Relevance of Skip Metastases for Squamous Cell Carcinoma of the Oral Tongue and the Floor of the Mouth

Abstract

To analyze the therapeutic implications of the distribution of neck metastases (NM) in patients with squamous cell carcinoma (SCC) of the tongue and the floor of the mouth (FOM). From January 1987 through December 1997, 339 previously untreated patients with T1-2 N0 M0 SCC of the tongue and the FOM underwent primary surgical treatment in our institution. A retrospective review of the pathology reports and outcome of these patients was made to ascertain the prevalence and distribution of NM. Patients were grouped by clinical neck status at the time of neck dissection: elective neck dissection (END) in the NO neck and subsequent therapeutic dissection (STD) in the neck observed which converted clinically to N+ or regional recurrences after END. All patients were classified according to the American Joint Committee on Cancer (AJCC)/UICC 2002 TNM classification. All patients underwent surgical treatment of the primary cancer and had negative margins at frozen section. Overall incidence of NM was 41.3%. Twenty-seven point eight percent of T1 N0 M0 and 48.2% of T2 N0 M0 patients developed NM (P = .0004). Occult neck metastases occurred in 24.1% of patients. Clinically, N+ metastases occurred in 23.6% of patients. The overall incidence of NM in levels IV and V was 8.5%. Neck level IV nodes were involved in only 1.5% of patients in the END group versus 23.7% in the STD group (P < 0.001). Level V was always associated to nodal metastases in other neck levels. Only 2% of patients in our study presented "skip metastases" in the neck. Neck levels I and II were at great risk for the development of NM (46.9% and 75.3% respectively). Levels IV (6.5%) and V (2%) were rarely involved in our group of patients. The results found in this study support the indication of supraomohyoid neck dissection for N0 and a more comprehensive neck dissection (levels I-V) for N+ patients in Stage I-II SCC of the tongue and FOM. C-4.