Adverse effect of splenectomy on growth and survival with murine lymphosarcoma

Recent reports suggest that splenectomy may improve host resistance and inhibit solid tumor growth. The effect of splenectomy on lymphoid tumors in less clear. This study evaluates and compares the effect of splenectomy on tumor growth, therapy and survival in murine lymphosarcoma and mammary tumor. Gardner lymphosarcoma (5 x 10(5) cells) was implanted subcutaneously into 400 6C3HED mice (20 g). Two hundred mice underwent splenectomy 10 days previously. Animals were randomly placed into four groups. Group I (tumor alone) and Group II (splenectomy and tumor) received no further therapy. Group III (tumor) and Group IV (splenectomy and tumor) received cyclophosphamide (50 mg/kg/day x 3 days) beginning 10 days after implantation. The rate of implantation was similar in all groups (greater than 90%). Tumor growth was localized in controls, but was widespread in splenectomized mice. Survival analysis at 30 days showed an increased mortality in untreated mice (Group II) following splenectomy (p less than .02). Survival was (13/102) 12.75% Group I versus (8/103) 7.77% Group II. Survival was similar in mice receiving chemotherapy (36%) and was (p less than .001) greater than the untreated groups (12%). A similar protocol in mice with mammary tumor showed no differences between groups in tumor localization or survival postsplenectomy. These data suggest that splenectomy adversely affects localization and survival in murine lymphosarcoma but not in solid tumor. The variable effect of this operation on the natural history of lymphoid versus solid neoplasia questions the advisability of splenectomy in staging of patients with lymphosarcoma.