Sublobar Resection versus Stereotactic Body Radiation Therapy for Clinical Stage I Non–Small Cell Lung Cancer: A Study Using Data from the Korean Nationwide Lung Cancer Registry / Journal of the Korean Cancer Association, 대한암학회지

Purpose@#Stereotactic body radiotherapy (SBRT) had been increasingly recognized as a favorable alternative to surgical resection in patients with high risk for surgery. This study compared survival outcomes between sublobar resection (SLR) and SBRT for clinical stage I non–small cell lung cancer (NSCLC). @*Materials and Methods@#Data were obtained from the Korean Association of Lung Cancer Registry, a sampled nationwide database. This study retrospectively reviewed 382 patients with clinical stage I NSCLC who underwent curative SLR or SBRT from 2014 to 2016. @*Results@#Of the patients, 43 and 339 underwent SBRT and SLR, respectively. Patients in the SBRT group were older and had worse pulmonary function. The 3-year overall survival (OS) rate was significantly better in the SLR group compared with the SBRT group (86.6% vs. 57%, log-rank p < 0.001). However, after adjusting for age, sex, tumor size, pulmonary function, histology, smoking history, and adjuvant therapy, treatment modality was not an independent prognostic factor for survival (hazard ratio, 0.99; 95% confidence interval, 0.43 to 2.77; p=0.974). We performed subgroup analysis in the following high-risk populations: patients who were older than 75 years; patients who were older than 70 years and had diffusing capacity of lung for carbon monoxide ≤ 80%. In each subgroup, there were no differences in OS and recurrence-free survival between patients who underwent SLR and those who received SBRT. @*Conclusion@#In our study, there were no significant differences in terms of survival or recurrence between SBRT and SLR in medically compromised stage I NSCLC patients. Our findings suggest that SBRT could be considered as a potential treatment option for selected patients.

Recent Trends of Medical Expenses Associated with Radiation Therapy in Korea Based on HIRA Big Data / Journal of the Korean Cancer Association, 대한암학회지

Purpose@#We aimed to determine the trends in the use of radiotherapy (RT) and the expenses associated with it in South Korea. @*Materials and Methods@#The statistical data of the claims and reimbursement records provided on the Health and Insurance Review and Assessment Service website were utilized. This included information such as the number of patients, fractions, medical expenses according to treatment codes, in/outpatient, sex, age, and regions of hospitals. We analyzed data from 2016 to 2020. @*Results@#With a growing RT infrastructure and an increase in the number of radiation oncologists, the expenses for RT were 605.5 million USD in 2020, which had increased 1.5 times from 394.7 million USD in 2016. This growth was mainly because of the increased usage of advanced RT techniques. Furthermore, the proportion of intensity-modulated radiation therapy (IMRT) expenses in the total expenses increased by 1.6 times from 48.8% in 2016 to 76.9% in 2020. Advanced techniques were used more commonly in older individuals or children. However, the proportion of IMRT expenses increased mostly in young women. Additionally, geographical differences in RT use and expense were observed, although the gap in the IMRT fractions decreased among the regions. @*Conclusion@#Recent medical expenses associated with RT in Korea have increased in tandem with technological advances and changes in demographics.

Re-irradiation with Moderate Hypo-fractionation Using Intensity Modulated Photon or Proton Radiation Therapy in Locally Recurrent Squamous Cell Carcinoma of Nasopharynx / Journal of the Korean Cancer Association, 대한암학회지

Purpose@#This study aimed to analyze the treatment outcomes of locally recurrent nasopharyngeal cancer (NPC) patients following moderate hypo-fractionation re-irradiation (re-RT). @*Materials and Methods@#Sixty locally recurrent NPC patients underwent hypo-fractionation re-RT. Forty-eight point three percentage had rT3-4, and 30.0% did keratinizing squamous cell carcinoma. Intensity-modulated radiation therapy (IMRT), with or without intensity-modulated proton therapy (IMPT), was used in 66.7% of patients. @*Results@#With the median follow-up of 22 months (range, 2 to 254 months), 31 patients (51.7%) died, 38 (63.3%) developed further treatment failure, and 30 (50.0%) developed ≥ grade 3 toxicity (including seven grade 5) at time of analysis. The 2- and 5-year rates of overall survival, local failure-free survival, and ≥ grade 3 toxicity-free survival were 57.9% and 45.8%, 64.1% and 52.5%, and 54.8% and 44.9%, respectively. In multivariate analyses, worse factors for overall survival (OS) were iT3-4 (p=0.010) and age at re-RT ≥ 53 years (p=0.003), those for local failure-free survival (LFFS) were rT3-4 (p=0.022) and rN0-1 (p=0.035), and those for toxicity-free survival (TFS) were iT3-4 (p=0.020) and re-IMRT/IMPT (p=0.030), respectively. Cumulative dose or fraction size ≥ 3 Gy at re-RT, however, showed no significance for OS, LFFS and TFS. @*Conclusion@#Current re-RT with modern RT techniques by moderate hypo-fractionation scheme seemed feasible in treating locally recurrent NPC patients.

Patterns of Proton Beam Therapy Use in Clinical Practice between 2007 and 2019 in Korea / Journal of the Korean Cancer Association, 대한암학회지

Purpose@#Proton beam therapy (PBT) is a state-of-the-art technology employed in radiotherapy (RT) for cancer patients. This study characterized how PBT has been used in clinical practice in Korea. @*Materials and Methods@#Patients who received any type of RT between 2007 and 2019 were identified from the radiation oncology registry of the two PBT facilities operating in Korea (National Cancer Center and Samsung Medical Center). The chi-square test was used to identify patient- and treatment-related characteristics associated with the receipt of PBT. @*Results@#A total of 54,035 patients had been treated with some form of RT in the two institutions, of whom 5,398 received PBT (10.0%). The number of patients who receive PBT has gradually increased since PBT first started, from 162 patients in 2007 to 1,304 patients in 2019. Among all types of cancer, PBT use in liver cancer has been steadily increasing from 20% in 2008-2009 to 32% in 2018-2019. In contrast, that in prostate cancer has been continuously decreasing from 20% in 2008-2009 to < 10% in 2018-2019. Male sex, very young or old age, stage I-II disease, residency in non-capital areas, a definitive setting, a curative treatment aim, enrollment in a clinical trial, re-irradiation and insurance coverage were significantly associated with the receipt of PBT (all p < 0.05). @*Conclusion@#Since PBT started in Korea, the number of patients receiving PBT has increased to more than 1,000 per year and treatment indications have expanded. Liver cancer is the most common primary tumor among all PBT cases in Korea.

Physical and Biological Characteristics of Particle Therapy for Oncologists / Journal of the Korean Cancer Association, 대한암학회지

Particle therapy is a promising and evolving modality of radiotherapy that can be used to treat tumors that are radioresistant to conventional photon beam radiotherapy. It has unique biological and physical advantages compared with conventional radiotherapy. The characteristic feature of particle therapy is the “Bragg peak,” a steep and localized peak of dose, that enables precise delivery of the radiation dose to the tumor while effectively sparing normal organs. Especially, the charged particles (e.g., proton, helium, carbon) cause a high rate of energy loss along the track, thereby leading to high biological effectiveness, which makes particle therapy attractive. Using this property, the particle beam induces more severe DNA double-strand breaks than the photon beam, which is less influenced by the oxygen level. This review describes the general biological and physical aspects of particle therapy for oncologists, including non-radiation oncologists and beginners in the field.

Physical and Biological Characteristics of Particle Therapy for Oncologists / Journal of the Korean Cancer Association, 대한암학회지

Particle therapy is a promising and evolving modality of radiotherapy that can be used to treat tumors that are radioresistant to conventional photon beam radiotherapy. It has unique biological and physical advantages compared with conventional radiotherapy. The characteristic feature of particle therapy is the “Bragg peak,” a steep and localized peak of dose, that enables precise delivery of the radiation dose to the tumor while effectively sparing normal organs. Especially, the charged particles (e.g., proton, helium, carbon) cause a high rate of energy loss along the track, thereby leading to high biological effectiveness, which makes particle therapy attractive. Using this property, the particle beam induces more severe DNA double-strand breaks than the photon beam, which is less influenced by the oxygen level. This review describes the general biological and physical aspects of particle therapy for oncologists, including non-radiation oncologists and beginners in the field.

Radiation Therapy Outcome and Clinical Features of Duodenal-Type Follicular Lymphoma / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: Duodenal-type follicular lymphoma (FL) is a rare variant of FL. There is still no consensus on the initial treatment, and clinical features including endoscopic findings are not familiar to most physicians. The objective of this study was to evaluate the outcome of patients who were initially treated with radiation therapy for duodenal-type FL. MATERIALS AND METHODS: We retrospectively analyzed 20 patients who were consecutively diagnosed with duodenal-type FL between 2008 and 2017. All patients received radiation therapywith curative intent. RESULTS: The median age of the patients was 52 years (range, 26 to 66 years), and females were predominant. Most patients (n=18, 90%) had stage I disease, and were diagnosed by a regular health examination in an asymptomatic state. The histological grade was one in 19 patients (95%), and the endoscopic findings were diffuse nodular (n=8), whitish granular (n=8), and mixed pattern (n=4). Radiation therapy was delivered to 17 patients with 24 Gy in 12 fractions, and to three patients with 30.6-36 Gy in 18 fractions. All patients were evaluated with endoscopy for response to radiation therapy, and complete response was achieved in 19 patients (95%). At the time of analysis, all patients survived without any evidence of late toxicities related with radiation therapy. CONCLUSION: Taken together, radiation therapy alone could be effective in controlling duodenal lesion. A further study with longer follow-up duration is warranted to confirm our findings.

Clinical outcomes in patients treated with radiotherapy after surgery for cervical cancer

PURPOSE: The purpose of this study was to analyze clinical outcomes from cervical cancer and stratify patients into risk groups for prognostic factors for early-stage disease. MATERIALS AND METHODS: We retrospectively reviewed patients with stage IB or IIA cervical cancer treated with adjuvant radiotherapy (RT) or concurrent chemoradiotherapy (CCRT) following primary surgery at Samsung Medical Center from 2001 to 2011. Adjuvant RT was added for patients with intermediate-risk factors, and adjuvant CCRT was performed on high-risk patients after surgery. RESULTS: We reviewed 247 patients—149 in the high-risk group and 98 in intermediate-risk group. The median follow-up was 62 months. Loco-regional failure (LRF) alone occurred in 7 patients (2.8%), distant metastasis alone in 37 patients (15.0%) and LRF with DM in 4 patients (1.6%). The 5-year disease-free survival (DFS) and overall survival (OS) rates for both groups were 79.7% and 87.6%, respectively. In the high-risk group, the 5-year DFS and OS probabilities were 72.5% and 81.9%, respectively. Histologic type, pathologic tumor size, and the number of pelvic lymph node (PLN) metastasis were significant prognostic factors for DFS and OS. We suggest a scoring system (0–3) using these prognostic factors to predict poor prognosis in high-risk patients. Using this system, patients with higher scores have higher recurrence and lower survival rates. CONCLUSION: In the high-risk cervical-cancer group who received primary surgery and adjuvant CCRT, non-squamous type, large tumor size and the number of PLN metastasis were significant prognostic factors, and the number of these factors was associated with survival rates.

Activation of DDR2 Involved in Atherosclerosis by Oxidative Stress

BACKGROUND: Reactive Oxygen species have been known to be a key factor to promote atherosclerosis. DDR2(Discoidin Domain Receptor 2) is a cell surface receptor tyrosine kinase which is activated by fiber collagen. Recently, DDR2 was suggested to be involved in activation of smooth muscle cell in blood vessel of atherosclerosis. METHODS: The effect of antioxidant, N-acetyl cysteine and H2O2(Hydrogen peroxide) in the activation of DDR2 by collagen was studied using HEK293 cells expressing DDR2. The direct activation of DDR2 tyrosine kinase domain by tyrosine phosphorylation upon the treatment of H2O2 was analysed after the kinase domain was expressed in sf9 cells. RESULTS: H2O2 enhanced DDR2 auto-phosphorylation and its cellular signaling to induce MMP-1 expression. However N-acetyl cysteine suppressed the DDR2 activation. The reactive oxygen induced tyrosine phosphorylation in DDR2 tyrosine kinase domain to activate its tyrosine kinase activity. CONCLUSIONS: DDR2 activity can be up-regulated by oxidative stress and this provides a mechanism that DDR2 plays a critical role when reactive oxygen species promote atherosclerosis. Therefore inhibition of the activated DDR2 could be a new therapeutic strategy for atherosclerosis.

Biochemical characterizations reveal different properties between CDK4/cyclin D1 and CDK2/cyclin A

CDK2 and CDK4 known promoter of cell cycling catalyze phosphorylation of RB protein. Enzyme specificity between two CDKs that work at a different cell cycle phase is not clearly understood. In order to define kinase properties of CDK2 and CDK4 in complex with cycline A or cycline D1 in relation to their respective role in cell cycling regulation, we examined enzymatic properties of both CDK4/cycline D1 and CDK2/cycline A in vitro. Association constant, Km for ATP in CDK4/cyclin D1 was found as 418 micrometer, a value unusually high whereas CDK2/cyclin A was 23 micrometer, a value close to most of other regulatory protein kinases. Turnover value for both CDK4/cyclin D1 and CDK2/cyclin A were estimated as 3.4 and 3.9 min(-1)respectively. Kinetic efficiency estimation indicates far over one order magnitude less efficiency for CDK4/cyclin D1 than the value of CDK2/cycline A (9.3 pM(-1)min(-1)and 170 pM(-1)min(-1)respectively). In addition, inhibition of cellular CDK4 caused increase of cellular levels of ATP, even though inhibition of CDK2 did not change it noticeably. These data suggest cellular CDK4/cyclin D1 activity is tightly associated with cellular ATP concentration. Also, analysis of phosphorylated serine/threonine sites on RB catalyzed by CDK4/cyclin D1 and CDK2/cyclin A showed significant differences in their preference of phosphorylation sites in RB C-terminal domain. Since RB is known to regulate various cellular proteins by binding and this binding is controlled by its phosphorylation, these data shown here clearly indicate significant difference in their biochemical properties between CDK4/cyclin D1 and CDK2/cyclin A affecting regulation of cellular RB function.