Additional non-sentinel lymph node metastases in early oral cancer patients with positive sentinel lymph nodes

Abstract

To determine risk factors for additional non-sentinel lymph node metastases in neck dissection specimens of patients with early stage oral cancer and a positive sentinel lymph node biopsy (SLNB). A retrospective analysis of 36 previously untreated SLNB positive patients in our institution and investigation of currently available literature of positive SLNB patients in early stage oral cancer was done. Degree of metastatic involvement [classified as isolated tumor cells (ITC), micro- and macrometastasis] of the sentinel lymph node (SLN), the status of other SLNs, and additional non-SLN metastases in neck dissection specimens were analyzed. Of 27 studies, comprising 511 patients with positive SLNs, the pooled prevalence of non-SLN metastasis in patients with positive SLNs was 31 %. Non-SLN metastases were detected (available from 9 studies) in 13, 20, and 40 % of patients with ITC, micro-, and macrometastasis in the SLN, respectively. The probability of non-SLN metastasis seems to be higher in the case of more than one positive SLN (29 vs. 24 %), the absence of negative SLNs (40 vs. 19 %), and a positive SLN ratio of more than 50 % (38 vs. 19 %). Additional non-SLN metastases were found in 31 % of neck dissections following positive SLNB. The presence of multiple positive SLNs, the absence of negative SLNs, and a positive SLN ratio of more than 50 % may be predictive factors for non-SLN metastases. Classification of SLNs into ITC, micro-, and macrometastasis in the future SLNB studies is important to answer the question if treatment of the neck is always needed after positive SLNB.

Surgical consensus guidelines on sentinel node biopsy (SNB) in patients with oral cancer

“…Disease recurrence after END not infrequently occurs in the contralateral neck (30%‐39%); this may be as a result of altered lymphatic drainage following surgery or simply that the tumor primary lymphatic drainage was not only to the ipsilateral neck. There are currently no prospective randomized studies comparing survival outcome for SNB vs END, but SNB appears to have an advantage in accurately mapping both sides of the neck (up to 13% contralateral drainage in well‐lateralized tumors), early detection of both micrometastasis, and extra‐capsular deposits (up to 58% metastatic deposits are isolated tumor cells (ITCs) or micrometastasis), allowing a higher salvage rate after recurrence (43% vs 91%). The detailed pathological evaluation that SNB allows provides information on micrometastasis (multiple on occasion) and ECS that can be overlooked by standard histological evaluation of a neck dissection.…”

Serial step sections at narrow intervals with immunohistochemistry are required for accurate histological assessment of sentinel lymph node biopsy in oral squamous cell carcinoma

“…In our study, the majority (50.8%) of SNs diagnosed as positive by SSS with IHC were classified as ITC. Our findings indicate that SSS with IHC of the entire SN remains necessary because the current standard of care stipulates completion neck dissection following identification of ITCs 15,36 . Further work is required to elucidate the clinical significance of ITCs against patient outcomes, in particular whether the presence of a single cell mandates completion neck dissection.…”

Predictive factors for dissection-free sentinel node micrometastases in early oral squamous cell carcinoma

“…In the present study, if metastatic focus was small enough and positive SN was not accompanied by positive NSN, hidden NSN metastases tended not to occur. Multiple positive SN was reported as one of the predictive factors for NSN metastasis 26 . Generally, metastasis in multiple lymph nodes is a factor for poor prognosis.…”