Objective: To evaluate the impact of the number of dissected lymph nodes on survival of patients with stage T3N0M0 thoracic esophageal squamous cell carcinoma (ESCC).
Methods: The clinicopathlogical dada of 249 patients with stage T3N0M0 thoracic ESCC were analyzed retrospectively. The median age of the 249 patients (171 males and 78 females) was 60-year old. The primary lesions were located in the upper- in 40, middle- in 177, and lower-thoracic esophagus in 45 patients. The median length of the lesions was 5 cm (range 2-12 cm). As for the severity of adhesion after surgery, there were 35 with no adhesion, 90 with mild-, and 124 patients with severe adhesion. The median number of dissected lymph nodes (dissected LN) at surgery was 9 (range 1-27), among them, less than 6 dissected LNs in 55, 6-11 dissected LNs in 133, and 11 or more dissected LNs in 61 cases. There were 210 patients with moderately or highly, and 39 with poorly differentiated cancer. 98 patients were treated with surgery alone, and 151 with postoperative adjuvant treatment.
Results: The follow-up deadline was July 2013. The 1-, 3-, and 5-year overall survival rates were 90.0%, 68.7% and 55.2%, respectively. The 1-, 3-, and 5-year survival rates were 85.5%, 63.6% and 39.1% in patients with <6 dissected LNs, 89.5%, 67.7% and 56.9% in patients with 6-11 dissected LNs, and 95.1%, 75.4% and 66.2% in patients with >11 dissected LNs, respectively (P=0.073). The survival was shorter in patients with <6 dissected LNs than patients with >11 dissected LNs (P=0.022). The subgroup analysis showed that in patients with middle-thoracic ESCC, the length of lesion ≤5 cm or mild adhesion after surgery and the number of dissected LNs were associated with survival after surgery.
Conclusions: For patients with stage T3N0M0 thoracic ESCC after surgery, the number of dissected LNs is an important factor affecting the survival, and at least 6 or more lymph nodes should be dissected. If lymphadenectomy is not adequately performed, postoperative adjuvant therapy should be recommend.