A Longitudinal Metagenomic Comparative Analysis of Oral Microbiome Shifts in Patients Receiving Proton Radiation versus Photon Radiation for Head and Neck Cancer

Introduction

Due to the radiation-sparing effects on salivary gland acini, changes in the composition of the oral microbiome may be a driver for improved outcomes in patients receiving proton radiation, with potentially worse outcomes in patients exposed to photon radiation therapy. To date, a head-to-head comparison of oral microbiome changes at a metagenomic level with longitudinal sampling has yet to be performed in these patient cohorts.

Methods and Materials

To comparatively analyze oral microbiome shifts during head and neck radiation therapy, a prospective pilot cohort study was performed at the Maryland Proton Treatment Center and the University of Maryland Marlene and Stewart Greenebaum Comprehensive Cancer Center. A longitudinal metagenomic comparative analysis of oral microbiome shifts was performed at three time points (pre-radiation, during radiation, and immediately post-radiation). Head and neck cancer patients receiving proton radiation (n = 4) were compared to photon radiation (n = 4). Additional control groups included healthy age- and sex-matched controls (n = 5), head and neck cancer patients who never received radiation therapy (n = 8), and patients with oral inflammatory disease (n = 3).

Results

Photon therapy patients presented with lower microbial alpha diversity at all timepoints, and there was a trend towards reduced species richness as compared with proton therapy. Healthy controls and proton patients exhibited overall higher and similar diversity. A more dysbiotic state was observed in patients receiving photon therapy as compared to proton therapy, in which oral microbial homeostasis was maintained. Mucositis was observed in 3/4 photon patients and was not observed in any proton patients during radiation therapy. The bacterial de novo pyrimidine biosynthesis pathway and the nitrate reduction V pathway were comparatively higher following photon exposure. These functional changes in bacterial metabolism may suggest that photon exposure produces a more permissive environment for the proliferation of pathogenic bacteria.

Conclusion

Oral microbiome dysbiosis in patients receiving photon radiation may be associated with increased mucositis occurrence. Proton radiation therapy for head and neck cancer demonstrates a safer side effect profile in terms of oral complications, oral microbiome dysbiosis, and functional metabolic status.

Long-Term Outcomes of Non-Vestibular Cranial Nerve Schwannomas Treated with Fractionated Stereotactic Radiotherapy and Stereotactic Radiosurgery

PURPOSE/OBJECTIVE(S)

Non-vestibular cranial nerve schwannomas (NVCNS) are rare tumors that account for approximately 10% of cranial nerve schwannomas. They are commonly treated with radiation therapy (XRT) due to their location often precluding safe resection. We examined the long-term outcomes of NVCNS treated with XRT as primary management and for post-operative salvage.

MATERIALS/METHODS

We conducted a retrospective review of patients with NVCNS treated with fractionated stereotactic radiation therapy (FSRT) or Gamma Knife Stereotactic Radiosurgery (GK-SRS) from 1996 to 2018 at our institution. We examined patient demographics, cranial nerve (CN) involvement, CN function pre-/post-XRT, treatment volume (TV), toxicity, surgery pre-XRT, and local control. Kaplan-Meier analysis was performed for evaluation of local control.

RESULTS

We identified 66 patients (38 female, 28 male) with NVCNS, a portion of whom had tumors involving more than one cranial nerve. Forty-six (69.7%) were treated with FSRT (median dose 50.4 Gy in 1.8 Gy/fraction; range 45-54 Gy), and 20 (30.3%) with GK-SRS (median dose 12 Gy; range 12-15 Gy). Median follow-up time was 92.5 months (5-306). Median Karnofsky Performance Status was 90 (70-100). Median age at start of XRT was 45 years old (15-92). Prior to XRT, 34.8% (23) of patients had surgical resection, with median time from surgery to XRT of 4.25 months (0.5-130 months). Median treatment volume was 4.72 cc (0.26-29). The cranial nerve most commonly involved was CN V (48.4%), followed by CN X (15.2%), CN VII (13.6%), CN VI (6.1%), CN XII (6.1%), CN III (6.1%), and CN IX (3%). Twenty-nine (43.9%) patients experienced grade 1 acute toxicity during treatment. Six (9%) patients experienced grade 1 chronic toxicity. No grade 2 or higher acute or chronic toxicity was observed. No significant difference in rates of acute or chronic toxicity was observed between patients treated with GK-SRS vs. FSRT. Post-XRT, 37 patients (56.1%) had improvement in CN function/symptom, 24 patients (36.3%) had stable function/symptoms, and 5 patients (7.6%) had worsening function/symptoms. Local control at one and five years was 100%. In-field recurrence was observed in one patient (1.5%), at 9 years post-XRT. For salvage this patient was treated with a second course of FSRT to the recurrent tumor.

CONCLUSION

Our large institutional series with long term follow up showed excellent local control of NVCNS treated with FSRT or GK-SRS both for primary management and post-operative salvage. Treatment is well tolerated, with high rates of preservation or improvement of CN function, and minimal acute and chronic toxicity.

Comprehensive Quality of Life Report from a Prospective Clinical Trial of 4DCT-Ventilation Functional Lung Avoidance Radiation Therapy

PURPOSE/OBJECTIVE(S)

Functional imaging has been developed that uses 4DCT images and image processing to generate lung ventilation maps (4DCT-ventilation). 4DCT-ventilation functional avoidance uses 4DCT-images to generate plans that avoid functional regions of the lung with the goal of reducing pulmonary toxicity. A 4DCT-ventilation functional avoidance, phase II, multi-center clinical trial was completed, and patient reported outcomes (PRO) measured. PROs are an essential measure of quality-of-life following radiotherapy. The purpose of this work is to quantify PRO changes for lung cancer patients treated with functional avoidance and to compare PROs against clinical pneumonitis.

MATERIALS/METHODS

Patients with locally advanced lung cancer receiving curative intent radiotherapy (prescriptions of 45-75 Gy) and chemotherapy were accrued. Each patient had a 4DCT-ventilation image generated using 4DCT data. Favorable arc geometry and optimization techniques were used to generate functional avoidance plans. PRO instruments included the Functional Assessment of Cancer Therapy Lung (FACT-L) questionnaire and the Visual Analog Scale (VAS) administered pre-treatment and 3-, 6-, and 12-months post-treatment to gather data on physical, social, emotional, functional, and pulmonary well-being. The percentage of patients with clinically significant decline was calculated using the FACT-TOI (Trial Outcome Index), FACT-LCS (Lung Cancer Subscale), and VAS instruments. To evaluate the correlation between PROs and clinical toxicity, the percentage of clinically significant FACT-LCS decline was compared (Chi-square test) for patients who did or did not experience grade 2+ pneumonitis.

RESULTS

Fifty-nine patients completed baseline PRO surveys. Median age was 65, 83% of patients had non-small-cell lung cancer, with 75% having stage III disease. Clinically significant FACT-TOI decline at, 3, 6, and 12 months was 46.3%, 38.5%, and 26.8%, respectively. The percentage of patients with clinically significant FACT-LCS decline was 33.3%, 33.3%, and 29.3%, at 3 months, 6 months, and 12 months, respectively. The percentage of patients with clinically significant VAS decline at 3, 6, and 12 months was 18.9%, 20.0%, and 18.6%, respectively. Patients who experienced grade 2+ pneumonitis had a greater percentage of clinically significant decline at all time-points with the results reaching significance (p = 0.045) at 6 months.

CONCLUSION

The study presents the first comprehensive evaluation of PROs for patients treated with 4DCT-ventilation functional avoidance. The data show that 20-40% of patients had clinically significant decline and that PROs had a strong correlation with pneumonitis. The PRO data demonstrate that functional avoidance results in low rates of patient reported outcome clinical decline and provide seminal results to be used in phase III studies.

Incidence of Brain Metastasis as First Event in Patients with Esophageal Carcinoma: a Report from Three Prospective Alliance Clinical Trials

PURPOSE

Historically, reported incidence of brain metastasis secondary to esophageal carcinoma is low. We sought to determine the incidence of brain metastasis in a contemporary cohort of patients with carcinoma of the esophagus.

METHODS

Data from patients with localized esophageal carcinoma prospectively enrolled on three curative intent Alliance treatment trials (N0044, N0342, N044E) were reviewed including time to diagnosis of first progression event (brain versus other site) and overall survival.

RESULTS

Eighty-five patients comprised the cohort of which 85% were male and 86% had adenocarcinoma primary tumor histology. Thirty-nine of the 85 patients had documented progression to any site, and of those, brain metastasis occurred as the first event in 15% (6 of 39). Adenocarcinoma was the primary histology in all 6 patients and tumor grade was high (3 or 4) in 5 of the 6 patients (one not documented). Median time to brain metastasis (9.6 months) versus non-brain metastasis (12.4 months) and median survival after first progression (5.4 months versus 8.1 months, respectively) were not statistically different.

CONCLUSION

In this prospective cohort of patients with esophageal carcinoma, those with high-grade adenocarcinoma appear to have a higher incidence of brain metastasis than historically reported. The pattern of brain metastases corroborates recent findings in terms of incidence, predominance of adenocarcinoma primary tumor histology, timing after diagnosis, and overall survival. Further study to confirm these findings, as well as the value of baseline, restaging and follow-up cranial imaging for brain metastasis is recommended.

CLINICALTRIALS

GOV IDENTIFIERS

NCT00022139 (NCCTG N0044), NCT00100945 (NCCTG N0342), and NCT00100945 (NCCTG N044E).

The Effect of Body Mass Index and Residence in Food Priority Areas on Patterns-of-Care and Cancer Outcomes in Patients With Stage III Non-Small Cell Lung Cancer

PURPOSE

Patients living in food priority areas (FPAs), where access to healthy meals is challenging, may be at greater risk of nutritional deficits, leading to poorer cancer outcomes. Currently, there are no published data analyzing how FPAs affect patterns-of-care or outcomes for patients with locally advanced non-small cell lung cancer (NSCLC). We aimed to analyze the effect of residing in an FPA on treatments rendered and cancer outcomes in patients with stage III NSCLC treated at a single institution.

METHODS AND MATERIALS

This is a retrospective study of 573 patients with locally advanced NSCLC consecutively treated from January 2000 to January 2020. χ² and Mann-Whitney U tests were performed to determine differences between select variables. Kaplan-Meier analysis and Cox proportional hazard models were used to analyze overall survival (OS) and freedom from recurrence. Cox regression with forward model selection was used for multivariate analysis.

RESULTS

Thirty-two percent of patients resided in an FPA (n = 183) and were more likely to self-identify as Black (P < .0001), single (P < .001), <60 years of age (P = .001), and uninsured (P < .0001), with a lower median income (P < .001). Patients in FPAs also had lower mean pre-chemoradiation (CRT) albumin (P = .002), lower pre-CRT body mass index (BMI) (P = .026), and were less likely to receive trimodality therapy (P ≤ .001) compared with patients not living in FPAs. There was no difference in OS or freedom from recurrence between the 2 cohorts. However, in patients with a normal BMI, either pre-CRT (median OS, 18.4 vs 25.0 months; P = .005) or after CRT (15.1 vs 28.1 months, P = .002), residing in an FPA resulted in an OS detriment.

CONCLUSIONS

We demonstrated a clear socioeconomic divide in our patient population with stage III NSCLC, where residing in FPAs was associated with less-aggressive therapy and an OS detriment for patients with a normal-weight BMI. We are currently conducting a prospective study characterizing the nutritional needs of patients, particularly those who live in FPAs.

Inline small-angle X-ray scattering-coupled chromatography under extreme hydrostatic pressure

As continuing discoveries highlight the surprising abundance and resilience of deep ocean and subsurface microbial life, the effects of extreme hydrostatic pressure on biological structure and function have attracted renewed interest. Biological small-angle X-ray scattering (BioSAXS) is a widely used method of obtaining structural information from biomolecules in solution under a wide range of solution conditions. Due to its ability to reduce radiation damage, remove aggregates, and separate monodisperse components from complex mixtures, size-exclusion chromatography-coupled SAXS (SEC-SAXS) is now the dominant form of BioSAXS at many synchrotron beamlines. While BioSAXS can currently be performed with some difficulty under pressure with non-flowing samples, it has not been clear how, or even if, continuously flowing SEC-SAXS, with its fragile media-packed columns, might work in an extreme high-pressure environment. Here we show, for the first time, that reproducible chromatographic separations coupled directly to high-pressure BioSAXS can be achieved at pressures up to at least 100 MPa and that pressure-induced changes in folding and oligomeric state and other properties can be observed. The apparatus described here functions at a range of temperatures (0°C-50°C), expanding opportunities for understanding biomolecular rules of life in deep ocean and subsurface environments.

Cost effectiveness of treatment strategies for high risk prostate cancer

BACKGROUND

Patients with high-risk prostate cancer (HRPC) have multiple accepted treatment options. Because there is no overall survival benefit of one option over another, appropriate treatment must consider patient life expectancy, quality of life, and cost.

METHODS

The authors compared quality-adjusted life years (QALYs) and cost effectiveness among treatment options for HRPC using a Markov model with three treatment arms: (1) external-beam radiotherapy (EBRT) delivered with 20 fractions, (2) EBRT with 23 fractions followed by low-dose-rate (LDR) brachytherapy boost, or (3) radical prostatectomy alone. An exploratory analysis considered a simultaneous integrated boost according to the FLAME trial (ClinicalTrials.gov identifier NCT01168479).

RESULTS

Treatment strategies were compared using the incremental cost-effectiveness ratio (ICER). EBRT with LDR brachytherapy boost was a cost-effective strategy (ICER, $20,929 per QALY gained). These results were most sensitive to variations in the biochemical failure rate. However, the results still demonstrated cost effectiveness for the brachytherapy boost paradigm, regardless of any tested parameter ranges. Probabilistic sensitivity analysis demonstrated that EBRT with LDR brachytherapy was favored in 52% of 100,000 Monte Carlo iterations. In an exploratory analysis, EBRT with a simultaneous integrated boost was also a cost-effective strategy, resulting in an ICER of $62,607 per QALY gained; however, it was not cost effective compared with EBRT plus LDR brachytherapy boost.

CONCLUSIONS

EBRT with LDR brachytherapy boost may be a cost-effective treatment strategy compared with EBRT alone and radical prostatectomy for HRPC, demonstrating high-value care. The current analysis suggests that a reduction in biochemical failure alone can result in cost-effective care, despite no change in overall survival.

Psychosocial impact of the War in Ukraine on pediatric cancer patients and their families receiving oncological care outside their country at the onset of hostilities

Psychosocial care of pediatric cancer patients and their families is as critical as the medical and surgical components of their therapies. Strains on family communication and structure and financial need are linked to poorer psychological outcomes for both patients and families. It is critical that children remain as connected as possible to their communities and extended families during therapy. For Ukrainian pediatric cancer patients receiving care outside of their nation's borders on February 24, 2022, the Russian invasion of Ukraine compounded these problems. Based on conversations with patients and parents, we evaluated the psychosocial impact of war on pediatric Ukrainian cancer patients and their families who had left their country before the onset of the conflict to undergo treatment of pediatric malignancies at our medical center. These families shared with us the problems they have experienced after the Russian invasion of Ukraine. Their concerns can be summarized in 4 categories: (1) emotional stress experienced by the patients, families and relatives related to the dangers of war; (2) difficulties in obtaining previous hospital records in Ukraine; (3) medical expenses; and (4) uncertainty regarding the patient's and their family's future and the ability of the children to ever return to their homes. Psychosocial distress relating to the violence of war will hopefully pass in near future, but our pediatric patients and their families will continue to face stressors related to displacement and financial concerns for some time to come.

Respect, justice and learning are limited when patients are deidentified data subjects

Introduction

Critical for advancing a Learning Health System (LHS) in the U.S., a regulatory safe harbor for deidentified data reduces barriers to learning from care at scale while minimizing privacy risks. We examine deidentified data policy as a mechanism for synthesizing the ethical obligations underlying clinical care and human subjects research for an LHS which conceptually and practically integrates care and research, blurring the roles of patient and subject.

Methods

First, we discuss respect for persons vis‐a‐vis the systemic secondary use of data and tissue collected in the fiduciary context of clinical care. We argue that, without traditional informed consent or duty to benefit the individual, deidentification may allow secondary use to supersede the primary purpose of care. Next, we consider the effectiveness of deidentification for minimizing harms via privacy protection and maximizing benefits via promoting learning and translational care. We find that deidentification is unable to fully protect privacy given the vastness of health data and current technology, yet it imposes limitations to learning and barriers for efficient translation. After that, we evaluate the impact of deidentification on distributive justice within an LHS ethical framework in which patients are obligated to contribute to learning and the system has a duty to translate knowledge into better care. Such a system may permit exacerbation of health disparities as it accelerates learning without mechanisms to ensure that individuals' contributions and benefits are fair and balanced.

Results

We find that, despite its established advantages, system‐wide use of deidentification may be suboptimal for signaling respect, protecting privacy or promoting learning, and satisfying requirements of justice for patients and subjects.

Conclusions

Finally, we highlight ethical, socioeconomic, technological and legal challenges and next steps, including a critical appreciation for novel approaches to realize an LHS that maximizes efficient, effective learning and just translation without the compromises of deidentification.

Impact of the Early COVID-19 Pandemic on Gender Participation in Academic Publishing in Radiation Oncology

Purpose

Materials and Methods

Results

Conclusions

Emerging Cybersecurity Threats in Radiation Oncology

Purpose

Modern image guided radiation therapy is dependent on information technology and data storage applications that, like any other digital technology, are at risk from cyberattacks. Owing to a recent escalation in cyberattacks affecting radiation therapy treatments, the American Society for Radiation Oncology's Advances in Radiation Oncology is inaugurating a new special manuscript category devoted to cybersecurity issues.

Methods and Materials

We conducted a review of emerging cybersecurity threats and a literature review of cyberattacks that affected radiation oncology practices.

Results

In the last 10 years, numerous attacks have led to an interruption of radiation therapy for thousands of patients, and some of these catastrophic incidents have been described as being worse than the coronavirus disease of 2019 impact on centers in New Zealand.

Conclusions

Cybersecurity threats continue to evolve, making combatting these attacks more difficult for health care organizations and requiring a change in strategies, tactics, and culture around cyber security in health and radiation oncology. We recommend an assume breach mentality (threat-informed defense posture) and adopting a cloud-first and zero-trust security strategy. A reliance on computer-driven technology makes radiation oncology practices more vulnerable to cyberattacks. Health care providers should increase their resilience and cyber security maturity. The increase in the diversity of these attacks demands improved preparedness and collaboration between oncologic treatment centers both nationwide and internationally to protect patients.

Molecular Brightness Approach for FRET Analysis of Donor-Linker-Acceptor Constructs at the Single Molecule Level: A Concept

In this report, we have developed a simple approach using single-detector fluorescence autocorrelation spectroscopy (FCS) to investigate the Förster resonance energy transfer (FRET) of genetically encoded, freely diffusing crTC2.1 (mTurquoise2.1-linker-mCitrine) at the single molecule level. We hypothesize that the molecular brightness of the freely diffusing donor (mTurquoise2.1) in the presence of the acceptor (mCitrine) is lower than that of the donor alone due to FRET. To test this hypothesis, the fluorescence fluctuation signal and number of molecules of freely diffusing construct were measured using FCS to calculate the molecular brightness of the donor, excited at 405 nm and detected at 475/50 nm, in the presence and absence of the acceptor. Our results indicate that the molecular brightness of cleaved crTC2.1 in a buffer is larger than that of the intact counterpart under 405-nm excitation. The energy transfer efficiency at the single molecule level is larger and more spread in values as compared with the ensemble-averaging time-resolved fluorescence measurements. In contrast, the molecular brightness of the intact crTC2.1, under 488 nm excitation of the acceptor (531/40 nm detection), is the same or slightly larger than that of the cleaved counterpart. These FCS-FRET measurements on freely diffusing donor-acceptor pairs are independent of the precise time constants associated with autocorrelation curves due to the presence of potential photophysical processes. Ultimately, when used in living cells, the proposed approach would only require a low expression level of these genetically encoded constructs, helping to limit potential interference with the cell machinery.

Predicting Adverse Pathologic Features and Clinical Outcomes of Resectable Pancreas Cancer With Preoperative CA 19-9

Background

We evaluated preoperative CA 19-9 levels in patients with resected pancreatic cancer to analyze whether they were predictive of clinical outcomes and could help select patients for additional therapy. We hypothesized that elevated CA 19-9 would be associated with worse pathologic findings and oncologic outcomes.

Methods

This study assessed 509 patients with non-metastatic pancreatic adenocarcinoma who underwent resection at our institution from 1995-2011 and had preoperative CA 19-9 recorded. No patients received neoadjuvant therapy. CA 19-9 level was analyzed as a continuous and a dichotomized (> vs. ≤ 55 U/mL) variable using logistic and Cox models.

Results

Median follow-up was 7.8 years, and the median age was 66 years (33-90). 64% of patients had elevated preoperative CA 19-9 (median: 141 U/mL), that did not correlate with bilirubin level or tumor size. Most patients had ≥ T3 tumors (72%) and positive lymph nodes (62%). The rate of incomplete (R1 or R2) resection was 19%. Increasing preoperative CA 19-9 was associated with extra-pancreatic extension (p=0.0005), lymphovascular space invasion (p=0.0072), incomplete resection [HR (95% CI) 2.0 (1.2-3.5)], and lower OS [HR = 1.6 (1.3-2.0)]. Each doubling in preoperative CA 19-9 value was associated with an 8.3% increased risk of death [HR = 1.08 (1.02-1.15)] and a 10.0% increased risk of distant recurrence [HR = 1.10 (1.02-1.19)]. Patients classified as non-secretors had comparable outcomes to patients with normal CA 19-9.

Conclusions

Elevated preoperative CA 19-9 level was associated with adverse pathologic features, incomplete resection, and inferior clinical outcomes. Neither tumor size nor bilirubin confound an elevated CA 19-9 level. Preoperative CA 19-9 level may help select patients for additional therapy.

Plan quality effects of maximum monitor unit constraints in pencil beam scanning proton therapy for central nervous system and skull base tumors

PURPOSE/OBJECTIVE(S)

With reports of CNS toxicity in patients treated with proton therapy at doses lower than would be expected based on photon data, it has been proposed that heavy monitor unit (MU) weighting of pencil beam scanning (PBS) proton therapy spots may potentially increase the risk of toxicity. We evaluated the impact of maximum MU weighting per spot (maxMU/spot) restrictions on PBS plan quality, prior to implementing clinic-wide maxMU/spot restrictions.

MATERIALS/METHODS

PBS plans of 11 patients, of which 3 plans included boosts, for a total of 14 PBS sample cases were included. Per sample case, a single dosimetrist created 4 test plans, gradually reducing the maxMU/spot in the plan. Test Plan 1, unrestricted in maxMU/spot, was the reference for all restricted plan comparisons (comparison sets 2 vs. 1; 3 vs. 1; and 4 vs. 1). The impact of MU/spot restrictions on plan quality metrics were analyzed with Wilcoxon signed rank test analyses. Treatment delivery time was modeled for a representative case.

RESULTS

A total of 14 PBS sample cases, 7 (50%) single-field optimized, 7 (50%) multi-field optimized, 9 (64%) delivering > 3500 cGy, 9 (64%) with 3 beams, and 7 (50%) without a range shifter were included. There were no differences in plan quality metrics of target coverage (V95% and V100% prescription), conformality and gradient indices, hot spot volume (V105% prescription), and dose to normal brain (V10%/30%/50%/70%/90%/100% prescription) with reductions of allowable maxMU/spot across all comparison sets (p > 0.05). Max MU/spot restrictions did not increase treatment delivery time when analyzed for a representative case.

CONCLUSION

MaxMU/spot restrictions within the thresholds evaluated in this study did not degrade overall plan quality metrics. Future studies should evaluate spot weighting with linear energy transfer/relative biologic effectiveness-informed planning to determine if spot weighting manipulation impacts clinical outcomes and mitigates toxicity.

Fluorescence depolarization dynamics of ionic strength sensors using time-resolved anisotropy

Eukaryotic cells exploit dynamic and compartmentalized ionic strength to impact a myriad of biological functions such as enzyme activities, protein-protein interactions, and catalytic functions. Herein, we investigated the fluorescence depolarization dynamics of recently developed ionic strength biosensors (mCerulean3-linker-mCitrine) in Hofmeister salt (KCl, NaCl, NaI, and Na₂SO₄) solutions. The mCerulean3-mCitrine acts as a Förster resonance energy transfer (FRET) pair, tethered together by two oppositely charged α-helices in the linker region. We developed a time-resolved fluorescence depolarization anisotropy approach for FRET analyses, in which the donor (mCerulean3) is excited by 425-nm laser pulses, followed by fluorescence depolarization analysis of the acceptor (mCitrine) in KE (lysine-glutamate), arginine-aspartate, and arginine-glutamate ionic strength sensors with variable amino acid sequences. Similar experiments were carried out on the cleaved sensors as well as an E6G2 construct, which has neutral α-helices in the linker region, as a control. Our results show distinct dynamics of the intact and cleaved sensors. Importantly, the FRET efficiency decreases and the donor-acceptor distance increases as the environmental ionic strength increases. Our chemical equilibrium analyses of the collapsed-to-stretched conformational state transition of KE reveal that the corresponding equilibrium constant and standard Gibbs free energy changes are ionic strength dependent. We also tested the existing theoretical models for FRET analyses using steady-state anisotropy, which reveal that the angle between the dipole moments of the donor and acceptor in the KE sensor are sensitive to the ionic strength. These results help establish the time-resolved depolarization dynamics of these genetically encoded donor-acceptor pairs as a quantitative means for FRET analysis, which complement traditional methods such as time-resolved fluorescence for future in vivo studies.

Costs of Definitive Chemoradiation, Surgery, and Adjuvant Radiation Versus De-Escalated Adjuvant Radiation per MC1273 in HPV+ Cancer of the Oropharynx

PURPOSE

De-escalated treatment for human papillomavirus (HPV)+ oropharynx squamous cell carcinoma (OPSCC) has shown promising initial results. Health-care policy is increasingly focusing on high-value care. This analysis compares the cost of care for HPV+ OPSCC treated with definitive chemoradiation (CRT), surgery and adjuvant radiation (RT), and surgery and de-escalated CRT on MC1273.

METHODS AND MATERIALS

MC1273 is a prospective, phase 2 study evaluating adjuvant CRT to 30 to 36 Gy plus docetaxel for HPV+ OPSCC after surgery for high-risk patients. Matched standard-of-care control groups were retrospectively identified for patients treated with definitive CRT or adjuvant RT. Standardized costs were evaluated before radiation, during treatment (during RT), and at short-term (6 month) and long-term (7-24 month) follow-up periods.

RESULTS

A total of 56 definitive CRT, 101 adjuvant RT, and 66 MC1273 patients were included. The CRT arm had more T3-4 disease (63% vs 17-21%) and higher N2c-N3 disease (52% vs 20-24%) vs both other groups. The total treatment costs in the CRT, adjuvant RT, and MC1273 groups were $47,763 (standard deviation [SD], $19,060], $57,845 (SD, $17,480), and $46,007 (SD, $9019), respectively, and the chemotherapy and/or RT costs were $39,936 (SD, $18,480), $26,603 (SD, $12,542), and $17,864 (SD, $3288), respectively. The per-patient, per-month, average short-term follow-up costs were $3860 (SD, $10,525), $1072 (SD, $996), and $972 (SD, $833), respectively, and the long-term costs were $978 (SD, $2294), $485 (SD, $1156), and $653 (SD, $1107), respectively. After adjustment for age, T-stage, and N-stage, treatment costs remained lower for CRT and MC1273 versus adjuvant RT ($45,450 and $47,114 vs $58,590, respectively; P < .001), whereas the total per-patient, per-month follow-up costs were lower in the MC1273 study group and adjuvant RT versus CRT ($853 and $866 vs $2030, respectively; P = .03).

CONCLUSIONS

MC1273 resulted in 10% and 20% reductions in global costs compared with standard-of-care adjuvant RT and definitive CRT treatments. Substantial cost savings may be an added benefit to the already noted low toxicity and maintained quality of life of treatment per MC1273.

Improving the Clinical Treatment of Vulnerable Populations in Radiation Oncology

The increasing role of radiation oncology in optimal cancer care treatment brings to mind the adage that power is never a gift, but a responsibility. A significant part of the responsibility we in radiation oncology bear is how to ensure optimal access to our services. This article summarizes the discussion initiated at the 2019 American Society for Radiation Oncology Annual Meeting educational panel entitled “Improving the Clinical Treatment of Vulnerable Populations in Radiation Oncology: Latin, African American, Native American, and Gender/Sexual Minority Communities.” By bringing the discussion to the printed page, we hope to continue the conversation with a broader audience to better define the level of responsibility our field bears in optimizing cancer care to the most vulnerable patient populations within the United States.

Scholarly Publishing in the Wake of COVID-19

The speed at which the COVID-19 pandemic spread across the globe and the accompanying need to rapidly disseminate knowledge have highlighted the inadequacies of the traditional research/publication cycle, particularly the slowness and the fragmentary access globally to manuscripts and their findings. Scholarly communication has slowly been undergoing transformational changes since the introduction of the Internet in the 1990s. The pandemic response has created an urgency that has accelerated these trends in some areas. The magnitude of the global emergency has strongly bolstered calls to make the entire research and publishing lifecycle transparent and open. The global scientific community has collaborated in rapid, open, and transparent means that are unprecedented. The general public has been reminded of the important of science, and trusted communication of scientific findings, in everyday life. In addition to COVID-19-driven innovation in scholarly communication, alternative bibliometrics and artificial intelligence tools will further transform academic publishing in the near future.

Physician Practice Variability in the Use of Extended-Fraction Radiation Therapy for Bone Metastases: Are We Choosing Wisely?

PURPOSE:

Routine use of extended-fraction (> 10 fractions) radiation therapy (RT) for palliation of bone metastases is recognized as a low-value intervention by the American Society for Radiation Oncology. We examined contemporary practice patterns of, and physician characteristics associated with extended-fraction RT use.

MATERIALS AND METHODS:

We conducted a retrospective cohort study using Medicare fee-for-service data. We included patients who underwent 2- or 3-dimensional external-beam RT for bone metastases between January 1, 2016, and December 31, 2018. Physicians treating > 10 patients over the study period were analyzed for their individual practice. Hierarchic logistic regression modeling was used to identify patient- and physician-level factors associated with extended-fraction RT use.

RESULTS:

A total of 12,221 patients (median age, 75.6 years; 40.9% women, 87.6% white) were included. The rate of extended-fraction RT was 23.4%. A total of 1,432 physicians treated any patient. Among the 382 physicians treating > 10 patients, 127 (33.2%) used extended-fraction RT > 30% (consensus threshold). Physician factors associated with decreased odds of extended-fraction RT were years since medical school graduation (≤ 10 years and 11-20 years v ≥ 31 years: adjusted odds ratio [aOR], 0.32 [95% CI, 0.20 to 0.51] and 0.64 [95% CI, 0.44 to 0.93]) and practicing in the Northeast or Midwest versus the South (aOR, 0.36 [95% CI, 0.22 to 0.58] and 0.48 [95% CI, 0.31 to 0.74]). Physicians treating > 20 patients ( v 11-14 patients) over the study period had increased odds of delivering extended-fraction RT (aOR, 1.53 [95% CI, 1.10 to 2.12]).

CONCLUSION:

In this study, almost one fourth of patients received extended-fraction RT, and one third of physicians had an extended-fraction RT use rate of > 30%. Personalized feedback of performance data, clinical pathways and peer review, and updated reimbursement models are potential mechanisms to address this low-value care.

FRET Analysis of Ionic Strength Sensors in the Hofmeister Series of Salt Solutions Using Fluorescence Lifetime Measurements

Living cells are complex, crowded, and dynamic and continually respond to environmental and intracellular stimuli. They also have heterogeneous ionic strength with compartmentalized variations in both intracellular concentrations and types of ions. These challenges would benefit from the development of quantitative, noninvasive approaches for mapping the heterogeneous ionic strength fluctuations in living cells. Here, we investigated a class of recently developed ionic strength sensors that consists of mCerulean3 (a cyan fluorescent protein) and mCitrine (a yellow fluorescent protein) tethered via a linker made of two charged α-helices and a flexible loop. The two helices are designed to bear opposite charges, which is hypothesized to increase the ionic screening and therefore a larger intermolecular distance. In these protein constructs, mCerulean3 and mCitrine act as a donor-acceptor pair undergoing Förster resonance energy transfer (FRET) that is dependent on both the linker amino acids and the environmental ionic strength. Using time-resolved fluorescence of the donor (mCerulean3), we determined the sensitivity of the energy transfer efficiencies and the donor-acceptor distances of these sensors at variable concentrations of the Hofmeister series of salts (KCl, LiCl, NaCl, NaBr, NaI, Na₂SO₄). As controls, similar measurements were carried out on the FRET-incapable, enzymatically cleaved counterparts of these sensors as well as a construct designed with two electrostatically neutral α-helices (E6G2). Our results show that the energy transfer efficiencies of these sensors are sensitive to both the linker amino acid sequence and the environmental ionic strength, whereas the sensitivity of these sensors to the identity of the dissolved ions of the Hofmeister series of salts seems limited. We also developed a theoretical framework to explain the observed trends as a function of the ionic strength in terms of the Debye screening of the electrostatic interaction between the two charged α-helices in the linker region. These controlled solution studies represent an important step toward the development of rationally designed FRET-based environmental sensors while offering different models for calculating the energy transfer efficiency using time-resolved fluorescence that is compatible with future in vivo studies.

Proton beam therapy utilization in adults with primary brain tumors in the United States

The utilization of proton beam therapy (PBT) as the primary treatment of adults with primary brain tumors (APBT) was evaluated through query of the National Cancer Database (NCDB) between the years 2004 and 2015. International Classification of Diseases for Oncology code for each patient was stratified into six histology categories; high-grade gliomas, medulloblastomas, ependymomas, other gliomas, other malignant tumors, or other benign intracranial tumors. Demographics of the treatment population were also analyzed. A total of 1,296 patients received PBT during the 11-year interval for treatment of their primary brain tumor. High-grade glioma, medulloblastoma, ependymoma, other glioma, other malignant, and other benign intracranial histologies made up 39%, 20%, 13%, 12%, 13%, and 2% of the cohort, respectively. The number of patients treated per year increased from 34 to 300 in years 2004 to 2015. Histologies treated with PBT varied over the 11-year interval with high-grade gliomas comprising 75% and 45% at years 2004 and 2015, respectively. The majority of the patient population was 18-29 years of age (59%), Caucasian race (73%), had median reported income of over $63,000 (46%), were privately insured (68%), and were treated at an academic institution (70%). This study characterizes trends of malignant and benign APBT histologies treated with PBT. Our data from 2004 through 2015 illustrates a marked increase in the utilization of PBT in the treatment of APBT and shows variability in the tumor histology treated over this time.

Impact of Patient Stage and Disease Characteristics on the proposed Radiation Oncology Alternative Payment Model (RO-APM)

PURPOSE

The proposed Radiation Oncology Alternative Payment Model (RO-APM) released on July 10, 2019, represents a dramatic shift from fee-for-service (FFS) reimbursement in radiation therapy (RT). This study compares historical revenue at Mayo Clinic to the RO-APM and quantifies the effect that disease characteristics may have on reimbursement.

METHODS AND MATERIALS

FFS Medicare reimbursements were determined for patients undergoing RT at Mayo Clinic from 2015 to 2016. Disease categories and payment episodes were defined as per the RO-APM. Average RT episode reimbursements were reported for each disease site, except for lymphoma and metastases, and stratified by stage and disease subcategory. Comparisons with RO-APM reimbursements were made via descriptive statistics.

RESULTS

A total of 2098 patients were identified, of whom 1866 (89%) were categorized per the RO-APM; 840 (45%) of those were aged >65 years. Breast (33%), head and neck (HN) (14%), and prostate (11%) cancer were most common. RO-APM base rate reimbursements and sensitivity analysis range were lower than historical reimbursement for bladder (-40%), cervical (-34%), lung (-28%), uterine (-26%), colorectal (-24%), upper gastrointestinal (-24%), HN (-23%), pancreatic (-20%), prostate (-16%), central nervous system (-13%), and anal (-10%) and higher for liver (+24%) and breast (+36%). Historical reimbursement varied with stage (stage III vs stage I) for breast (+57%, P < .01), uterine (+53%, P = .01), lung (+50%, P < .01), HN (+24%, P = .01), and prostate (+13%, P = .01). Overall, for patients older than 65 years of age, the RO-APM resulted in a -9% reduction in total RT reimbursement compared with historical FFS (-2%, -15%, and -27% for high, mid, and low adjusted RO-APM rates).

CONCLUSIONS

Our findings indicate that the RO-APM will result in significant reductions in reimbursement at our center, particularly for cancers more common in underserved populations. Practices that care for socioeconomically disadvantaged populations may face significant reductions in revenue, which could further reduce access for this vulnerable population.

ASTRO Journals' Data Sharing Policy and Recommended Best Practices

Transparency, openness, and reproducibility are important characteristics in scientific publishing. Although many researchers embrace these characteristics, data sharing has yet to become common practice. Nevertheless, data sharing is becoming an increasingly important topic among societies, publishers, researchers, patient advocates, and funders, especially as it pertains to data from clinical trials. In response, ASTRO developed a data policy and guide to best practices for authors submitting to its journals. ASTRO's data sharing policy is that authors should indicate, in data availability statements, if the data are being shared and if so, how the data may be accessed.

N-Acetylcysteine Rinse for Thick Secretion and Mucositis of Head and Neck Chemoradiotherapy (Alliance MC13C2): A Double-Blind Randomized Clinical Trial

OBJECTIVE

To determine whether N-acetylcysteine rinse was safe and could improve thickened secretions and dry mouth during and after radiotherapy.

PATIENTS AND METHODS

We designed a prospective pilot double-blind, placebo-controlled randomized clinical trial (Alliance MC13C2). Adult patients (age ≥18 years) were enrolled if they underwent chemoradiotherapy (≥60 Gy). Patients initiated testing rinse within 3 days of starting radiotherapy. With swish-and-spit, they received 10% N-acetylcysteine (2500 mg daily) or placebo rinse solution 5 times daily during radiotherapy and 2 weeks postradiotherapy. The primary aim was to evaluate N-acetylcysteine in improvement of saliva viscosity with the Groningen Radiotherapy-Induced Xerostomia questionnaire. Secondary aims included evaluating xerostomia improvement by the same questionnaire and with the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Head and Neck-35 Questions survey and adverse-event profiles. The type I error rate was 20%.

RESULTS

Thirty-two patients undergoing chemoradiotherapy were enrolled. Baseline characteristics were balanced for placebo (n=17) and N-acetylcysteine (n=15). N-acetylcysteine was better for improving sticky saliva (area under curve, P=.12). Scores of multiple secondary end points favored N-acetylcysteine, including sticky saliva daytime (P=.04), daytime and total xerostomia (both P=.02), pain (P=.18), and trouble with social eating (P=.15). Repeated measures models confirmed the findings. Taste was a major dissatisifer for N-acetylcysteine rinse; however, both testing rinses were safe and well tolerated overall.

CONCLUSION

Our pilot data showed that N-acetylcysteine rinse was safe and provided strong evidence of potential efficacy for improving thickened saliva and xerostomia by patient-reported outcome. A confirmatory phase 3 trial is required.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT02123511.

Google Search Trends in Oncology and the Impact of Celebrity Cancer Awareness

Introduction

There is widespread public interest when celebrities are diagnosed with cancer. We sought to assess how this interest impacts awareness of prevalent cancers.

Methods

We reviewed common cancer-related search terms using Google Trends (Google LLC, Mountain View, CA) between the years 2004 and 2017 and retrospectively correlated these findings with media or celebrity-related events. The Google Trends application was used to obtain the “search volume index” (SVI), defined as the number of searches for a specific term standardized to the total number of searches over that time period. Data were presented in a graphical format. Isolated peaks of greater than 25% from the baseline SVI were identified. Using the date of the peaks, a further search was performed to determine if any event in the media triggered the peak.

Results

“Lung Cancer,” “Pancreas Cancer,” “Endometrial Cancer,” “Cervical Cancer,” “Brain Cancer,” and “Glioblastoma” each had the highest peak correspond with a celebrity-related event covered in the media. These search terms displayed several additional isolated peaks, the majority of which could all be correlated with a significant media event (%). The search term “Breast Cancer” consistently had a peaked interest during October (breast cancer awareness month). Breast cancer events relating to public figures had little to no relative impact on search volume during this period. None of the other cancer search terms displayed the same cyclical pattern during their respective awareness months. Colon, rectal, and prostate cancer demonstrated stable search volumes over time, without an isolated peak.

Conclusion

Internet search activity among English speakers of most general cancer terms exhibit peaks coinciding with events that occur to celebrity figures or advances in medicines that are substantially covered in the media. In all cases but “breast cancer,” these events lend to higher search activity as compared to campaigns and awareness months. Our study suggests that media coverage of public figures with cancer may trigger substantial Internet interest in non-breast cancers, more so than traditional efforts to raise awareness.

Identifying the Most Costly Patients in Radiation Oncology and Predicting the Top Spenders

PURPOSE:

Quality payment programs aim to adjust payments on the basis of quality and cost; however, few quality metrics exist in radiation oncology. This study evaluates and predicts the top spenders (TS) after radiation therapy (RT).

MATERIALS AND METHODS:

Patient characteristics, cancer details, treatments, toxicity, and survival data were collected for patients treated with RT at Mayo Clinic from 2007 to 2016. Standardized costs were obtained and adjusted for inflation. TSs were identified as those with greater than 93rd percentile costs (≥ $120,812). Prediction models were developed to predict TSs using training and validation sets using information available at consultation, after RT, and at last follow-up.

RESULTS:

A total of 15,131 patients were included and 1,065 TSs identified. Mean cost overall was $55,290 (median, $39,996) for all patients. Prediction models 1, 2, and 3 had concordance statistics of 0.83 to 0.83, 0.85 to 0.85, and 0.87 to 0.88, respectively in training and validation, indicating excellent prediction of TSs. Factors that were most predictive of TSs included stage N/A and stage 4 ( v stage 0; odds ratio [OR], 18.23 and 8.44, respectively; P < .001); hematologic, upper GI, skin and lung cancers ( v breast; OR, 11.45, 7.69, 3.81, and 2.43, respectively; P < .01); immunotherapy, surgery, and chemotherapy use (OR, 4.36, 2.51, and 1.61, respectively; P < .01); hospitalizations within 90 days of RT (OR, 2.26; P < .01); or death during the episode (OR, 1.56; P < .01).

CONCLUSION:

This is the first study of its kind to predict with high accuracy the highest spenders in radiation oncology. These patients may benefit from pre-emptive management to mitigate costs, or may require exclusion or adjustment from quality payment programs.

Adjuvant chemoradiation in pancreatic cancer: impact of radiotherapy dose on survival

BACKGROUND

To evaluate the impact of radiation dose on overall survival (OS) in patients treated with adjuvant chemoradiation (CRT) for pancreatic ductal adenocarcinoma (PDAC).

METHODS

A multicenter retrospective analysis on 514 patients with PDAC (T1-4; N0-1; M0) treated with surgical resection with macroscopically negative margins (R0-1) followed by adjuvant CRT was performed. Patients were stratified into 4 groups based on radiotherapy doses (group 1: < 45 Gy, group 2: ≥ 45 and < 50 Gy, group 3: ≥ 50 and < 55 Gy, group 4: ≥ 55 Gy). Adjuvant chemotherapy was prescribed to 141 patients. Survival functions were plotted using the Kaplan-Meier method and compared through the log-rank test.

RESULTS

Median follow-up was 35 months (range: 3-120 months). At univariate analysis, a worse OS was recorded in patients with higher preoperative Ca 19.9 levels (≥ 90 U/ml; p < 0.001), higher tumor grade (G3-4, p = 0.004), R1 resection (p = 0.004), higher pT stage (pT3-4, p = 0.002) and positive nodes (p < 0.001). Furthermore, patients receiving increasing doses of CRT showed a significantly improved OS. In groups 1, 2, 3, and 4, median OS was 13.0 months, 21.0 months, 22.0 months, and 28.0 months, respectively (p = 0.004). The significant impact of higher dose was confirmed by multivariate analysis.

CONCLUSIONS

Increasing doses of CRT seems to favorably impact on OS in adjuvant setting. The conflicting results of randomized trials on adjuvant CRT in PDAC could be due to < 45 Gy dose generally used.

Effect of Doxepin Mouthwash or Diphenhydramine-Lidocaine-Antacid Mouthwash vs Placebo on Radiotherapy-Related Oral Mucositis Pain: The Alliance A221304 Randomized Clinical Trial

IMPORTANCE

Oral mucositis causes substantial morbidity during head and neck radiotherapy. In a randomized study, doxepin mouthwash was shown to reduce oral mucositis-related pain. A common mouthwash comprising diphenhydramine-lidocaine-antacid is also widely used.

OBJECTIVE

To evaluate the effect of doxepin mouthwash or diphenhydramine-lidocaine-antacid mouthwash for the treatment of oral mucositis-related pain.

DESIGN, SETTING, AND PARTICIPANTS

A phase 3 randomized trial was conducted from November 1, 2014, to May 16, 2016, at 30 US institutions and included 275 patients who underwent definitive head and neck radiotherapy, had an oral mucositis pain score of 4 points or greater (scale, 0-10), and were followed up for a maximum of 28 days.

INTERVENTIONS

Ninety-two patients were randomized to doxepin mouthwash (25 mg/5 mL water); 91 patients to diphenhydramine-lidocaine-antacid; and 92 patients to placebo.

MAIN OUTCOME AND MEASURES

The primary end point was total oral mucositis pain reduction (defined by the area under the curve and adjusted for baseline pain score) during the 4 hours after a single dose of doxepin mouthwash or diphenhydramine-lidocaine-antacid mouthwash compared with a single dose of placebo. The minimal clinically important difference was a 3.5-point change. The secondary end points included drowsiness, unpleasant taste, and stinging or burning. All scales ranged from 0 (best) to 10 (worst).

RESULTS

Among the 275 patients randomized (median age, 61 years; 58 [21%] women), 227 (83%) completed treatment per protocol. Mucositis pain during the first 4 hours decreased by 11.6 points in the doxepin mouthwash group, by 11.7 points in the diphenhydramine-lidocaine-antacid mouthwash group, and by 8.7 points in the placebo group. The between-group difference was 2.9 points (95% CI, 0.2-6.0; P = .02) for doxepin mouthwash vs placebo and 3.0 points (95% CI, 0.1-5.9; P = .004) for diphenhydramine-lidocaine-antacid mouthwash vs placebo. More drowsiness was reported with doxepin mouthwash vs placebo (by 1.5 points [95% CI, 0-4.0]; P = .03), unpleasant taste (by 1.5 points [95% CI, 0-3.0]; P = .002), and stinging or burning (by 4.0 points [95% CI, 2.5-5.0]; P < .001). Maximum grade 3 adverse events for the doxepin mouthwash occurred in 3 patients (4%); diphenhydramine-lidocaine-antacid mouthwash, 3 (4%); and placebo, 2 (2%). Fatigue was reported by 5 patients (6%) in the doxepin mouthwash group and no patients in the diphenhydramine-lidocaine-antacid mouthwash group.

CONCLUSIONS AND RELEVANCE

Among patients undergoing head and neck radiotherapy, the use of doxepin mouthwash or diphenhydramine-lidocaine-antacid mouthwash vs placebo significantly reduced oral mucositis pain during the first 4 hours after administration; however, the effect size was less than the minimal clinically important difference. Further research is needed to assess longer-term efficacy and safety for both mouthwashes.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02229539.