Evaluation of Tumor Control and Normal Tissue Complication Probability in Head and Neck Cancers with Different Sources of Radiation: A Comparative Study

Introduction: The ultimate goal of radiation treatment planning is to yield a high tumor control probability (TCP) with a low normal tissue complication probability (NTCP). Historically  dose volume histogram (DVH) with only volumetric dose distribution was utilized as a popular tool for plan evaluation  hence present study aimed to compare the radiobiological effectiveness of the cobalt-60 (Co-60) gamma photon and 6MV X-rays of linear accelerators (Linac) in the radiotherapy of head and neck tumors.  Materials and Methods: TCP and NTCP were calculated using DVH through the BIOPLAN software developed by Sanchez-Nieto and Nahum . The treatment planning was performed for all the patients using both treatment modalities (i.e., Co-60 and 6 MV Linac). The TCP was also manually calculated using a mathematical formula proposed by Brenner’s et al. Results: The average TCP calculated by the BIOPLAN for Co-60 and 6 MV X-rays were 44.6% and 60.8%, respectively. Furthermore, the average NTCPs obtained for the organ at risk, namely optic nerve, for Co-60 and 6 MV X-ray were 0.24 % and 0.03 %, respectively. Regarding the spinal cord, the average NTCPs for Co-60 gamma photon and 6 MV X-ray of Linac were 0.05 % and 0.002%, respectively. Conclusion: As the findings of the present study indicated, Co-60 unit could provide comparable TCP along with minimal NTCP, compared to the high-cost technologies of Linac. The design of treatment plans based on the radiobiological parameters facilitated the judicious choice of physical parameters for the achievement of high TCP and low NTCP

Genomic analysis of SARS-CoV-2 Circulating during Second and Third Wave of COVID-19 in Nepal

Background: In Nepal, since the first detection of COVID-19 case in January 2020, the total cases have rose to almost a million with more than 12,000 deaths. Till now, WHO has classified 5 variants of SARS-Cov2 as variant of concerns at different time points causing many waves in different countries and regions at different time points. Nepal had also faced three distinct waves of COVID-19 caused by different variant of COVID 19. The objective of this study was to perform whole-genome sequencing of SARS-CoV-2 circulating in different waves of COVID-19 in Nepal and investigate its variant or lineage. Methods: In this study, samples from 49 SARS-CoV-2 infected subjects from May 2021 to January 2022, were investigated. The methodology followed RNA extraction, real-time PCR for confirmation and whole-genome sequencing. The consensus genomes were interpreted with appropriate bioinformatics tools and databases. Results: Sequence analysis of 49 genomes revealed to be of Delta (n=27) and Omicron Variant (n=22). The mutations in the consensus genomes contained the defining mutations of the respective lineages/variants. There were 20 genomes of Omicron sub-lineage BA.2, 1 of BA.1.1 and 1 of B.1.1.529. Conclusions: This study provides concise genomic evidence of presence of Delta and Omicron variant of COVID-19 in Nepal. Delta and Omicron variants were driving the second wave and the third wave of COVID-19 respectively in Nepal. Therefore, the genomic surveillance must be increased to clearly map out the pandemic and strategize vaccination approaches in the country. Keywords: COVID-19; delta, omicron; Nepal;SARS-CoV-2; whole-genome sequencin

Empirical Anthelmintic Therapy for Patients with Eosinophilia in Nepal: A Prospective Cohort Study

Eosinophilia is common in low-resource countries and usually implies helminthiasis. Since helminthiasis is a common cause of eosinophilia and its diagnosis is cumbersome, we hypothesized that broad-spectrum anthelmintic therapy may decrease the eosinophil count and eventually cure helminthiasis, whether microbiologic diagnosis is established or not. We recruited patients with eosinophilia aged 5 years and older who presented to Dhulikhel hospital, Nepal. Patients were treated with albendazole and ivermectin. A stool sample for microscopy was obtained. Of a total of 113 patients, 106 had a follow-up visit and 56 were classified as responders to treatment (defined as a decrease in eosinophil count to below 500 cells/µL, or an absolute decrease of more than 1000 cells/µL). For all patients, we found an absolute decrease in the eosinophil count and for the responding group (more than 50% of the whole cohort), the eosinophil count decreased substantially. All stool samples were negative. The reason for a lack of response in the remaining patients is unclear. In order to ascertain whether eosinophilia should be an indication for anthelmintic treatment, a randomized controlled study of empirical treatment after a thorough microbiologic workup is needed

The epidemiology of typhoid fever in the Dhulikhel area, Nepal: A prospective cohort study.

INTRODUCTION:Typhoid fever (TF) continues to cause considerable morbidity and mortality in Nepal, but only limited epidemiologic data is available about TF outside Kathmandu. METHODS:As part of an interventional trial, we performed a prospective cohort study of bacteremic TF patients in Dhulikhel Hospital between October 2012 and October 2014. Demographic, epidemiological, clinical, and microbiologic data were recorded. RESULTS:116 bacteremic typhoid patients were included in the study. Most were young, healthy, adults (mean age 27.9±12 years), 41.4% of whom were female. More than 70% of patients were employed in non-manual services or were university students. Salmonella Typhi accounted for 64/115 (55.7%) of all isolates, while Salmonella Paratyphi accounted for 51/115 (44.3%), of which 42 were Paratyphi A and 9 Paratyphi B. A significant proportion of TF cases occurred also during the dry season (48/116, 41.6%). The clinical presentation of Salmonella Typhi and Paratyphi infections was similar, except for a greater proportion of arthralgia in patients with Salmonella Typhi. Most Salmonella Typhi and Paratyphi isolates were resistant to nalidixic acid and susceptible to older antibiotics. One Salmonella Paratyphi isolate was resistant to ceftriaxone. CONCLUSIONS:TF remains common in the Dhulikhel area, even among those with a high level of education. Public health measures aimed at reducing the incidence of TF in the Dhulikhel area are warranted. The relative burden of TF caused by Salmonella Paratyphi is rising; a vaccine with activity against Salmonella Paratyphi is needed. Since Salmonella Paratyphi B was more prevalent in this cohort than in large cohorts of patients from Kathmandu, it is likely that there are significant regional variations in the epidemiology of TF outside Kathmandu

Investigation of acute encephalitis syndrome with implementation of metagenomic next generation sequencing in Nepal

Abstract Background The causative agents of Acute Encephalitis Syndrome remain unknown in 68–75% of the cases. In Nepal, the cases are tested only for Japanese encephalitis, which constitutes only about 15% of the cases. However, there could be several organisms, including vaccine-preventable etiologies that cause acute encephalitis, when identified could direct public health efforts for prevention, including addressing gaps in vaccine coverage. Objectives This study employs metagenomic next-generation-sequencing in the investigation of underlying causative etiologies contributing to acute encephalitis syndrome in Nepal. Methods In this study, we investigated 90, Japanese-encephalitis-negative, banked cerebrospinal fluid samples that were collected as part of a national surveillance network in 2016 and 2017. Randomization was done to include three age groups (15-years). Only some metadata (age and gender) were available. The investigation was performed in two batches which included total nucleic-acid extraction, followed by individual library preparation (DNA and RNA) and sequencing on Illumina iSeq100. The genomic data were interpreted using Chan Zuckerberg-ID and confirmed with polymerase-chain-reaction. Results Human-alphaherpes-virus 2 and Enterovirus-B were seen in two samples. These hits were confirmed by qPCR and semi-nested PCR respectively. Most of the other samples were marred by low abundance of pathogen, possible freeze-thaw cycles, lack of process controls and associated clinical metadata. Conclusion From this study, two documented causative agents were revealed through metagenomic next-generation-sequencing. Insufficiency of clinical metadata, process controls, low pathogen abundance and absence of standard procedures to collect and store samples in nucleic-acid protectants could have impeded the study and incorporated ambiguity while correlating the identified hits to infection. Therefore, there is need of standardized procedures for sample collection, inclusion of process controls and clinical metadata. Despite challenging conditions, this study highlights the usefulness of mNGS to investigate diseases with unknown etiologies and guide development of adequate clinical-management-algorithms and outbreak investigations in Nepal

Prevalence of Sexually Transmitted Infections among Married Women in Rural Nepal

Introduction. We have previously determined the prevalence of human papillomavirus (HPV) infection among women in rural Nepal. In the current study, we also wanted to examine the prevalence of and risk factors for other sexually transmitted infections (STIs) in the same population. Methods. Population-based study of nonpregnant women ≥ 15 years who were married or had a history of marriage in the past, residing in five rural villages in Nepal. Data on sociodemographic characteristics, reproductive history, and genitourinary symptoms were collected, and a gynecological examination was conducted. Cervical samples were analyzed by real-time PCR for Neisseria gonorrhoeae, Chlamydia trachomatis, and Trichomonas vaginalis and HPV, and a serum sample was analyzed for syphilis, hepatitis B virus (HBV) and HIV infection by serology. Results. Of 2416 eligible women, 62% participated. Trichomoniasis, Chlamydia trachomatis infection, HPV and HBV infection, and syphilis were detected in 5.4%, 0.8%, 14.3%, 0.3%, and 0.2% of the women. None had gonorrhea or HIV infection. Of those with genitourinary symptoms, 6.3% had a curable STI. Vaginal discharge classified as abnormal by gynecological examination, but not self-reported discharge, was significantly associated with laboratory diagnosis of a curable STI. Risk factors for trichomoniasis were reproductive age and high cast/ethnicity. Due to low prevalence, risk factors for other STIs could not be disclosed. Conclusion. We observed high prevalence of HPV infection followed by trichomoniasis, while other STIs were rare among women in rural Nepal. There was no association between genitourinary symptoms and laboratory-confirmed STIs

Correlation of PD-L1 expression with toxicities and response in oropharyngeal cancers treated with definitive chemoradiotherapy

INTRODUCTION: The programmed death receptor ligand 1 (PD-L1) is a cell-surface glycoprotein expressed in tumour cells (TCs) and is also upregulated in tumour infiltrating lymphocytes. The effect of PD-L1 expression on TCs and tumour-infiltrating lymphocytes (TILs) on acute radiation toxicity and response in oropharyngeal squamous cell carcinoma treated with concurrent chemoradiotherapy is less known. MATERIAL AND METHODS: Squamous cell carcinoma of oropharynx with stage II-IVA (AJCC 8(th)) were recruited in this prospective observational study. Definitive radiation therapy (RT) of 70 Gray in 35 fractions at 2 Gray per fraction, 5 fractions a week in 2 phases was delivered with concurrent chemotherapy (cisplatin 40 mg/m(2) weekly). Patients were assessed weekly for acute toxicities with Radiation Therapy Oncology Group criteria. Response assessment was done at 3 months post RT according to World Health Organization response assessment criteria. The programmed death receptor ligand 1 expression in TCs and TILs was correlated with acute toxicity and survival. RESULTS: Of 51 patients, 20 (39.2%) had PD-L1 expression in TCs and 18 (35.3%) in TILs. Patients with PD-L1 expression in TCs had fewer grade ≥ 3 oral mucositis (25% vs. 58%; p = 0.02) and grade ≥ 3 dysphagia (25% vs. 55%; p = 0.046). The programmed death receptor ligand 1-tumour infiltrating lymphocytes positives had lower ≥ 3 grade oral mucositis (22% vs. 58%; p = 0.02) and ≥ 3 grade dysphagia (17% vs. 58%; p = 0.007). Two-year overall and progression-free survival rate for the PD-L1-tumour-positive vs. PD-L1-tumour-negative group was not different (p > 0.5). CONCLUSIONS: Positive PD-L1 expression is associated with fewer acute radiation toxicities, and this could be used as a potential biomarker

Pelvic bone anatomy vs implanted gold seed marker registration for image-guided intensity modulated radiotherapy for prostate carcinoma: Comparative analysis of inter-fraction motion and toxicities

Objectives: We compared the prostate motion variability and toxicities between patients treated with gold marker registration based IG-IMRT (IG-IMRT-M) and bony landmark registration based IG-IMRT (IG-IMRT-B). Methods: T1c-T3b (node negative), intermediate and high risk (non-metastatic) adenocarcinoma of prostate, age ≥18 years, Karnofsky Performance Status of ≥70 were included in this retrospective study. The prostate motion variability, acute and late radiation toxicities between the two treatment arms (IG-IMRT-M versus IG-IMRT-B) were compared. Results: Total of 35 patients (17 for IG-IMRT-M and 18 for IG-IMRT-B) were treated with a median radiotherapy dose of 76 Gray. The prostate variability observed with and without markers in millimeter was 4.1 ± 2.3 vs 3.7 ± 2.1 [Antero-Posterior (A-P); p = 0.001], 2.3 ± 1.5 vs 2.1 ± 1.2 [Superior-Inferior (S-I); p = 0.095] and 1.1 ± 1.7 vs 0.4 ± 1.4 [Left-Right (L-R); p = 0.003]. There was higher acute toxicity in IG-IMRT-B arm compared to IG-IMRT-M arm in terms of grade ≥2 diarrhea [50% vs 11% OR = 7.5 (1.3–42.7); p = 0.02] and grade ≥2 proctitis [38% vs 5.8%, OR = 10.1 (1.09–94.1); p = 0.04]. At a median follow up of 36 months, the late genitourinary toxicities grade ≥2 [27% vs 0%; p = 0.04] were higher in the IG-IMRT-B arm compared to IG-IMRT-M arm. Conclusions: IG-IMRT-M detects higher prostate motion variability as compared to IG-IMRT-B, inferring a significant prostate motion inside fixed pelvic bony cavity. The addition of marker based image guidance results in higher precision of prostate localization and lesser acute and late toxicities