The present case revealed simultaneous pulmonary metastases from colon and prostate cancer in the same lobe. Although a case of primary lung cancer with metastatic lymph node from prostate cancer has been reported, simultaneous pulmonary metastases from colorectal and prostate cancer are uncommon [1].
Surgical resection of a metastatic lung tumor is a feasible treatment option, especially in colorectal cancer patients. In contrast, the clinical significance of pulmonary metastasectomy in prostate cancer has not been established. This is because most pulmonary metastases from prostate cancer reveal lymphangitic spread, not nodules as in the present case, and are usually concomitant with bone metastases. While bone metastasis is the most frequent dissemination and a prognostic factor in prostate cancer, pulmonary metastasis is less frequent and has no impact on survival because of high sensitivity to endocrine therapy [2,3]. Because of these findings, clinical significance of pulmonary metastasectomy from prostate cancer is not established [4].
Although pulmonary metastases from prostate cancer account for 23% to 63% in autopsy series [2,5-7], only 3.6% to 21.2% of them are clinically evident [3,8,9]. These data suggest that more pulmonary metastases from prostate cancer might exist than expected and tend to be overlooked clinically. In the present case, the metastases were overlooked before surgery, in spite of the visualization on CT retrospectively (Figure 1B).