Carbon Ion Radiation Therapy for Nonmetastatic Castration-Resistant Prostate Cancer: A Retrospective Analysis.

Purpose: Treatment outcomes of definitive photon radiation therapy for nonmetastatic castration-resistant prostate cancer (nmCRPC) are reportedly unsatisfactory. Carbon ion radiation therapy (CIRT) has shown favorable tumor control in various malignancies, including radioresistant tumors. Therefore, we retrospectively evaluated the clinical outcomes of CIRT for nmCRPC. Methods and Materials: Patients with nmCRPC (N0M0) treated with CIRT at a total dose of 57.6 Gy (relative biologic effectiveness) in 16 fractions or 51.6 Gy (relative biologic effectiveness) in 12 fractions were included. The castration-resistant status received a diagnosis based on prostate-specific antigen kinetics showing a monotonic increase during primary androgen deprivation therapy or the need to change androgen deprivation therapy. Clinical factors associated with patient prognosis were explored. Twenty-three consecutive patients were identified from our database. The median follow-up period was 63.6 months (range, 14.1-120). Results: Seven patients developed biochemical relapse, 6 had clinical relapse, and 4 died of the disease. The 5-year overall survival, local control rate, biochemical relapse-free survival, and clinical relapse-free survival were 87.5%, 95.7%, 70.3%, and 75.7%, respectively. One patient with diabetes mellitus requiring insulin injections and taking antiplatelet and anticoagulant drugs developed grade 3 hematuria and bladder tamponade after CIRT. None of the patients developed grade 4 or worse toxicity. Conclusions: The present findings indicate the acceptable safety and favorable efficacy of CIRT, encouraging further research on CIRT for nmCRPC.

Characterization of the signal transduction cascade for inflammatory gene expression in fibroblasts with ATM-ATR deficiencies after Ionizing radiation.

BACKGROUND AND PURPOSE: Ionizing radiation (IR) induces DNA double-strand breaks (DSBs), leading to micronuclei formation, which has emerged as a key mediator of inflammatory responses after IR. This study aimed to investigate the signaling cascade in inflammatory gene expression using fibroblasts harboring DNA damage response deficiency after exposure to IR. MATERIALS AND METHODS: Micronuclei formation was examined in human dermal fibroblasts derived from patients with deficiencies in ATM, ATR, MRE11, XLF, Artemis, or BRCA2 after IR. RNA-sequencing analysis was performed to assess gene expression, pathway mapping, and the balance of transcriptional activity using the transcription factor-based downstream gene expression mapping (TDEM) method developed in this study. RESULTS: Deficiencies in ATM, ATR, or MRE11 led to increased micronuclei formation after IR compared to normal cells. RNA-seq analysis revealed significant upregulation of inflammatory expression in cells deficient in ATM, ATR, or MRE11 following IR. Pathway mapping analysis identified the upregulation of RIG-I, MDA-5, IRF7, IL6, and interferon stimulated gene expression after IR. These changes were pronounced in cells deficient in ATM, ATR, or MRE11. TDEM analysis suggested the differential activation of STAT1/3-pathway between ATM and ATR deficiency. CONCLUSION: Enhanced micronuclei formation upon ATM, ATR, or MRE11 deficiency activated the cGAS/STING, RIG-I-MDA-5-IRF7-IL6 pathway, resulting in its downstream interferon stimulated gene expression following exposure to IR. Our study provides comprehensive information regarding the status of inflammation-related gene expression under DSB repair deficiency after IR. The generated dataset may be useful in developing functional biomarkers to accurately identify patients sensitive to radiotherapy.

The IL-17-IL-17RA axis is required to promote osteosarcoma progression in mice.

Osteosarcoma is rare but is the most common bone tumor. Diagnostic tools such as magnetic resonance imaging development of chemotherapeutic agents have increased the survival rate in osteosarcoma patients, although 5-year survival has plateaued at 70%. Thus, development of new treatment approaches is needed. Here, we report that IL-17, a proinflammatory cytokine, increases osteosarcoma mortality in a mouse model with AX osteosarcoma cells. AX cell transplantation into wild-type mice resulted in 100% mortality due to ectopic ossification and multi-organ metastasis. However, AX cell transplantation into IL-17-deficient mice significantly prolonged survival relative to controls. CD4-positive cells adjacent to osteosarcoma cells express IL-17, while osteosarcoma cells express the IL-17 receptor IL-17RA. Although AX cells can undergo osteoblast differentiation, as can patient osteosarcoma cells, IL-17 significantly inhibited that differentiation, indicating that IL-17 maintains AX cells in the undifferentiated state seen in malignant tumors. By contrast, IL-17RA-deficient mice transplanted with AX cells showed survival comparable to wild-type mice transplanted with AX cells. Biopsy specimens collected from osteosarcoma patients showed higher expression of IL-17RA compared to IL-17. These findings suggest that IL-17 is essential to maintain osteosarcoma cells in an undifferentiated state and could be a therapeutic target for suppressing tumorigenesis.

HLA Class I Expression Is Associated with DNA Damage and Immune Cell Infiltration into Dysplastic and Neoplastic Lesions in Ulcerative Colitis.

Human leukocyte antigen class I (HLA-I) is considered a genetic pathogen for ulcerative colitis (UC). This study aimed to investigate the significance of DNA damage and HLA-I expression in infiltrating immune cells and immune checkpoint protein PD-L1 expression in dysplasia/colitic cancer (CC) and sporadic colorectal cancer (SCRC). We performed immunohistochemical staining for HLA-I, PD-L1, γH2AX (DNA damage marker), and immune cell markers such as CD8, FOXP3, CD68, and CD163 (in surgically resected specimens from 17 SCRC patients with 12 adjacent normal mucosa (NM) and 9 UC patients with 18 dysplasia/CC tumors. The ratio of membrane HLA-I-positive epithelial cells in UC and dysplasia/CC tissues was significantly higher than that in NM and SCRC. High HLA-I expression in dysplasia/CC was associated with high positivity of γH2AX and PD-L1 expression compared to SCRC. The infiltration of CD8-positive T cells and CD68-positive macrophages in HLA-I-high dysplasia/CC was significantly higher than in UC and SCRC. Dysplasia/CC specimens with DNA damage exhibited high levels of HLA-I-positive epithelial cells with high CD8- and CD68-positive immune cell infiltration compared to UC and SCRC specimens. Targeting DNA damage in UC may regulate immune cell infiltration, immune checkpoint proteins, and carcinogenesis by modulating DNA damage-induced HLA-I antigen presentation.

Efficacy of immune checkpoint inhibitor treatment for head and neck mucosal melanoma recurrence in patients treated with carbon-ion radiotherapy.

BACKGROUND: Carbon-ion radiotherapy (C-ion RT) is effective for head and neck mucosal melanoma (HN-MM), including radioresistant mucosal melanoma. Melanoma also responds effectively to immune checkpoint inhibitors (ICIs). Data on the efficacy and safety of ICIs for HN-MM are insufficient. AIMS: To analyze the efficacy and safety of ICI salvage therapy in patients with HN-MM recurrence after C-ion RT. METHODS AND RESULTS: This retrospective study analyzed the medical records of 52 patients with HN-MM treated with C-ion RT between 2012 and 2020. A dose of 57.6 or 64.0 Gy (relative biological effectiveness) was provided in 16 fractions. The primary endpoint was 3-year overall survival (OS) rate. The median follow-up time was 26.8 months for all patients. A total of 29 patients had local recurrence or distant metastasis, and 16 patients who received ICI therapy. The 3-year OS rate in the ICI group (n = 16) and best supportive care group (n = 13) were 53.8% and 0.0%, respectively (p = 0.837); the difference was not statistically significant. There were no deaths after 1 year among patients who underwent ICI therapy. No adverse events associated with C-ion RT were related to or exacerbated by ICI. CONCLUSION: ICI salvage therapy is effective and safe for patients with HN-MM recurrence after C-ion RT.

CD8-positive Tumor-infiltrating Lymphocytes and Prognosis in Radiotherapy for Uterine Cervical Squamous Cell Carcinoma.

BACKGROUND/AIM: Prognostic factors, including CD8-positive tumor-infiltrating lymphocytes (CD8+TILs), in definitive radiotherapy (RT) for squamous cell carcinoma (SqCC) of the uterine cervix need to be studied. This study aimed to explore these factors in a retrospective cohort. PATIENTS AND METHODS: Patients with SqCC who underwent definitive RT comprising external beam RT and intracavitary brachytherapy at our facility between April 2006 and November 2013 were evaluated. CD8 immunohistochemistry was performed in pre-treatment biopsy samples to analyze the prognostic significance of CD8+TILs in the tumor nest. Positive staining was defined as at least one CD8+ lymphocyte infiltrating the tumor area in the specimen. RESULTS: In total, 150 consecutive patients were included. Among them, 66 (43.7%) patients had International Federation of Gynecology and Obstetrics (FIGO, 2008 edition) stage IIIA or higher progressive disease. The median follow-up period was 61 months. In the entire cohort, the 5-year cumulative rates of overall survival (OS), progression-free survival (PFS), and pelvic recurrence-free rate (PRFR) were 75.6%, 69.6%, and 84.8%, respectively. Of the 150 patients, 120 (80.0%) patients were CD8+TIL positive. The independent favorable prognostic factors were FIGO stage I or II disease, administration of concurrent chemotherapy, and CD8+TILs for OS (p=0.028, 0.005, and 0.038, respectively); FIGO stage I or II disease and CD8+TILs for PFS (p=0.015 and <0.001, respectively); and CD8+TILs for PRFR (p=0.017). CONCLUSION: The presence of CD8+TILs in the tumor nest may be a favorable prognostic factor of survival after definitive RT in patients with SqCC of the uterine cervix.

Carbon-ion radiotherapy for inoperable upper tract ureteral cancer.

AIM: This study aimed to report initial results of hypofractionated carbon-ion radiotherapy (C-ion RT) for inoperable upper tract ureteral cancer. METHODS: Retrospective chart review was performed for five consecutive patients with medically inoperable ureter cancer that was treated with radical C-ion RT between December 2013 and December 2014. The median age of the patients was 80 years (range, 68-84 years). The reasons for inoperability were advanced age, post-contralateral nephrectomy, alcoholic cirrhosis, both advanced age and contralateral renal function degeneracy, and pneumonia. The median size of tumor was 2.8 cm (range, 2.2-4.0 cm). Diagnostic imaging did not identify lymph node metastases or distant metastases in any case. All patients underwent C-ion RT (52.8 Gy relative biological effectiveness; 12 fractions in 3 weeks). The clinical target volume encompassed the growth tumor volume with a 5-mm margin bilaterally; there was a 40-mm margin craniocaudally but the clinical target volume did not encompass the whole ureter. RESULTS: Within a median follow-up time of 32.9 months (range, 24-36 months), two patients died and three remained alive. Neither local recurrence nor regional lymph node metastases were observed. Secondary bladder tumor was observed in four patients, and one patient had a liver metastasis. Grade 1 hematuria was observed in two patients, and Grade 3 pyelonephritis was observed in one patient as acute toxicity. Ureteral obstruction was observed in two patients. CONCLUSION: C-ion RT might be a useful treatment option for inoperable ureter cancer.

Calreticulin Upregulation in Cervical Cancer Tissues From Patients After 10 Gy Radiation Therapy.

Purpose: Understanding the immune response during radiation therapy (RT) in a clinical setting is imperative for maximizing the efficacy of combined RT and immunotherapy. Calreticulin, a major damage-associated molecular pattern that is exposed on the cell surface after RT, is presumed to be associated with the tumor-specific immune response. Here, we examined changes in calreticulin expression in clinical specimens obtained before and during RT and analyzed its relationship with the density of CD8+ T cells in the same patient set. Methods and Materials: This retrospective analysis evaluated 67 patients with cervical squamous cell carcinoma who were treated with definitive RT. Tumor biopsy specimens were collected before RT and after 10 Gy irradiation. Calreticulin expression in tumor cells was evaluated via immunohistochemical staining. Subsequently, the patients were divided into 2 groups according to the level of calreticulin expression, and the clinical outcomes were compared. Finally, the correlation between calreticulin levels and density of stromal CD8+ T cells was evaluated. Results: The calreticulin expression significantly increased after 10 Gy (82% of patients showed an increase; P < .01). Patients with increased calreticulin levels tended to show better progression-free survival, but this was not statistically significant (P = .09). In patients with high expression of calreticulin, a positive trend was observed between calreticulin and CD8+ T cell density, but the association was not statistically significant (P = .06). Conclusions: Calreticulin expression increased after 10 Gy irradiation in tissue biopsies of patients with cervical cancer. Higher calreticulin expression levels are potentially associated with better progression-free survival and greater T cell positivity, but there was no statistically significant relationship between calreticulin upregulation and clinical outcomes or CD8+ T cell density. Further analysis will be required to clarify mechanisms underlying the immune response to RT and to optimize the RT and immunotherapy combination approach.

Association between Tumor Mutational Burden, Stromal CD8+ Tumor-Infiltrating Lymphocytes, and Clinical Factors in Cervical Cancers Treated with Radiotherapy.

BACKGROUND: Tumor mutational burden (TMB) and stromal CD8-positive tumor-infiltrating lymphocytes (CD8+TILs) serve important roles in antitumor immune responses to radiotherapy. This study aimed to elucidate the association between TMB, CD8+TILs, and clinical factors in patients with cervical cancer treated with radiotherapy. METHODS: Patients with squamous cell carcinoma of the uterine cervix treated with definitive radiotherapy, and with available somatic mutation data and immunohistochemical staining data from identical tumor tissues, were enrolled retrospectively. The association between TMB and/or CD8+TIL density and patient characteristics, mutation profiles, and treatment outcome was analyzed. RESULTS: The study analyzed 44 patients (median follow-up period, 61 months). There was no significant correlation between TMB and CD8+TIL density, or between TMB or CD8+TIL density and patient characteristics. TMB-high or CD8+TIL density-low status was associated with worse overall survival and distant metastasis-free survival; the predictive value of these factors became greater when used in combination. TMB-high or CD8+TIL density-high status was associated with ARID1A mutations. CONCLUSIONS: These data indicate independence of TMB and CD8+TIL density and the involvement of ARID1A alterations in antitumor immune responses in patients with cervical cancers treated with radiotherapy, warranting further mechanistic research and prospective validation.

Comparative Analysis of the Antitumor Immune Profiles of Paired Radiotherapy-naive and Radiotherapy-treated Cervical Cancer Tissues.

BACKGROUND/AIM: This study aimed to elucidate the effect of radiotherapy on expression of immune response-related genes in cervical cancer tissues. MATERIALS AND METHODS: Tumor tissues were obtained from 16 patients with cervical cancer before initiation of radiotherapy and after treatment with 10 Gy X-rays, delivered in five fractions. Expression of 730 immune response-related genes was assessed using an nCounter PanCancer Immune Profiling Panel (NanoString Technologies. Seattle, WA, USA). RESULTS: Of the 730 genes examined, 41 showed significant changes (fold change of >1.5 or <0.66) in expression in post-radiotherapy samples (28 up-regulated and 13 down-regulated). Analysis of immune cell type-specific genes suggested predominant upregulation of those related to innate immunity postradiotherapy. Interestingly, cytotoxic T-lymphocyte-associated protein (CTLA4), a key negative regulator of T-cell activation, was marked down-regulated in 93.7% of patients, with an average fold-change of 2.0. CONCLUSION: To our knowledge, this study is the first to show down-regulation of CTLA4 in clinical cervical cancer tissues after treatment with radiotherapy.

Double-layer omics analysis of castration- and X-ray-resistant prostate cancer cells.

Castration-resistant prostate cancer shows resistance to not only androgen deprivation therapy (ADT) but also X-ray therapy. On the other hand, carbon ion beams have a high biological effect and are used for various cancers showing resistance to X-ray therapy. The purposes of this study are to clarify the difference in the sensitivity of Castration-resistant prostate cancer to X-ray and carbon ion beams and to elucidate the mechanism. The androgen-insensitive prostate cancer cell line LNCaP-LA established by culturing the androgen-sensitive prostate cancer cell line LNCaP for 2 years in androgen-free medium was used for this study. First, colony formation assays were performed to investigate its sensitivity to X-ray and carbon ion beams. Next, DNA mutation analysis on 409 cancer-related genes and comprehensive transcriptome analysis (RNA-seq) were performed with a next-generation sequencer. Lethal dose 50 values of X-rays for LNCaP and LNCaP-LA were 1.4 Gy and 2.8 Gy, respectively (P < 0.01). The Lethal dose 50 values of carbon ion beams were 0.9 Gy and 0.7 Gy, respectively (P = 0.09). On DNA mutation analysis, AR mutation was observed specifically in LNCaP-LA. From RNA-seq, 181 genes were identified as differentially expressed genes (DEGs; FDR <0.10, P < 0.00076) between LNCaP and LNCaP-LA. Function analysis suggested that cell death was suppressed in LNCaP-LA, and pathway analysis suggested that the NRF2-pathway involved in intracellular oxidative stress prevention was activated in LNCaP-LA. LNCaP-LA showed X-ray resistance compared to LNCaP and sensitivity to carbon ion beams. The AR mutation and the NRF2-pathway were suggested as causes of resistance.

DNA damage promotes HLA class I presentation by stimulating a pioneer round of translation-associated antigen production.

Antigen presentation by the human leukocyte antigen (HLA) on the cell surface is critical for the transduction of the immune signal toward cytotoxic T lymphocytes. DNA damage upregulates HLA class I presentation; however, the mechanism is unclear. Here, we show that DNA-damage-induced HLA (di-HLA) presentation requires an immunoproteasome, PSMB8/9/10, and antigen-transporter, TAP1/2, demonstrating that antigen production is essential. Furthermore, we show that di-HLA presentation requires ATR, AKT, mTORC1, and p70-S6K signaling. Notably, the depletion of CBP20, a factor initiating the pioneer round of translation (PRT) that precedes nonsense-mediated mRNA decay (NMD), abolishes di-HLA presentation, suggesting that di-antigen production requires PRT. RNA-seq analysis demonstrates that DNA damage reduces NMD transcripts in an ATR-dependent manner, consistent with the requirement for ATR in the initiation of PRT/NMD. Finally, bioinformatics analysis identifies that PRT-derived 9-mer peptides bind to HLA and are potentially immunogenic. Therefore, DNA damage signaling produces immunogenic antigens by utilizing the machinery of PRT/NMD.

Dosimetric analysis of intraocular hemorrhage in nonsquamous head and neck cancers treated with carbon-ion radiotherapy.

BACKGROUND AND PURPOSE: Carbon-ion radiotherapy is an attractive treatment option for unresectable/inoperable, nonsquamous cancers of the head and neck. Intraocular hemorrhage associated with carbon-ion radiotherapy for head and neck cancer is largely an unresearched area; hence, we investigated its incidence and predictive factors. MATERIAL AND METHODS: We evaluated 79 patients (i.e., 158 eyes) with nonsquamous cancers of the head and neck treated by carbon-ion radiotherapy with a follow-up period of ≥12 months. Dosimetric parameters such as Dmax, Dmean and Vd [volume irradiated with "d" Gy (RBE)] and age, gender, primary site, histology and comorbidities were analyzed as predictors of intraocular hemorrhage. RESULTS: Seven (8.9%) of 79 patients (158 eyes) developed intraocular hemorrhage with a median latent period of 24 months (range, 15-47 months). The 5-year cumulative incidence of intraocular hemorrhage was 6%. Dmax and V10-60 for eyeballs, retina and optic nerves were significantly higher in intraocular hemorrhage group than the rest (p <0.001 for Dmax and V10-60). On univariate analysis, V40 ≥0.83 cm3 and ≥0.66 cm3 (p = 0.001) and Dmax ≥54.75 Gy (RBE) and ≥54.58 Gy (RBE) (p = 0.002) for eyeball and retina, respectively, were predictors of intraocular hemorrhage. Additionally, maxillary primary (p = 0.025) and younger age (age <60 years, p = 0.048) were significant risk factors for intraocular hemorrhage. CONCLUSIONS: Dosimetric parameters such as V40 and Dmax for the eyeball, retina and maxillary sinus primary and younger age were significant predictors of intraocular hemorrhage following carbon-ion radiotherapy.

A Preliminary Study of Assessing Gaze, Interoception and School Performance among Children with Neurodevelopmental Disorders: The Feasibility of VR Classroom.

Children with developmental disabilities (DDs) have sensory modulation disorders that interrelate school performance. Virtual reality (VR) has demonstrated the potential to become a neuropsychological assessment modality. This study was conducted to explore the feasibility of the VR classroom for assessing their characteristics of gaze, school performance, and interoception. School-aged children were assigned to the DD group or control group. A VR classroom was designed to evaluate their gaze patterns to distracting events. Interoception was assessed using the Heart Rate Perception test and the Multidimensional Assessment of Interoceptive Awareness (MAIA). The DD group had a significantly longer gaze duration on the virtual teacher during 30-45 s of the VR classroom event (p < 0.05). The mean score of the quiz and the Heart Rate Perception test showed a significant tendency to be lower than the children of the control group. The DD group scored significantly lower in six of eight subscales of the MAIA. These results showed the potential of VR classroom to evaluate the difference of sensory modulation between school-aged children with DDs and typically developed children. Future research is necessary to investigate the validity of the VR environment used in this study.

Carbon-ion Radiotherapy for Inoperable Head and Neck Bone and Soft-tissue Sarcoma: Prospective Observational Study.

BACKGROUND/AIM: Bone and soft-tissue sarcomas of the head and neck have very poor prognoses. This prospective study aimed to investigate the efficacy and safety of carbon-ion radiotherapy (C-ion RT) for bone and soft-tissue sarcoma of the head and neck. PATIENTS AND METHODS: The present study was a prospective clinical study that included 10 consecutive patients diagnosed with bone and soft-tissue sarcoma of the head and neck who were treated with C-ion RT between 2012 and 2018 at our institution. C-Ion RT consisted of 70.4 Gy (relative biological effectiveness) in 16 fractions. RESULTS: The 3-year local control, overall survival, and progression-free survival rates for patients overall were 72.9%, 77.8%, and 36%, respectively. CONCLUSION: The present study demonstrated the efficacy of C-ion RT for bone and soft-tissue sarcoma of the head and neck; adverse events were within the expected range.

Expression of non-homologous end joining factor, Ku80, is negatively correlated with PD-L1 expression in cancer cells after X-ray irradiation.

The growing importance of antitumour immunity by cancer immunotherapy has prompted studies on radiotherapy-induced immune response. Previous studies have indicated that programmed cell death-1 ligand (PD-L1) expression is regulated by DNA damage signalling. However, PD-L1 up-regulation after radiotherapy has not been fully investigated at the clinical level, particularly in the context of expression of DNA repair factors. The present study examined the correlation of mRNA expression between PD-L1 and non-homologous end joining (NHEJ) factors using The Cancer Genome Atlas database analysis. Among NHEJ factors, Ku80 mRNA expression was negatively correlated with PD-L1 mRNA expression levels in several types of cancer (colon adenocarcinoma, breast invasive carcinoma, skin cutaneous melanoma, lung adenocarcinoma, head and neck squamous cell carcinoma, uterine corpus endometrial carcinoma, cervical squamous cell carcinoma and endocervical adenocarcinoma). To verify the negative correlation in clinical samples, the present study analysed whether Ku80 expression levels affected PD-L1 up-regulation after radiotherapy using cervical squamous cell carcinoma samples. Quantitative evaluation using software analysis of immunohistochemically stained slides revealed that patients with low Ku80 positivity in biopsy specimens demonstrated increased PD-L1 expression levels after 10 Gy irradiation (Spearman's rank correlation coefficient=-0.274; P=0.017). Furthermore, PD-L1 induction levels in tumour cells after 10 Gy of irradiation were significantly inversely correlated with Ku80 expression levels (Spearman's rank correlation coefficient=-0.379; P<0.001). The present study also confirmed that short interfering RNA-mediated Ku80 depletion was associated with greater X-ray-induced PD-L1 up-regulation in HeLa cells. These results indicated that radiotherapy could enhance PD-L1 induction in tumour cells with low Ku80 expression in a clinical setting. Furthermore, these data highlighted Ku80 as a potential predictive biomarker for immune checkpoint therapy combined with radiotherapy.

Relationship between oral mucositis and the oral bacterial count in patients with head and neck cancer undergoing carbon ion radiotherapy: A prospective study.

BACKGROUND AND PURPOSE: Acute adverse events, such as oral mucositis, can affect treatment success in patients undergoing head and neck radiotherapy. In this study, we aimed to identify the relationship between oral mucositis and oral bacterial counts during carbon ion radiotherapy (C-ion RT) in patients with head and neck cancer. MATERIALS AND METHODS: This prospective study included patients with head and neck tumors treated with C-ion RT between 2017 and 2019. C-ion RT consisted of treatment at 57.6, 64.0, or 70.4 Gy (relative biological effectiveness) in 16 fractions. Bacterial counts in the saliva and the back of the tongue were measured using a rapid oral bacteria quantification system. The relationship between the oral bacterial count and oral mucositis was subsequently analyzed. RESULTS: In total, 46 patients were included in the analysis. The bacterial count in the saliva gradually increased from the commencement of C-ion RT and peaked at 16 fractions. Bacterial counts at the back of the tongue were already high at the beginning of C-ion RT; however, they decreased with continued treatment, peaked at 16 fractions, and subsequently decreased again. Patients with bacterial counts exceeding the mean before C-ion RT (high-count group) did not experience more severe mucositis than those with counts below the mean (low-count group). However, patients in the high-count group tended to experience faster-onset mucositis and slower healing than those in the low-count group. CONCLUSION: Bacterial counts may aid in the development of clinical strategies for C-ion RT-induced oral mucositis.

High tumor mutational burden predicts worse prognosis for cervical cancer treated with radiotherapy.

PURPOSE: Tumor mutational burden (TMB) is a surrogate biomarker of neo-antigens and high TMB status is associated with favorable response to immune-checkpoint inhibitors (ICIs). This study aimed to elucidate the association between TMB and the outcome of definitive radiotherapy in patients with cervical cancer. MATERIALS AND METHODS: TMB and treatment outcome were retrospectively analyzed in patients with newly diagnosed cervical cancer treated with definitive radiotherapy available with somatic mutation data of pre-treatment tumors obtained using a commercially available gene panel. RESULTS: The study enrolled 98 patients (median follow-up period, 61 months). The median TMB was 9.5 mutations per megabase (range, 3.0-35.5 mutations per megabase). After dichotomization based on this median value, the 5-year overall survival (OS) for TMB-high patients was significantly worse than that of TMB-low patients (61.1% vs. 82.2%). Multivariate analysis identified high TMB status as a significant prognostic factor for worse OS, along with advanced stage, para-aortic lymph node involvement, and absence of concurrent chemotherapy. CONCLUSION: These data indicate that TMB is a potential prognostic factor for worse survival in patients with cervical cancer treated with definitive radiotherapy, thereby providing a rationale for treatment of TMB-high cervical cancers with a combination of ICIs plus radiotherapy. This retrospective study of 98 patients demonstrates for the first time that tumor mutational burden (TMB) is an independent prognostic factor for worse overall survival of patients treated with definitive radiotherapy, providing a rationale for treatment of TMB-high cervical cancers with a combination of immune-checkpoint inhibitors plus radiotherapy.

64Cu-ATSM Predicts Efficacy of Carbon Ion Radiotherapy Associated with Cellular Antioxidant Capacity.

Carbon ion radiotherapy is an emerging cancer treatment modality that has a greater therapeutic window than conventional photon radiotherapy. To maximize the efficacy of this extremely scarce medical resource, it is important to identify predictive biomarkers of higher carbon ion relative biological effectiveness (RBE) over photons. We addressed this issue by focusing on cellular antioxidant capacity and investigated 64Cu(II)-diacetyl-bis(N4-methylthiosemicarbazone) (64Cu-ATSM), a potential radioligand that reflects an over-reduced intracellular environment. We found that the carbon ion RBE correlated with 64Cu-ATSM uptake both in vitro and in vivo. High RBE/64Cu-ATSM cells showed greater steady-state levels of antioxidant proteins and increased capacity to scavenge reactive oxygen species in response to X-rays than low RBE/64Cu-ATSM counterparts; this upregulation of antioxidant systems was associated with downregulation of TCA cycle intermediates. Furthermore, inhibition of nuclear factor erythroid 2-related factor 2 (Nrf2) sensitized high RBE/64Cu-ATSM cells to X-rays, thereby reducing RBE values to levels comparable to those in low RBE/64Cu-ATSM cells. These data suggest that the cellular activity of Nrf2-driven antioxidant systems is a possible determinant of carbon ion RBE predictable by 64Cu-ATSM uptake. These new findings highlight the potential clinical utility of 64Cu-ATSM imaging to identify high RBE tumors that will benefit from carbon ion radiotherapy.