ASICS trial: Avoiding Sentinel lymph node biopsy In select Clinical node negative breast cancer patients 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. Therefore, we
designed the ASICS trial: Avoiding Sentinel lymph node biopsy In select
Clinical node negative breast cancer patients after neoadjuvant Systemic
therapy.

The primary objective is to evaluate whether SLNB can safely be omitted in
breast cancer patients with HER2+ or TN tumors who achieve rCR on MRI after
NST. Secondary, quality of life will be assessed in patients with and without
SLNB.

The ASICS trial (Avoiding Sentinel lymph node biopsy In select Clinical node
negative breast cancer patients after neoadjuvant Systemic therapy) is a
prospective non-inferiority registration trial investigating the safety of
omitting SLNB after NST in cN0 patients with HER2+(hormone receptor [HR] +/-)
or TN tumors who achieve rCR on MRI after NST. The primary endpoint is axillary
recurrence after 5 years. The important secondary endpoint is quality of life
(specifically axillary morbidity and level of cancer worry), measured with the
questionnaires EORTC QLQ-BR23 and EORTC QLQ-C30, and the cancer worry score,
pre-operative at 6 months and after 1, 3 and 5 years post-operative.If
registration of Patient Reported Outcome Measures (PROM), which includes the
EORTC-C30 and EORTC-BR23, are integrated in standard care at the Antoni van
Leeuwenhoek, PROM data will be used to assess quality of life. cN0 patients
with standard care (SLNB) will be asked to participate as control group.

Study participants will have the benefit of avoidance of axillary surgery and
the complications associated with it (i.e. bleeding, wound infection,
paresthesia, numbness, pain, lymphedema and arm movement impairment). The risk
of a tumor-positive SLNB within the eligible patients is low (<3%). Moreover,
previous studies indicate that omission of removal of axillary nodes in cN0
patients with a very low risk of tumor-positive SLNs after NST should not
affect prognosis, as this is mainly determined by tumor biology. Study
participants will be monitored yearly for disease recurrence up to 5 years, and
will be asked to complete quality of life questionnaires at 5 points in time.
It is estimated that completing the questionnaires will take 10 to 15 minutes
at a time.