​Some members of the multidisciplinary KKH team who developed SMART (from left to right): Assoc Prof Lim Geok Hoon, Head and Senior Consultant, KK Breast Department; Ms Ng Ruey Pyng, Assistant Director, Nursing, KK Breast Department; Dr Mihir Ananta Gudi, Senior Consultant, Department of Pathology and Laboratory Medicine, and Dr Teo Sze Yiun, Head and Senior Consultant, Department of Diagnostic and Interventional Imaging.


More than 2,000 women in Singapore are diagnosed with breast cancer each year. A multidisciplinary team at KK Women’s and Children’s Hospital (KKH) has devised a SMART (Skin Mark clipped Axillary nodes Removal Technique) surgical technique to enhance the safety and cost-effectiveness of lymph node removal for women with advanced stage breast cancer.

The SMART technique utilises a less invasive workflow involving ultrasound-guided skin marking, to replace the conventional usage of a lymph node localisation device inserted into the patient’s armpit.

“SMART offers a radiation-free, safer alternative method for the localisation and removal of clipped lymph nodes, allowing the patient an opportunity to avoid the complications associated with complete lymph node removal, or axillary clearance – such as lymphoedema,” shares Associate Professor Lim Geok Hoon, Head and Senior Consultant, KK Breast Department, KKH, who led the development of SMART.

To date, more than 15 patients have benefited from this novel technique. The positive outcomes of SMART have been validated through a research study, funded by KKH Health Fund Grant, which was published in the Cancer Medicine journal in March 2020 (click here to read the full paper).


SMART technique eliminates the need for a localisation device

The current treatment for advanced stage breast cancer generally involves the surgical removal of cancerous cells in the breast, and the metastatic lymph nodes in the armpit. In patients who undergo pre-operative chemotherapy, the originally metastatic lymph nodes could be marked by a clip. After chemotherapy, a localisation device – typically a radioactive iodine seed, wire or magnetic seed – is inserted next to the clip, to enable the breast surgeon to locate and surgically remove the clipped lymph node, which is assessed for response to chemotherapy.

However, localisation devices come at an additional cost and patients may be met with known risks such as radiation exposure, device displacement or breakage.

“Recognising this, our team of breast surgeons, pathologists, radiologists and breast care nurses devised SMART as a less invasive alternative, removing the need for a localisation device – and its associated risks and limitations – altogether,” adds Assoc Prof Lim.


SMART localisation of clipped lymph node via ultrasound-guided skin marking

The SMART technique involves the radiologist preoperatively marking the position of the clipped lymph node on the patient’s skin (Figure 1).

Figure 1. A mark made directly above the identified lymph node by the radiologist on the day of operation

During surgery, the breast surgeon inserts a 21 G needle at the site of the ‘X’ mark (Figure 2A). An incision is made and skin flaps are raised. A stitch is then placed at the base of the needle and the needle is removed (Figure 2B). A one-centimetre all-around margin is marked out around the stitch and the axillary tissue is resected based on this marking. The depth of resection is based on the distance from the clipped lymph node to the skin as measured by ultrasound.


Figure 2. Surgery to locate the clipped lymph node for removal and histological assessment

The resected clipped lymph node then undergoes histological assessment to test for the presence of residual cancerous cells. Should the test results indicate a negative finding for cancer, the patient could be spared an axillary clearance.

“SMART is advantageous because it is radiation-free, wireless and non-invasive during preoperative localisation. In suitable patients with an excellent response to chemotherapy, it could enable them a trial of axillary preservation and a better quality of life post-surgery. SMART is also significantly cheaper than other localisation devices, and would be particularly useful in centres where localisation devices are not available,” says Assoc Prof Lim.