This study evaluates utility of a novel technique using India Ink to aid in the identification and retrieval of axillary lymph nodes during surgery, in breast cancer patients with suspicious lymph nodes.

The first part of the study will evaluate the feasibility of the technique in patients who commence their treatment with surgery. Provided its success, the second part of the study will evaluate the applicability of this same technique in patients who receive chemotherapy before having surgery.

Breast cancer is the leading cause of cancer mortality among females. Sentinel lymph node biopsy helps avoid axillary lymph node dissection and the associated morbidity. However, its utility is unclear in patients with biopsy proven axillary disease that has been treated with neoadjuvant chemotherapy. The objective of our study is to evaluate a) the feasibility of a novel technique of preoperatively tattooing suspicious lymph nodes with India ink, their intraoperative identification and retrieval in patients undergoing upfront breast and axillary surgery(Phase I); and b) the application of this technique in patients who undergo surgery after receiving neo-adjuvant chemotherapy i.e. lag time between tattooing and lymph node retrieval (Phase II) with the ultimate objective to see if the status of the excised sentinel and tattooed lymph node will be predictive of the status of the axilla.

A quasi-experimental pilot study will be conducted to evaluate the feasibility of tattooing suspicious lymph nodes with sterile black India ink. The study will be conducted in two phases, with the second phase conditional upon the successful results of the first. In Phase I, only 10 patients who are committed to undergo upfront surgery (without neoadjuvant chemotherapy) will be included. These patients will have the suspicious lymph node tattooed by injecting India ink at the time of ultrasound guided core needle biopsy. Intraoperatively, the axilla will be inspected to determine whether India ink tattooed in the lymph nodes can be visualized by the surgeon. Microscopic inspection for the presence of the dye in nodes retrieved by sentinel biopsy and/or axillary dissection will also be done. In Phase II, this process will be repeated for patients who undergo surgery after neoadjuvant chemotherapy and concordance between the sentinel, tattooed and non-sentinel nodes will be determined.

Ethical approval was obtained from the Aga Khan University Ethical Review Board (ERC# 2018-0345-1105). The process of sentinel node biopsy is a safe and routinely performed procedure at our institution. Intradermal injection of methylene blue can lead to skin necrosis; intra-parenchymal injection can cause induration and erythema with associated pain. These side effects can be minimized by diluting methylene blue which will be done. The complications that can result from all additional steps of study procedures will be discussed with the patient and their full responsibility will be borne by the institution. Although sterile black India Ink is safe to administer but possible side effects can include mucosal inflammation due to spillage of the ink, abscess formation and others such as an allergic reaction. If any of these situations are encountered full responsibility to treat the side effects will be borne by the study team using departmental funds.

Inclusion Criteria:

• Breast cancer patient (biopsy proven or clinically suspected) with clinically suspicious (palpable on clinical exam or abnormal by ultrasound criteria but not biopsied yet) ipsilateral axillary lymph node(s). The ultrasonographic examination will be considered suspicious for metastasis if one or more of following criteria are present: 1. Eccentric cortical enlargement (>3 mm) or lobulation with displacement of hilum 2. Absent hilum and irregular border and hypoechoic echotexture 3. Spherical node 4. Perinodal vascularity. (18-20)
• Participants willing to undergo axillary lymph node percutaneous biopsy with marking/tattooing of the biopsied lymph node at AKUH
• Participants intending to have definitive surgery at AKUH

Exclusion Criteria:

• Participants with terminal disease like renal failure will be excluded because these conditions can have profound effect on their course of treatment
• Participants with distant metastases
• Participants with prior breast or axillary surgery
• Participants with bilateral breast cancer, and those who have already had an axillary core needle biopsy prior to inclusion (to avoid a second procedure for tattooing)
• Participants with recurrent breast malignancy because their course of treatment might be different
• Participants that were initially suspected to have breast cancer, but pathology results did not confirm the diagnosis
• Pregnant and lactating women
• Men with breast cancer

Patients reporting to Breast Surgery Clinic at Aga Khan University, Main Campus in Karachi, Pakistan