Immunological effects of chemotherapy and radiotherapy against brain tumors.
BACKGROUND
The mainstays of brain tumor therapy are surgery, radiotherapy and chemotherapy. Cancer immunotherapy is explored as an additional treatment modality. However, emerging evidence indicates that also radio- and chemotherapy have immunological effects in addition to their cytotoxic and cytostatic activities.


METHODS
We summarize the literature on radio- and chemotherapy-mediated immunological effects in primary and secondary brain tumors and outline open questions within the field. To this end, a literature search was performed using the terms 'brain tumor', 'immune system', 'immunogenic cell death', 'vaccination', 'checkpoint inhibition', 'radiotherapy', 'chemotherapy' and derivations thereof. Expert commentary: Immunological effects of chemo- and radiotherapy in brain tumors involve direct immunogenic modulations of tumor cells, changes of the microenvironment and functional alterations of innate and adaptive immune cells. Each treatment modality can exert various effects that comprise both immune-stimulatory and immunosuppressive mechanisms. A detailed knowledge of these mechanisms is indispensable for an optimal combination of conventional anti-tumor treatments and novel immunotherapeutic approaches.
a Department of Neurology and Brain Tumor Center , University Hospital Zurich, University of Zurich , Zurich , Switzerland.
Tobias
T
Weiss
a Department of Neurology and Brain Tumor Center , University Hospital Zurich, University of Zurich , Zurich , Switzerland.
Michael
M
Weller
a Department of Neurology and Brain Tumor Center , University Hospital Zurich, University of Zurich , Zurich , Switzerland.
Patrick
P
Roth
D056704:Adaptive Immunity / Q000276:immunology; D000818:Animals; D000970:Antineoplastic Agents / Q000008:administration & dosage* / Q000494:pharmacology; D001932:Brain Neoplasms / Q000276:immunology / Q000628:therapy*; D003131:Combined Modality Therapy; D006801:Humans; D007113:Immunity, Innate / Q000276:immunology; D007167:Immunotherapy / Q000379:methods*; D059016:Tumor Microenvironment / Q000276:immunology
D000970:Antineoplastic Agents
Radiotherapy; brain tumor; checkpoint inhibition; chemotherapy; glioblastoma; immunogenic cell death; vaccination