Sang Hee Youn

Background: Testicular irradiation presents technical challenges due to the temperature-dependent cremasteric reflex causing positional variability, yet detailed immobilization protocols addressing this issue and cone-beam computed tomography (CBCT)-based setup data remain lacking. This formative and preliminary single-patient descriptive technical report describes a temperature-controlled immobilization technique and reports preliminary setup observations from its clinical application. Methods: A 74-year-old male with primary testicular diffuse large B-cell lymphoma (DLBCL) received prophylactic contralateral testicular irradiation. The immobilization protocol combined a custom thermoplastic device with infrared warming to maintain the scrotal surface temperature at 36–36.5 °C, intended to facilitate a relaxed scrotal position prior to and during each fraction under temperature-controlled conditions. Treatment was delivered using a three-field three-dimensional conformal radiotherapy (3D-CRT) technique (30.6 Gy in 17 fractions), and seven CBCT scans were used to document interfraction setup measurements. Results: The treatment was completed as planned with adequate target coverage (clinical target volume [CTV] D97% = 100%) and minimal organ-at-risk (OAR) doses. Setup measurements showed a CTV root-mean-square displacement (RMS) of 3.8 mm and a mean Dice similarity coefficient (DSC) of 0.85, while the testis alone showed an RMS of 5.2 mm and a mean DSC of 0.73. Conclusions: The temperature-controlled immobilization technique was feasibly implemented, and the setup measurements observed during its application showed a CTV RMS of 3.8 mm and a mean DSC of 0.85. These findings may provide a practical reference for institutions encountering this rare clinical scenario.

Primary squamous cell carcinoma (SCC) of the prostate is a rare and biologically aggressive malignancy lacking a standardized management strategy. De novo primary SCC arising without prior androgen deprivation therapy or radiotherapy is uncommon and presents significant diagnostic and therapeutic challenges. We present the clinical presentation, diagnostic evaluation, treatment strategy, and early therapeutic response of de novo primary SCC of the prostate in a 56-year-old male with end-stage renal disease on maintenance hemodialysis. The patient presented with gross hematuria and a bulky prostate mass invading the bladder with bilateral pelvic lymphadenopathy despite low prostate-specific antigen (PSA) levels. Histopathological and immunohistochemical analyses confirmed pure SCC, staged as cT4N1M0. Because systemic chemotherapy was contraindicated and surgery was not feasible, definitive whole-pelvis radiotherapy with a simultaneous integrated boost was administered. Marked tumor regression was observed one month after treatment. Subsequent imaging demonstrated extensive tumor necrosis with fistulous communication in the context of locally invasive disease. Because long-term oncologic durability could not be assessed owing to non-oncologic clinical deterioration, these findings suggest that definitive radiotherapy may provide meaningful locoregional tumor control in selected medically inoperable patients with de novo prostatic SCC.

Accurate real-time dosimetry is key in megavoltage radiotherapy; however, many detectors require external biasing or complex instrumentation. This study evaluated thin-film CdTe solar cells operating in photovoltaic (zero-bias) mode as medical dosimeters. Superstrate ITO/CdS/CdTe/Cu/Au devices were fabricated and irradiated with 6-MV photons from a clinical linear accelerator to 20 kGy cumulative dose. Electrical and dosimetric properties were assessed based on AM 1.5 current–voltage measurements, external quantum efficiency (EQE), dose linearity, dose-rate dependence, field-size dependence, percentage depth dose (PDD), and one-month reproducibility. With increasing dose (5–20 kGy), the open-circuit voltage and fill factor decreased by ~2–3%, the short-circuit current density by ~10%, retaining ~87% initial efficiency. Series and shunt resistances were stable, while EQE decreased uniformly (~5%), indicating degradation mainly from increased nonradiative recombination. Dose–signal linearity remained intact, and post-irradiation sensitivity loss was corrected with a single calibration factor. Dose-rate dependence was minor; low reverse bias (~3–7 V) enhanced response without nonlinearity. Field-size and PDD responses agreed with ionization chamber data within ~1%, and weekly stability was within ~1%. Parallel stacking of two cells increased signal nearly linearly. CdTe solar-cell detectors thus enable zero-bias, real-time, stable, and scalable dosimetry and strongly agree with reference standards.

Gastric cancer is the fifth most common disease in the world and the fourth most common cause of death. It is diagnosed through esophagogastroduodenoscopy with biopsy; however, there are limitations in finding lesions in the early stages. Recently, research has been actively conducted to use liquid biopsy to diagnose various cancers, including gastric cancer. Various substances derived from cancer are reflected in the blood. By analyzing these substances, it was expected that not only the presence or absence of cancer but also the type of cancer can be diagnosed. However, the amount of these substances is extremely small, and even these have various variables depending on the characteristics of the individual or the characteristics of the cancer. To overcome these, we collected methylated DNA fragments using MeDIP and compared them with normal plasma to characterize gastric cancer tissue or patients’ plasma. We attempted to diagnose gastric cancer using the characteristics of cancer reflected in the blood through the cancer tissue and patients’ plasma. As a result, we confirmed that the consistency of common methylated fragments between tissue and plasma was approximately 41.2% and we found the possibility of diagnosing and characterizing cancer using the characteristics of the fragments through SFR and 5′end-motif analysis.

Gastric cancer is the 5th most common disease in the world and the 4th most common cause of death. It is diagnosed through esophagogastroduodenoscopy with biopsy, however there are limitations in finding lesions in the early stages. Recently, research has been actively conducted to use liquid biopsy to diagnose various cancers, including gastric cancer. Various substances derived from cancer are reflected in the blood. By analyzing these substances, it was expected that not only the presence or absence of cancer but also the type of cancer can be diagnosed. However, the amount of these substances is extremely small, and even these have various variables depending on the characteristics of the individual or the characteristics of the cancer. To overcome these, we collected methylated DNA fragments using MeDIP and compared them with normal plasma to characterize gastric cancer tissue or patient’s plasma. And we attempted to diagnose gastric cancer using the characteristics of cancer reflected in the blood through the cancer tissue and patient’s plasma. As a result, we confirmed that the consistency of common methylated fragments between tissue and plasma was approximately 41.2%, and found the possibility of diagnosing and characterizing cancer using the characteristics of the fragments through SFR and 5'end-motif analysis.

Introduction: The treatment for advanced-stage or refractory cutaneous T-cell lymphoma (CTCL) is largely palliative. Due to the rarity of the disease, there are few randomized controlled trials and large-scale prospective studies. Therefore, the treatment of advanced-stage CTCL remains challenging. Patient concerns and diagnosis: A 64-years-old man who had received narrowband UVB phototherapy for several years presented with a generalized rash with widespread polycyclic erosions and painful ulcers on his hands and feet. We restaged him as stage III CTCL. Interventions and outcomes: He was treated with high-dose radiation for curative purposes and 3-dimensional conformal radiation therapy to both hands and feet. At the 2-year follow-up after the end of radiotherapy, the irradiated skin had recovered to normal soft, smooth skin with localized fibrosis and hypopigmented skin. He reported an excellent quality of life, and his hands and feet were free to move. Conclusion: CTCL at an advanced stage could require dose escalation with local radiotherapy for curative purposes. High-dose 3-dementional conformal radiation therapy could be effective and has tolerable toxicities.

Purpose: We examined regression patterns in pediatric optic pathway gliomas (OPGs) after proton beam therapy (PBT) and evaluated local control and visual outcomes.Methods: A total of 42 brain magnetic resonance imaging (MRI) scans from seven consecutive sporadic OPGs that were initially treated with chemotherapy and received PBT between June 2007 and September 2016 at the National Cancer Center, Korea were analyzed. Patients underwent brain MRI regularly before and after PBT. Total tumor, cystic lesion, and solid enhancing lesion area delineation and volume calculations were performed on gadolinium‐enhanced T1‐weighted MRI using Eclipse version 13, Varian.Results: The median follow‐up period after PBT was 70 months (range 47–88). The median age at the time of PBT was 7 years (range 4–16) and the median duration of chemotherapy before referral to PBT center was 25 months (range 3–70). The median time to the greatest increase in cystic volume was 32 months (range 12–43) after PBT. Solid enhancing lesion volume gradually decreased throughout the follow‐up period. On an individual basis, total volume change was varied. However, on average, it regressed, although at a slower rate than solid enhancing lesion volume did. The local control rate was 85.7% (5‐year progression‐free survival rate, 80%; 5‐year overall survival rate, 100%) and the rate of vision preservation was 71.4% (five of seven patients).Conclusion: The regression patterns in pediatric OPGs after PBT involve significant cystic change. Therefore, total volume is not appropriate for evaluating response. Care by a multidisciplinary team is necessary to manage clinical symptoms related to radiologic changes.

Background: A high proportion of pediatric patients with brain tumors (BTs) are known to experience a decline in neurocognitive function after treatment. We prospectively examined neuropsychological functioning of patients with BTs of varying tumor types at different time points before, during, and after proton beam therapy.Materials and methods: A total of 98 patients with posterior fossa tumors (PFTs; n = 33), germ cell tumors (GCTs; n = 52), and other supratentorial tumors (STTs; n = 13) underwent baseline neuropsychological assessments and 57 patients underwent follow‐up assessments.Results: All groups displayed significantly lower performance intelligence quotient (PIQ) and processing speed (PS) scores than the normative means at baseline. The PFT group exhibited significantly lower scores for full‐scale IQ, PIQ, PS, attention, and executive function. The GCT group displayed full‐scale IQ scores within the normal range, but a significantly high proportion had memory deficits. In the STT group, all functions except for the PIQ and PS were intact. Longitudinal evaluations demonstrated stable global IQ scores over time in all groups. In the PFT group, verbal comprehension, attention, and PS improved over time. However, in the GCT group, verbal IQ scores declined significantly and psychological problems worsened over time, which were correlated with poorer neurocognitive function at 3–5 years after treatment. In the STT group, no significant changes were observed.Conclusion: Because patients with BTs exhibit various types of neurocognitive deficit before radiotherapy, early cognitive treatment tailored to the tumor type maybe beneficial. Interventions for psychological problems and memory function may be necessary, especially for patients with GCT.

Objective The aim of this study was to compare the clinical outcomes of chemoradiotherapy with or without bevacizumab in patients with newly diagnosed International Federation of Gynecology and Obstetrics (FIGO) stage IVB cervical cancer. Methods 41 patients with stage IVB cervical cancer who underwent chemoradiotherapy between August 2015 and December 2017 were retrospectively analyzed. This study included 11 patients who received bevacizumab before or after radiotherapy (group A) and 30 patients who received conventional chemoradiotherapy without bevacizumab (group B). We excluded the following patients: those with dual primary cancers; those whose pathologic diagnosis was neither squamous cell carcinoma nor adenocarcinoma; those who did not undergo radiotherapy; or those from whom follow-up data could not be collected. We analyzed the treatment responses, toxicities, progression-free survival, and overall survival rates. Results A total of 41 patients were included in the analysis. The median follow-up was 19 months (range 3–108). The response rates at 3 months after treatment were 90.9% in group A and 83.3% in group B (p=0.54). After completing all treatments, the complete response rates were 81.8% in group A and 47% in group B (p=0.04). Grade ≥3 gastrointestinal toxicities, including bleeding, fistula, perforation, and obstruction, were more frequent in group A (54.5%) than in group B (6.7%) (p=0.003). The 12 month progression-free survival and overall survival rates were similar in both arms (12 month progression-free survival: 45.5% vs 46.7%, respectively, p=0.22; 12 month overall survival: 81.8% vs 72.9%, respectively, p=0.57). Patients with node-only metastasis had better 12 month progression-free survival in group B than in group A (59.1% vs 42.9%, respectively, p=0.04). However, the responses to both treatments did not differ in patients with organ metastasis. Conclusions Bevacizumab for stage IVB cervical cancer is associated with higher complete response rates. However, patients treated with bevacizumab experienced more bowel toxicities. Bevacizumab did not improve progression-free survival among patients with node-only metastasis.