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.

Effects of dose and dose-averaged linear energy transfer on pelvic insufficiency fractures after carbon-ion radiotherapy for uterine carcinoma.

BACKGROUND AND PURPOSE: The correlation between dose-averaged linear energy transfer (LETd) and its therapeutic or adverse effects, especially in carbon-ion radiotherapy (CIRT), remains controversial. This study aimed to investigate the effects of LETd and dose on pelvic insufficiency fractures after CIRT. MATERIAL AND METHODS: Among patients who underwent CIRT for uterine carcinoma, 101 who were followed up for > 6 months without any other therapy were retrospectively analyzed. The sacrum insufficiency fractures (SIFs) were graded according to the Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer toxicity criteria. The correlations between the relative biological effectiveness (RBE)-weighted dose, LETd, physical dose, clinical factors, and SIFs were evaluated. In addition, we analyzed the association of SIF with LETd, physical dose, and clinical factors in cases where the sacrum D50% RBE-weighted dose was above the median dose. RESULTS: At the last follow-up, 19 patients developed SIFs. Receiver operating characteristic curve analysis revealed that the sacrum D50% RBE-weighted dose was a valuable predictor of SIF. Univariate analyses suggested that LETd V10 keV/µm, physical dose V5 Gy, and smoking status were associated with SIF. Cox regression analysis in patients over 50 years of age validated that current smoking habit was the sole risk factor for SIF. Therefore, LETd or physical dose parameters were not associated with SIF prediction. CONCLUSION: The sacrum D50% RBE-weighted dose was identified as a risk factor for SIF. Additionally, neither LETd nor physical dose parameters were associated with SIF prediction.

Risk of secondary malignancy after radiotherapy for breast cancer: long-term follow-up of Japanese patients with breast cancer.

PURPOSE: There have been very few reports of secondary malignancies after breast cancer treatment in Asia, particularly in Japan. This study aimed to evaluate the risk of secondary malignancies after radiotherapy (RT) in Japanese breast cancer patients. METHODS: This single-center retrospective study included patients who underwent RT between July 1961 and September 2006 for postoperative breast cancer. A total of 702 patients with a follow-up period of more than 5 years were analyzed. All malignancies observed at more than 5 years after the start of RT were defined as secondary malignancies. To calculate the relative risk (RR) of secondary malignancies, we applied data from the National Cancer Center in Japan. RESULTS: The median observation period was 9.7 (interquartile range 7.1-18.2) years. The cumulative person-years of observation were 6879.4. The RR of contralateral breast cancer increased by 1.85-fold (95% confidence interval [CI] 1.05-3.26) among patients compared with that among the general population; however, the difference was not significant (p = 0.053). The RR of secondary malignancies other than breast cancer increased by 2.71-fold (95% CI 1.99-3.70, p < 0.001) among the patients compared with the general population. Even when only malignancies detected more than 10 years after RT were defined as secondary malignancies, the RR of secondary malignancies other than breast cancer was 1.91 (95% CI 1.33-2.73, p < 0.001). CONCLUSION: The incidence of secondary malignancies after RT may be somewhat higher in Japanese patients with breast cancer than in the general population.

Clinical advantage and outcomes of computed tomography-based transvaginal hybrid brachytherapy performed only by sedation without general or saddle block anesthesia.

BACKGROUND: Three-dimensional image-guided brachytherapy is the standard of care in cervical cancer radiotherapy. In addition, the usefulness of the so-called "hybrid brachytherapy (HBT)" has been reported, which involves the addition of needle applicators to conventional intracavitary brachytherapy for interstitial irradiation. AIM: To evaluate the clinical outcomes of CT-based HBT consisting of transvaginal insertion of needle applicators (CT-based transvaginal HBT) and only intravenous sedation without general or saddle block anesthesia. METHODS AND RESULTS: This is a retrospective chart review of patients who received definitive radiotherapy, including CT-based transvaginal HBT, between February 2012 and July 2019. The inclusion criteria were as follows: (i) histologically diagnosed disease, (ii) untreated cervical cancer, (iii) International Federation of Gynecology and Obstetrics (FIGO) stage IB1-IVA disease in the 2008 FIGO staging system, and (iv) patients who underwent CT-based transvaginal HBT at least once in a series of intracavitary brachytherapy. Overall, 54 patients fulfilled the eligibility criteria in the present study. The median follow-up period was 32 (IQR, 19-44) months. No patient complained of symptoms such as persistent bleeding or abdominal pain after the treatment. The 3-year local control (LC), disease-free survival, and overall survival rates for all 54 patients were 86.6%, 60.3%, and 90.7% (95% CI [81.3%-100.0%]), respectively. The 3-year LC rate was 87.7% in patients with FIGO III-IVA and 90.4% in tumor size >6.0 cm. The incidence rate of late adverse events, grade ≥3, in the rectum and bladder was 0% and 1.8%, respectively. In the dose-volume histogram analyses, transvaginal HBT increased the dose of HR-CTVD90 by ~7.5% without significantly increasing the dose of organs at risk. CONCLUSION: Considering the favorable clinical outcomes, CT-based transvaginal HBT may be a good option for treating cervical cancer.

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.

Analysis of radiotherapy-induced alteration of CD8+ T cells and PD-L1 expression in patients with uterine cervical squamous cell carcinoma.

Radiotherapy induces an immune response in the cancer microenvironment that may influence clinical outcome. The present study aimed to analyse the alteration of CD8+ T-cell infiltration and programmed death-ligand 1 (PD-L1) expression following radiotherapy in clinical samples from patients with uterine cervical squamous cell carcinoma. Additionally, the current study sought to analyse the association between these immune responses and clinical outcomes. A total of 75 patients who received either definitive chemoradiotherapy or radiotherapy were retrospectively analyzed. CD8+ T-cell infiltration and PD-L1 expression were determined by immunohistochemistry using biopsy specimens before radiotherapy (pre-RT) and after 10 Gy radiotherapy (post-10 Gy). The PD-L1+ rate was significantly increased from 5% (4/75) pre-RT to 52% (39/75) post-10 Gy (P<0.01). Despite this increase in the PD-L1+ rate post-10 Gy, there was no significant association between both pre-RT and post-10 Gy and overall survival (OS), locoregional control (LC) and progression-free survival (PFS). On the other hand, the CD8+ T-cell infiltration density was significantly decreased for all patients (median, 23.1% pre-RT vs. 16.9% post-10 Gy; P=0.038); however, this tended to increase in patients treated with radiotherapy alone (median, 17.7% pre-RT vs. 24.0% post-10 Gy; P=0.400). Notably, patients with high CD8+ T-cell infiltration either pre-RT or post-10 Gy exhibited positive associations with OS, LC and PFS. Thus, the present analysis suggested that CD8+ T-cell infiltration may be a prognostic biomarker for patients with cervical cancer receiving radiotherapy. Furthermore, immune checkpoint inhibitors may be effective in patients who have received radiotherapy, since radiotherapy upregulated PD-L1 expression in cervical cancer specimens.

Carbon-ion Radiotherapy for Isolated Lymph Node Metastasis After Surgery or Radiotherapy for Lung Cancer.

Purpose: Mediastinal and hilar lymph node metastasis is one of the recurrence patterns after definitive treatment of lung cancer. Salvage radiotherapy (RT) can be a treatment option for lymph node metastasis. However, the usefulness of additional RT remains unclear after surgery or RT for the primary lung tumor. We retrospectively evaluated the efficacy and safety of hypofractionated carbon-ion RT for isolated lymph node metastasis. Methods and Materials: Between April 2013 and August 2016, 15 consecutive patients with isolated lymph node metastasis underwent carbon-ion RT. The pretreatment evaluations confirmed the isolated lymph node metastasis and the absence of local recurrence or distant metastasis, which was oligometastatic disease. The median age was 72 (range, 51-83) years, with 11 male patients. The first treatments for primary lung tumors were carbon-ion RT for 8 patients and surgery for 7 patients. There were 9 adenocarcinomas, 4 squamous cell carcinomas, 1 adenosquamous cell carcinoma, and 1 mucoepidermoid carcinoma. Most patients (93%) were irradiated with 52.8 Gy relative biological effectiveness in 12 fractions for 3 weeks. There were no patients treated with concurrent or adjuvant therapy such as chemotherapy, molecular-targeted therapy, or immunotherapy. Adverse events were evaluated according to the Common Terminology Criteria for Adverse Events (version 4.0). Results: The median follow-up for surviving patients was 28 months. One patient experienced local lymph node recurrence, and the 2-year local control rate was 92% for all patients. Distant metastasis was observed in 7 patients, and 2-year progression-free survival rate was 47%. During follow-up, there were 4 deaths from lung cancer, and the 2-year overall survival rate was 75%. There were 2 patients with acute grade 2 esophagitis and 2 with late grade 2 cough, which were improved by conservative therapy. There were no other grade 2 or higher adverse events. Conclusions: Hypofractionated carbon-ion RT showed excellent local control and overall survival without severe toxicities in lung cancer patients with isolated lymph node metastasis after surgery or carbon-ion RT for primary lung tumors. A multi-institutional prospective study is required to establish the efficacy and safety of carbon-ion RT.