Lung cancer: An immunologic viewpoint and the prospects for immunotherapy.

The size of the lung cancer problem and the dismal results of conventional therapy justify close attention to the possibilities of immunotherapy. Lung cancer patients, like other tumor patients, are often relatively immunosuppressed although an immune response directed against autochthonous tumor cells can usually be demonstrated. All conventional forms of therapy, surgery, chemotherapy, and particularly radiation therapy, are further immunosuppressive, which, there is reason to believe, jeopardizes a successful outcome. Immunotherapy seeks to counteract this either by nonspecfic immunoenhancement or by enhancing reactivity to tumor specific antigens. The results of immunotherapy trials in lung cancer patients suggest that survival can be prolonged and survivorship increased by immunotherapy, although the benefit is inconclusuve at present. Optimal conditions for immunotherapy, as presently understood, are outlined. Practical questions about the optimal use of current immunotherapy regimens need to be answered, but a more aggressive approach to lung cancer therapy when combined with immunotherapy seems justified. Im pariicular, the criteria for operability will need to be redefined, particularly as regards oat cell cancer and large tumors which cannot be completely resected but in which "debulking" may contribute to the success of subsequent radiation and immunotherapy. Possible future immunotherapy regimens applicable to lung cancer are proposed, with the reservation that their success is likely to be directly related to their practicability.