Avoiding Sentinel Lymph Node Biopsy in Breast Cancer Patients After Neoadjuvant Chemotherapy (ASICS)

Avoiding Sentinel Lymph Node Biopsy In Select Clinical Node Negative Breast Cancer Patients After Neoadjuvant Systemic Therapy: the ASICS Trial

This study evaluates whether SLNB can safely be omitted in breast cancer patients with HER2+ or TN tumors who achieve a radiological complete response on MRI after neoadjuvant systemic therapy

Axillary staging in clinically node negative (cN0) breast cancer patients with neoadjuvant systemic therapy (NST; i.e. chemo- and immunotherapy), is preferably performed with sentinel lymph node biopsy (SLNB) after NST. The probability of a tumor-positive SLNB post-NST is low. cN0 patients with Human Epidermal growth factor Receptor 2- positive (HER2+) or triple negative (TN) breast cancer who achieve radiologic complete response (rCR) of the breast on MRI, have the lowest probability of a tumor-positive SLNB post-NST (<3%). Omitting removal of axillary lymph nodes in clinically node negative patients does not increase the rate of distant metastases nor breast cancer mortality. Performing SLNB can cause short- and long-term morbidity, reducing quality of life. The additional value of performing SLNB in patients with a very low risk of tumor-positive axillary lymph nodes should be investigated.

No sentinel lymph node biopsy will be performed in clinically node-negative triple-negative or HER2-positive breast cancer patients with a radiologic complete response on MRI. Participants will be asked to complete quality of life questionnaires at baseline (prior to surgery), 6 months, 1, 3 and 5 years follow-up. A control group consisting of 100 clinically node-negative patients receiving standard treatment will be used to compare QoL scores. This group consists of patients that do not wish to participate in the experimental group (i.e., no sentinel node lymph node biopsy) or patients that are not eligible.

To show that sentinel lymph node biopsy after neoadjuvant systemic therapy can be omitted in clinically node-negative HER2+ or TN breast cancer patients who achieve radiological complete response on MRI without compromising the 5 - year axillary recurrence rate (i.e, < 6% axillary recurrences within 5 years).

To compare study participants in whom sentinel lymph node biopsy is omitted to patients with sentinel lymph node biopsy on breast cancer related quality of life, especially axillary morbidity score. This is measured with the EORTC-BR23 scale. The arm morbidity score consists of 3 items, points ranging from 1 - 4 per item. A higher score indicates more morbidity.

To compare study participants in whom sentinel lymph node biopsy is omitted to patients with sentinel lymph node biopsy on level of cancer worry, using the cancer worry scale (CWS). The CWS consists of 8 items, with 1-4 points per item and a maximum score of 32 points. Higher scores indicate more frequent cancer worry.

To assess 5-year recurrence-free survival in clinically node-negative HER2+ or TN patients with radiologic complete response on MRI in whom sentinel lymph node biopsy is omitted.

To assess 5-year overall survival in clinically node-negative HER2+ or TN patients with radiologic complete response on MRI in whom sentinel lymph node biopsy is omitted.

To assess 5-year disease specific survival in clinically node-negative HER2+ or TN patients with radiologic complete response on MRI in whom sentinel lymph node biopsy is omitted.

To assess 5-year axillary recurrence-free survival in patients with and without a pathological complete response

To assess 5-year recurrence-free survival in patients with and without a pathological complete response

Inclusion Criteria: Women, aged ≥ 18 years Invasive HER2+ (HR+/-) or TN breast cancer Primary tumor (T), clinical stage T1-3 Neoadjuvant systemic therapy (NST), at least 3 cycles Tumor stage assessed with breast MRI before start NST Clinically node-negative before start NST (no suspect ALNs on ultrasound and FGD-PET/CT, or negative cyto-/histopathology in case of suspect nodes) MRI after or during NST shows radiologic complete response Written and signed informed consent Exclusion Criteria: Primary tumor (T) clinical stage T4 Patients without ultrasound or FDG-PET/CT pre-NST History of breast cancer ipsilateral breast Synchronous contralateral breast cancer Synchronous M1 disease