Immunoradiotherapy as An Effective Therapeutic Strategy in Lung Cancer: From Palliative Care to Curative Intent.

Lung cancer is one of the main causes of cancer-related mortality worldwide. Over the years, different therapeutic modalities have been adopted depending on tumor stage and patient characteristics, such as surgery, radiotherapy (RT), and chemotherapy. Recently, with the development of immune-checkpoint inhibitors (ICI), the treatment of metastatic and locally advanced non-small cell lung cancer (NSCLC) has experienced a revolution that has resulted in a significant improvement in overall survival with an enhanced toxicity profile. Despite this paradigm shift, most patients present some kind of resistance to ICI. In this setting, current research is shifting towards the integration of multiple therapies, with RT and ICI being one of the most promising based on the potential immunostimulatory synergy of this combination. This review gives an overview of the evolution and current state of the combination of RT and ICI and provides evidence-based data that can improve patient selection. The combination in lung cancer is a safe therapeutic approach that improves local control and progression-free survival, and it has the potential to unleash abscopal responses. Additionally, this treatment strategy seems to be able to re-sensitize select patients that have reached a state of resistance to ICI, further enabling the continuation of systemic therapy.

Changes of CD68, CD163, and PD-L1 tumor expression during high-dose-rate and pulsed-dose-rate brachytherapy for cervical cancer.

PURPOSE: We hypothesized that radiation doses delivered with high-dose-rate (HDR) and pulsed-dose-rate (PDR) brachytherapy in patients with cervical cancer could trigger immune stimulation by modulating immune cells in the tumor microenvironment. The objective was to determine CD68, CD163, and PD-L1 expression in biopsies from patients with cervical cancer and to compare the effects of HDR vs. PDR brachytherapy on the expression of these proteins. METHODS AND MATERIALS: Nineteen consecutive women (mean age, 55.9 years) with histologically proven cervical cancer scheduled for brachytherapy after standard external beam irradiation therapy combined with platinum-based chemotherapy were included in a prospective study. Core tissue biopsies were obtained before radiochemotherapy (biopsy #1), after completion of radiochemotherapy and before brachytherapy (biopsy #2), and 2 weeks after completion of brachytherapy (biopsy #3). HDR or PDR brachytherapy was delivered according to availability of equipment. CD68, CD163, and PD-L1 immunohistochemical expression was estimated using a quantitative method. Conditional logistic regression models were used to assess the relationship between gene expression and time of biopsy for each brachytherapy technique. RESULTS: In relation to CD68 and CD163, statistically significant relationships between gene expression and biopsy tissue samples were not found in any of the brachytherapy techniques, although there was trend toward downexpression of CD68 and CD163 in biopsies #2 and #3 in the HDR brachytherapy cohort only. There was a significant increase in PD-L1 expression in biopsy #3 also in the HDR cohort as compared with the PDR cohort. CONCLUSIONS: Decreased CD68 and CD163 expression did not reach statistical significance, but this trend may have clinical translational potential. Overexpression of PD-L1 in tissue biopsies taken at 14 days in the HDR brachytherapy cohort may tentatively suggest that this time period would be an adequate interval for blockade of the PD-1/PD-L1 axis.

Preliminary Study of the Effect of Stereotactic Body Radiotherapy (SBRT) on the Immune System in Lung Cancer Patients Unfit for Surgery: Immunophenotyping Analysis.

An immunophenotyping analysis was performed in peripheral blood samples from seven patients with lung cancer unfit for surgery treated with stereotactic body radiotherapy (SBRT). The objective was to characterize the effect of SBRT on the host immune system. Four patients received 60 Gy (7.5 Gy × 8) and three 50 Gy (12.5 Gy × 4). Analyses were performed before SBRT, 72 h after SBRT, and at one, three, and six months after the end of SBRT. Of note, there was a specific increase of the immunoactive component of the immune system, with elevation of CD56+highCD16+ natural killer (NK) cells (0.95% at baseline to 1.38% at six months), and a decrease of the immunosuppressive component of the immune system, with decreases of CD4+CD25+Foxp3+CDA5RA- regulatory T cells (4.97% at baseline to 4.46% at six months), granulocytic myeloid-derived suppressor cells (G-MDSCs) (from 66.1% at baseline to 62.6% at six months) and monocytic (Mo-MDSCs) (8.2% at baseline to 6.2% at six months). These changes were already apparent at 72 h and persisted over six months. SBRT showed an effect on systemic immune cell populations, which is a relevant finding for supporting future combinations of SBRT with immunotherapy for treating lung cancer patients.