Exceptional Response to Pembrolizumab in HER2-Positive Gallbladder Carcinoma with High Tumor Mutational Burden.

PURPOSE: Patients with advanced cholangiocarcinoma, including gallbladder cancer, typically have a poor prognosis owing to limited effective chemotherapy options. The field of genotype-directed therapy in patients with cholangiocarcinoma is advancing. However, limited clinical data are currently available to evaluate the efficacy of molecularly targeted therapy. METHODS: Herein, we report the case of a 67-year-old man diagnosed with human epidermal growth factor receptor-2 (HER2)-positive and tumor mutation burden-high (TMB-H) cholangiocarcinoma. The HER2-positive and TMB-H characteristics were identified using comprehensive genomic profiling after showing resistance to gemcitabine and S-1 therapy. In the absence of clinical trials for HER2-positive cancer at that time, the patient was treated with pembrolizumab, which is used for TMB-H solid tumors in clinical practice. RESULTS: After receiving pembrolizumab, the patient experienced significant shrinkage in the primary tumor and liver metastases. Thus far, the patient has been receiving pembrolizumab for approximately 10 months. CONCLUSION: To our knowledge, this is the first report showing the efficacy of pembrolizumab in a patient with cholangiocarcinoma harboring both HER2-positive and TMB-H.

Implementation of optically simulated luminescent dosimeter for quality control of gamma ray dose of an accelerator-based neutron source.

BACKGROUND: Neutron beams utilized for performing BNCT are composed of a mixture of neutrons and gamma rays. Although much of the dose delivered to the cancer cells comes from the high LET particles produced by the boron neutron capture reaction, the dose delivered to the healthy tissues from unwanted gamma rays cannot be ignored. With the increase in the number of accelerators for BNCT, a detector system that is capable of measuring gamma ray dose in a mixed neutron/gamma irradiation field is crucial. Currently, BeO TLDs encased in quartz glass are used to measure gamma ray dose in a BNCT irradiation field. However, this type of TLD is no longer commercially available. A replacement dosimetry system is required to perform the recommended ongoing quality assurance of gamma ray measurement for a clinical BNCT system. PURPOSE: The purpose of this study is to evaluate the characteristics of a BeO OSLD detector system under a mixed neutron and gamma ray irradiation field and to assess the suitability of the system for routine quality assurance measurements of an accelerator-based BNCT facility. METHODS: The myOSLD system by RadPro International GmbH was evaluated using the accelerator-based neutron source designed for clinical BNCT (NeuCure BNCT system). The readout constancy, linearity, dose rate effect, and fading effect of the OSLD were evaluated. Free-in-air and water phantom measurements were performed and compared with the TLD results and Monte Carlo simulation results. The PHITS Monte Carlo code was used for this study. RESULTS: The readout constancy was found to be stable over a month-long period and similar to the TLD results. The OSLD readout signal was found to be linear, with a high coefficient of determination (R2 ≥ 0.999) up to a proton charge of 3.6 C. There was no significant signal fading or dose rate dependency. The central axis depth dose and off-axis dose profile measurements agreed with both the TLD and Monte Carlo simulation results, within one standard deviation. CONCLUSION: The myOSLD system was characterized using an accelerator system designed for clinical BNCT. The experimental measurements confirmed the OSLD achieved similar, if not superior to, the currently utilized dosimetry system for routine QA of an accelerator-based BNCT system. The OSLD system would be a suitable replacement for the current TLD system for performing routine QA of gamma ray dose measurement in a BNCT irradiation field.

Boron neutron capture therapy delays the decline in neurological function in a mouse model of metastatic spinal tumors.

Metastatic spinal tumors are increasingly prevalent due to advancements in cancer treatment, leading to prolonged survival rates. This rising prevalence highlights the need for developing more effective therapeutic approaches to address this malignancy. Boron neutron capture therapy (BNCT) offers a promising solution by delivering targeted doses to tumors while minimizing damage to normal tissue. In this study, we evaluated the efficacy and safety of BNCT as a potential therapeutic option for spine metastases in mouse models induced by A549 human lung adenocarcinoma cells. The animal models were randomly allocated into three groups: untreated (n = 10), neutron irradiation only (n = 9), and BNCT (n = 10). Each mouse was administered 4-borono-L-phenylalanine (250 mg/kg) intravenously, followed by measurement of boron concentrations 2.5 h later. Overall survival, neurological function of the hindlimb, and any adverse events were assessed post irradiation. The tumor-to-normal spinal cord and blood boron concentration ratios were 3.6 and 2.9, respectively, with no significant difference observed between the normal and compressed spinal cord tissues. The BNCT group exhibited significantly prolonged survival rates compared with the other groups (vs. untreated, p = 0.0015; vs. neutron-only, p = 0.0104, log-rank test). Furthermore, the BNCT group demonstrated preserved neurological function relative to the other groups (vs. untreated, p = 0.0004; vs. neutron-only, p = 0.0051, multivariate analysis of variance). No adverse events were observed post irradiation. These findings indicate that BNCT holds promise as a novel treatment modality for metastatic spinal tumors.

Rapid tumor progression complicated with liver abscess in a patient with gastric cancer receiving nivolumab therapy.

Immune checkpoint inhibitors have been approved for treating various cancer types. However, several studies reported rapid tumor progression, a condition known as hyperprogressive disease, after treatment with immune checkpoint inhibitors. We present the case of a 73-year-old man diagnosed with recurrent gastric cancer with liver and lymph node metastases detected in the presence of obstructive jaundice. Concomitant administration of nivolumab with cytotoxic chemotherapy as first-line chemotherapy effectively controlled the tumor. Nevertheless, once cytotoxic chemotherapy was discontinued and nivolumab monotherapy was initiated to treat liver abscess complications, the tumor rapidly progressed, ultimately leading to the patient's death. This is the first report on rapid tumor growth observed during subsequent treatment with nivolumab after initial antitumor effects were confirmed. This case report describes the possibility of rapid tumor growth in patients receiving immune checkpoint inhibitor therapy, including in cases where this therapy showed antitumor efficacy in the initial therapeutic evaluation. Therefore, patients receiving immune checkpoint inhibitor therapy need to be monitored.

Therapeutic Effects of CDK4/6 Inhibitors in Gastric and Colonic Metastases From Breast Cancer: A Case Report.

Breast cancer often metastasizes to the lungs, bones, liver, and brain; however, gastric and colonic metastases from breast cancer are rare. Nevertheless, here, we present the case of a 50-year-old woman diagnosed with recurrent breast cancer, exhibiting gastric and colonic metastases that were detected when she experienced intermittent abdominal pain. The differentiation between primary gastric cancer and metastasis from breast cancer was made through immunohistochemical staining. The patient underwent treatment with palbociclib, a cyclin-dependent kinase (CDK)4/6 inhibitor, and anastrozole, with no significant adverse effects. Subsequent upper and lower endoscopic examinations following the initiation of these treatments revealed tumor shrinkage in both gastric and colonic metastases. This case report presents the first instance in which morphological changes in gastrointestinal metastasis induced by CDK4/6 inhibitors could be evaluated.

Efficacy of tyrosine kinase inhibitors in patients with non-small-cell lung cancer with performance status 4: a case series and review of the literature.

BACKGROUND: Current guidelines for non-small-cell lung cancer (NSCLC) recommend that each tyrosine kinase inhibitor (TKI) is indicated even for driver mutation-positive patients with a poor performance status (PS). In previous studies, most patients had a PS of 2-3, but those with a PS of 4 were very few. Therefore, the efficacy of TKIs in patients with NSCLC with a PS of 4 remains unclear. CASE PRESENTATION: We retrospectively reviewed the clinical records of four patients with NSCLC with PS 4 treated with TKIs: an 89-year-old Japanese woman (Case 1), a 80-year-old Japanese woman (Case 2), an 50-year-old Japanese man (Case 3), and a 81-year-old Japanese woman (Case 4). Genetic alterations were epidermal growth factor receptor (EGFR), MET exon 14 skipping, BRAFV600E, and ROS1 proto-oncogene receptor tyrosine kinase (ROS1). One case with ROS1 fusion showed a significant response with the recovery of PS. However, in the remaining three cases (i.e., EGFR, MET exon 14 skipping, and BRAFV600E mutations), patients died despite the administration of TKIs. These three patients had to be hospitalized at the end of their life to receive treatment. CONCLUSIONS: This is the first case series to summarize the efficacy of TKIs in patients with NSCLC with a PS of 4. Additionally, this case series poses a question concerning the indication of TKIs for older patients with a PS of 4.

The first case of splenic flexure volvulus treated with reduced port surgery using single-incision laparoscopy.

INTRODUCTION: Splenic flexure volvulus (SFV) is a rare disease. We encountered a case of SFV, caused by congenital anomalies and persistent constipation. CASE PRESENTATION: A 43-year-old woman with a 35-year history of persistent constipation presented to the emergency department with acute lower abdominal pain. She had no past surgical history, and her vital signs were stable. A contrast-enhanced computed tomography (CE-CT) scan confirmed the SFV diagnosis. We initially performed endoscopic repositioning. To prevent recurrence, a laparoscopic left hemicolectomy was then carried out using reduced port surgery (RPS). She experienced no postoperative complications and was discharged seven days post-surgery. DISCUSSION: While SFV is typically managed through endoscopic repositioning followed by definitive surgical intervention to prevent recurrence, we successfully employed RPS in this case. Patients with SFV might be prime candidates for RPS due to the non-attachment of the descending colon to the retroperitoneum. Additionally, since SFV is a benign condition that doesn't necessitate lymph node dissection, it aligns well with the capabilities of RPS. Postoperatively, the patient experienced improved constipation symptoms. We hypothesize that this SFV was a result of a combination of factors: intestinal over-length, chronic constipation, and the loose adhesion of the descending colon to the retroperitoneum. CONCLUSION: This case demonstrates that RPS can be efficacious in treating SFV.

Development of optimization method for uniform dose distribution on superficial tumor in an accelerator-based boron neutron capture therapy system.

To treat superficial tumors using accelerator-based boron neutron capture therapy (ABBNCT), a technique was investigated, based on which, a single-neutron modulator was placed inside a collimator and was irradiated with thermal neutrons. In large tumors, the dose was reduced at their edges. The objective was to generate a uniform and therapeutic intensity dose distribution. In this study, we developed a method for optimizing the shape of the intensity modulator and irradiation time ratio to generate a uniform dose distribution to treat superficial tumors of various shapes. A computational tool was developed, which performed Monte Carlo simulations using 424 different source combinations. We determined the shape of the intensity modulator with the highest minimum tumor dose. The homogeneity index (HI), which evaluates uniformity, was also derived. To evaluate the efficacy of this method, the dose distribution of a tumor with a diameter of 100 mm and thickness of 10 mm was evaluated. Furthermore, irradiation experiments were conducted using an ABBNCT system. The thermal neutron flux distribution outcomes that have considerable impacts on the tumor's dose confirmed a good agreement between experiments and calculations. Moreover, the minimum tumor dose and HI improved by 20 and 36%, respectively, compared with the irradiation case wherein a single-neutron modulator was used. The proposed method improves the minimum tumor volume and uniformity. The results demonstrate the method's efficacy in ABBNCT for the treatment of superficial tumors.

Eldest gastric cancer patient with high microsatellite instability responding to pembrolizumab.

Pembrolizumab has been associated with a high tumor response rate among high microsatellite instability (MSI-H) cancer patients. The efficacy and safety of pembrolizumab in the treatment of MSI-H gastric cancer (GC) patients aged ≥ 85 years have not been reported. This study reports the case of an 89-year-old woman diagnosed with stage IIA MSI-H GC based on her chief complaint of abdominal pain. We considered surgery, but it was contraindicated due to the patient's age and cardiovascular comorbidity. Therefore, we administered pembrolizumab after receiving approval from the ethics committee, and no significant adverse events were noted. The tumor was markedly responsive to pembrolizumab, and the computed tomography and endoscopic findings revealed a complete response. This is the first report on the efficacy and safety of pembrolizumab in the treatment of GC in an "oldest old" patient with MSI-H.

Dabrafenib plus trametinib treatment for a patient with BRAF V600E-mutated large-cell lung carcinoma and a poor performance status.

Dabrafenib plus trametinib is active against metastatic lung cancer with the BRAF V600E mutation. However, the feasibility of dabrafenib plus trametinib for patients with a poor performance status (PS) has not been reported. We report the case of an 80-year-old woman was diagnosed with metastatic large-cell lung carcinoma. Her general statuses worsened due to cancer, resulting in a PS of 4. Genotype testing revealed a BRAF V600E mutation. The patient received dabrafenib plus trametinib without significant adverse effects. This report is the first to describe dabrafenib plus trametinib administration for large-cell lung carcinoma in a patient with a poor PS.

A Challenging Case of Streptococcus pneumoniae Meningitis in a 64-Year-Old Woman Who Presented with Symptoms of Cerebellar Hemorrhage.

BACKGROUND There is a recognized association between bacterial meningitis and intracranial hemorrhage. However, acute neurological symptoms at presentation, with confirmation of hemorrhage on imaging, may delay further investigations, including blood culture for diagnosing an infection. This report presents a challenging case of Streptococcus pneumoniae meningitis in a 64-year-old woman who presented with symptoms of cerebellar hemorrhage. CASE REPORT This report describes a 64-year-old woman who had a medical history of untreated diabetes mellitus. She was brought to our hospital with headache and impaired consciousness, complicated with fever. Based on the hemorrhage in the left cerebellar hemisphere detected in the head CT findings, the patient was initially diagnosed with cerebellar hemorrhage. However, a positive blood culture after 12 hours of admission made the physician consider a central nervous system infection as the cause of the hemorrhage and perform a lumbar puncture. Therefore, the patient was diagnosed with acute bacterial meningitis caused by Streptococcus pneumoniae, and antibiotic treatment was started immediately. Although her general condition improved after antibiotic treatment, her mental status did not improve completely. CONCLUSIONS This report highlights that the clinicians should be aware that bacterial meningitis may result in intracranial hemorrhage. Patients with symptoms of a hemorrhagic stroke should be thoroughly investigated to avoid a delay in the treatment of infection.

Intensity-modulated irradiation for superficial tumors by overlapping irradiation fields using intensity modulators in accelerator-based BNCT.

The distribution of the thermal neutron flux has a significant impact on the treatment efficacy. We developed an irradiation method of overlapping irradiation fields using intensity modulators for the treatment of superficial tumors with the aim of expanding the indications for accelerator-based boron neutron capture therapy (BNCT). The shape of the intensity modulator was determined and Monte Carlo simulations were carried out to determine the uniformity of the resulting thermal neutron flux distribution. The intensity modulators were then fabricated and irradiation tests were conducted, which resulted in the formation of a uniform thermal neutron flux distribution. Finally, an evaluation of the tumor dose distribution showed that when two irradiation fields overlapped, the minimum tumor dose was 27.4 Gy-eq, which was higher than the tumor control dose of 20 Gy-eq. Furthermore, it was found that the uniformity of the treatment was improved 47% as compared to the treatment that uses a single irradiation field. This clearly demonstrates the effectiveness of this technique and the possibility of expanding the indications to superficially located tumors.

Cerebral Venous Thrombosis as an Initial Presentation of Ulcerative Colitis.

Cerebral venous thrombosis (CVT) is a rare complication of ulcerative colitis (UC) that is potentially fatal once it occurs. This report describes a case of CVT that led to a diagnosis of UC. A 48-year-old woman was diagnosed with CVT due to paresthesia and weakness and was hospitalized for treatment. She developed bloody diarrhea on admission and was further diagnosed with UC based on endoscopic and pathologic findings. Treatment of UC with steroids and sulfasalazine was administered immediately. Her condition improved significantly within several days following treatment. After discharge, the patient experienced no recurrence of either CVT or UC flare-up over the last five years. This report describes CVT as an initial presentation of UC. This is also the first report of a long-term follow-up following successful treatment of CVT with concomitant UC.

Exceptional response to alectinib for duodenal carcinoma with ALK fusion: A case report and literature review.

Patients with advanced duodenal carcinoma usually have a poor prognosis due to limited effective chemotherapy options. The study for genotype-directed therapy in patients with duodenal carcinoma is progressing. However, no clinical data assessing the efficacy of molecularly targeted therapy are presently available. We report the case of a 64-year-old woman who was diagnosed with anaplastic lymphocyte kinase (ALK) fusion-positive advanced duodenal carcinoma. Echinoderm microtubule associated protein like-4 (EML4)-ALK rearrangement was detected by comprehensive genomic profiling after resistance to first-line chemotherapy. The patient received alectinib, an ALK inhibitor, with marked shrinkage in primary tumor and liver metastases. She is currently being treated with alectinib for 6 months or more. This is the first report of the efficacy of alectinib in a patient with duodenal carcinoma harboring ALK fusion. Additionally, this case report suggests that the practical use of next-generation sequencing may expand optimal treatment choices in rare solid tumors, including duodenal carcinoma.

Development of an irradiation method for superficial tumours using a hydrogel bolus in an accelerator-based BNCT.

The aim of this study is the development of an irradiation method for the treatment of superficial tumours using a hydrogel bolus to produce thermal neutrons in accelerator-based Boron Neutron Capture Therapy (BNCT).To evaluate the neutron moderating ability of a hydrogel bolus, a water phantom with a hydrogel bolus was irradiated with an epithermal neutron beam from a cyclotron-based epithermal neutron source. Phantom simulating irradiation to the plantar position was manufactured using three-dimensional printing technology to perform an irradiation test of a hydrogel bolus. Thermal neutron fluxes on the surface of a phantom were evaluated and the results were compared with the Monte Carlo-based Simulation Environment for Radiotherapy Applications (SERA) treatment planning software. It was confirmed that a hydrogel bolus had the same neutron moderating ability as water, and the calculation results from SERA aligned with the measured values within approximately 5%. Furthermore, it was confirmed that the thermal neutron flux decreased at the edge of the irradiation field. It was possible to uniformly irradiate thermal neutrons by increasing the bolus thickness at the edge of the irradiation field, thereby successfully determining uniform dose distribution. An irradiation method for superficial tumours using a hydrogel bolus in the accelerator-based BNCT was established.

Clinical and molecular factors for selection of nivolumab or irinotecan as third-line treatment for advanced gastric cancer.

BACKGROUND: The use of nivolumab or irinotecan as the third-line treatment for patients with advanced gastric cancer (AGC) remains controversial. METHODS: This study analyzed patients with AGC treated with nivolumab or irinotecan (nivolumab group or irinotecan group, respectively) from May 2016 to April 2019 following two or more previous lines of chemotherapy. Univariate survival analysis was conducted to identify the clinical and molecular factors associated with progression-free survival (PFS). RESULTS: A total of 156 patients (74 treated with nivolumab and 82 treated with irinotecan) were analyzed. The median PFS was 1.9 months in both treatment groups. The median overall survival (OS) was 7.2 and 6.2 months in the nivolumab and irinotecan groups, respectively. Eastern Cooperative Oncology Group performance status of 1 or more, liver metastasis, a large tumor size at baseline, and HER2-positive status were associated with a worse PFS in the nivolumab group compared with the irinotecan group. The nivolumab group showed a significantly longer PFS (median 3.1 versus 2.0 months) and OS (median 12.9 versus 7.8 months) than the irinotecan group in patients with 0 or 1 of these factors, whereas the irinotecan group showed a significantly longer PFS (median 1.0 versus 1.8 months) and a trend of longer OS (median 3.9 versus 6.1 months) in patients with ⩾2 of these factors. CONCLUSIONS: Some clinical and molecular factors were associated with outcomes following nivolumab or irinotecan as the third- or later-line treatment in patients with AGC. These factors must be considered while selecting an optimal treatment option.

Intestinal Perforation due to Neutropenic Enterocolitis in a Patient Treated with Bevacizumab for Ovarian Cancer.

Intestinal perforation is a rare adverse event of antineoplastic therapy. However, once it occurs, it is potentially fatal. This report describes a case of intestinal perforation caused by bevacizumab in a patient with ovarian cancer who concurrently developed neutropenic enterocolitis. A 66-year-old woman diagnosed with metastatic ovarian cancer received combination chemotherapy with carboplatin, gemcitabine, and bevacizumab. On day 14, she developed grade 4 pancytopenia and febrile neutropenia, which resulted in neutropenic enterocolitis and intestinal perforation. Emergency surgery was performed, and an intestinal perforation found in the ascending colon was closed. Postoperatively, she developed an intra-abdominal abscess requiring peritoneal drainage. She was discharged from the hospital on recovery.

Improved efficacy of taxanes and ramucirumab combination chemotherapy after exposure to anti-PD-1 therapy in advanced gastric cancer.

BACKGROUND: The efficacy and safety of chemotherapy (CTx) after anti-PD-1 therapy in patients with advanced gastric cancer (AGC) remains unclear. METHODS: Medical records of consecutive patients with AGC treated with both CTx (taxanes plus ramucirumab, taxanes monotherapy or irinotecan) and anti-PD-1 therapy from June 2015 to April 2019 were retrospectively analysed. Patients were divided into two groups based on prior exposure to anti-PD-1 therapy: anti-PD-1-exposed and anti-PD-1-naïve groups. CTx-related outcomes were compared between two groups in the overall population and each CTx population. RESULTS: In total, 233 patients (67 anti-PD-1-exposed, 166 anti-PD-1-naïve) were included. In the overall population, the objective response rate (ORR) to CTX was 44.6% in the anti-PD-1-exposed group and 19.6% in the anti-PD-1-naïve group (p=0.001); the median progression-free survivals (PFS) were 3.7 months and 3.3 months (HR=0.82, p=0.20), respectively. Among patients receiving taxanes plus ramucirumab (n=149), ORR (60.6% vs 20.0%, p<0.001) and median PFS (4.8 vs 3.4 months, p=0.004, HR=0.56) were significantly better in the anti-PD-1-exposed group (n=39) compared with the anti-PD-1-naïve group (n=110). These differences were not observed in patients receiving taxane monotherapy (n=34) or irinotecan (n=50). CTx after anti-PD-1 therapy showed no severe or unexpected adverse events. CONCLUSIONS: Prior anti-PD-1 therapy might increase tumour response to taxanes plus ramucirumab without unexpected adverse events, which warrants further investigations in a large cohort.

Enhanced tumor response to radiotherapy after PD-1 blockade in metastatic gastric cancer.

BACKGROUND: Immune checkpoint inhibitors may enhance the efficacy of radiotherapy (RT) in cancer treatment but the effect remains unknown in metastatic gastric cancer (mGC). This study aimed to compare the tumor shrinkage by palliative RT for mGC patients with or without previous exposure to anti-PD-1 therapy. METHODS: Data of 36 mGC patients who had received palliative RT from April 2013 to May 2019 were analyzed. Primary tumor responses were evaluated through a volumetric measurement-based method using computed tomography (CT) and endoscopic responses were evaluated in patients who underwent endoscopy before and after RT. Tumor microenvironment (TME) immune status was investigated by analyzing tumor-infiltrating lymphocytes by flow cytometry. RESULTS: Among 36 patients, 18 had previous exposure to anti-PD-1 before RT showing no significant differences in baseline characteristics with the other 18 patients without exposure to anti-PD-1 treatment. Tumor responses were observed in 28% (5/18) and none (0/18) in the anti-PD-1-exposed vs. naïve group, respectively (P = 0.045). Five out of eight patients in the anti-PD-1-exposed group, who underwent endoscopy after RT showed partial response, but none in the anti-PD-1-naïve patients showed response (P = 0.026). Increase in the CD8+ T cell/effector regulatory T cell ratio in TILs after anti-PD-1 therapy was noted in three responders to RT, but not in the other three non-responders. CONCLUSIONS: Prior exposure to anti-PD-1 therapy increases tumor response to RT. Immune profiling suggests that anti-PD-1 therapy may enhance the efficacy of RT by immunoactivation in the TME.