History of sentinel node and validation of the technique

Lymphatic tumour spread and its implications for treatment and survival have been studied for centuries. Different theories regarding the dissemination of solid tumours have been introduced, based on experimental data and observations during follow-up of cancer patients. These resulted in discussion about the place of regional lymph node dissection in the treatment of diseases that were thought either to be systemic from the beginning or to spread initially to lymph nodes. Elective regional lymph node dissections became controversial because of overtreatment of the many patients without lymph node metastases. These patients suffer from associated morbidity without survival benefit. With the introduction of the sentinel node concept, a minimally invasive procedure became available for detection of occult lymph node metastases. This report describes the history and the validation of the technique, with particular reference to breast cancer.Bartholin was the first to notice the existence of a 'lymphatic' in 1653. Numerous subsequent investigations elucidated the intricate lymphatic system. Virchow, in the nineteenth century, formulated the theory that lymph nodes filter particulate matter from lymph. This important assumption led to the awareness that cancer could be cured at an early stage with adequate surgery, in contradiction to the Greek philosophy implying that cancer is the local manifestation of a systemic disease. The next logical step in the evolution of Virchow's theory was the introduction of the radical mastectomy by Halsted at the end of the nineteenth century [1].To determine the barrier function of lymph nodes, several investigators injected inanimate particles or tumour cells into certain afferent lymphatics in animal models. Studying mesenteries of dogs and rabbits, Gilchrist saw no passage of carbon suspensions through any node after injections with varying pressures [2]. Zeidman and Buss injected stained V2 carcinoma cells into the afferent lymphati