Omitting Completion Axillary Treatment in Sentinel Node Positive Breast Cancer Patients Undergoing a Mastectomy

• Completion axillary treatment (Procedure): Completion axillary treatment according to the Dutch breast cancer guideline

Primary outcomes

• Regional recurrence rate [up to ten years]: Regional recurrence is defined as tumour recurrence and as residual tumour that became clinically apparent in ipsilateral axillary, infraclavicular and supraclavicular lymph nodes (pathologically proven).

Sex: Female, ages: 18 Years to any

Inclusion Criteria:

* Female
* Aged 18 years or older
* Pathologically confirmed invasive unilateral breast carcinoma
* A clinical T1-2 tumour (including multifocal or multicentric breast cancer)
* Will be or is treated with mastectomy
* Clinically node negative: no signs of axillary lymph node metastases at physical examination and preoperative axillary ultrasound (or negative cyto-/histopathology)
* Sentinel lymph node procedure and its pathologic evaluation should be performed according to the Dutch breast cancer guideline
* pN1mi(sn) or pN1(sn): at least one and a maximum of three axillary sentinel lymph nodes containing micro- and/or macrometastases
* Written informed consent

Exclusion Criteria:

* Clinically node positive pre-operative
* Sentinel lymph nodes only containing isolated tumour cells (<0.2 mm)
* Solitary parasternal sentinel lymph node metastasis (pN1b)
* Bilateral breast cancer
* Irradical resection of primary tumour at time of randomization (applicable in case the mastectomy is performed before randomization)
* Evidence of metastatic disease
* History of invasive breast cancer
* Previous treatment of the axilla with surgery or radiotherapy (except surgery for hidradenitis suppurativa or for other superficially located skin lesions, such as naevi)
* Pregnant or nursing
* Other prior malignancies within the past 5 years (except successfully treated basal cell and squamous cell skin cancer, carcinoma in situ of the cervix or carcinoma in situ of the ipsilateral or contralateral breast) or unsuccessfully treated malignancies > 5 years before randomization
* Unable or unwilling to give informed consent

• Results publication: van Roozendaal LM, de Wilt JH, van Dalen T, van der Hage JA, Strobbe LJ, Boersma LJ, Linn SC, Lobbes MB, Poortmans PM, Tjan-Heijnen VC, Van de Vijver KK, de Vries J, Westenberg AH, Kessels AG, Smidt ML. The value of completion axillary treatment in sentinel node positive breast cancer patients undergoing a mastectomy: a Dutch randomized controlled multicentre trial (BOOG 2013-07). BMC Cancer. 2015 Sep 3;15:610. doi: 10.1186/s12885-015-1613-2. PMID 26335105

• Marjolein L Smidt, MD, PhD, Principal investigator, Maastricht University Medical Centre+, Maastricht, the Netherlands
• Hans JW de Wilt, MD, PhD, Principal investigator, Radboud University Medical Centre, Nijmegen, the Netherlands