Neoplastic seeding

Livraghi et al. (2003) recently reported in a multi-center study on complications encountered in patients treated with RFA of liver tumors 2320 patients with 3554 lesions treated were analyzed. Of these patients 1610 patients were suffering from HCC. The depicted mortality rate and major complications rate was 0.3% (n = 3) and 2.2% (w = 50), respectively. The most frequent complications were peritoneal hemorrhage, neoplastic seeding, intrahe-patic abscesses, and intestinal perforation. The incidence of complications was related to the number of RF sessions performed in the individual patient. Minor complications (no further action required, no prolonged hospital stay) were observed in less than 5% of the patients. 

The two primary pathways of metastasis are hematogenous and lymphatic. Other, less-common modes of disease spread include dissemination via cerebrospinal fluid and transabdominal spread within the peritoneal cavity. Tumors are constantly shedding neoplastic cells into the systemic circulation or surrounding lymphatics. This process may begin early in the hfe of the tumor and often increases with time. The time course for metastasis depends largely on the biology of the tumor. Breast cancer, for example, tends to metastasize very early. Not all of the shed cancer cells, or seeds, result in a metastatic lesion. The seed must first find the appropriate soU, or an environment suitable for growth. This process is illustrated in the diverse patterns... 

N3. Nakamura, Y., Gindhart, T. D., Winterstein, D., Tomita, I., Seed, J. L., and Colburn, N. H., Early superoxide dismutase-sensitive event promotes neoplastic transformation in mouse epidermal JB6 cells. Carcinogenesis (London) 9, 203-207 (1988). 

L.A. Braby (Pacific Northwest Laboratories) is studying the malignant transformation of mammalian cells exposed to alpha particles that pass through the cell nuclei in an attempt to elucidate the mechanisms of action of radiation. The mechanisms of cell killing by alpha particles (M. Raju, Los Alamos Laboratories), cell neoplastic transformation from alpha particles (S.B. Curtis, Lawrence Berkeley Laboratory), and pulmonary tissue injury from radon/radon daughter exposure (T.M. Seed, Argonne National Laboratory) are also under investigation. 

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