higher local recurrences rates after breast conserving treatment. Local recurrence is between 9 and 32% when EIDC + in stead of 1 - 10% when negative, the range depending on the surgical technique (tumourectectomy versus quadrantectomy), and the radiation doses delivered (1,39,56,57). Work Up Clinical examination, with measurement and documentation of the localisation of the tumour mass with pictures in supine position, mammography, ultrasonography and if indicated MRI, are mandatory to document local tumour extension. The diagnosis of malignancy should be documented by fine needle aspiration cytology, core biopsy or microscopic examination of the resection specimen. Nodal and distant spread must be investigated and the tumour stage assessed according to the UICC TNM classification. The breast surgeon, radiation oncologist and if indicated a medical oncologist jointly make the decision about the modalities of breast cancer treatment to be used. During breast conserving surgery, the surgeon should mark the tumour bed with 4 to 6 clips indicating the cranio-caudal, medio-lateral and (antero)-posterior limits of the resected volume. If there is doubt about residual micro-calcifications, postoperative mammography must be performed. If initial treatment with systemic neo-adjuvant hormono- or chemotherapy, and/or external beam radiotherapy, regression and localisation of possible residual disease must also be documented by mammography, ultrasonography, or MRI. Indications, Contra-indications The main indications for brachytherapy in breast cancer are as a boost in radiotherapy in breast conserving treatment and less frequent as sole treatment of selected small tumours after surgery, or as treatment of thoracic wall recurrences in already irradiated areas. • Interstitial boost irradiation of the primary tumour site after breast conserving surgery. For that reason, interstitial boosts may be preferred to external beam boosts with electrons or photons for of deeply seated tumour sites. When the CTV extends deeper than 28 mm under the epidermis, implants have a better dose distribution in terms of the volume of the irradiated breast tissue and dose to the skin blood vessels than electron beam boosts (53,54). If there is a high risk of local recurrence (eg. if the section margins are positive) and a higher boost dose is planned, the ballistic advantage of an interstitial implant over electron beams is even more important. • Interstitial boost irradiation of the primary tumour site after neo-adjuvant systemic chemotherapy and /or external radiotherapy of the whole breast with clinical complete or partial remission in tumours not amenable to primary conservative surgery. This category includes tumours 30 - 70 mm in diameter, non-metastatic or with limited nodal extension, which are usually treated by mastectomy. Interstitial brachytherapy boost after whole breast irradiation has been shown to provide significantly higher local control rate than electron or cobalt beam boost in retrospective (35) and randomised studies (10). In case of partial remission, conservative resection of residual tumour can be carried out before implantation (4). It has also be advocated as boost method in the treatment of locally advanced breast cancer after primary chemo or hormonotherapy and external beam irradiation (14) • Postoperative interstitial irradiation alone of the primary tumour site after breast conserving surgery in selected low risk T1 and small T2N0-1 breast cancer, (26,36,59). Since the follow -up 4 5