A Second Malignancy Is the Major Cause of Death among Thoracic Squamous Cell Esophageal Cancer Patients Negative for Lymph Node Involvement

The aim of the present study was to determine the major causes of death among esophageal cancer patients whose lymph nodes did not show metastasis at the time they received esophagectomy, and to consider strategies for improving survival rates among these patients. Between 1989 and 1999, 93 of our patients who underwent curative esophagectomy with extended lymph node dissection for thoracic squamous cell esophageal cancer showed no lymph node metastasis. We followed up these node-negative patients for as long as 10 years and determined the major causes of death. Sixty-three patients were still alive after esophagectomy, although 30 had died. Six patients died within 3 years after esophagectomy as a direct result of recurrence of their esophageal cancer; 13 died as a result of a second (extraesophageal) malignancy. Within the first 3 years, the major causes of death were recurrence (35%) and the second malignancy (35%); thereafter, the major cause was only the second malignancy (54%). There was no difference in the survival rates among patients with earlier, synchronous, or subsequent malignancies. Univariate and multivariate analyses of the 10-year survival showed the independent prognostic factors to be recurrence of esophageal cancer and development of a second malignancy, which respectively increased the risk of death 6.4 and 2.7 times. The major cause of reduced survival among thoracic squamous esophageal cancer patients, whose lymph nodes did not show metastasis, was a second malignancy. New strategies aimed at preventing or treating synchronous and subsequent malignancies could prolong the survival of these patients.