[Clinical study of synchronous multiple primary lung cancers; problems in diagnosis and treatment].

We evaluated retrospectively 33 patients with synchronous multiple primary lung cancers. These were 20 men and 13 women, with a mean age of 67 years (range, 51-79 years). In 27 cases, the tumors were located in the ipsilateral lung, and in 6 cases, they were in the bilateral lung. In patients with synchronous multiple primary lung cancers, combinations of adenocarcinoma and adenocarcinoma (12 cases, 36.4%), adenocarcinoma and others (6 cases, 18.2%) were most commonly observed histologically. Lobectomy was performed in 18, bi-lobectomy in 3, pneumonectomy in 4, lobectomy with partial resection in 6, and lobectomy with laser therapy or irradiation in 2 patients. Overall 5-year survival rate of this disease was 78.3%. Eight patients died within 1 year after surgical resection, and 2 of them died of treatment-related accident. Although optimal treatment of choice for synchronous multiple primary lung cancers remains an unresolved problem, we think that careful planning of the treatment for this disease including selection of surgical methods is much important.