Document Type: Research Articles
Department of Surgery, Yokohama City University, Yokohama, Japan.
Department of General Thoracic Surgery, Yokohama Medical center, Yokohama, Japan.
Department of Biostatistics and Epidemiology, Yokohama City University, Yokohama, Japan.
Objective: This study was designed to visually represent postoperative recurrence patterns using event dynamics
and to assess sex-based differences in the timing of recurrence for non-small cell lung cancer. Methods: We studied
829 patients (538 men, 291 women) with NSCLC who underwent complete pulmonary resection in 9 hospitals. Event
dynamics with the use of life-table methods were evaluated, and only first events (distant metastases or local recurrence)
were considered. The effects of sex, histological type, pathological stage, and smoking history were studied. Result:
The resulting smoothed hazard rate curves indicated that the recurrence risk pattern definitely correlated with sex, with
a sharp peak in the first year in men and a broad peak during the first 2 to 3 years in women. These findings were also
confirmed by analyses according to pathological stage, histological type, and smoking history. Conclusion: The peak
times of recurrence differed considerably between men and women. The delayed time of peak recurrence in women,
associated with a longer disease-free interval within subsets of patients with similar disease stage, histological type,
and smoking status, might account for the better survival in women.