The significance of a solitary lung shadow in patients with colon carcinoma

From 1949 through 1970, 54 colon cancer patients developed a synchronous or a metachronous solitary lung shadow. Twenty-five had colon carcinoma metastases and 29 had separate primary lung cancers. Forty-two percent were asymptomatic and their opacities were discovered by routine chest roentgenograms. Survival bears no relationship to age, sex, stage of colon cancer, or interval from colon cancer to excision of the pulmonary tumor. There seems to be a relationship to adequate pulmonary excision including regional lymphatics. Of 40 patients who underwent pulmonary procedures (25 metastatic and 15 primary lung cancer), secondary involvement of regional lymphatics was noted in 11 patients, including 7 who had daughter metastases secondary to the colon deposit. The over-all 5-year survival in this series was 35% in the metastatic group and 24% in the lung primary group. All 5-year survivors in the primary group, for unknown reasons, had yet a third primary cancer. To insure proper surveillance, a strict periodic and systematic continual followup must be maintained, which includes chest roentgenogram coverage. The ambiguity of a solitary lung shadow in the presence of a colon cancer requires clarification as to its exact nature without delay. In this way, proper treatment can be instituted and a more accurate prognosis given.