Page 80 - Sentinel lymph node biopsy in oral cavity cancer - Inne J. den Toom

Chapter 4 important that all future studies report SLN metastases in these categories. Only then the question if SLNB can be used as treatment, and not only as diagnostic procedure, in patients selected by the type of tumour deposit in SLNs can be answered. In breast cancer SLNB is accepted as standard diagnostic technique for clinically node negative patients. Complete axillary lymph node dissection is generally recommended if the SLNB is positive. Non-SLN metastases are detected in 35 to 50% of SLN positive patients. Only some series report the prevalence of ITC and distinction between ITC and micrometastasis could be difficult.42 The reported rate of micrometastasis as largest tumour deposit in SLN positive breast cancer patients varies considerably: from 24 to 93%.43 In patients with tumour deposits in SLNs the prevalences of ITC, micrometastasis and macrometastasis is 7-16%, 16-32% and 58-78%, respectively. Non- SLN metastases are found in 0-13%, 12-27% and 48-50% in patients with ITC, micro- and macrometastases in SLNs, respectively.44,49 Different nomograms in predicting non-SLN metastases in breast cancer patients with a positive SLNB have been developed, usually including largest detected size of SLN metastasis and the proportion of involved SLNs among all removed SLNs.43 The treatment strategy for micrometastasis in SLN is under debate. It has been suggested to refrain patients with ITC in their SLN from axillary lymph node dissection.44-46 A recent review including 7,151 breast cancer patients with positive SLNB in whom an axillary lymph node dissection was omitted revealed an axillary recurrence rate of 0.7% (range 0-7.1%) for macrometastasis and 0.3% (range 0-3.4%) for micrometastasis and ITC. Unfortunately, micrometastasis and ITC could not be analyzed separately and details regarding adjuvant treatment were lacking in the majority of studies.50 Since breast cancer patients are often treated with adjuvant systemic therapy these strategies can not easily be translated to early oral cancer patients who are usually treated with surgery as monotherapy. A meta-analysis of predictive factors for non-SLN metastases in breast cancer patients with a positive SLN confirmed a high likelihood of non-SLN metastases for size of SLN metastasis of more than 2 mm (macrometastasis; odds ratio (OR) 4.22), extracapsular extension in the SLN (OR 4.10), one or less negative SLN (OR 2.66), more than one positive SLN (OR 2.60), tumour size > 2cm (OR 2.41), a ratio of positive SLN of more than 50% (OR 2.25) and lymphovascular invasion (OR 2.24).51 Recently the same authors developed a risk score based on these parameters.52 78