The development of optimal pathological assessment of sentinel lymph nodes for melanoma

Abstract

1158 sentinel lymph nodes (SLNs), excised from patients with primary cutaneous melanoma, were assessed pathologically using histology with immunohistochemistry (IHC) on all nodes, and RT-PCR for Mart-1 and tyrosinase on 55 nodes. RT-PCR was compared with the histology and IHC assessed on the same nodes. The evaluation of progressively more detailed protocols for histology and IHC modulated by the RT-PCR results led to a procedure that consistently detects metastases in 34% of patients submitted to SLN biopsy for cutaneous melanomas with a vertical growth phase and a mean thickness of 2.02 mm (range 0.25, with regression, to 19 mm). As this technique is virtually free of false positives and produces only a marginally lower detection rate than RT-PCR, which was subject to false positives of 7% in our study, it is suggested that this extended protocol should be the basis on which further evaluation of the place of RT-PCR in SLN assessment takes place. The evolved protocol described here has been adopted by the EORTC as the standard procedure for pathological handling of sentinel lymph nodes for melanoma when SLN status is a criterion in their clinical trials or studies.

Stage migration after minor changes in histologic estimation of tumor burden in sentinel lymph nodes

“…This often includes examining several levels of the SLNs and the use of immunohistochemistry. [8][9][10][11] To our knowledge, no worldwide standardization of SLN histological protocols currently exists; in fact, protocols often vary considerably even between neighboring institutions. For example, in a survey of 240 European institutions, 123 different breast cancer SLN protocols were reported.…”

“…12 This considerable variation in protocols results in substantial differences in reported metastasis detection rates. [8][9][10][11] Indeed, the more detailed protocols have been shown to up-stage some patients from lymph node negative to lymph node positive, an up-staging that will affect the treatment of patients, as has been shown for breast cancer. 13 In breast cancer, staging includes metastasis size estimates 14 and thus this parameter influences the choice of treatment.…”

Cutting a sentinel lymph node into slices is the optimal first step for examination of sentinel lymph nodes in melanoma patients

“…Excellent detection rates of up to 33.8% were achieved. 4,6 However, as reported by others, 24 we experienced difficulties in detecting single cells or small metastases without using the MART-1 antibody. MART-1 was therefore added at five different positions in our bivalving protocol (see Table 1).…”

“…In clinical practice, the detection rates reported varied widely, between 14 and 33.8%. [3][4][5][6][7][8][9][10] This has to be attributed, at least to some extent, to differences in the processing of the sentinel lymph nodes for pathology. To provide comparability between different institutions, standardised pathological protocols are required.…”

“…Excellent detection rates of up to 33.8% have been achieved using this protocol, which is currently recommended by the European Organisation for Research and Treatment of Cancer (EORTC). 4,6 We have consecutively applied both types of histological processing at our institute. In this study, we compare a multiple slices protocol with a bivalving protocol in terms of sensitivity and the workload placed on the pathology laboratory.…”