Lymphocytopenia and Cytotoxic Therapy in Patients with Advanced Ovarian Cancer

Abstract

The relationship between 5-year survival and the mean number of circulating lymphocytes during 1 month after beginning a combined therapy was investigated in 175 patients with advanced epithelial ovarian cancer to understand why myelosuppression caused by a cytotoxic treatment is almost inseparable from its benefit. Patients received a combined therapy consisting of primary cytoreductive surgery followed by different systemic treatments according to three schemes: conventional chemotherapy with cisplatinum and cyclophosphanum (CP), conventional chemotherapy with paclitaxel and carboplatinum (TP), or lower-half body irradiation (LHBI). The TP scheme included premedication with dexamethasone. The LHBI involve irradiation with a total dose of 9 Gy (3 Gy daily) in patients with primary disease. LHBI with a total dose of 1 Gy (0.1 Gy daily) was used for patients with primary disease or relapse. The LHBI treatment included five final courses of thiophosphamide/5-fluorouracil for patients with primary cancer or conventional local radiotherapy up to a total dose of 30 Gy (2 Gy daily) for relapsed patients. Survival curves were analyzed by exponential approximation, and 5-year exponential mortality rates were calculated. The mortality rates were compared with the relative decline in the mean number of circulating lymphocytes after 1 month of therapy. If pretreatment lymphocytopenia did not exceed 0.7 109 cells /L, a linear dependency of the exponential death rate from the relative deviation of cells in the range of 1.16 to 0.7 (p < 0.001) was observed. The inevitable side effect of cytotoxic cancer therapy in the form of lymphocytopenia sheds doubt on the actual existence of effective antineoplastic immunity; however, it provides a logical background of the morphogenic function of some circulating mononuclear cells in relation to proliferating tissues, including malignant tissues.