Outcomes of Patients Treated in the UK Proton Overseas Programme: Non-central Nervous System Group

AIMS

The UK Proton Overseas Programme (POP) was launched in 2008. The Proton Clinical Outcomes Unit (PCOU) warehouses a centralised registry for collection, curation and analysis of all outcomes data for all National Health Service-funded UK patients referred and treated abroad with proton beam therapy (PBT) via the POP. Outcomes are reported and analysed here for patients diagnosed with non-central nervous system tumours treated from 2008 to September 2020 via the POP.

MATERIALS AND METHODS

All non-central nervous system tumour files for treatments as of 30 September 2020 were interrogated for follow-up information, and type (following CTCAE v4) and time of onset of any late (>90 days post-PBT completion) grade 3-5 toxicities.

RESULTS

Four hundred and ninety-five patients were analysed. The median follow-up was 2.1 years (0-9.3 years). The median age was 11 years (0-69 years). 70.3% of patients were paediatric (<16 years). Rhabdomyosarcoma (RMS) and Ewing sarcoma were the most common diagnoses (42.6% and 34.1%). 51.3% of treated patients were for head and neck (H&N) tumours. At last known follow-up, 86.1% of all patients were alive, with a 2-year survival rate of 88.3% and 2-year local control of 90.3%. Mortality and local control were worse for adults (≥25 years) than for the younger groups. The grade 3 toxicity rate was 12.6%, with a median onset of 2.3 years. Most were in the H&N region in paediatric patients with RMS. Cataracts (30.5%) were the most common, then musculoskeletal deformity (10.1%) and premature menopause (10.1%). Three paediatric patients (1-3 years at treatment) experienced secondary malignancy. Seven grade 4 toxicities occurred (1.6%), all in the H&N region and most in paediatric patients with RMS. Six related to eyes (cataracts, retinopathy, scleral disorder) or ears (hearing impairment).

CONCLUSIONS

This study is the largest to date for RMS and Ewing sarcoma, undergoing multimodality therapy including PBT. It demonstrates good local control, survival and acceptable toxicity rates.

P01.07.A Neurocognitive outcomes after proton beam therapy for skull base tumours

Background

Evidence suggests that Proton Beam Therapy (PBT) may lessen the risk of neurocognitive decline (NCD) by reducing the dose to the normal brain as compared to conventional photon radiotherapy (XRT). We report the incidence of moderate-severe (Grade ≥3) NCD in adults treated for skull base chordomas and chondrosarcomas within the United Kingdom’s Proton Overseas Programme (POP).

Material and Methods

Baseline (pre-PBT) and follow-up clinical outcomes data were prospectively collected as part of a national PBT-outcomes registry, which started in 2008 . This registry is curated by a dedicated Proton Clinical Outcomes Unit. Specifically, late toxicities ≥G3 as per CTCAE (Common Terminology Criteria for Adverse Events) v4.0 definition, occurring later than 90 days after treatment completion, were recorded. This study focuses on the incidence of memory impairment (MI) in the adult (≥25 y) cohort.

Results

Between 2008-2018, 141 adult patients were treated for skull base chordomas (77 patients, 54.6%) and chondrosarcomas (64 patients, 45.4%) via the POP (the majority -62.8%- treated at the University of Florida PBT Institute). Median age at treatment was 51 years (range 26-77). Median prescription dose was 73.8 GyRBE (70-75.6), with a median dose per fraction of 1.8 Gy (1.2-2.1). Of note, the median dose for chondrosarcomas was 70.2 GyRBE (70-75.6), whereas the median dose for chordomas was 73.8 GyRBE (72-75.6). Median follow up was 39 months (0-138). On clinical assessment, 4 patients (2 chordomas, 2 chondrosarcomas) were reported with G3 MI after a median time of 43 months (27-49). None of them had impaired memory at baseline, nor relevant neurological comorbidities. Median age of those who developed G3 MI was 63 y (39-70). Median prescription dose was 72.9 GyRBE (70-73.8). Plans were available for 3 of these 4 patients. Relevant dose statistics to hippocampi and temporal lobes were extracted. Dmean to the omo- and contralateral hippocampi in these 3 patient plans were: patient 1) 33.7 and 11.6 GyRBE; patient 2) 28.1 and 24.4 Gy; patient 3) 8.7 and 8.2 GyRBE, respectively. V20 to the omo- and contralateral temporal lobes in the same patients were: patient 1) 47% and 10%; patient 2) 29% and 28.7%; patient 3) 30% and 28%, respectively. Suggested constraints for these structures are: Dmean &lt; 20 Gy to the hippocampi and V20Gy &lt;10% to the temporal lobes.

Conclusion

Our results indicate that adult patients undergoing high dose radiation for radioresistant tumours may experience detrimental effects on memory. Neurocognitive baseline and follow-up assessment is not routinely performed in this age group but might be appropriate to explore which domains of cognitive function are mainly affected. Larger cohorts are warranted to establish predictive factors and better understand dose volume effect of brain structures and neurocognitive sequelae.

Estimating the percentage of patients who might benefit from proton beam therapy instead of X-ray radiotherapy

OBJECTIVES

High-energy Proton Beam Therapy (PBT) commenced in England in 2018 and NHS England commissions PBT for 1.5% of patients receiving radical radiotherapy. We sought expert opinion on the level of provision.

METHODS

Invitations were sent to 41 colleagues working in PBT, most at one UK centre, to contribute by completing a spreadsheet. 39 responded: 23 (59%) completed the spreadsheet; 16 (41%) declined, arguing that clinical outcome data are lacking, but joined six additional site-specialist oncologists for two consensus meetings. The spreadsheet was pre-populated with incidence data from Cancer Research UK and radiotherapy use data from the National Cancer Registration and Analysis Service. 'Mechanisms of Benefit' of reduced growth impairment, reduced toxicity, dose escalation and reduced second cancer risk were examined.

RESULTS

The most reliable figure for percentage of radical radiotherapy patients likely to benefit from PBT was that agreed by 95% of the 23 respondents at 4.3%, slightly larger than current provision. The median was 15% (range 4-92%) and consensus median 13%. The biggest estimated potential benefit was from reducing toxicity, median benefit to 15% (range 4-92%), followed by dose escalation median 3% (range 0 to 47%); consensus values were 12 and 3%. Reduced growth impairment and reduced second cancer risk were calculated to benefit 0.5% and 0.1%.

CONCLUSIONS

The most secure estimate of percentage benefit was 4.3% but insufficient clinical outcome data exist for confident estimates. The study supports the NHS approach of using the evidence base and developing it through randomised trials, non-randomised studies and outcomes tracking.

ADVANCES IN KNOWLEDGE

Less is known about the percentage of patients who may benefit from PBT than is generally acknowledged. Expert opinion varies widely. Insufficient clinical outcome data exist to provide robust estimates. Considerable further work is needed to address this, including international collaboration; much is already underway but will take time to provide mature data.

A Novel Model and Infrastructure for Clinical Outcomes Data Collection and Their Systematic Evaluation for UK Patients Receiving Proton Beam Therapy

AIMS

To establish an infrastructure for sustainable, comprehensive data collection and systematic outcomes evaluation for UK patients receiving proton beam therapy (PBT).

MATERIALS AND METHODS

A Proton Outcomes Working Group was formed in 2014 to develop a national minimum dataset for PBT patients and to define a clinically integrated informatics solution for data collection. The Christie Proton Beam Therapy Centre formed its Proton Clinical Outcomes Unit in 2018 to collect, curate and analyse outcomes data prospectively for UK-treated patients and retrospectively for UK patients referred abroad for PBT since 2008 via the Proton Overseas Programme (POP).

RESULTS

A single electronic form (eForm) was developed to capture the agreed data, using a data tree approach including conditional logic: data items are requested once, further questions depend on previous answers and are sensitive to tumour site and patient pathway time point. Relevant data automatically populate other forms, saving time, prompting completeness of clinical assessments and ensuring data consistency. Completed eForm data populate the electronic patient record and generate individualised outputs, including consultation letters, treatment summary and surveillance plans, based on organs at risk irradiated, age and sex. All data regarding POP-treated patients are verified and migrated into the system, ensuring that patient data, whether overseas or UK treated, are consistently recorded. The eForm utilises a 'user friendly' web portal interface, the Clinical Web Portal, including clickable tables and infographics. Data items are coded to a universally recognised standard comparable with other data systems. Patient-reported outcomes are also integrated, highlighting significant toxicities and prompting a response. Outcomes data can be correlated with dosimetric DICOM data to support radiation dose modelling.

CONCLUSION

Outcomes data from both POP-treated and The Christie-treated patients support long-term care, allow evaluation of PBT efficacy and safety, assist future selection of PBT patients and support hypothesis generation for future clinical trials.

Artificial intelligence technology for diagnosing COVID-19 cases: a review of substantial issues

Today, the world suffers from the rapid spread of COVID-19, which has claimed thousands of lives. Unfortunately, its treatment is yet to be developed. Nevertheless, this phenomenon can be decelerated by diagnosing and quarantining patients with COVID-19 at early stages, thereby saving numerous lives. In this study, the early diagnosis of this disease through artificial intelligence (AI) technology is explored. AI is a revolutionizing technology that drives new research opportunities in various fields. Although this study does not provide a final solution, it highlights the most promising lines of research on AI technology for the diagnosis of COVID-19. The major contribution of this work is a discussion on the following substantial issues of AI technology for preventing the severe effects of COVID-19: (1) rapid diagnosis and detection, (2) outbreak and prediction of virus spread, and (3) potential treatments. This study profoundly investigates these controversial research topics to achieve a precise, concrete, and concise conclusion. Thus, this study provides significant recommendations on future research directions related to COVID-19.

Structural and molecular modelling studies of antimelanogenic piper-amide TRPM1 antagonists

Piper-amides exhibit diverse biological activities, including antimelanogenic effects. In our previous studies, we identified a potent piper-amide derivative that inhibited melanogenesis via the TRPM1 calcium channel. Despite its potential as a therapeutic target, the three-dimensional structure of TRPM1 is still not available. Thus, structure-guided compound design and the discovery of novel inhibitors of melanogenesis have been limited. In the present study, a series of computational methods, including homology modelling, docking, molecular dynamics simulation and field-based pharmacophore modelling, were integrated to explore the structural features of natural piper-amide-like compounds related to the TRPM1 target. These studies suggested the binding mode and provided a 3D pharmacophore model of the ligands, which can be helpful in understanding the TRPM1-ligand interactions at the molecular level and in designing potent antagonists of TRPM1.

Abstract P6-05-03: Genomic diversity of ductal carcinoma in situ (DCIS) as a driver of invasion and metastasis

Background: Recent evidence indicates that breast cancers may have high levels of heterogeneity. Based on principles of tumor evolution, we are investigating whether DCIS with higher levels of intra-tumoral genetic heterogeneity are more likely to progress to invasive and/or metastatic disease.

Methods: Cases (DCIS with co-existing invasive or metastatic cancer) and controls (pure DCIS) are identified from Duke Pathology archives. From cases and controls, we are analyzing two areas of DCIS separated by &gt;1cm with germ line DNA from the same subject to measure allele frequencies of somatic mutations and copy number variation (CNV). Small amounts of FFPE derived DNA are made into NGS libraries for full exome sequencing and hybridization to a 4.2 million element SNP array. Comparison of allele frequencies and CNV is made between specimens from the same cancer to assess heterogeneity.

Results: We identified a series of pure DCIS (controls for this study) and generated high coverage sequencing data from 20ng of FFPE DNA from 12 samples (4 subjects, germline + 2 DCIS containing areas from each subject) as proof of principle. We compared the occurrence of deletions, insertions and SNP's after a 20X coverage filtration. From these data, we identified between 50 to greater than 600 sequence changes in these DCIS compared to normal DNA. Present/absent calls and allele frequencies indicate both significant and variable degrees of heterogeneity even in these pure DCIS samples. Additional data is now being gathered and analyzed based on this established technical approach.

Conclusion: We have demonstrated the feasibility of acquiring high quality NGS data from archival DCIS specimens allowing us to test the hypothesis that genetic heterogeneity is a driving force in breast cancer progression. The degree and nature of this heterogeneity will be assessed in a panel of pure DCIS and DCIS co-existing with invasive and/or metastatic cancer. We are now generating and analyzing these data for Symposium presentation.

Citation Format: King LM, Marks JR, Hall AH, Temko D, Graham TA, Mardis ER, Maley CC, Hwang E. Genomic diversity of ductal carcinoma in situ (DCIS) as a driver of invasion and metastasis. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P6-05-03.

Expression levels of histone deacetylases and acetylation of histone H4 and tubulin associated with breast cancer progression

Abstract #2051

Background: Excess histone deacetylase (HDAC) activity can induce global hypoacetylation of histone and non-histone protein substrates, altering gene expression patterns and cell behavior potentially associated with malignant transformation. However, HDAC expression and protein acetylation have not previously been studied in the context of breast cancer progression.&#x2028; Materials and Methods: We performed immunohistochemistry (IHC) to assess expression levels of acetylated histone H4 (acH4), acH4K12, acTubulin, HDAC1, HDAC2 and HDAC6 in formalin fixed paraffin embedded sections with synchronous normal epithelium (N), ductal carcinoma in situ (DCIS), and invasive ductal carcinoma (IDC) components from 58 archived samples at UCSF. Staining was assessed on the basis of H-score, defined as the sum of the intensity of staining (0-3) multiplied by % of stained cells for each intensity (score range 0-300). H-score differences between groups were tested for significance using either the Mann-Whitney test or the Wilcoxon signed rank test for paired samples.&#x2028; Results: From N to DCIS, there was a marked reduction in histone acetylation (acH4, acH4K12). Tubulin acetylation, a marker of non-histone protein acetylation, showed a smaller reduction. Expression of all three HDACs was also reduced, but to a lesser extent than histone acetylation. Moreover, from DCIS to IDC, the same pattern of changes in acetylation and HDAC expression was seen, although these differences were of smaller magnitude than between N and DCIS. All markers were significantly different between N and DCIS (all p&lt;0.0001) and between DCIS and IDC (all p&lt;0.03). ER-negative tumors exhibited greater changes from N to DCIS than did ER-positive tumors, particularly for acH4 and HDAC1 (p=0.05 and 0.0001 respectively). High-grade invasive tumors showed more significant changes from N to DCIS than low/intermediate grade tumors for acH4, acH4K12, acTubulin, and HDAC1 (p=0.0009, 0.006, 0.05, and &lt;0.0001 respectively). The change in protein acetylation and HDAC expression with cancer progression did not differ by HER2 status or age (≤50 or &gt;50).&#x2028; &#x2028; Conclusions: Overall there was a pattern of hypoacetylation associated with malignant progression, with normal epithelium exhibiting the highest acH4, acH4K12, and acTubulin levels and IDC exhibiting the lowest levels. Paradoxically, expression of HDAC 1, 2 and 6 was not increased; thus, our data support that histone hypoacetylation is not regulated by HDAC expression but rather by modulation of HDAC activity. Outcome studies and clinical trials are needed to assess the prognostic significance of these findings and to determine how effectively HDAC inhibitors could reverse the hypoacetylation observed in progression from N to DCIS and IDC.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 2051.

200 REPROGRAMMING OF Oct-4 FOLLOWING EQUINE SOMATIC CELL NUCLEAR TRANSFER

Oct-4, a POU domain-containing transcription factor encoded by Pou5f1, is selectively expressed in pre-implantation embryos and pluripotent stem cells, but not in somatic cells. Because of such a unique expression feature, Oct-4 can serve as a useful reprogramming indicator in somatic cell nuclear transfer (SCNT). Compared with data of Oct-4 expression in mouse and bovine cloned embryos, little is known about this gene in equine nuclear transfer. In the present study, we investigated Oct-4 expression in donor cells, oocytes, and SCNT embryos to evaluate reprogramming of equine somatic cells following nuclear transfer. Horse ovaries were obtained from a local slaughterhouse and the oocytes collected from the ovaries were matured in vitro in an M199-based medium (Galli et al. 2003 Nature 424, 635) for 24 h. Donor cells were derived from biopsy tissue samples of adult horses and cultured for 1 to 5 passages. Standard nuclear transfer procedures (Zhou et al. 2008 Mol. Reprod. Dev. 75, 744–758) were performed to produce cloned embryos derived from equine adult somatic cells. Cloned blastocysts were obtained after 7 days of in vitro culture of reconstructed embryos. Total RNA were extracted using Absolutely RNA Miniprep/Nanoprep kits (Stratagen, La Jolla, CA) from oocytes (n = 200), donor cells, and embryos (n = 5). DNase I treatment was included in the procedure to prevent DNA contamination. Semiquantitative RT-PCR was performed with optimized cycling parameters to analyze Oct-4, GDF9, and β-actin in equine donor cells, oocytes, and cloned blastocysts. The RT-PCR products were sequenced to verify identity of the genes tested. The relative expression abundance was calculated by normalizing the band intensity of Oct-4 to that of β-actin in each analysis. No transcript of Oct-4 was detected in equine somatic cells used as donor nuclei, consistent with its expression patterns in other animal species, whereas Oct-4 was abundantly expressed in equine SCNT blastocysts derived from the same donor cell line. Oct-4 transcripts were also detected in equine oocytes and whether any maternally inherited Oct-4 mRNA persisted up to the blastocyst stage was unclear in this study. We selected GDF9 to address this question; GDF9 was abundantly detected in equine oocytes, consistent with its expression pattern in mouse and bovine, but not detected in donor cells and cloned blastocysts, suggesting that the GDF9 mRNA from the oocyte was degraded at least by the blastocyst stage. The results from this study imply occurrence of Oct-4 reprogramming in equine SCNT blastocysts, and future analysis for more developmentally important genes is needed to better understand reprogramming at molecular levels in this species.

5 INHIBITION OF FOOT AND MOUTH DISEASE VIRUS IN VITRO USING RNA INTERFERENCE

The use of short-hairpin RNA (shRNA) targeting viral genomes has shown great promise in human medicine and in vitro research in animal agriculture. However, this research has not been extrapolated into livestock applications. Foot and mouth disease virus (FMDV) is a world-wide disease resulting in decreased production and export limitations in countries with endemic FMDV, as well as severe economical impacts if an outbreak occurs in an FMDV-free country. The long-term goal for this project is to produce transgenic cattle that express shRNA targeting the FMDV genome resulting in resistance to infection. As a starting point, five siRNA and one non-targeting control siRNA (Null) were developed targeting different highly conserved regions of a FMDV type-A based replicon. The siRNA were transfected into BHK cells 48 h before viral RNA challenge. Eighteen hours post challenge the cells were lysed and analyzed. Three siRNA targeting the non-structural polymerase protein exhibited severe knockdown of 87, 90, and 92% when compared with the Null siRNA transfected control. The siRNA targeting the VPG3 cap protein reduced activity by 59%, and the siRNA targeting the internal ribosomal entry site had a minimal effect of 15% reduction. Based upon these results, we produced recombinant lentiviral particles designed to deliver the shRNA sequence targeting the FMDV genome and the fluorescent marker, dsRed, into a bovine fetal fibroblast cell line. This transgenic cell line expressing the most effective shRNA (based on initial siRNA screening) was used for somatic cell nuclear transfer to create bovine embryos. One hundred and sixty oocytes were enucleated, of which 149 had successful fusion resulting in 35 blastocysts after in vitro culture. Two embryos per recipient were transferred into five recipients. At Day 40 of pregnancy three of the five recipients had a fetus, but no heart beat could be detected. We are currently in the process of creating another cell line and repeating this experiment. If successful, transgenic calves will be visually and genetically analyzed for expression of dsRed and shRNA targeting FMDV. Transgenic and control animals/tissues will then be analyzed for resistance to infection with FMDV.

308 DEVELOPMENT OF TRANSGENIC LIVESTOCK WITH REDUCED MYOSTATIN EXPRESSION USING RNA INTERFERENCE

RNA interference (RNAi) is a means of regulating gene expression by targeting mRNA in a sequence-specific manner for degradation or translational inhibition. Short hairpin RNAs (shRNAs) and siRNAs have been extensively employed for manipulating gene expression in a wide range of species. However, the great majority of this work has involved in vitro studies with cells grown in culture. Our goal for this project is to produce transgenic livestock in which myostatin, a negative regulator of muscle growth, has been targeted for silencing by RNAi. In theory, livestock in which myostatin has been silenced should exhibit increased muscle growth and development. To that end, we designed shRNAs to target the bovine myostatin mRNA sequence. The shRNAs were cloned into a lentiviral vector that contains a cytomegalovirus promoter controlling green fluorescent protein and shRNA expression as well as neomycin resistance. Infective lentivirus was made in HEK293T cells through co-transfection of the lentiviral vector, a packaging plasmid, and a plasmid expressing the VSVG pseudotype. Bovine fetal fibroblasts were transduced, selected using Geneticin®, and nuclear transfer was utilized to produce cloned transgenic embryos. There were 186 fusion attempts resulting in 160 fused embryos (fusion rate = 86%). Of these, 54 reached the blastocyst stage (34%) and 10 embryos were transferred into 5 recipient females (2 embryos per recipient). At 40 days, ultrasound revealed 1 confirmed pregnancy. Current plans are to harvest this fetus at 90 days and analyze it for evidence of myostatin knockdown. The production of transgenic animals exhibiting myostatin knockdown through lentiviral-mediated RNAi will demonstrate the utility of RNAi in the study of gene function in large animal models without the need for homologous recombination techniques, which are currently inefficient in species other than mice.

Chlorine and chlorine dioxide treatment to reduce or remove EBDCs and ETU residues in a solution

Calcium hypochlorite (Ca(OCl)(2)) and chlorine dioxide (ClO(2)), common disinfecting and bleaching chemicals used in the food industry, are potent oxidizing agents. In this paper, the degradation effects of chlorine dioxide on mancozeb and ethylenethiourea (ETU) residues were investigated in a model system and compared with those of liquid chlorine, under various conditions such as differing concentration, pH, reaction time, and temperature. All samples were analyzed for residues by GLC and HPLC. Rate of mancozeb degradation was dependent on pH, with pH 4.6 being the most effective. Mancozeb residues decreased 40-100% with chlorine and chlorine dioxide treatments. ETU residue concentrations in mancozeb solutions were monitored over 60 min. Under controlled conditions, the ETU residue concentrations increased up to 15 min reaction time and then decreased in all three pH ranges. Treatment with both chlorine and chlorine dioxide at pH 4.6, yielded no ETU residues at both 10 and 21 degrees C. The results show that chlorine dioxide gives excellent degradation effects at lower concentrations than liquid chlorine.