Radio-Immunotherapy: A Case Report of 'Abscopal Hyper-Progression'?

The radio-immunization effects of radiotherapy with abscopal tumor regressions have been documented in several experimental and clinical studies. Here, we present a patient with bladder cancer and relapsed metastatic disease to the left supraclavicular/axillary area and left lung. Concurrent weekly hypofractionated radiotherapy of both areas (8Gy/fraction/week, four fractions in total) and bi-weekly immunotherapy with anti-programmed cell death protein 1 (anti-PD-1) monoclonal antibodies resulted in complete regression of the axillary metastatic masses and of the lung metastasis, three months after the onset of therapy. In CT scans, however, a sternum infiltrating mass growing proximal to the margins of the radiotherapy fields was strikingly evident, while multiple hepatic metastases also appeared. Lymphopenia during radio-immunotherapy was recorded. The current report does not confirm the abscopal effects of radio-immunotherapy and furthermore, suggests that progressive disease or even hyper-progression may occur in a subgroup of patients. Although radio-vaccination is a well-established phenomenon, it is evident that we still miss major aspects of host/tumor-immune interactions with radiation.