"Return trip" metastases from the liver to the pancreas in Syrian golden hamsters

In 1889, Paget suggested that metastases resulted only when "seed" (certain tumor cells) and "soil" (specific affinity for certain organs) were matched. We report here, the results of implantation of a hamster nitrosamine-induced pancreatic cancer tissue into the liver in six animals and the resulting metastases to the "primary organ". Survival time and metastatic sites at necropsy were studied. Tumor growth in the primary implantation site was observed in 5 out of 6 hamsters (83.3%) that died of cancer. Survival time ranged from 82 to 199 days. Metastases were found in the splenic lobe of the pancreas in all 5 (100%) successfully-implanted animals. This homologous implantation model of "return trip" in metastasis may be a useful tool for further research about the process of cancer metastasis. Moreover, it may be useful especially in the assessment of the "seed and soil" hypothesis.