RADT-46. SYSTEMATIC REVIEW OF RADIOSENSITIZERS FOR MALIGNANT BRAIN TUMORS: POTENTIAL FOR LEARNING FROM PAST FAILURES

INTRODUCTION

Radiation therapy (RT) is the cornerstone of management of malignant CNS tumors but its efficacy is limited in hypoxic tumors. Although numerous radiosensitizer compounds have been developed to enhance the effect of RT, progress has been stagnant. Through this systematic review of the literature on radiosensitizers for malignant CNS tumors, we have sought to provide an overview of radiosensitizers developed to date, summarize their safety and efficacy, and evaluate areas for possible improvement.

METHODS

PUBMED, EMBASE, Cochrane, and Web of Science were searched using terminology pertaining to radiosensitizers for brain tumor RT according to PRISMA guidelines. Publications reporting clinical evidence of non-antineoplastic radiosensitizers with RT for malignant CNS tumors were included. Pre-specified variables were extracted. Outcomes of interest were overall survival, progression-free survival, adverse events, and quality-of-life outcomes.

RESULTS

Forty-eight publications were identified which included 20 unique non-antineoplastic radiosensitizing agents. Only 2/20 agents, fluosol with oxygen, and efaproxiral, showed improvement in outcomes in patients with glioblastoma and brain metastasis, respectively. A larger study was not able to confirm the latter. While molecular similarities between these two agents were not identifiable, the effective mechanism of action allowed them to modulate hypoxia from within blood vessels, without crossing blood-brain barrier. Nine agents required dose modification, change of schedule, or complete discontinuation due to toxicities.

CONCLUSION

Despite decades of research, progress in the field of radiosensitizers for malignant CNS tumors has been limited. Available data demonstrates the lack of progress in identifying effective radiosensitizers for brain tumors. Of the many non-antineoplastic radiosensitizers that have been tested, only two have showed (limited) efficacy by targeting tumor oxygenation. Alternative strategies such as synthetic drug design, based on a mechanism of action that is independent of crossing the blood-brain barrier, may be necessary. Such studies are currently underway.

Mutational landscape of head and neck squamous cell carcinomas in a South Asian population

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer type globally and contributes significantly to burden of disease in South Asia. In Pakistan, HNSCC is among the most commonly diagnosed cancer in males and females. The increasing regional burden of HNSCC along with a unique set of risk factors merited a deeper investigation of the disease at the genomic level. Whole exome sequencing of HNSCC samples and matched normal genomic DNA analysis (n=7) was performed. Significant somatic single nucleotide variants (SNVs) were identified and pathway analysis performed to determine frequently affected signaling pathways. We identified significant, novel recurrent mutations in ASNS (asparagine synthetase) that may affect substrate binding, and variants in driver genes including TP53, PIK3CA, FGFR2, ARID2, MLL3, MYC and ALK. Using the IntOGen platform, we identified MAP kinase, cell cycle, actin cytoskeleton regulation, PI3K-Akt signaling and other pathways in cancer as affected in the samples. This data is the first of its kind from the Pakistani population. The results of this study can guide a better mechanistic understanding of HNSCC in the population, ultimately contributing new, rational therapeutic targets for the treatment of the disease.

Three-dimensional Visualization Software Assists Learning in Students with Diverse Spatial Intelligence in Medical Education

This study evaluated effect of mental rotation (MR) training on learning outcomes and explored effectiveness of teaching via three-dimensional (3D) software among medical students with diverse spatial intelligence. Data from n = 67 student volunteers were included. A preliminary test was conducted to obtain baseline level of MR competency and was utilized to assign participants to two experimental conditions, i.e., trained group (n = 25) and untrained group (n = 42). Data on the effectiveness of training were collected to measure participants' speed and accuracy in performing various MR activities. Six weeks later, a large class format (LCF) session was conducted for all students using 3D software. The usefulness of technology-assisted learning at the LCF was evaluated via a pre- and post-test. Students' feedback regarding MR training and use of 3D software was acquired through questionnaires. MR scores of the trainees improved from 25.9±4.6 points to 28.1±4.4 (P = 0.011) while time taken to complete the tasks reduced from 20.9±3.9 to 12.2±4.4 minutes. Males scored higher than females in all components (P = 0.016). Further, higher pre- and post-test scores were observed in trained (9.0±1.9 and 12.3±1.6) versus untrained group (7.8±1.8; 10.8±1.8). Although mixed-design analysis of variance suggested significant difference in their test scores (P < 0.001), both groups reported similar trend in improvement by means of 3D software (P = 0.54). Ninety-seven percent of students reported technology-assisted learning as an effective means of instruction and found use of 3D software superior to plastic models. Software based on 3D technologies could be adopted as an effective teaching pedagogy to support learning across students with diverse levels of mental rotation abilities.

Development of Criteria Highly Suggestive of Spinal Tuberculosis

BACKGROUND

In a developing country there is a need for development of criteria that can be used for the diagnosis of spinal tuberculosis, which is common in that region.

METHODS

Demographic, clinical, and radiologic features of spinal tuberculosis and spinal epidural tumors have been compared statistically, and inferences have been drawn in terms of P values, sensitivity, specificity, positive predictive values, and negative predictive values.

RESULTS

A statistically significant relationship was found between spinal tuberculosis and spinal pain, fever, gradually progressive lower limb weakness, contrast-enhancing epidural ± paravertebral lesions, continuous levels affected, spinal deformity, and raised erythrocyte sedimentation rate.

CONCLUSIONS

These relationships were considered the most probable criteria for the diagnosis of spinal tuberculosis.

Abstract 4370: ASNS and other significant mutations in head and neck squamous cell carcinomas: mutational landscape in a South Asian population

Head and neck cancers are the sixth most common cancer type globally and contribute significantly to the burden of disease in South Asia. Specifically in Pakistan, they are the most commonly diagnosed cancer in males and the second most common in females. The increasing burden of head and neck squamous cell carcinoma (HNSCC) in the region along with a unique set of risk factors merited a deeper investigation of the disease at the genomic level. Whole exome sequencing of HPV-negative HNSCC samples and matched normal genomic DNA (n = 7) was performed. Smoking, oral tobacco use and alcohol were identified risk factors in the study cohort. Significant somatic single nucleotide variants (SNVs) were identified and pathway analysis performed to determine most frequently affected signaling pathways. Significant, novel recurrent mutation in ASNS (asparagine synthetase) and driver mutations in previously reported genes, including TP53, PIK3CA, FGFR2, ARID2, MLL3, MYC and ALK, were identified. Using the IntOGen platform, we identified MAP kinase, cell cycle, actin cytoskeleton regulation, PI3K-Akt signaling and other pathways in cancer as among the most commonly affected pathways in all the samples. This data is the first of its kind from the Pakistani population. The results of this study can guide a better mechanistic understanding of HNSCC in the population, ultimately contributing new, rational therapeutic targets for the treatment of the disease.

Citation Format: Sadiq Rehmani, Safina Abdul Razzak, Sarosh Madhani, M Kamran Azim, Rashdia Ahmed, Mumtaz Khan, Kulsoom Ghias. ASNS and other significant mutations in head and neck squamous cell carcinomas: mutational landscape in a South Asian population [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4370. doi:10.1158/1538-7445.AM2017-4370

Gestational diabetes mellitus and the predisposing factors

OBJECTIVE

To evaluate the occurrence of gestational diabetes mellitus and its association with demographic and anthropometric variables in pregnant women.

METHODS

This cross-sectional study was conducted at the Aga Khan University Hospital, Abbasi Shaheed Hospital and Memon Hospital in Karachi, from February 2014 to December 2015, and comprised pregnant women who were screened by 75-g 2-hour oral glucose tolerance test, (24-28 weeks of gestation) and classified as per the criteria of the International Association of Diabetes and Pregnancy Study Group. Weight, body mass index and serum glycated haemoglobin levels were measured. Women with pre-gestational diabetes were excluded. SPSS 21 was used for data analysis.

RESULTS

Of the 1,210 participants, 208(17.2%) had gestational diabetes, while 1,002(82.8%) did not have the condition. Gestational diabetes was associated with advancing age, deranged glycated haemoglobin, elevated body mass index at booking (p<0.001) and history of first-degree type 2 diabetic relatives (p=0.05). When stratified according to ethnicities, no difference was observed in terms of gestational diabetes predilection among those who had the condition (p>0.05).

CONCLUSIONS

Pre-existing adiposity and presence of strong family history rendered a considerable number of pregnant women to suffer from gestational diabetes.