1. Combining radiotherapy and immunotherapy in definitive treatment of head and neck squamous cell carcinoma : review of current clinical trialsGaber Plavc, Primož Strojan, 2020, review article Abstract: Head and neck squamous cell carcinoma (HNSCC) presents as locally advanced disease in a majority of patients and is prone to relapse despite aggressive treatment. Since immune checkpoint inhibitors (ICI) have shown clinically significant efficacy in patients with recurrent/metastatic HNSCC (R/M HNSCC), a plethora of trials are investigating their role in earlier stages of disease. At the same time, preclinical data showed the synergistic role of concurrently administered radiotherapy and ICIs (immunoradiotherapy) and explained several mechanisms behind it. Therefore, this approach is prospectively tested in a neoadjuvant, definitive, or adjuvant setting in non-R/M HNSCC patients. Due to the intricate relationship between host, immunotherapy, chemotherapy, and radiotherapy, each of these approaches has its advantages and disadvantages. In this narrative review we present the biological background of immunoradiotherapy, as well as a rationale for, and possible flaws of, each treatment approach, and provide readers with a critical summary of completed and ongoing trials. Conclusions. While immunotherapy with ICIs has already become a standard part of treatment in patients with R/M HNSCC, its efficacy in a non-R/M HNSCC setting is still the subject of extensive clinical testing. Irradiation can overcome some of the cancer%s immune evasive manoeuvres and can lead to a synergistic effect with ICIs, with possible additional benefits of concurrent platinum-based chemotherapy. However, the efficacy of this combination is not robust and details in trial design and treatment delivery seem to be of unprecedented importance.
Keywords: head and neck neoplasms, immunoradiotherapy, radiotherapy, immunotherapy
Published in DiRROS: 16.07.2024; Views: 8; Downloads: 3
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3. Pulsed low dose-rate irradiation response in isogenic HNSCC cell lines with different radiosensitivityVesna Todorović, Ajda Prevc, Martina Nikšić Žakelj, Monika Savarin, Simon Buček, Blaž Grošelj, Primož Strojan, Maja Čemažar, Gregor Serša, 2020, original scientific article Abstract: . Management of locoregionally recurrent head and neck squamous cell carcinomas (HNSCC) is challenging due to potential radioresistance. Pulsed low-dose rate (PLDR) irradiation exploits phenomena of increased radiosensitivity, low-dose hyperradiosensitivity (LDHRS), and inverse dose-rate effect. The purpose of this study was to evaluate LDHRS and the effect of PLDR irradiation in isogenic HNSCC cells with different radiosensitivity. Materials and methods. Cell survival after different irradiation regimens in isogenic parental FaDu and radioresistant FaDu-RR cells was determined by clonogenic assay; post irradiation cell cycle distribution was studied by flow cytometry; the expression of DNA damage signalling genes was assesed by reverse transcription-quantitative PCR. Results. Radioresistant Fadu-RR cells displayed LDHRS and were more sensitive to PLDR irradiation than parental FaDu cells. In both cell lines, cell cycle was arrested in G2/M phase 5 hours after irradiation. It was restored 24 hours after irradiation in parental, but not in the radioresistant cells, which were arrested in G1-phase. DNA damage signalling genes were under-expressed in radioresistant compared to parental cells. Irradiation increased DNA damage signalling gene expression in radioresistant cells, while in parental cells only few genes were under-expressed. Conclusions. We demonstrated LDHRS in isogenic radioresistant cells, but not in the parental cells. Survival of LDHRSpositive radioresistant cells after PLDR was significantly reduced. This reduction in cell survival is associated with variations in DNA damage signalling gene expression observed in response to PLDR most likely through different regulation of cell cycle checkpoints.
Keywords: DNA damage, isogenic cell lines, low dose irradiation, pulsed low dose-rate irradiation, radiosensitivity
Published in DiRROS: 12.07.2024; Views: 40; Downloads: 14
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8. Prognostic value of some tumor markers in unresectable stage IV oropharyngeal carcinoma patients treated with concomitant radiochemotherapyErika Šoba, Marjan Budihna, Alojz Šmid, Nina Gale, Hotimir Lešničar, Branko Zakotnik, Primož Strojan, 2015, original scientific article Abstract: The aim of the study was to investigate how the expression of tumor markers p21, p27, p53, cyclin D1, EGFR, Ki-67, and CD31 influenced the outcome of advanced inoperable oropharyngeal carcinoma patients, treated with concomitant radiochemotherapy. Patients and methods. The pretreatment biopsy specimens of 74 consecutive patients with inoperable stage IV oropharyngeal squamous cell carcinoma treated with concomitant radiochemotherapy were in retrospective study processed by immunochemistry for p21, p27, p53, cyclin D1, EGFR, Ki-67, and CD31. Disease-free survival (DFS) was assessed according to the expression of tumor markers. Results. Patients with a high expression of p21 (%10%), p27 (>50%), Ki-67 (>50%), CD31 (>130 vessels/mm2) and low expression of p53 (<10%), cyclin D1 (<10%) and EGFR (<10%) (favorable levels - FL) had better DFS than patients with a low expression of p21 (<10%), p27 (%50%), Ki-67 (%50%), CD31 (<130 vessels/mm2) and high expression of p53 (%10%), cyclin D1 (%10%) and EGFR (%10%) (unfavorable levels - UL). However, statistical significance in survival between FL and UL was achieved only for p27 and cyclin D1. DFS significantly decreased with an increasing number of markers with an unfavorable level per tumor (1%4 vs. 5%7) (78% vs. 32%, respectively; p = 0.004). The number of markers per tumor with UL of expression retained prognostic significance also in multivariate analysis. Conclusions. Statistical significance in survival between FL and UL emerged only for p27 and cyclin D1. The number of markers per tumor with UL of expression was an independent prognostic factor for an adverse outcome .
Keywords: oropharynx, radiochemotherapy, tumor markers
Published in DiRROS: 22.04.2024; Views: 241; Downloads: 63
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9. Distant metastasis of rectal adenocarcinoma in a temporary tracheostomaRobert Šifrer, Primož Strojan, Nina Zidar, Miha Žargi, Aleš Grošelj, Milena Krajinović, 2014, review article Keywords: temporary tracheostoma, distant metastasis, rectal adenocarcinoma, rak (medicina), traheostoma, zasevki, metastaziranje, žlezni rak
Published in DiRROS: 11.04.2024; Views: 257; Downloads: 123
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