Mammocare Press Release

As you know, Dr Tan is passionate about providing the most up-to-date and scientifically proven care for all her patient’s breast health concerns. As such, she makes it a point also to write articles to high impact medical journals. These articles mainly describe techniques not previously mentioned, or to confirm her competence in a particular area of breast surgery.

Her most recent article was published in the January 2008 issue of the World Journal of Surgery on an improved method of identifying the sentinel node biopsy.1 She is the first surgeon internationally to suggest this modification in print.

Part of the complete treatment for invasive breast cancer and more aggressive non-invasive cancers (ductal carcinoma in situ) requires knowledge of whether cancer has spread to the lymph nodes. Previously, the standard method for understanding lymph node status was to remove all the lymph nodes under the arm pit (axilla), also known as axillary dissection or clearance. Usually, 15-25 lymph nodes are removed in an axillary clearance. This may result in complications like numbness in the arm pit and lymphoedema, a delayed swelling of the arm which can be troublesome to treat.

A technique has been developed to reduce the likelihood of complications with axillary clearance. This is called sentinel lymph node biopsy, which is the identification of the first lymph node to be affected by cancer, if at all the cancer cells have begun to spread. Before a surgeon can embark on this technique, he or she should first demonstrate an identification rate that is sufficiently high and that false negative rate is sufficiently low. Identification rate is calculated by dividing the number of times that the surgeon is able to identify the sentinel node over the total number of procedures that he or she does. This is expressed as a percentage. The false negative rate is the number of times the sentinel node identified shows no cancer, but the remaining lymph nodes are found to have cancer spread. This may lead to undertreatment of the cancer.

According to experts in the field, an acceptable identification rate for sentinel node biopsy should be at least 85% at the minimum, 2,3 better if it is more than 95%,4 and false negative rates should be less than 5%.2-4

Dr Tan has already published her personal results on sentinel lymph node biopsy.5 Her identification rates and false negative rates are well within the recommended guidelines. Her data was collected from as early on as from November 2002.

It may be of interest to know about one other publication on sentinel node biopsy for breast cancer from Singapore. These may be found at:

In this study by another set of surgeons, the authors’ false negative rates were listed as 16.7%. Dr Malycha’s comments were that this rate was higher than what is regarded as acceptable.

As of 21 March 2008, there are no other publications in Singapore providing identification rates and false negative rates for sentinel node biopsy for breast cancer in any other local facility or by any other local surgeon. There have been a few other write ups but these were in the public print media, rather than in scientific medical journals. It was mentioned that sentinel node was introduced in Singapore two years before 2006. In her article, Dr Tan stated that she included patients that had this procedure done in Singapore by her as early as in 2002.

As mentioned, Dr Tan’s identification rates are already within acceptable range. However, she is not satisfied just to be ‘adequate’. She takes the technique one step further by improving it some more. To her identification rate which is already ‘good enough’, she adds a modification which has been accepted by the international medical community, as evidenced by its publication in a highly regarded medical journal.

For more information regarding her techniques, you may wish to make an appointment to see her at MammoCare. Dr Tan would also be happy to show you the references that have been quoted here.

  1. Tan MP. Cost/Accuracy ratio analysis in breast cancer patients undergoing ultrasound-guided fine-needle aspiration cytology, sentinel node biopsy, and frozen section of node. World J Surg 2008;32:125-6
  2. Lyman GH et al. American Society of Clinical Oncology guideline recommendations for sentinel lymph node biopsy in early-stage breast cancer. J Clin Oncol. 2005;23:7703-20.
  3. 1.Canadian Association of General Surgeons and American College of Surgeons Evidence Based Reviews in Surgery. 23. ASCO recommended guidelines for sentinel lymph node biopsy for early-stage breast cancer. Evidence-based medicine. A new approach to teaching the practice of medicine. Can J Surg 2007;50:482-4.
  4. Schwartz GF. Clinical practice guidelines for the use of axillary sentinel lymph node biopsy in carcinoma of the breast: current update. Breast J 2004;10:85-8.
  5. MP. Surmounting the challenges of sentinel lymph node biopsy for breast cancer in non-tertiary centres and community-based practices. ANZ J Surg. 2006;76:306-9.

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