Role of the regional lymph nodes in the cure of a murine lymphosarcoma

Abstract

Using an experimental model with a transplanted murine lymphosarcoma, several observations strongly suggest that following tumor transplantation, there is a selective transient accumulation of tumor cells in the regional lymph nodes. Furthermore, the surgical removal of these lymph nodes immediately prior to or within a week following implantation of the tumor cells significantly impairs the cure of the tumor by a dose of local irradiation which in control animals cures 83%. Local irradiation of the regional lymph nodes (3000 rads single dose) produced a moderate decrease in cure rates, not as severe as that observed in the lymphadenectomized animals. It is postulated that there is a critical period of time during which an immune response is initiated in the regional lymph nodes, following antigen injection. If tumor cells have reached the regional lymph nodes and the immune response has been initiated by the time a tumor becomes clinically apparent, then prophylactic irradiation or dissection of these lymph nodes should not interfere with tumor control by the usual therapeutic methods. However, if this is not the case, and the body has not recognized the tumor antigens, then lymphadenectomy and to a much lesser degree, irradiation, may result in less effective therapeutic results. Further understanding of the processes involved in tumor dissemination in patients is necessary to correlate these experimental observations with the clinical management of cancer.

Cytocidal activity and proliferative ability of macrophages infiltrating the EMT6 tumor

“…Mice were injected intradermally in the flank with lo5 viable EMT6 cells. Six days later when tumors had reached about 2 mm in diameter, half the mice were cured by locally irradiating the tumor with 5,000 R X-ray (250 kVp, I5 mA, 2 mm Cu HVL at 400 Rjmin) as previously described (Perez et al, 1973) in order to evaluate acquired resistance. The other half were left untreated in order to evaluate concomitant resistance.…”

Lymph Node Metastases

“…12 Lymph node permeability is due, in part, to intranodal shunts that have been demonstrated by electron microscopy and functional studies.5·7'8 Lymph node permeability is also due to lymphaticovenous shunts in the afferent lymphatic Accepted for publication May 16,1984 system, both within the node and about the node.6·913 In fact, lymph nodes have to be ineffective filters, functionally, and permit the passage of bacteria, lymphocytes, and other cells, or they might become clogged and cause edema. 12 Lymph node permeability is due, in part, to intranodal shunts that have been demonstrated by electron microscopy and functional studies.5·7'8 Lymph node permeability is also due to lymphaticovenous shunts in the afferent lymphatic Accepted for publication May 16,1984 system, both within the node and about the node.6·913 In fact, lymph nodes have to be ineffective filters, functionally, and permit the passage of bacteria, lymphocytes, and other cells, or they might become clogged and cause edema.…”

Experimental lymphatic metastasis

“…The reactions in distant nodes were similar. It seems clear (Crile, 1968;Perez et al, 1973) that the first draining node is essential for the first step of the immune response but that later the whole lymphoreticular system reacts.…”