Timing of sentinel lymph node biopsy in cutaneous squamous cell carcinoma

To the Editor: Sentinel lymph node biopsy (SLNB) is the gold standard in nodal staging for several malignancies, 1 Kell M.R. Kerin M.J. Sentinel lymph node biopsy. BMJ. 2004; 328: 1330-1331https://doi.org/10.1136/bmj.328.7452.1330 Crossref PubMed Scopus (26) Google Scholar and its role in cutaneous squamous cell carcinoma (CSCC) is emerging. SLNB is most often performed prior to or concurrent with tumor removal, because excision and reconstruction are thought to disrupt the lymphatic flow and interfere with the ability to locate sentinel nodes. However, several high-risk factors in CSCC, such as tumor depth and perineural invasion, are only discovered after pathologic examination, so SLNB may not be considered until after excision. Several studies in melanoma support the efficacy of SLNB when performed after wide excision, 2 Gannon C.J. Rousseau Jr., D.L. Ross M.I. et al. Accuracy of lymphatic mapping and sentinel lymph node biopsy after previous wide local excision in patients with primary melanoma. Cancer. 2006; 107: 2647-2652https://doi.org/10.1002/cncr.22320 Crossref PubMed Scopus (92) Google Scholar ,3 Leong W.L. Ghazarian D.M. McCready D.R. Previous wide local excision of primary melanoma is not a contraindication for sentinel lymph node biopsy of the trunk and extremity. J Surg Oncol. 2003; 82: 143-146https://doi.org/10.1002/jso.10205 Crossref PubMed Scopus (34) Google Scholar but the impact of SLNB timing relative to primary CSCC tumor removal has not yet been elucidated. 4 Tejera-Vaquerizo A. Cañueto J. Llombart B. Martorell-Calatayud A. Sanmartín O. Predictive value of sentinel lymph node biopsy in cutaneous squamous cell carcinoma based on the AJCC-8 and Brigham and Women’s Hospital staging criteria. Dermatol Surg. 2020; 46: 857-862https://doi.org/10.1097/DSS.0000000000002170 Crossref PubMed Scopus (9) Google Scholar Therefore, the objective of this study was to analyze data from the existing CSCC literature to evaluate the success of SLNB before and after excision.