Multicentricity in resected occult bronchogenic squamous cell carcinoma.

The frequency and the treatment of multicentricity in 127 patients with resected roentgenographically occult bronchogenic squamous cell carcinoma were studied. The cumulative rate and the incidence of postoperative metachronous multiple primary lung cancer were 0.11 at 5 years after initial operation and 0.022 per patient-year, respectively. The cumulative rate and the incidence of second primary lung cancer, which includes synchronous and subsequent metachronous cancer in patients with initial lung cancer, were 0.17 at 5 years after the initial operation and 0.041 per patient-year, respectively. The cumulative rate and the incidence of third primary lung cancer in patients with second primary lung cancer were 0.47 at 5 years, which was significantly higher (p = 0.05) than that of second primary lung cancer, and 0.11 per patient-year, respectively. In all 12 patients with synchronous multiple primary lung cancer, no recurrence was observed after treatment, but 3 had subsequent multiple primary lung cancer. Among the 13 patients with postoperative metachronous multiple primary lung cancer, recurrence was observed in 1 of the 6 patients who underwent resection and in 2 of the 4 patients treated with laser or radiation therapy or both. The overall survival rate at 5 years after initial operation in patients with solitary and those with multicentric occult bronchogenic squamous cell carcinomas was 0.90 and 0.59, respectively.