The abscopal effect is mediated by a systemic anti-tumor immune response and reflects the regression of non-irradiated metastatic lesions at a distance from the primary site of irradiation. This review will focus on understanding the biological rationale behind the abscopal effect of radiotherapy (RT), which has a recently renewed interest as a result of the successes achieved with immunotherapy and RT in combination. Both RT and immunotherapy are standard components of modern treatment regimens. Combination of these two modalities results in an increased response in the irradiated lesions themselves and the metastatic regions distant from the site of irradiation. We will summarize the abscopal effect of radiotherapy, in particular, the synergistic effect of RT and immunotherapy.
Treatment choices for recurrent glioblastoma patients are sparse and the results are not satisfactory. In this retrospective analysis, we evaluated the results of re-irradiation of locally recurrent glioblastoma patients with an image-guided, fractionated, frameless stereotactic radiotherapy (SRT) technique. We treated 37 patients with the diagnosis of recurrent glioblastoma from September 2009 to December 2011. SRT was performed in a median five fractions (range, 1-5 fractions) with CyberKnife(®) (Accuray Incorporated, Sunnyvale, CA, USA). The dose given ranged from 14 to 32 Gy (median, 30 Gy). The median volume of the GTV was 24 cc (range, 2-81 cc). Median follow-up was 9.3 months. Five patients had regression in their lesions, 14 had stable disease, progression was observed in eight patients, and seven patients had pseudoprogression. The median survival following SRT was 10.6 months (range, 1.1-20 months) and overall survival following initial treatment was 35.5 months. The time to progression following SRT was 7.9 months in median. Patients with pseudoprogression had significantly longer survival after the first magnetic resonance imaging (MRI) compared to those with regression, stable or progressive disease (p = 0.012). The median survival after SRT for patients with pseudoprogression was 20 months. Patients who had GTV <24 cc had significantly longer survival following SRT compared to those with lesions ≥24 cc (p = 0.015). Patients who had chemotherapy after SRT had a median survival of 16.8 months. This was 9.7 months for patients who were not prescribed any chemotherapy (p = 0.062).
BackgroundThis study aimed to compare the therapeutic outcomes and fatal carotid blow out syndrome (CBOS) incidence rates between two different stereotactic body radiotherapy (SBRT) protocols.MethodsThe study included 75 patients with inoperable locally recurrent head and neck cancer treated with SBRT in our department between June 2007 and March 2011. The first 43 patients were treated sequentially (group I). Then our SBRT protocol was changed due to the high rate of CBOS, and the following 32 patients were treated every other day in a prospective institutional protocol (group II).ResultsMedian overall survival in group I and group II was 11 months and 23 months, respectively (P = 0.006). We observed 11 cases of CBOS. Only 1 of 7 patients (14%) with CBOS survived in group I, whereas 2 of 4 patients (50%) in group II remain alive. CBOS free median overall survivals were 9 months, and 23 months in group I and group II respectively (P = 0.002). The median radiation dose received by the carotid artery in patients with CBOS was 36.5 Gy (range: 34–42.8 Gy), versus 34.7 Gy (range: 0–44 Gy) in the patients that didn’t have CBOS (P = 0.15). CBOS did not occur in any of the patients with a maximum carotid artery radiation dose <34 Gy.ConclusionsEvery other day SBRT protocol for re-irradiation of recurrent head and neck cancer is promising in terms of decreasing the incidence of fatal CBOS.
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