Combined action of virus injection and local tumor irradiation on tumor growth in mice.

The dynamics of SCCVII transplantable tumor growth in C3H/H mice was determined after local tumor irradiation and/or virus (NDV LaSota) i.p. injection. The virus applied alone significantly suppressed tumor growth, particularly until the 19th day after tumor transplantation. Local irradiation with 30 Gy resulted in tumor disappearance followed with its regrowth about 15 days later. However, if the virus was injected after the irradiation, there was no tumor growth until the end of the 31 day observation period. It should be noted that virus application prior to local irradiation did not have any additional influence on tumor growth. Thus, the pronounced efficacy of virus applied after tumor irradiation deserves attention. It is possible that the virus injected after irradiation induced a chain of cytokine production joining the action of tumor destruction induced by irradiation. This should be further studied in clarifying the approaches to combined tumor therapy with possible cell-free vaccine production.