RISAS Procedure in Node Positive Breast Cancer Following NAC (RISAS)

Primary Radioactive Iodine Seed Localisation in the Axilla in Axillary Node Positive Breast Cancer Combined With Sentinel Node Procedure (RISAS) Following Neoadjuvant Chemotherapy

Chemotherapy in clinically node positive breast cancer patients is increasingly administrated in a neoadjuvant setting. The standard treatment regimen in these cases is then: neoadjuvant chemotherapy (NAC) followed by breast surgery and an axillary lymph node dissection (ALND). NAC results in axillary pathologic complete response (pCR) in 1 out of 3 patients, indicating a complete absence of axillary metastases after completion of NAC. In such events, ALND can be regarded as overtreatment that creates unnecessary morbidity. Less invasive axillary surgery which can accurately assess axillary pCR is therefore preferred over standard ALND in all patients. In case of detection of remaining axillary lymph node metastases by this less invasive axillary surgical procedure, completion axillary treatment is standard of care. The novel RISAS procedure is introduced as a possible less invasive axillary staging procedure. RISAS procedure contains Radioactive Iodine Seed localisation in the Axilla in axillary node positive breast cancer combined with a Sentinel node procedure. The iodine seed in the axillary lymph node metastasis will be placed prior to start of NAC.

All patients will undergo RISAS procedure, followed by axillary lymph node dissection in a one-step surgical procedure.

RISAS procedure contains Radioactive Iodine Seed localisation in the Axilla in axillary node positive breast cancer combined with a Sentinel node procedure.

Identification rate and accuracy (sensitivity, negative predictive value (NPV) and false negative rate (FNR)) of RISAS-procedure for identifying axillary pCR, with 95% confidence intervals will be calculated.

Participants will be followed from the moment of first out-hospital clinic visit untill final breast surgery, an expected average of 4 months.

The identification rate and accuracy (sensitivity, NPV and FNR) of both techniques used in RISAS-procedure (i.e. SLNB and MARI) for identifying axillary pCR, will be calculated separately as well.

Participants will be followed from the moment of first out-hospital clinic visit untill final breast surgery, an expected average of 4 months.

Inclusion Criteria: Female patient with pathologically confirmed axillary lymph node positive invasive primary breast cancer, treated with neoadjuvant chemotherapy Willing and able to undergo all study procedures. Has personally provided written informed consent. Exclusion Criteria: Age < 18 Pregnancy or lactation Contra indications for undergoing iodine seed placement or sentinel lymph node biopsy, such as allergic reaction on iodine, 99m Technetium or patent blue. Recurrent breast cancer Previous axillary surgery or radiotherapy Patients with periclavicular lymph node metastases (cN3) Patients with advanced breast cancer (i.e. patients with distant metastases, treated without any furter surgical procedures)

van Nijnatten TJA, Simons JM, Smidt ML, van der Pol CC, van Diest PJ, Jager A, van Klaveren D, Kam BLR, Lobbes MBI, de Boer M, Verhoef K, Koppert LB, Luiten EJT. A Novel Less-invasive Approach for Axillary Staging After Neoadjuvant Chemotherapy in Patients With Axillary Node-positive Breast Cancer by Combining Radioactive Iodine Seed Localization in the Axilla With the Sentinel Node Procedure (RISAS): A Dutch Prospective Multicenter Validation Study. Clin Breast Cancer. 2017 Aug;17(5):399-402. doi: 10.1016/j.clbc.2017.04.006. Epub 2017 Apr 19.