AIM: Metastasis size in @entity320 sentinel lymph nodes (SLNs) is an emerging prognostic factor. Two European @entity320 treatment trials include SLN @entity3 diameters as inclusion criteria. Whilst diameter estimates are sensitive to the number of sections examined, the level of this bias is largely unknown. We performed a prospective multicentre study to compare the European Organisation for Research and Treatment of @entity5 (EORTC) recommended protocol with a protocol of complete step-sectioning. METHODS: One hundred and thirty-three consecutive SLNs from seven SLN centres were analysed by five central sections 50 m apart (EORTC Protocol) followed by complete 250 m step-sectioning. RESULTS: Overall, 29 @entity1 (21.8%) were SLN-positive. The EORTC Protocol missed eight of these metastases (28%), one @entity3 measuring less than 0.1mm in diameter, seven measuring between 0.1 and 1mm. Complete step-sectioning at 250 m intervals (Extensive Protocol) missed one @entity3 (3%) that measured less than 0.1mm. Thirteen treatment courses (34%) performed if inclusion was based on the Combined Protocol would not be performed if assessed by the EORTC Protocol. Thus, 10 @entity1 would be without completion lymph node dissection (EORTC MINITUB study), whilst three @entity1 would not be eligible for anti- @entity4386 trial (EORTC protocol 18071). The corresponding number with the Extensive Protocol would be three; one @entity1 for the MINITUB registration study and two @entity1 for the anti- @entity4386 study. CONCLUSIONS: Examining SLNs by close central sectioning alone (EORTC Protocol) misses a substantial number of metastases and underestimates the maximum @entity3 diameter, leading to important changes in @entity1 eligibility for various treatment protocols.

Treatment influencing down-staging in EORTC XXXX Group sentinel node histological protocol compared with complete step-sectioning: a national multicentre study.

@entity1 :: ('9606', 'Species') :: ['patients', 'patient'] @entity5 :: ('MESH:D009369', 'Disease') :: ['Cancer'] @entity3 :: ('MESH:D009362', 'Disease') :: ['metastasis'] @entity4386 :: ('1493', 'Gene') :: ['CTLA4'] @entity320 :: ('MESH:D008545', 'Disease') :: ['melanoma']
@entity320 :: (MESH:D008545,Disease) :: ['Melanoma']
