Course Of Chemoradiotherapy Research Articles

Plasma sICAM-1 correlates with tumor volume before primary radiochemotherapy of head and neck squamous cell carcinoma patients.

Biomarkers are of major interest to optimize diagnosis, prognosis and to guide treatment in head and neck cancer patients. Especially blood-based biomarkers appear promising as they can be easily collected and repeatedly analyzed during the course of radiochemotherapy. At first, for a broad overview, multiple immune markers were evaluated in six plasma samples of three head and neck squamous cell carcinoma (HNSCC) patients at the beginning and the end of radio-chemotherapy. In this pre-selection, the soluble Intercellular Adhesion Molecule 1 (sICAM-1) appeared most promising. Thus, this marker was measured in multiple samples (n = 86) during treatment and follow-up in a cohort of eleven patients and correlated with tumor features and clinical data. We found a strong correlation between the initial levels of sICAM-1 in the plasma and the gross tumor volumes of the primary tumor and the involved lymph nodes. However, during the course of treatment no systematic dynamics could be identified. Toxicity or infections did not seem to influence sICAM-1 concentrations. sICAM-1 appears to reflect the pre-treatment total tumor burden (primary tumor and involved lymph nodes) in head and neck tumor patients. However, it does not seem to be a dynamic marker reflecting response during radiochemotherapy. Thus, if our findings are confirmed in future, sICAM-1 could be used as a staging marker: if high sICAM-1 levels but low tumor burden are found it might be reasonable to intensify staging investigations to rule out further, yet undetected, tumor sites.

Reduced-dose radiation in human papillomavirus-associated oropharyngeal carcinoma can improve outcome: a systematic review and meta-analysis.

Despite its effectiveness, the standard course of chemoradiation for the treatment of human papillomavirus (HPV)-related oropharyngeal carcinoma (OPC) results in considerable treatment-related adverse effects. Studies proved that HPV-positive OPC is very sensitive to radiotherapy. Using de-escalation therapy as a new strategy is critical to maintaining positive outcomes while alleviating side effects. However, some studies hold that reduced dose causes insufficient effect on tumor killing. We conducted this systematic review and meta-analysis of survival and adverse reactions in patients with HPV-related OPC by retrospective analysis and evaluated the therapeutic effect of reducing the radiation dose. Data were double-selected and extracted by searching seven electronic databases, Original studies in all language treated HPV-associated OPC with reduced-dose and standard-dose therapies were included. Overall survival (OS), progression-free survival (PFS), and incidence rates of adverse events were obtained by pooling analyses. Statistical analyses were performed using RStudio Version 1.1.383 (RStudio, Boston, MA, USA) via the Meta-Analysis R Package (metafor). Heterogeneity was evaluated using the I2 statistic and the Cochran Q test. We used Stata (version 15.0) for forest graph. Thirteen studies were included in this meta-analysis, involving a dose range of 66-70 Gy for the standard treatment regimen and <66 Gy for the reduced-dose group. There was no significant difference in the age of the patients in the standard and the reduced treatment groups (60.9±5.9 vs. 58.6±2.4 years). Nine studies were included as standard cohort and thirteen studies were enrolled as reduced-dose cohort. The 2- and 3-year overall survival rates in the reduced-dose group (95.66% and 91.51%, respectively) were superior to those in the standard-dose group (88.36% and 87.46%, respectively). There was no significant difference in PFS between the two groups. A systematic review of articles on dose reduction and the standard dose was also conducted. The most common complication in reduced-dose radiation was oral mucositis (36.4%), followed by decreased white blood cell (WBC) count (30.5%) and dry mouth (29.1%). Reducing the radiation dose in patients with HPV-related OPC substantially alleviates the treatment toxicities and optimizes the quality of life of patients while at the same time maintaining favorable oncologic outcomes.

BIOM-37. EVALUATION OF TEMPORALIS MUSCLE THICKNESS WITH TOXICITY AND SURVIVAL IN GLIOBLASTOMA PATIENTS RECEIVING CHEMORADIATION

Abstract BACKGROUND Treatment-related toxicity is common in patients with glioblastoma (GBM) receiving chemotherapy and radiotherapy (RT). Temporalis muscle thickness (TMT) is a biomarker associated with sarcopenia and worse clinical outcomes in GBM, however its relation to treatment toxicity is less studied. We hypothesize that TMT may predict toxicity and survival in GBM patients. METHODS We reviewed consecutive patients with IDH-wildtype GBM treated from 2014-2019 at a single academic center. TMT was retrospectively assessed on T1-weighted MRI scans and dichotomized based upon previously validated sex-specific cutoff values. TMT was measured on baseline MRI scan at time of diagnosis. Cox regression multivariable analysis (MVA) was used to assess survival. RESULTS We evaluated 351 patients with median age of 60y (range 20-94) and median follow-up of 14mo. Most patients were male (59%), baseline KPS &amp;gt;70 (95%), and MGMT unmethylated (55%). After maximal safe resection, most patients received standard (90%) or hypofractionated (10%) RT with concurrent systemic therapy (89%). On MVA, baseline low TMT (HR 1.93, p=0.01), age &amp;gt;65y, baseline KPS, and MGMT-unmethylated status were associated with worse OS. On MVA, baseline low TMT (HR 1.95, p=0.01), age &amp;gt;65y, MGMT-unmethylated status, and discontinuing systemic therapy were associated with worse profession-free survival (PFS). 21 patients did not complete anticipated treatment course of chemoradiation and adjuvant systemic therapy due to toxicity, primarily thrombocytopenia, associated with worse OS on MVA (HR 1.99, p&amp;lt; 0.01). Low TMT was associated with higher risk of stopping treatment due to adverse events (OR 5.25, p&amp;lt; 0.01) independent of age, sex, extent of resection, RT dose on MVA. CONCLUSION Baseline low TMT was associated with worse PFS and OS, and it was associated with treatment interruption due to treatment toxicity in GBM patients. While further validation is needed, TMT may help identify patients who will benefit from aggressive symptom management or treatment deintensification.

Radiomic Study for Objectification of Diagnostics and Complex Treatment of Glioblastoma

Introduction.Glioblastoma is a neuroepithelial malignant brain tumour of predominantly astrocytic origin with an aggressive course and an extremely unfavorable prognosis. Since the median of overall survival with glioblastoma is 14.6 months after complex treatment that includes a combination of surgical treatment, radiation therapy and chemotherapy, the development a personalized approach in the diagnosis and treatment of glioblastomas is appeared to be urgent.Materials and methods. MRIs of a patient undergoing chemoradiotherapy for glioblastoma G4 were performed on the following MRI scanners: Philips Ingenia 1.5T and Philips Ingenia Ambient 1.5T. The analysis of MR-images was carried out using the Matlab 2021 apps.Results and discussion.MR-images were analyzed before and after surgery, and after a course of chemoradiotherapy. The statistical characteristics of the local brightness distribution of the lesion image, which are described by statistical texture parameters, were analyzed as informative features of the lesion area on the images. Initial confirmation of the ability to objectify diagnosis and treatment using the above statistical parameters of T2 MR images of lesion area has been obtained.Conclusion.The aim of further research in this area is to use radiomic study for planning and monitoring the treatment of high-grade gliomas, estimate disease outcomes, and analyze the response to complex treatments in a predictive way.

Radiation Immunodynamics as the Foundation of Immune-Guided Radiotherapy: Changes in Peripheral CD14+PD-L1+ Myeloid Cells over the Course of Chemoradiation and Association with Survival for New Diagnosis of Glioblastoma

<h3>Purpose/Objective(s)</h3> Radiation immunodynamics, or the understanding of immune markers over a fractionated course of radiotherapy (RT), is a critical intermediate step in developing personalized RT approaches, including Immune-guided Radiotherapy (IM-GRT). Peripheral-origin myeloid cells are a major component of the glioblastoma (GBM) tumor microenvironment. The effect of adjuvant chemoradiation (CRT) on programmed death-ligand 1 (PD-L1)-expressing suppressive myeloid cells is unknown. We hypothesize that PD-L1⁺ monocytes increase from baseline in the peripheral blood of patients with GBM undergoing CRT. <h3>Materials/Methods</h3> Tumor and peripheral blood were collected from a prospective, single-institution, biospecimen protocol of newly diagnosed GBM participants undergoing CRT. A neuropathologist selected regions of interest within baseline formalin-fixed, paraffin-embedded tissue for digital spatial profiling. Expression for PD-L1 on CD163⁺ regions of interest is quantified relative to isotype and presented as fold change. Flow cytometry was performed on peripheral blood immune cells at seven time points in relation to CRT: one prior to start, five weekly during, and one month after completion. Flow cytometry data are expressed as percent frequency (%fx) of CD14⁺ monocytes. Correlative studies focusing on plasma analytes, metabolic proteins, and bulk RNA sequencing were also performed. Relationships between PD-L1 and overall survival (OS) or progression-free survival (PFS) were assessed by Cox model. "Survivors" were alive 2 years after diagnosis. <h3>Results</h3> A total of 15 cases with baseline PD-L1 assessment are included. Digital spatial profiling (n=10) of tumor identified PD-L1 expression within regions of interest with CD163⁺ myeloid cells is increased in non-survivors compared to survivors (log2FC=0.28; padj<0.05). The median %fx of peripheral blood CD14⁺ PD-L1⁺ cells at the pre-CRT baseline is 39.2% among survivors and 16.0% among non-survivors, and not associated with OS (HR=0.98, p=0.36) or PFS (HR=0.99, p=0.7). Comparing to baseline, the %fx of CD14⁺PD-L1⁺ cells at week 4 during CRT decreases (median fold change 0.49, range 0.08-0.92) in survivors but increases (median fold change 1.86, range 0.31-4.32) in non-survivors. Such a mid-CRT change (in terms of fold change) is significantly associated with OS (HR=2.21, p=0.008) but not PFS (HR=1.33, p=0.17). One month after CRT, the median %fx is 4.9% in survivors and 19.7% in non-survivors, and not associated with OS (HR=1.04, p=0.11) or PFS (HR=1.02, p=0.33). <h3>Conclusion</h3> This is the first study to demonstrate changes in peripheral CD14⁺PD-L1⁺ myeloid cells over the course of CRT and to associate these changes with survival outcome. Dynamic biomarker assessments, like radiation immunodynamics, may identify patients who would benefit from immune adjuvants while undergoing CRT in neuro-oncology and other disease sites.

Tumor Microbiome Composition in Vaginal and Vulvar Cancers during Chemoradiation

<h3>Purpose/Objective(s)</h3> Infection with HPV is associated with vaginal microbiome alterations including higher abundance of Lactobacillus gasseri and Gardnerella vaginalis. Cervical dysbiosis is a risk factor for cervical cancer but less is known about the composition of the tumor microbiome of vaginal and vulvar cancers. In gynecological cancers, surgery, chemotherapy, and radiation are associated with significant shifts in the vaginal microbiome. The purpose of this study is to explore the composition of the tumor microbiome in vaginal and vulvar cancers during and after chemoradiation (CRT) treatment. <h3>Materials/Methods</h3> Tumor swabs from 10 females diagnosed with vulvar (n=3) or vaginal (n=7) cancer were serially collected and analyzed by 16Sv4 rRNA gene sequencing over the course of CRT with four time points collected. Changes in richness by alpha diversity was assessed using paired Wilcoxon signed-rank tests. Linear discriminant analysis effect size (LEfSe) was used to identify distinct taxa that were differentially enriched in baseline samples versus end-of-treatment samples. Principal coordinates analysis (PCoA) analysis using PERMANOVA was used to compare the microbiome of vaginal and vulvar cancer types. Skin toxicity was assessed by searching patients' medical records for clinical findings in the treatment area as well as the use of Mepilex, Nystatin, Diflucan, Antibiotics, and Domeboro recorded during their weekly follow-up appointments. <h3>Results</h3> Wilcoxon signed-rank tests of each time point to baseline sample values did not show statistically significant differences during any of the time points (p>0.05). PCoA pairwise PERMANOVA tests demonstrated statistically significant differences between vaginal and vulvar tumor types (p=0.027). LEfSe demonstrated an increase in relative abundance of taxa Sutterellaceae and Bacteriodia at the end of treatment. Skin toxicity during radiation treatment was present in all vulvar patients and most (71%) vaginal patients but cannot be correlated with microbiome features due to small cohort size. <h3>Conclusion</h3> Our preliminary results demonstrate that richness of vulvar and vaginal samples remained stable during CRT. The microbiome of the tumor microenvironments in vaginal and vulvar samples demonstrated differences in composition. Future studies should be performed to further assess the impact of Sutterellaceae and Bacteriodia on the gynecological microbiota and whether they are associated with increased skin toxicity during CRT treatment.

Concurrent Chemo-radiotherapy in Anal Squamous Cell Carcinoma: A Retrospective Review of a Tertiary Centre Experience.

Anal cancer is a rare form of gastrointestinal malignancy, and treatment is often confined to specialist centres. It has a high cure rate with non-surgical approach resulting in organ preservation. The current accepted schedule is chemo-radiotherapy (CRT) with 5-fluorouracil and mitomycin with radiotherapy doses between 50.4 and 53.2 Gray in 28 fractions. This study included patients who had histological confirmation of squamous cell carcinoma and had completed the full CRT course for anal cancer between 2008 and 2018 in our centre. Data was collected retrospectively assessing demographics, staging, surgery, relapse, latest follow-up, date of death, CRT regimen and TNM stage. Outcome data and stoma reversal rate were analysed. Overall, 87 patients were included in the study. At diagnosis 94.3% of patients had T2-T4 disease, and 44.8% had involvement of positive loco-regional lymph nodes. Overall survival (OS) probability at 1, 3 and 5years were 98.8%, 87.4% and 83.7%, respectively. Results also revealed a statistically significant effect of time from diagnosis to the start of radiotherapy on OS (p = 0.039). Sixty-nine (79.3%) patients achieved complete remission at last follow-up. Twenty-one patients (24%) underwent surgery for a de-functioning stoma, and only five of these patients subsequently received stoma reversal surgery. Our data reflects the efficacy of CRT as the primary modality of treatment in the management of anal squamous cell carcinoma with effective organ preservation and disease control. Early stoma reversal may also enhance quality of life.

Feasibility of a novel non-invasive swab technique for serial whole-exome sequencing of cervical tumors during chemoradiation therapy.

BackgroundClinically relevant genetic predictors of radiation response for cervical cancer are understudied due to the morbidity of repeat invasive biopsies required to obtain genetic material. Thus, we aimed to demonstrate the feasibility of a novel noninvasive cervical swab technique to (1) collect tumor DNA with adequate throughput to (2) perform whole-exome sequencing (WES) at serial time points over the course of chemoradiation therapy (CRT).MethodsCervical cancer tumor samples from patients undergoing chemoradiation were collected at baseline, at week 1, week 3, and at the completion of CRT (week 5) using a noninvasive swab-based biopsy technique. Swab samples were analyzed with whole-exome sequencing (WES) with mutation calling using a custom pipeline optimized for shallow whole-exome sequencing with low tumor purity (TP). Tumor mutation changes over the course of treatment were profiled.Results216 samples were collected and successfully sequenced for 70 patients (94% of total number of tumor samples collected). A total of 33 patients had a complete set of samples at all four time points. The mean mapping rate was 98% for all samples, and the mean target coverage was 180. Estimated TP was greater than 5% for all samples. Overall mutation frequency decreased during CRT but mapping rate and mean target coverage remained at >98% and >180 reads at week 5.ConclusionThis study demonstrates the feasibility and application of a noninvasive swab-based technique for WES analysis which may be applied to investigate dynamic tumor mutational changes during treatment to identify novel genes which confer radiation resistance.

Management of Tracheal Stent Granulations: A Novel Approach

This is a case of a 29 year old female, diagnosed with adenoid cystic carcinoma of trachea who had previously undergone bronchoscopy, de-bulking of the tumour, stenting of trachea with a metallic stent followed by a course of chemo-radiotherapy. She then presented to our hospital with complaints of breathing difficulty. On rigid telescopy of larynx, a metallic stent was visualised below the level of the vocal cords with a mass lesion over it narrowing the airway. Contrast enhanced CT scan of neck and thorax showed a tracheal stent with soft tissue thickening at proximal and distal ends. By using VV-ECMO, in this patient we were able to perform satisfactory airway evaluation, biopsy of mass at upper and lower end of tracheal stent using a rigid bronchoscope with Hopkins telescope and optical forceps and KTP laser assisted excision of granulation tissue with full endoscopic visualisation and without any complications.

Abstract 2430: The role of cellular iron and the homeostatic iron regulator (HFE) in high-grade brain tumor cell migration

Abstract High-grade brain tumors such as grade III astrocytoma and glioblastoma represent among the most difficult to manage malignancies facing oncological practice. Diffuse migration and invasion into adjacent healthy brain tissue yields complete surgical resection of these tumors unfeasible. As a result, despite receiving maximal surgical resection and an aggressive course of chemoradiation, the majority of high-grade brain tumor patients suffer from recurrent disease. Increased expression levels of the homeostatic iron regulator gene (HFE) in high-grade brain tumors have been correlated with poorer outcomes. HFE is known to influence cellular iron metabolism by inhibiting transferrin-mediated iron uptake yet little is known regarding how HFE or iron impact the migratory capabilities of high-grade brain tumor cells. In order to better understand how HFE expression and cellular iron metabolism influence cell migration in high grade brain tumors, we utilized brain tumor cell lines that had been genetically manipulated to express different levels of HFE. We observed that knocking down HFE in KR158 or LN229 glioma cell lines resulted in significantly decreased migratory capacity. Since HFE is known to inhibit transferrin mediated iron uptake, we studied how directly modulating the iron status of glioma cells impacted their ability to migrate. Treatment of a panel of glioma cell lines: LN229, T98G, U87, KR158, with iron in the form of hemin or ferric ammonium citrate resulted in significantly reduced migration. Furthermore, the iron-induced reduction in migration could be rescued by the addition of deferoxamine, an iron chelator. Cell viability in response to the iron treatments was assayed and found to not be significantly altered - suggesting that cellular iron status was influencing migratory capacity independent of cell viability. To gain mechanistic insights into HFE and iron-induced effects on cell migration, we analyzed the Chinese Glioma Genome Atlas (CGGA) for correlations between HFE and the Rho GTPases RHOA, RAC1, and CDC42 – genes which are known to play a crucial role in determining the migratory capacity of cancer cells. Interestingly, we found statistically significant correlations between the Rho GTPases RHOA, RAC1, CDC42 and HFE in both grade III astrocytoma and glioblastoma patient cohorts. Immunoblotting of iron treated glioma cell lines demonstrated that expression of RhoA and Cdc42 was reduced suggesting that alterations in Rho GTPase expression and signaling may play a role in iron-induced effects on cell migration. Our results demonstrate that targeting cancer cell iron metabolism as an addition to existing treatment regimens may be a promising avenue for further investigation. Citation Format: Ganesh Shenoy, Katie Troike, Kondaiah Palsa, Madison Kuhn, Quinn Wade, Becky Slagle-Webb, Amanda Snyder, Chachrit Khunsriraksakul, Justin D. Lathia, Dhimant Desai, Hong-Gang Wang, Elizabeth Proctor, James R. Connor. The role of cellular iron and the homeostatic iron regulator (HFE) in high-grade brain tumor cell migration [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2430.

ДИНАМИКА РЕОЛОГИЧЕСКИХ СВОЙСТВ СЛЮНЫ У ОНКОПАЦИЕНТОВ С ОРАЛЬНЫМ МУКОЗИТОМ В ПРОЦЕССЕ ЛЕЧЕНИЯ

Oral mucosal cancer is diagnosed worldwide. There are approximately 350,000 patients annually and it accounts for 5% of all malignant neoplasms detected in Europe and the USA. More than 60% of patients with initial treatment in medical institutions are assigned III–IV stage, which requires combined or complex treatment. Under the influence of chemo-radiation therapy, the salivary glands are affected and the physico-chemical properties of saliva change: viscosity, pH, salivation rate, etc.&#x0D; The study involved 89 people from the V.M. Efetov Crimean Republican Oncological Clinical Dispensary with a diagnosis of cancer of the oral mucosa, who, depending on the type of treatment (developed or traditional), were divided into two groups: the main one – using Laetrile in the form of rinses or oral baths for 8–14 days and the control – antitumor treatment according to the protocol (0.06% chlorhexidine solution, ointments for the elements of the lesion – levomycol, vaseline, pharmacy lotion and decoctions of chamomile and sage herbs).&#x0D; A clinical and laboratory evaluation of the salivation function was performed: the volume, salivation rate and relative viscosity of the oral fluid were studied. Oral fluid after irritation of the tongue with a food irritant (0.5% citric acid) was collected in a graduated tube for 5–10 minutes and the volume was determined. The salivation rate and saliva viscosity were determined using an Oswald’s viscometer using the technique of T.L. Redinova (1986).&#x0D; The features of salivation dysfunction in oncopatients receiving chemo-radiation therapy of the oral cavity are a decrease in volume (0.14 ± 0.01 ml) and velocity (0.42 ± 0.018 ml/min), as well as an increase in viscosity (7.42 ± 0.25 p.u.) saliva. The use of Laetrile for 10–14 days from the beginning of the course of chemo-radiation therapy can significantly prevent a decrease in the volume and increase in the viscosity of saliva and minimize the associated decrease in quality of life.

Preoperative Chemoradiotherapy plus Nivolumab before Surgery in Patients with Microsatellite Stable and Microsatellite Instability-High Locally Advanced Rectal Cancer.

Preoperative chemoradiotherapy (CRT) and surgical resection are the standard treatment for locally advanced rectal cancer (LARC). Combining immune checkpoint inhibitors with radiation suggests a promising approach for enhancing efficacy. We investigated the efficacy of CRT followed by nivolumab and surgery in patients with LARC. In phase I, we investigated the feasibility of sequentially combined CRT, 5 cycles of nivolumab, and radical surgery. In phase II, patients with microsatellite stable (MSS) and microsatellite instability-high (MSI-H) LARC were evaluated. Three patients in phase I received full courses of CRT and nivolumab without dose modification; the schedule was recommended for phase II. A pathologic complete response (pCR) was centrally confirmed in 30% [11/37; 90% confidence interval (CI), 18%-44%] and 60% (3/5) of the MSS and exploratory MSI-H cohorts, respectively. While immune-related severe adverse events were observed in 3 patients, no treatment-related deaths were observed. In 38 patients with MSS who underwent surgery, pCR rates of 75% (6/8) and 17% (5/30; P = 0.004, Fisher exact test) were observed in those with programmed cell death ligand 1 (PD-L1) tumor proportion score ≥1% and <1%, respectively; IHC staining was performed using pre-CRT samples. In 24 patients with MSS, pre-CRT samples were analyzed by flow cytometry; pCR rates of 78% (7/9) and 13% (2/15; P = 0.003, Fisher exact test) were observed for CD8+ T cell/effector regulatory T cell (CD8/eTreg) ratios of ≥2.5 and <2.5, respectively, in tumor-infiltrating lymphocytes. CRT followed by consolidation nivolumab could increase pCR. PD-L1 expression and an elevated CD8/eTreg ratio were positive predictors in patients with MSS LARC.

Circulating concentrations of citrulline, neopterin, kynurenine, and tryptophan during chemoradiation in patients with cervical carcinoma

Abstract The aim of this study was to investigate the changes in circulating concentrations of citrulline, neopterin, kynurenine, and tryptophan during the course of chemoradiation in patients with cervical cancer. Sixteen patients with histologically confirmed carcinoma of the uterine cervix, aged 53 ± 15 years (range 29–76 years), were included in this study. Plasma neopterin, kynurenine, and tryptophan were determined with an enzyme-linked immunosorbent assay. Plasma citrulline was measured with high-performance liquid chromatography. Compared to baseline, citrulline concentration was markedly and statistically significantly decreased at visits 2, 3, and 4, while returning to pretreatment concentrations at visit 5. A significant increase in serum neopterin concentrations was observed at visits 4 and 5. With the exception of decreased kynurenine/tryptophan ratio at visit 3, no significant changes were observed in the concentrations of kynurenine, tryptophan, and kynurenine/tryptophan ratio throughout the course of the treatment. In conclusion, present data demonstrate that citrulline concentrations decrease early and neopterin concentrations increase late during the course of chemoradiation in patients with cervical carcinoma. Citrulline represents a biomarker of intestinal toxicity in this population.

RBIO-05. THE IMPACT OF STEREOTATIC RADIOSURGERY (SRS) FOR THE RESIDUAL LESIONS OF PINEAL NON-GERMINOMATOUS GERM CELL TUMORS (NGGCTS) FOLLOWING CONVENTIONAL RADIOTHERAPY: A RETROSPECTIVE STUDY

Abstract OBJECTIVE To evaluate the safety and efficacy of stereotatic radiosurgery (SRS) in treating residual lesions of pineal non-germinomatous germ cell tumors (NGGCTs) after conventional radiotherapy. METHODS The patients admitted to Guangdong Sanjiu Brain Hospital from 1 January 2008 to 31 December 2018 who diagnosed with pineal NGGCTs pathologically or clinically were retrospectively analyzed. Among those, the patients received conventional radiotherapy with or without SRS were included. The residual lesions after radiotherapy were defined with a maximum diameter &amp;gt; 10mm. Prognosis related parameters such as local control rate, progress-free survival, overall survival and treatment-related toxicity were determined. RESULTS The median follow-up time was 34 months (range 8-142 months). The objective response rate and disease control rate were 71.4% and 95.2%, respectively. Three-year progression-free survival rate was 85.2% and 3-year total survival rate was 88.0%. The univariate analysis revealed that both age and concurrent chemotherapy were not correlated with the prognosis (P=0.286, 0.824). Partial tumor resection before radiotherapy and chemotherapy, AFP &amp;gt;500ng/ml, and no more than 4 cycles of adjuvant chemotherapy were poor prognostic factors (P=0.037, 0.010, 0.006). Moreover, no acute radiation response was observed after treatment with SRS. Only 1 out of 27 patients (3.7%) had brain neurotoxicity related to a prolonged course of radiochemotherapy. CONCLUSION SRS for residual lesions of NGGCTs following conventional radiotherapy appears to be well tolerant and improved local control. However, the therapeutic efficacy of conventional radiotherapy combined with SRS warrants further investigations in a large-scale randomized controlled clinical trials.

Dynamic Tumor Mutational Profiling Using a Novel Non-Invasive Swab Technique for Serial Whole Exome Sequencing of Cervical Tumors During Chemoradiation Therapy

Clinically relevant genetic predictors of radiation response for cervical cancer are understudied due to the morbidity of repeat invasive biopsies required to obtain genetic material. We have developed a novel noninvasive cervical swab technique to collect tumor DNA with adequate throughput to perform whole exome sequencing (WES) at serial timepoints over the course of chemoradiation therapy (CRT). We hypothesize that characterization of dynamic changes in the mutational landscape of cervical tumors during the course of CRT will allow for identification of molecular signatures correlating with therapy response.A total of 69 patients with FIGO stage IB-IVA cervical cancer who underwent definitive CRT were prospectively enrolled on an IRB approved clinical trial. Cervical tumor DNA samples were collected by a noninvasive swab technique at baseline, and after 1, 3, and 5 weeks of CRT. Matched buccal DNA swabs were obtained to filter somatic mutations for each patient. An initial cohort included 24 patients (81 samples) and a second cohort included 45 patients (135 samples). WES was performed on the Illumina HiSeq 4000 series. Raw sequencing data were aligned to a human reference genome and MuTect was applied to detect somatic single nucleotide variants (SNV). Tumor purity (TP) was estimated from the distribution of variant allelic fractions of SNVs. In patients with pelvic MRIs at baseline and week 5 of CRT, 3D tumor volumes (TV) were generated (n = 6,8). Regression analysis was used to evaluate the goodness of fit between TP and TV.Estimated TP was highly correlated with TV in both cohorts (R2 = 0.969 and 0.858). Between the two cohorts, there was overlap in 4 of the top 5 genes (80%) containing the greatest number of exonic mutations across all timepoints (PIK3CA, MUC4, TPRXL, TTN). The number of altered genes present at baseline decreased over time in both cohorts. When normalized to TP, relative mutational burden decreased among standard and exceptional responders (< 20% TV remaining at week 5 of CRT) and increased among poor responders (> 20% TV remaining at week 5). The top ranked genes by magnitude of change at week 5 included MUC2, PARP10 and PIK3CA. Pathway analysis of these top ranked genes mapped to key radiation response pathways including regulation of the G1/S transition.We validated this method of performing serial WES over the course of CRT in 2 independent prospective patient cohorts, highlighting the robustness of our novel noninvasive technique. This allowed for the identification of a panel of potential genes involved in CRT resistance. Future directions include examination of dynamic changes in copy number variation, indels, and tumor mutational burden towards a comprehensive analysis of clinically relevant drivers of CRT resistance. This may allow future targeted treatment for patients with a radioresistant genetic profile, or concurrent targeted therapy for tumors with actionable mutations.

Incidence and Impact of Lymphopenia Associated With Total Neoadjuvant Therapy for Low-Lying Rectal Tumors

To assess incidence of lymphopenia and its association with outcomes in patients treated with total neoadjuvant therapy (TNT) for low-lying rectal tumors.Patients with Stage II-III, low rectal adenocarcinomas treated from 2015-2018 with TNT were retrospectively reviewed. All patients were candidates for an APR surgical resection, but were treated with intent to omit surgery if they had a clinical complete response. All patients received definitive radiation (median dose 54 Gy, range 50-56 Gy, at 1.8-2 Gy/fx) with concurrent capecitabine, with additional chemotherapy (CT) delivered either prior to or following chemoradiation (CRT). Institutional results on patient outcomes have previously been reported with a clinical complete response rate of 75%; with only 19% of those ultimately requiring surgery for local recurrence. Absolute lymphocyte counts (ALC) were collected prior to initiating CRT and at 3-month intervals following CRT and graded based on severity of lymphopenia (absolute lymphocyte count < 1000/mm3) using CTCAE v5.0. A Cox proportional hazards model was used to identify if degree of lymphopenia was associated with receipt of surgery (as surgery was only performed for either incomplete response or local recurrence).A total of 28 patients with low rectal cancers were treated with TNT during this period, with ALC analyzed for the 26 who had detailed lymphocyte data available. 7 patients were treated with CT followed by CRT, receiving a median of 8 (range 4-8) cycles of CT, and 18 patients were treated with CRT followed by CT, receiving a median of 6 cycles (range 1-9). One patient refused CT after CRT. Prior to initiating CRT, the median ALC was 1,665/mm3 (range, 710-3,060/mm3), with lymphopenia present in only 4 patients (1 neoadjuvant CT and 3 adjuvant CT). The median ALC nadir during CRT was 450/mm3 (range, 230-900/mm3), with all 26 patients experiencing lymphopenia during the course of CRT: 4% Grade 1, 35% Grade 2, 61% Grade 3, and 0% Grade 4. Rates of lymphopenia at 3-, 6-, and 12-months post CRT were 73%, 81%, and 42%, respectively. On Cox regression analysis, increased pre-CRT and 12-month post-CRT lymphocyte counts were associated with a decreased risk of need for surgery (P < 0.05) and remained significant when accounting for the sequencing of CT, while lymphocyte count nadir during CRT and 3-/6-month post-CRT levels were not (P > 0.05).Despite the frequency of lymphopenia during CRT, the degree of lymphopenia during and up to 6 months after CRT did not appear to predict future surgery. However, increased pre-CRT and 12-month post-CRT ALC were associated with decrease need of surgery. CRT produces both oxidative stress and immune response stimulation to kill cancer cells. Patients with higher pre-CRT and 12-month post-CRT ALC may represent a population with more robust immune systems, producing more favorable tumor responses. Additional studies are warranted.

Dynamics of HMBG1 (High Mobility Group Box 1) during radiochemotherapy correlate with outcome of HNSCC patients

PurposeHigh Mobility Group Box 1 (HMGB1) protein has been described as a consensus marker for immunogenic cell death (ICD) in cancer. To personalize treatments, there is a need for biomarkers to adapt dose prescription, concomitant chemotherapy, and follow-up in radiation oncology. Thus, we investigated the levels of HMGB1 in plasma of patients with head and neck squamous cell carcinoma (HNSCC) during the course of radiochemotherapy and follow-up in correlation with oncologic outcome and clinical confounders.MethodsIn our pilot study, 11 patients with advanced HNSCC were treated with definitive radiochemotherapy. Blood samples were taken weekly during treatment and frequently at follow-up visits. HMGB1 levels as well as routine laboratory values were measured and clinical information was collected including tumor volume, infections, toxicity, and follow-up data.ResultsIn total, 85 samples were analyzed. In eight patients, HMGB1 levels (baseline vs. last available sample during treatment) were increasing and in three patients HMGB1 values were decreasing toward the end of treatment. All three patients with decreasing values developed tumor recurrence. By contrast, no relapse occurred in patients that showed increasing HMGB1 levels during therapy. Moreover, a positive correlation of HMGB1 levels with tumor volumes, C‑reactive protein (CRP) levels, infections, and grade three toxicity (RTOG) was observed.ConclusionHMGB1 might be a promising marker to monitor ICD in HNSCC during the course of radiochemotherapy. However, HMGB1 seems to reflect complex and diverse immunogenic responses and potential confounders. Infections and treatment-associated toxicity should be considered when interpreting the dynamics of HMGB1.

1168 Radiotherapy Dose for HPV Driven Oropharyngeal Cancer: What Is Enough?

Abstract Aim Squamous cell carcinoma of the oropharynx is associated with high-risk Human Papilloma Virus (HPV) infection. HPV positive oropharyngeal cancer is often more radiosensitive and first line treatment includes either radiotherapy or surgical resection. Trials are ongoing to establish situations in which radiation doses can be reduced with the aim of reducing late tissue toxicity (“de-escalation trials”) . We report a case in which a patient failed to complete his prescribed radiotherapy treatment, describe his clinical outcomes and the potential questions this situation raises. Method In 2009 a male patient presented with a right T2N0MO P16 positive tonsillar squamous cell carcinoma. He was scheduled to complete a course of chemoradiotherapy. However, he was only able to complete a third of the radiotherapy course. Due to unresolved symptoms, he underwent a right transoral laser extended tonsillectomy, however this showed only fibrous tissue. Results Despite not completing the radiotherapy course he has not experienced local recurrence of the tonsillar OPSCC 11 years post initial treatment. Conclusions This case illustrates that some patients with HPV driven oropharyngeal cancer can have a clinically significant tumour response to markedly lower doses of radiotherapy than is currently recommended. Further randomized controlled trials are required to establish the optimum dose in the management of HPV driven oropharyngeal squamous cell cancer.

Total neoadjuvant therapy in patients with locally advanced rectal cancer: A tertiary medical center experience.

The current standard of care for locally advanced rectal cancer (LARC) includes preoperative chemoradiation, followed by total mesorectal excision and adjuvant chemotherapy. This multimodality treatment improves local control but is associated with low compliance rates without clear beneficial effects on overall survival (OS) and distant metastasis. In this retrospective study, the charts of patients diagnosed with cT3/4 or cT2-node-positive rectal cancer between January 2011 and June 2019 were reviewed. The chemoradiation therapy (CRT) group received a long course of CRT with capecitabine followed by surgery and adjuvant chemotherapy. The total neoadjuvant therapy (TNT) group received 6 cycles mFOLFOX and a short course of radiation therapy followed by surgery. A total of 81 patients were included, among which 55 (67.9%) received CRT and 26 (32.1%) received TNT. In the CRT group, 15 (27.3%) patients achieved pathologic complete response (pCR) compared with 10 (38.5%) in the TNT group (P=0.22). A total of 19 (35.8%) cases in the CRT group downstaged to pT0N0 or pT1N0 compared with 11 (42.3%) in the TNT group (P=0.33). The 2-year disease-free survival (DFS) rate was 81.0% in the TNT group and 84.0% in the CRT group (P=0.15). Out of 55 patients in the CRT group, 30 patients received adjuvant chemotherapy, 22 (40.0% of CRT cases) of which completed a full course. All 26 patients in the TNT group received neoadjuvant chemotherapy, where 22 (84.6%) patients took a full course (P<0.001). In conclusion, the present study revealed that patients treated with TNT were more compliant to chemotherapy than those treated with CRT. A numerically higher pCR rate, and nodal and tumor downstaging were noted in the TNT group without significance. No difference was noted in the 2-year DFS. Longer follow-up is required.

The Evolving Genomic Landscape of Esophageal Squamous Cell Carcinoma Under Chemoradiotherapy.

Esophageal squamous cell carcinoma (ESCC) often recurs after chemoradiotherapy, and the prognosis of ESCC after chemoradiotherapy has not improved over the past few decades. The mutation process in chemoradiotherapy-resistant clones and the functional relevance of genetic alterations remain unclear. To address these problems, we performed whole-exome sequencing of 52 tumor samples from 33 patients with ESCC who received radiotherapy combined with 5-fluorouracil/platinum. In multiregion analyses of pretreatment and locally recurrent lesions from five cases, most driver gene-altered clones remained under chemoradiotherapy selection pressure, while few driver gene alterations were acquired at recurrence. The mutation signatures of recurrent ESCC, including increased deletion frequency and platinum dose-dependent base substitution signatures, were substantially different from those of primary ESCC and reflected the iatrogenic impacts of chemoradiotherapy. Single-region analysis of 28 pretreatment tumors indicated that focal copy-number gain at the MYC locus was significantly associated with poor progression-free survival and overall survival after chemoradiotherapy. MYC gain remained throughout the chemoradiotherapy course and potentially contributes to intrinsic resistance to chemoradiotherapy. Consistent with these findings, MYC copy number and mRNA and protein levels in ESCC cell lines correlated positively with resistance to radiotherapy, and MYC knockdown improved sensitivity to radiotherapy. Overall, these data characterize the clonal evolution process induced by chemoradiotherapy and clinically relevant associations for genetic alterations in ESCC. These findings increase our understanding of therapeutic resistance and support the rationale for precision chemoradiotherapy. SIGNIFICANCE: Whole-exome sequencing reveals the genetic evolution of ESCC during chemoradiotherapy, highlighting MYC gain in pretreatment tumors as a potential marker of therapy resistance.