The lymph node barrier to viable tumor cells before and after irradiation.

Abstract

AbstractThe effect of ionizing irradiation on the barrier function of the rabbit popliteal lymph node was studied using the V2 rabbit carcinoma. The popliteal lymph node acted as an effective barrier to viable V2 tumor cells for 2–3 weeks. Three weeks after tumor infusion, distant tumor growth was significantly increased in rabbits receiving 1000 rad and 3000 rad to the popliteal node. Six weeks after tumor infusion, all three groups had similar incidences of distant tumor growth. The number of tumor takes was similar in all groups. However, the tumor mass in the irradiated popliteal node was markedly smaller than the tumor mass in the control node at 3 weeks and 6 weeks. The earlier presence of tumor in the pelvic nodes of the irradiated rabbit may be dependent on the following factors: (a) irradiation decreased the barrier function of the lymph node, or (b) the irradiated lymph node was unable to retain growing cancer cells for the same length of time as the normal node. This effect of irradiation on the lymph node may be only a transient influence.