OBJECTIVE: The aim of this study was to estimate the time when pulmonary metastases began to grow in colorectal cancer (CRC) patients with isolated synchronous liver metastasis based on the tumor doubling time (DT). METHODS: We examined 23 pulmonary metastases in 14 patients detected after resection of liver metastases from CRC (group 1) and 19 pulmonary metastases in eight patients detected after initiation of hepatic arterial infusion chemotherapy for synchronous unresectable liver metastases (group 2). The regression line was determined from the chest X-ray films, and the DT was calculated. RESULTS: We estimated the DTs of pulmonary metastases as 65.0 +/- 28.9 and 76.2 +/- 23.0 days in groups 1 and 2, respectively, and the time when pulmonary metastases began to grow as 16-1418 and 112-1464 days before the resection of liver metastases for 19 lesions in 12 out of 14 patients of group 1 and before resection of primary CRC in group 2, respectively. CONCLUSION: It appears that in some CRC patients in whom the metastatic site is considered to be limited to the liver at diagnosis, occult pulmonary metastasis has already taken place.
OBJECTIVE: The aim of this study was to estimate the time when pulmonary metastases began to grow in colorectal cancer (CRC) patients with isolated synchronous liver metastasis based on the tumor doubling time (DT). METHODS: We examined 23 pulmonary metastases in 14 patients detected after resection of liver metastases from CRC (group 1) and 19 pulmonary metastases in eight patients detected after initiation of hepatic arterial infusion chemotherapy for synchronous unresectable liver metastases (group 2). The regression line was determined from the chest X-ray films, and the DT was calculated. RESULTS: We estimated the DTs of pulmonary metastases as 65.0 +/- 28.9 and 76.2 +/- 23.0 days in groups 1 and 2, respectively, and the time when pulmonary metastases began to grow as 16-1418 and 112-1464 days before the resection of liver metastases for 19 lesions in 12 out of 14 patients of group 1 and before resection of primary CRC in group 2, respectively. CONCLUSION: It appears that in some CRCpatients in whom the metastatic site is considered to be limited to the liver at diagnosis, occult pulmonary metastasis has already taken place.