Neck dissection field and lymph node density predict prognosis in patients with oral cavity cancer and pathological node metastases treated with adjuvant therapy

SummaryPathological lymph node metastases (pN+) are an established prognostic factor in oral cavity squamous cell carcinoma (OSCC). We retrospectively examined the prognostic significance of lymph node (LN) density in pN+ OSCC patients who underwent neck dissection (ND) and postoperative adjuvant therapy.We examined 309 pN+ patients who underwent levels I–III ND and 148 pN+ patients treated with levels I–V ND. The 5-year control and survival rates served as the main outcome measures.The 5-year rates for patients treated with levels I–III and I–V NDs were as follows: local control, 79%, 74% (p = 0.0630); neck control, 81%, 68% (p = 0.0014); distant metastasis, 21%, 36% (p = 0.0003); disease-free survival (DFS), 59%, 43% (p = 0.0001); disease-specific survival (DSS), 66%, 46% (p < 0.0001); and overall survival (OS), 49%, 37% (p = 0.0048), respectively. Multivariate analysis demonstrated that an LN density ⩾0.16 was an independent prognostic factor for 5-year neck control (all data presented as p, hazard ratio [95% confidence interval]) (0.003, 2.691 [1.412–5.128]), distant metastases (0.001, 2.831 [1.520–5.270]), DFS (<0.001, 2.464 [1.571–3.866]), and DSS (0.036, 1.781 [1.040–3.052]) in levels I–III ND patients. An LN density ⩾0.048 was an independent predictor of 5-year local control (0.004, 4.871 [1.654–14.344]), neck control (0.002, 24.738 [3.367–181.771]), DFS (<0.001, 4.151 [2.264–7.610]), DSS (<0.001, 3.791 [2.017–7.125]), and OS (<0.001, 2.806 [1.706–4.613]) in levels I–V ND patients.Our findings demonstrate the prognostic value of LN density for guiding treatment strategies in OSCC patients who are to receive adjuvant therapy.