Multiple lung cancers and/or precancerous lesions can be developed because many bronchi are exposed to carcinogens simultaneously according to the concept of 'Field Cancerization'. We had performed a careful bronchoscopic examination and analysed the patients of double bronchial lesions who received the separate pathologic evaluation.

We studied 21 patients of double bronchial lesions among 1855 patients of bronchoscopic examination from April 1990 to December 1993 in Korea Cancer Center Hospital. We classified the patients into three groups(double malignancies of different histology, double malignancies of same histology, and combination of malignant and benign lesions) and analysed the histologic type, location, radiologic findings, and clinical parameters.

Among 21 patients, six patients had double malignancies of different histology, eight had double malignancies of same histology, and seven had combination of malignant and benign lesions. Out of 14 double malignant cases, 11 cases are considered as synchronous multiple primary lung cancers. Combination of squamous cell carcinomas was found in 5 cases, combination of small cell carcinoma and squamous cell carcinoma was found in 4 cases. Combination of adenocarcinoma and squamous cell carcinoma and combination of squamous cell carcinoma and poorly differentiated carcinoma were found in 1 case respectively. All patients of synchronous multiple primary lung cancers were male and had long smoking history(average 40 pack years). Among 21 cases of double bronchial lesions, only one lesion could be detected by prebronchoscopic radiologic examination including chest CT in 15 cases.

The presence of double bronchial lesions including multiple primary lung cancers and the limitation of radiologic examination to detect early bronchial lesions encourage us to examine the whole bronchi carefully and to perform pathologic evaluations.