Malignant seeding is a term referring to the spread of cancer. It is often used in the context of the inadvertent spread of cancer cells through clinical processes. Cancer can spread in a variety of ways, and one uncommon but theoretically possible means is through the physical relocation of cancer cells during a medical procedure. For example, it has been asserted that there is risk of the spread of cancer along the tract that a needle travels during needle biopsies for some types of cancer. The level of risk is a subject of controversy, and the majority of the medical community agrees that in most cases there is no such risk (1, 2, 3). However, there is some opposition to the frequent use of biopsies and other invasive diagnostic techniques for this reason, especially within the domain of alternative medicine.
The risk of malignant seeding can become more pronounced when the cancer in question is mesothelioma, due to the particular nature of the disease. As with other cancers, certain invasive diagnostic procedures are sometimes necessary to properly diagnose and stage the cancer. These procedures may involve needle biopsy, chest tubes, thoracoscopy (examining the lungs through a scope), and surgical incisions. In individuals with malignant pleural mesothelioma (asbestos-related cancer of the lining of the lungs), undergoing these procedures may involve a significant risk of malignant seeding. In this case, the seeding usually manifests as cancerous lesions beneath the skin. Certain measures, such as the administration of preventative radiation therapy, can be taken to lessen the risk of malignant seeding (4).