Lung cancer as a second primary.

An unusually high association of other primary cancers (9.7%) was found during the analysis of 403 consecutive cases of carcinoma of the lung diagnosed at DGMC between 1960 and 1975. Incidence by stage included 17.3% for Stage I (75 cases) and 16.9% for Stage II (59 cases). Median survival by stage was not adversely affected by the associated malignancy. Incidence by histologic type was 15.6% for adenocarcinoma (132 cases), 7.7% for epidermoid (130 cases), 1.5% for oat (small cell) (67 cases), 12.5% for large cell (40 cases) and 11.8% for undifferentiated anaplastic type (34 cases). Of 31 cases of Stage I adenocarcinoma, 9 (29%) had second malignancies. Both adenocarcinoma and epidermoid carcinoma exhibited decreasing association of second malignances with increasing stage of lung cancer. The head and neck region was the location of the nonlung malignancy in 22 cases and the GU system in 11 cases. Two cases each of colon carcinoma and basal cell skin carcinoma were found and there was one case each of carcinoma of the pancreas, lymphoma and melanoma. The diagnosis of lung cancer was made first in only 3 instances. The appearance of solitary nodules in patients with known malignancy should receive strong consideration for vigorous diagnostic and therapeutic procedures. Future studies should consider carcinogenic stimuli that may be common etiologic factors in both malignancies.