1. Introduction
Oral cavity squamous cell carcinoma (OSCC) is the most common oral
cancer, and many treatments have been evaluated (1, 2). However, the
optimal method for evaluating neck nodes after removal of primary oral
cavity lesions in patients with early OSCC (stage T1 or 2) free from
lymph node metastasis (N0) remains unclear. Neck node removal prevents
clinical recurrence and significantly increases overall survival (OS)
(3, 4). Metastasis to the cervical lymph nodes is very important in the
prognosis, reducing survival by 50% (5). The risk of occult lymph node
metastasis in OSCC patients of clinical stage N0 is 20–30% (6, 7).
Traditionally, elective neck dissection (END) was considered for
patients with early stage OSCC. Several studies reported that this was
better than watchful waiting (until metastasis developed) (8-10). END
improved survival and reduced the recurrence rate. However, END may be
an unnecessarily invasive approach for patients at low risk of lymph
node involvement (8, 9). As END can affect shoulder motility and cause
persistent pain and scarring, an alternative is desirable. Sentinel node
biopsy (SNB) represents a compromise between END and watchful waiting,
and has often been used to accurately detect occult neck node metastases
(11, 12). SNB involves the injection of a radiotracer or methylene blue
to identify the lymph nodes that drain first from the primary cancer
(13, 14), and sensitivity and accuracy are high (15). However, long-term
follow-up data are lacking, and the false-positive rate can reach 36%
(15, 16). Few reviews or meta-analyses have compared the utility of SNB
and END, which we thus address herein. We also performed detailed
subgroup analyses by follow-up period.