Radiation Therapy With or Without Cisplatin for Local Recurrences of Endometrial Cancer: Results From an NRG Oncology/GOG Prospective Randomized Multicenter Clinical Trial

PURPOSE

Pelvic recurrence is a frequent pattern of relapse for women with endometrial cancer. A randomized trial compared progression-free survival (PFS) after treatment with radiation therapy alone as compared with concurrent chemotherapy.

MATERIALS AND METHODS

Between February 2008 and August 2020, 165 patients were randomly assigned 1:1 to receive either radiation treatment alone or a combination of chemotherapy and radiation treatment. The primary objective of this study was to determine whether chemoradiation therapy was more effective than radiation therapy alone at improving PFS.

RESULTS

The majority of patients had low-grade (1 or 2) endometrioid histology (82%) and recurrences confined to the vagina (86%). External beam with either the three-dimensional or intensity modulated radiation treatment technique was followed by a boost delivered with brachytherapy or external beam. Patients randomly assigned to receive chemotherapy were treated with once weekly cisplatin (40 mg/m2). Rates of acute toxicity were higher in patients treated with chemoradiation as compared with radiation treatment alone. Median PFS was longer for patients treated with radiation therapy alone as compared with chemotherapy and radiation (median PFS was not reached for RT v 73 months for chemoradiation, hazard ratio of 1.25 (95% CI, 0.75 to 2.07). At 3 years, 73% of patients treated definitively with radiation and 62% of patients treated with chemoradiation were alive and free of disease progression.

CONCLUSION

Excellent outcomes can be achieved for women with localized recurrences of endometrial cancer when treated with radiation therapy. The addition of chemotherapy does not improve PFS for patients treated with definitive radiation therapy for recurrent endometrial cancer and increases acute toxicity. Patients with low-grade and vaginal recurrences who constituted the majority of those enrolled are best treated with radiation therapy alone.

Using machine learning to mine mental health diagnostic groups from emergency department presentations before and during the COVID-19 pandemic

PURPOSE

The COVID-19 pandemic had a profound negative effect on mental health worldwide. The hospital emergency department plays a pivotal role in responding to mental health crises. Understanding data trends relating to hospital emergency department usage is beneficial for service planning, particularly around preparing for future pandemics. Machine learning has been used to mine large volumes of unstructured data to extract meaningful data in relation to mental health presentations. This study aims to analyse trends in five mental health-related presentations to an emergency department before and during, the COVID-19 pandemic.

METHODS

Data from 690,514 presentations to two Australian, public hospital emergency departments between April 2019 to February 2022 were assessed. A machine learning-based framework, Mining Emergency Department Records, Evolutionary Algorithm Data Search (MEDREADS), was used to identify suicidality, psychosis, mania, eating disorder, and substance use.

RESULTS

While the mental health-related presentations to the emergency department increased during the COVID-19 pandemic compared to pre-pandemic levels, the proportion of mental health presentations relative to the total emergency department presentations decreased. Several troughs in presentation frequency were identified across the pandemic period, which occurred consistently during the public health lockdown and restriction periods.

CONCLUSION

This study implemented novel machine learning techniques to analyse mental health presentations to an emergency department during the COVID-19 pandemic. Results inform understanding of the use of emergency mental health services during the pandemic, and highlight opportunities to further investigate patterns in presentation.

Statistical Analysis of Interfraction Dose Variations of High-Risk Clinical Target Volume and Organs at Risk for Cervical Cancer High-Dose-Rate Brachytherapy

Purpose

High-dose-rate (HDR) brachytherapy for cervical cancer treatment includes significant uncertainties. The aim of this study was to quantify the interfraction dosimetric variation (IDV) of the high-risk clinical target volume (HRCTV) from the prescribed dose and the corresponding effect on organ-at-risk (OAR) dose based on a comprehensive statistical analysis.

Methods and Materials

Fifty patients with cervical cancer treated with high-dose-rate intracavity brachytherapy from October 2019 to December 2020 were retrospectively analyzed. The OARs of interest were the rectum, bladder, sigmoid, and bowel. The dosimetric parameters evaluated for all patients was the dose absorbed by 90% of the HRCTV ( D 90 ) and the dose absorbed by 0.1 ( D 0.1 c c ) and 2 cm3 ( D 2 c c ) of each respective OAR. The HRCTV variations were from the prescribed dose and the OAR variations were from the corresponding tolerance dose. Distribution fitting of the HRCTV variations was determined to quantify the IDV. Comparative statistics of the HRCTV variations with the OAR variations were conducted to determine correlations.

Results

The mean HRCTV variation from the prescribed dose was -2.53% ± 8.74%. The HRCTV variations and OAR variations showed moderate to weak linear correlations despite the variations being relative to each other, with the bladder D 2 c c having the strongest correlation. There was a 30.0% (±2.62%, 95% confidence interval) probability of underdosing the HRCTV (-5% variation from prescription) and a 23.3% (±2.62%, 95% confidence interval) probability of overdosing the HRCTV (+5% variation from prescription). This tendency to underdose the HRCTV was a consequence of HRCTV IDV not being normally distributed.

Conclusions

HRCTV dosimetric variations and OAR variations were complexly correlated with the bladder D 2 c c having the strongest correlation. HRCTV IDV was best described as a left-skewed distribution that indicates a tendency of underdosing the HRCTV. The clinical significance of such dose variations is expected and will be further investigated.

Patient reported outcomes for cisplatin and radiation followed by carboplatin/paclitaxel versus carboplatin/paclitaxel for locally advanced endometrial carcinoma: An NRG oncology study

INTRODUCTION

Chemotherapy plus radiation (Cis-RT + CP) did not demonstrate superiority in prolonging relapse-free survival compared to chemotherapy alone in patients with stage III or IVA endometrial carcinoma. The impact of treatment on quality of life (QOL), neurotoxicity (NTX) and psychometric properties of the gastrointestinal (GI) symptoms subscale during treatment and up to 1 year are described herein.

METHODS

QOL assessments were scheduled at baseline, 6 weeks (post completion of RT (Cis-RT + CP) or prior to cycle 3 (CP)), then 18 weeks (end of treatment) and 70 weeks (1 year after the end of treatment) after starting treatment. QOL instruments included the FACT-En TOI, FACT/GOG-neurotoxicity (Ntx) subscale (short), and the gastrointestinal (GI) symptoms subscale.

RESULTS

At the end of treatment, patients receiving Cis-RT + CP reported a statistically significant decreased QOL when compared to CP. The decline in QOL was reflected in physical well-being, functional well-being, and endometrial cancer specific concerns, but the minimally important differences (MID) were not considered clinically meaningful. Patients in both groups reported increased chemotherapy-induced Ntx symptoms with the CP group having worse scores and reaching peak symptoms at the time of chemotherapy completion. Patients on Cis-RT + CP reported statistically significantly worse GI symptoms after radiation therapy compared to patients on CP, this occurred across assessment intervals, though the MID was not meaningful. Psychometric evaluations indicated that the GI symptom scale is reliable, valid, and responsive to change.

CONCLUSIONS

PROs indicate that the chemoradiotherapy group experienced worse HRQoL and GI toxicity compared to patients randomized to chemotherapy alone for locally advanced endometrial cancer though based on the MID, these were not clinically meaningful differences. The GI symptom subscale was a reliable and valid scale that has value for future trials.

TRIAL REGISTRATION

NCT00942357.

A Discrete-Event, Simulated Social Agent-Based Network Transmission (DESSABNeT) model for communicable diseases: Method and validation using SARS-CoV-2 data in three large Australian cities

IMPORTANCE

During pandemics Agent Based Models (ABMs) can model complex, fine-grained behavioural interactions occurring in social networks, that contribute to disease transmission by novel viruses such as SARS-CoV-2.

OBJECTIVE

We present a new agent-based model (ABM) called the Discrete-Event, Simulated Social Agent based Network Transmission model (DESSABNeT) and demonstrate its ability to model the spread of COVID-19 in large cities like Sydney, Melbourne and Gold Coast. Our aim was to validate the model with its disease dynamics and underlying social network.

DESIGN

DESSABNeT relies on disease transmission within simulated social networks. It employs an epidemiological SEIRD+M (Susceptible, exposed, infected, recovered, died and managed) structure. One hundred simulations were run for each city, with simulated social restrictions closely modelling real restrictions imposed in each location.

MAIN OUTCOME(S) AND MEASURE(S)

The mean predicted daily incidence of COVID-19 cases were compared to real case incidence data for each city. Reff and health service utilisation outputs were compared to the literature, or for the Gold Coast with daily incidence of hospitalisation.

RESULTS

DESSABNeT modelled multiple physical distancing restrictions and predicted epidemiological outcomes of Sydney, Melbourne and the Gold Coast, validating this model for future simulation work.

CONCLUSIONS AND RELEVANCE

DESSABNeT is a valid platform to model the spread of COVID-19 in large cities in Australia and potentially internationally. The platform is suitable to model different combinations of social restrictions, or to model contact tracing, predict, and plan for, the impact on hospital and ICU admissions, and deaths; and also the rollout of COVID-19 vaccines and optimal social restrictions during vaccination.

Management of multiple brain metastases via dual-isocenter VMAT stereotactic radiosurgery

Single-isocenter volumetric modulated arc therapy (VMAT) stereotactic radiosurgery (SRS) techniques to treat multiple brain metastases simultaneously can significantly improve treatment delivery efficiency, patient compliance, and clinic workflow. However, due to large number of brain metastases sharing the same MLC pair causing island blocking, there is higher low- and intermediate-dose spillage to the normal brain and higher dose to organs-at-risk (OAR). To minimize this problem and improve plan quality, this study proposes a dual-isocenter planning strategy that groups lesions based on hemisphere location (left vs right sided) in the brain parenchyma, providing less island blocking reducing the MLC travel distance. This technique offers simplified planning while also increasing patient comfort and compliance by allowing for large number of brain metastases to be treated in 2 groups. Seven complex patients with 5 to 16 metastases (64 total) were planned with a single-isocenter VMAT-SRS technique using a 10MV-FFF beam with a prescription of 20 Gy to each lesion. The isocenter was placed at the approximate geometric center of the targets. Each patient was replanned using the dual-isocenter approach, generating 2 plans and placing each isocenter at the approximate geometric center of the combined targets of each side with corresponding non-coplanar partial arcs. Compared to single-isocenter VMAT, dual-isocenter VMAT plans provided similar target coverage and dose conformity with less spread of intermediate dose to normal brain with reduction of dose to OAR. Reduction in total monitor units and beam on time was observed, but due to the second isocenter setup and verification, overall treatment time was increased. Dual-isocenter VMAT-SRS planning for multiple brain metastases is a simplified approach that provides superior treatment options for patient compliance who may not tolerate longer traditional treatment times as with individual isocenters to each target. This planning technique significantly reduces the amount of low- and intermediate-dose spillage, further sparing OAR and normal brain, potentially improving target accuracy though localization of left vs right-sided tumors for each isocenter set up.

Clinical validation of ring-mounted halcyon linac for lung SBRT: comparison to SBRT-dedicated C-arm linac treatments

Stereotactic body radiotherapy (SBRT) of lung tumors via the ring‐mounted Halcyon Linac, a fast kilovoltage cone beam CT‐guided treatment with coplanar geometry, a single energy 6MV flattening filter free (FFF) beam and volumetric modulated arc therapy (VMAT) is a fast, safe, and feasible treatment modality for selected lung cancer patients. Four‐dimensional (4D) CT‐based treatment plans were generated using advanced AcurosXB algorithm with heterogeneity corrections using an SBRT board and Halcyon couch insert. Halcyon VMAT‐SBRT plans with stacked and staggered multileaf collimators produced highly conformal radiosurgical dose distribution to the target, lower intermediate dose spillage, and similar dose to adjacent organs at risks (OARs) compared to SBRT‐dedicated highly conformal clinical noncoplanar Truebeam VMAT plans following the RTOG‐0813 requirements. Due to low monitor units per fraction and less multileaf collimator (MLC) modulation, the Halcyon VMAT plan can deliver lung SBRT fractions with an overall treatment time of less than 15 min (for 50 Gy in five fractions), significantly improving patient comfort and clinic workflow. Higher pass rates of quality assurance results demonstrate a more accurate treatment delivery on Halcyon. We have implemented Halcyon for lung SBRT treatment in our clinic. We suggest others use Halcyon for lung SBRT treatments using abdominal compression or 4D CT‐based treatment planning, thus expanding the access of curative ultra‐hypofractionated treatments to other centers with only a Halcyon Linac. Clinical follow‐up results for patients treated on Halcyon Linac with lung SBRT is ongoing.

An Automated knowledge-based planning routine for stereotactic body radiotherapy of peripheral lung tumors via DCA-based volumetric modulated arc therapy

Purpose

To develop a knowledge‐based planning (KBP) routine for stereotactic body radiotherapy (SBRT) of peripherally located early‐stage non‐small‐cell lung cancer (NSCLC) tumors via dynamic conformal arc (DCA)‐based volumetric modulated arc therapy (VMAT) using the commercially available RapidPlan^TM software. This proposed technique potentially improves plan quality, reduces complexity, and minimizes interplay effect and small‐field dosimetry errors associated with treatment delivery.

Methods

KBP model was developed and validated using 70 clinically treated high quality non‐coplanar VMAT lung SBRT plans for training and 20 independent plans for validation. All patients were treated with 54 Gy in three treatments. Additionally, a novel k‐DCA planning routine was deployed to create plans incorporating historical three‐dimensional‐conformal SBRT planning practices via DCA‐based approach prior to VMAT optimization in an automated planning engine. Conventional KBPs and k‐DCA plans were compared with clinically treated plans per RTOG‐0618 requirements for target conformity, tumor dose heterogeneity, intermediate dose fall‐off and organs‐at‐risk (OAR) sparing. Treatment planning time, treatment delivery efficiency, and accuracy were recorded.

Results

KBPs and k‐DCA plans were similar or better than clinical plans. Average planning target volume for validation was 22.4 ± 14.1 cc (7.1–62.3 cc). KBPs and k‐DCA plans provided similar conformity to clinical plans with average absolute differences of 0.01 and 0.01, respectively. Maximal doses to OAR were lowered in both KBPs and k‐DCA plans. KBPs increased monitor units (MU) on average 1316 (P < 0.001) while k‐DCA reduced total MU on average by 1114 (P < 0.001). This routine can create k‐DCA plan in less than 30 min. Independent Monte Carlo calculation demonstrated that k‐DCA plans showed better agreement with planned dose distribution.

Conclusion

A k‐DCA planning routine was developed in concurrence with a knowledge‐based approach for the treatment of peripherally located lung tumors. This method minimizes plan complexity associated with model‐based KBP techniques and improve plan quality and treatment planning efficiency.

Single-Isocenter Volumetric Modulated Arc Therapy (VMAT) Radiosurgery for Multiple Brain Metastases: Potential Loss of Target(s) Coverage Due to Isocenter Misalignment

Purpose A single-isocenter volumetric modulated arc therapy (VMAT) treatment to multiple brain metastatic patients is an efficient stereotactic radiosurgery (SRS) option. However, the current clinical practice of single-isocenter SRS does not account for patient setup uncertainty, which degrades treatment delivery accuracy. This study quantifies the loss of target coverage and potential collateral dose to normal tissue due to clinically observable isocenter misalignment. Methods and materials Nine patients with 61 total tumors (2-16 tumors/patient) who underwent Gamma Knife® SRS were replanned in Eclipse™ using 10 megavoltages (MV) flattening-filter-free (FFF) bream (2400 MU/min), using a single-isocenter VMAT plan, similar to HyperArc™ VMAT plan. Isocenter was placed in the geometric center of the tumors. The prescription was 20 Gy to each tumor. Average gross tumor volume (GTV) and planning target volume (PTV) were 1.1 cc (0.02-11.5 cc) and 1.9 cc (0.11-18.8 cc), respectively, derived from MRI images. The average isocenter to tumor distance was 5.5 cm (1.6-10.1 cm). Six-degrees of freedom (6DoF) random and systematic residual set up errors within [±2 mm, ±2o] were generated using an in-house script in Eclipse based on our pre-treatment daily cone-beam CT imaging shifts and recomputed for the simulated VMAT plan. Relative loss of target coverage as a function of tumor size and distance to isocenter were evaluated as well as collateral dose to organs-at risk (OAR). Results The average beam-on time was less than six minutes. However, loss of target coverage for clinically observable setup errors were, on average, 7.9% (up to 73.1%) for the GTV (p < 0.001) and 21.5% for the PTV (up to 93.7%; p < 0.001). The correlation was found for both random and systematic residual setup errors with tumor sizes; there was a greater loss of target coverage for small tumors. Due to isocenter misalignment, OAR doses fluctuated and potentially receive higher doses than the original plan. Conclusion A single-isocenter VMAT SRS treatment (similar to HyperArc™ VMAT) to multiple brain metastases was fast with < 6 min of beam-on time. However, due to small residual set up errors, single-isocenter VMAT, in its current use, is not an accurate SRS treatment modality for multiple brain metastases. Loss of target coverage was statistically significant, especially for smaller lesions, and may not be clinically acceptable if left uncorrected. Further investigation of correction strategies is underway.

On the use of single‐isocenter VMAT plans for SBRT treatment of synchronous multiple lung lesions: Plan quality, treatment efficiency, and early clinical outcomes

Cone‐beam computed tomography (CT)‐guided volumetric‐modulated arc therapy (VMAT) plans for stereotactic body radiotherapy (SBRT) treatment of synchronous multiple lung lesions with a flattening filter‐free (FFF) beam is a safe and highly effective treatment option for oligometastases lung cancer patients. Fourteen patients with metastatic non–small‐cell lung cancer (NSCLC) lesions (two to five) received a single‐isocenter VMAT SBRT treatment in our clinic. Four‐dimensional (4D) CT‐based treatment plans were generated using advanced AcurosXB‐based dose calculation algorithm using heterogeneity corrections with a single isocenter placed between/among the lesions. Compared to 10X‐FFF and traditional flattened 6X (6X‐FF) beams, 6X‐FFF beam produced highly conformal radiosurgical dose distribution to each target volume, reduced dose to adjacent organs at risk (OAR), and significantly reduced the lung SBRT fraction duration to < 3.5 min/fraction for 54/50 Gy treatments in 3/5 fractions — significantly improving patient convenience and clinic workflow. Early follow‐up CT imaging (mean, 9 months) results show high local control rates (100%) with no acute lung or rib toxicity. Longer clinical follow up in a larger patient cohort is ongoing to further validate the outcomes of this treatment approach.

Flattening filter free VMAT for a stereotactic, single-dose of 30 Gy to lung lesion in a 15-min treatment slot

Cone‐beam CT‐guided single dose of lung stereotactic body radiotherapy (SBRT) treatment with a flattening filter free (FFF) beam and volumetric modulated arc therapy (VMAT) is a safe and highly effective treatment modality for selective small lung lesions. Four‐dimensional (4D) CT‐based treatment plans were generated using advanced AcurosXB algorithm for heterogeneity corrections. 6X‐FFF beam produced highly conformal radiosurgical dose distribution to the target and reduced lung SBRT fraction duration to less than 10 min for a single dose of 30 Gy, significantly improving patient comfort and clinic workflow. Early follow‐up CT imaging results (mean, 8 months) show high local control rates (100%) with no acute lung or rib toxicity. Longer clinical follow‐up in a larger patient cohort managed in this fashion is underway to further validate this treatment approach.

Developing a Decision Support App for Computational Agriculture

In the age of climate change, increasing populations and more limited resources, efficient agricultural production is being sought by farmers across the world. In the case of smallholder farms with limited capacity to cope with years of low production, this is even more important. To help to achieve this aim, data analytics and decision support systems are being used to an ever greater extent. For rice/shrimp farmers in the Mekong Delta, Vietnam, trying to tune the conditions so that both crops can be successfully grown simultaneously is an ongoing challenge. In this paper, the design and development of a smartphone app, from a well researched Bayesian Belief Network, is described. This now gives farmers the ability to make better informed planting and harvesting decisions. The app has been initially well received by water management practitioners and farmers alike.

Integrating continuous differential evolution with discrete local search for meander line RFID antenna design

The automated design of meander line RFID antennas is a discrete self-avoiding walk (SAW) problem for which efficiency is to be maximized while resonant frequency is to be minimized. This work presents a novel exploration of how discrete local search may be incorporated into a continuous solver such as differential evolution (DE). A prior DE algorithm for this problem that incorporates an adaptive solution encoding and a bias favoring antennas with low resonant frequency is extended by the addition of the backbite local search operator and a variety of schemes for reintroducing modified designs into the DE population. The algorithm is extremely competitive with an existing ACO approach and the technique is transferable to other SAW problems and other continuous solvers. The findings indicate that careful reintegration of discrete local search results into the continuous population is necessary for effective performance.

Evaluation of plan quality and treatment efficiency for single-isocenter/two-lesion lung stereotactic body radiation therapy

Purpose/objectives

To evaluate the plan quality and treatment delivery efficiency of single‐isocenter/two‐lesions volumetric modulated arc therapy (VMAT) lung stereotactic body radiation therapy (SBRT).

Materials/methods

Eight consecutive patients with two peripherally located early stage nonsmall‐cell‐lung cancer (NSCLC) lung lesions underwent single‐isocenter highly conformal noncoplanar VMAT SBRT treatment in our institution. A single‐isocenter was placed between the two lesions. Doses were 54 or 50 Gy in 3 and 5 fractions respectively. Patients were treated every other day. Plans were calculated in Eclipse with AcurosXB algorithm and normalized to at least 95% of the planning target volume (PTV) receiving 100% of the prescribed dose. For comparison, two‐isocenter plans (isocenter placed centrally in each target) were retrospectively created. Conformity indices (CIs), heterogeneity index (HI), gradient index (GI), gradient distance (GD), and D_2cm were calculated. The normal lung V5, V10, V20, mean lung dose (MLD) and other organs at risk (OARs) doses were evaluated. Total number of monitor units (MUs), beam‐on time, and patient‐specific quality assurance (QA) results were recorded.

Results

The mean isocenter to tumor distance was 6.7 ± 2.3 cm. The mean combined PTV was 44.0 ± 23.4 cc. There was no clinically significant difference in CI, HI, GD, GI, D_2cm, and V20 including most of the OARs between single‐isocenter and two‐isocenter lung SBRT plans, evaluated per RTOG guidelines. However, for single‐isocenter plans as the distance between the lesions increased, the V5, V10, and MLD increased, marginally. The total number of MUs and beam‐on time was reduced by a factor of 1.5 for a single‐isocenter plan compared to a two‐isocenter plan. The single‐isocenter/two‐lesions VMAT lung SBRT QA plans demonstrated an accurate dose delivery of 98.1 ± 3.2% for clinical gamma passing rate of 3%/3 mm.

Conclusion

The SBRT treatment of two peripherally located lung lesions with a centrally placed single‐isocenter was dosimetrically equivalent to two‐isocenter plans. Faster treatment delivery for single‐isocenter treatment can improve patient compliance and reduce the amount of intrafraction motion errors for well‐suited patients.

Abstract A85: Receipt of adjuvant endometrial carcinoma treatment according to race: An NRG Oncology/Gynecologic Oncology Group 210 Study

Background: Black women diagnosed with endometrial cancer (EC) experience worse outcomes compared with white women. Differences in receipt of treatment are postulated to contribute to this disparity. While underuse of surgical treatment among black women is well documented, we know less about racial differences in adjuvant treatment. We therefore examined receipt of adjuvant treatment among black and white women in the NRG Oncology/Gynecology Oncology Group (GOG) 210 Study, a large prospective cohort of women with EC who received uniform surgical treatment but varying adjuvant therapy regimens.

Methods: Our analysis included 615 black and 4,283 white women with EC who underwent either an abdominal hysterectomy or laparoscopic-assisted vaginal hysterectomy with bilateral salpingo-oophorectomy and lymph node dissection. At study enrollment, women completed a questionnaire that assessed race as well as risk factors for EC. Tumor characteristics were available from surgical pathology reports and a centralized review by pathologists with expertise in gynecologic cancers. Adjuvant treatment was documented at the time of the postoperative clinical visits and was categorized as none (54.3%), radiotherapy only (16.5%), chemotherapy only (n=15.2%), and radiotherapy and chemotherapy (14.0%). We used polytomous logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for associations between race and receipt of adjuvant therapy in the overall study population and stratified by tumor subtype (combination of histology and grade) adjusted for age, income, education, and stage.

Results: Black compared with white women had higher odds of receiving combination radiotherapy and chemotherapy compared to no adjuvant therapy (OR=1.35, 95% CI=1.01-1.79) but no difference in receipt of radiotherapy only (OR=0.95, 95% CI=0.72-1.25) or chemotherapy only (OR=0.88 (0.64-1.20) was observed. In tumor-subtype stratified models, black women diagnosed with low-grade endometrioid (OR=2.04, 95% CI=1.06-3.93) or serous tumors (OR=1.81, 95% CI=1.07-3.08) had higher odds of receiving radiotherapy and chemotherapy than white women, but race was not associated with receipt of radiotherapy and chemotherapy for women with high-grade endometrioid, carcinosarcoma, mixed-cell, or clear-cell tumors. Moreover, the tumor-subtype stratified analyses revealed no racial differences in receipt of radiotherapy-only or chemotherapy-only regimens.

Conclusions: In this study of women with EC who received uniform surgical treatment, we observed racial differences in receipt of some adjuvant treatment regimens but not others. Among women with indolent (i.e., low-grade endometrioid) or aggressive (i.e., serous) tumors, black women had higher odds of receiving radiotherapy and chemotherapy compared to white women. Radiotherapy and chemotherapy treatment is potentially contraindicated for women with indolent tumors, which suggests a need to understand the reasons why clinicians might overprescribe these therapies for black women. Overall, our results suggest racial differences in receipt of radiotherapy and chemotherapy, but not for other regimens.

Citation Format: Ashley Felix, David Cohn, Theodore Brasky, David Mutch, William Creasman, Premal Thaker, Joan Walker, Richard Moore, Shashikant Lele, Saketh Guntupalli, Levi Downs, Christa Nagel, John Boggess, Michael Pearl, Olga Ioffe, Wei Deng, Marcus Randall, Louise Brinton. Receipt of adjuvant endometrial carcinoma treatment according to race: An NRG Oncology/Gynecologic Oncology Group 210 Study [abstract]. In: Proceedings of the Tenth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2017 Sep 25-28; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2018;27(7 Suppl):Abstract nr A85.

Solving multi-objective water management problems using evolutionary computation

Water as a resource is becoming increasingly more valuable given the changes in global climate. In an agricultural sense, the role of water is vital to ensuring food security. Therefore the management of it has become a subject of increasing attention and the development of effective tools to support participative decision-making in water management will be a valuable contribution. In this paper, evolutionary computation techniques and Pareto optimisation are incorporated in a model-based system for water management. An illustrative test case modelling optimal crop selection across dry, average and wet years based on data from the Murrumbidgee Irrigation Area in Australia is presented. It is shown that sets of trade-off solutions that provide large net revenues, or minimise environmental flow deficits can be produced rapidly, easily and automatically. The system is capable of providing detailed information on optimal solutions to achieve desired outcomes, responding to a variety of factors including climate conditions and economics.

Reirradiation Using Permanent Interstitial Brachytherapy: A Potentially Durable Technique for Salvaging Recurrent Pelvic Malignancies

PURPOSE

To present a time-to-failure (TTF) analysis for all patients treated with permanent interstitial brachytherapy (PIB) at our institution, with additional analyses to correlate successful reirradiation and to identify the frequency of severe grade 3 to 4 toxicity.

METHODS AND MATERIALS

Forty-two previously irradiated patients received curative or palliative intent PIB for a recurrent pelvic malignancy between January 2009 and August 2016. Minimum follow-up was 6 months after the PIB procedure. All patients had a biopsy-proven recurrence and were treated using PIB alone (n=32) or in combination with a short course of additional radiation therapy (n=10). Competing risk analyses were performed to assess the risk of failures in the presence of death without failure. Exploratory analyses were performed for factors related to failure using competing risk analyses and the Gray statistic.

RESULTS

A total of 61 PIB implants were performed among 42 patients with a median follow-up of 16.3 months. Fifty-two implants were performed as the first salvage reirradiation to a solitary recurrence (8 patients had more than 1 lesion); the success rate for initial reirradiation using PIB was 73% (38 cases out of 52), and the median TTF was not reached. Nine patients underwent a second repeat PIB to the same recurrence as a form of salvage; 3 (33%) remain without evidence of recurrence. The median TTF after second salvage was 7.7 months. Even with the limited sample size, prolonged TTF was marginally associated with definitive intent (P=.07) and the extent of disease at the time of PIB (P=.08). Grade 3+ toxicities were seen in 8 patients (16.7%).

CONCLUSIONS

Permanent interstitial brachytherapy is a feasible and potentially durable treatment modality that can be used to curatively salvage selected recurrent pelvic malignancies in a previously irradiated field.

A randomized phase III trial of cisplatin and tumor volume directed irradiation followed by carboplatin and paclitaxel vs. carboplatin and paclitaxel for optimally debulked, advanced endometrial carcinoma

5505

Background: Patients with stage III/IVA uterine cancer (UC) carry high risk of systemic and local recurrence. Chemotherapy was shown to reduce systemic recurrence, however the risk of local failure remains high. Methods: The primary endpoint of this open label, randomized phase III trial was to determine if treatment with cisplatin and volume-directed radiation followed by carboplatin and paclitaxel for 4 cycles (C-RT, experimental arm) reduces the rate of recurrence or death (i.e., increases recurrence-free survival, RFS) when compared to carboplatin and paclitaxel for 6 cycles (CT, control arm) in patients with stages III-IVA (<2 cm residual disease) or FIGO 2009 stage I/II serous or clear cell UC and positive cytology. Secondary objectives were assessment of overall survival (OS), acute and late toxicities, and quality of life. A 28.5% reduction in the rate of recurrence or death was considered significant. Treatment randomization and analysis were stratified by gross residual tumor and age. Results: Between 6/2009 and 7/2014, 813 patients were enrolled and randomized (407 C-RT and 406-CT). Of those, 733 were eligible (344 C-RT and 360 CT), and 680 received the trial intervention (333 C-RT and 347 CT). Median follow up is 47 months. Patients characteristics were balanced between arms. There were 201 (58%) > grd 3 toxicity events in the C-RT arm and 227 (63%) in the CT arm. The most common > grd 3 events were myelosupression (40% vs. 52%), gastrointestinal (13% vs. 4%), metabolic (15% vs. 19%), neurological (7% vs. 6%), infectious (4% vs. 5%). Treatment hazard ratio for RFS was 0.9 (C-RT vs. CT; CI 0.74 to 1.10). C-RT reduced the incidence of vaginal (3% vs. 7%, HR = 0.36, CI 0.16 to 0.82), pelvic and paraaortic recurrences (10% vs. 21%, HR=0.43, CI 02.8 to 0.66) compared to CT, but distant recurrences were more common with C-RT vs. CT (28% vs. 21%, HR 1.36, CI 1 to 1.86). The analysis is premature for OS comparison. Conclusions: Although C-RT reduced the rate of local recurrence compared to CT; the combined modality regimen did not increase RFS in optimally debulked, stage III/IVA UC. Clinical trial information: NCT00942357.

Serotonergic agents act on 5-HT3 receptors in the brain to block seizure-induced respiratory arrest in the DBA/1 mouse model of SUDEP

Drugs that enhance the action of serotonin (5-hydroxytrypamine, 5-HT), including several selective serotonin reuptake inhibitors (SSRIs), reduce susceptibility to seizure-induced respiratory arrest (S-IRA) that leads to death in the DBA/1 mouse model of sudden unexpected death in epilepsy (SUDEP). However, it is not clear if specific 5-HT receptors are important in the action of these drugs and whether the brain is the major site of action of these agents in this SUDEP model. The current study examined the actions of agents that affect the 5-HT₃ receptor subtype on S-IRA and whether intracerebroventricular (ICV) microinjection of an SSRI would reduce S-IRA susceptibility in DBA/1 mice. The data indicate that systemic administration of SR 57227, a 5-HT₃ agonist, was effective in blocking S-IRA in doses that did not block seizures, and the S-IRA blocking effect of the SSRI, fluoxetine, was abolished by coadministration of a 5-HT₃ antagonist, ondansetron. Intracerebroventricular administration of fluoxetine in the present study was also able to block S-IRA without blocking seizures. These findings suggest that 5-HT₃ receptors play an important role in the block of S-IRA by serotonergic agents, such as SSRIs, which is consistent with the abnormal expression of 5-HT₃ receptors in the brainstem of DBA mice observed previously. Taken together, these data indicate that systemically administered serotonergic agents act, at least, in part, in the brain, to reduce S-IRA susceptibility in DBA/1 mice and that 5-HT₃ receptors may be important to this effect.

Determination of prescription dose for Cs-131 permanent implants using the BED formalism including resensitization correction

PURPOSE

The current widely used biological equivalent dose (BED) formalism for permanent implants is based on the linear-quadratic model that includes cell repair and repopulation but not resensitization (redistribution and reoxygenation). The authors propose a BED formalism that includes all the four biological effects (4Rs), and the authors propose how it can be used to calculate appropriate prescription doses for permanent implants with Cs-131.

METHODS

A resensitization correction was added to the BED calculation for permanent implants to account for 4Rs. Using the same BED, the prescription doses with Au-198, I-125, and Pd-103 were converted to the isoeffective Cs-131 prescription doses. The conversion factor F, ratio of the Cs-131 dose to the equivalent dose with the other reference isotope (Fr: with resensitization, Fn: without resensitization), was thus derived and used for actual prescription. Different values of biological parameters such as α, β, and relative biological effectiveness for different types of tumors were used for the calculation.

RESULTS

Prescription doses with I-125, Pd-103, and Au-198 ranging from 10 to 160 Gy were converted into prescription doses with Cs-131. The difference in dose conversion factors with (Fr) and without (Fn) resensitization was significant but varied with different isotopes and different types of tumors. The conversion factors also varied with different doses. For I-125, the average values of Fr/Fn were 0.51/0.46, for fast growing tumors, and 0.88/0.77 for slow growing tumors. For Pd-103, the average values of Fr/Fn were 1.25/1.15 for fast growing tumors, and 1.28/1.22 for slow growing tumors. For Au-198, the average values of Fr/Fn were 1.08/1.25 for fast growing tumors, and 1.00/1.06 for slow growing tumors. Using the biological parameters for the HeLa/C4-I cells, the averaged value of Fr was 1.07/1.11 (rounded to 1.1), and the averaged value of Fn was 1.75/1.18. Fr of 1.1 has been applied to gynecological cancer implants with expected acute reactions and outcomes as expected based on extensive experience with permanent implants. The calculation also gave the average Cs-131 dose of 126 Gy converted from the I-125 dose of 144 Gy for prostate implants.

CONCLUSIONS

Inclusion of an allowance for resensitization led to significant dose corrections for Cs-131 permanent implants, and should be applied to prescription dose calculation. The adjustment of the Cs-131 prescription doses with resensitization correction for gynecological permanent implants was consistent with clinical experience and observations. However, the Cs-131 prescription doses converted from other implant doses can be further adjusted based on new experimental results, clinical observations, and clinical outcomes.

Serotonin and sudden death: differential effects of serotonergic drugs on seizure-induced respiratory arrest in DBA/1 mice

In the DBA/1 mouse model of sudden unexpected death in epilepsy (SUDEP), administration of a selective serotonin (5-HT) reuptake inhibitor (SSRI), fluvoxamine, completely suppressed seizure-induced respiratory arrest (S-IRA) at 30 min after administration (i.p.) in a dose-related manner without blocking audiogenic seizures (AGSz), but another SSRI, paroxetine, reduced S-IRA but with a delayed (24 h) onset and significant toxicity. A serotonin-norepinephrine reuptake inhibitor, venlafaxine, reduced S-IRA incidence, but higher doses were ineffective. A selective 5-HT7 agonist, AS-19, was totally ineffective in reducing S-IRA. In developing DBA/1 mice that had not previously experienced AGSz, administration of a nonselective 5-HT antagonist, cyproheptadine, induced a significantly greater incidence of S-IRA than that of saline. This study confirms that certain drugs that enhance the activation of 5-HT receptors are able to prevent S-IRA, but not all serotonergic drugs are equally effective, which may be relevant to the potential use of these drugs for SUDEP prevention. Serotonergic antagonists may be problematic in patients with epilepsy.

Impact of post-radiation biopsies on development of fistulae in patients with cervical cancer

OBJECTIVE

In the post-radiation patient, late vascular sequelae and fibrosis predispose women to poor tissue healing, such that small tissue injuries could theoretically evolve into much larger ones such as fistulae. We sought to determine if a correlation exists between invasive procedures such as post-treatment biopsies and the subsequent development of gynecologic fistulae.

METHODS

A retrospective review was performed evaluating all patients treated for cervical cancer at our institution between 1997 and 2010. Biopsies or pelvic surgeries were included if performed within the radiated field, and evaluated in a multivariate predictive model for development of gynecologic fistulae.

RESULTS

Out of 325 total patients, 27 patients with fistulae were identified (8.2%). 14 fistulae (51.9%) were considered toxicity-related, 6 (22.2%) resulted from primary disease, and 7 (25.9%) were attributable to recurrent disease. Eighty-nine patients underwent an invasive procedure (55 biopsies and 34 pelvic surgeries). Recurrent and/or residual cancer was found in 28 (31.5%) specimens, and of the 61 patients who underwent an invasive procedure and were not found to have evidence of recurrent disease, 9 (14.8%) subsequently developed a fistula at a median 3.08 months. An elevated dose of radiation to the rectum (OR 1.001 for dose >72 Gy, p=0.0005), advancing tumor stage (OR 5.38 for stage III, OR 10.47 for stage IV, p=0.0288), and a post-radiation biopsy (OR 5.27, p=0.013) were significantly associated with fistula development.

CONCLUSIONS

Performing a biopsy in an irradiated field is associated with a relatively low yield and significantly contributes to the risk for fistula development.

Effects of age, sex, and sertraline administration on seizure-induced respiratory arrest in the DBA/1 mouse model of sudden unexpected death in epilepsy (SUDEP)

DBA/1 mice are susceptible to audiogenic seizure-induced respiratory arrest (S-IRA), leading to death, which is a model of human sudden unexpected death in epilepsy (SUDEP). Female DBA/1 mice exhibited 71% susceptibility to S-IRA on the third daily test when seizure testing began at postnatal day (PND) 24-30, which was slightly (>10%) but not significantly lower than males. When initial seizure testing was delayed (to >7 weeks of age), DBA/1 mice of both sexes exhibited significantly reduced S-IRA susceptibility, as compared to mice tested initially at PND 24-30. These sex and age issues had not been previously evaluated and may be important for the future use of this SUDEP model. We also observed that 30 min after administering a selective serotonin reuptake inhibitor (SSRI), sertraline (40, 50, or 75 mg/kg i.p.), a significantly reduced S-IRA incidence in DBA/1 mice occurred without blocking seizures, which may be relevant to SUDEP prevention.

SU-E-T-462: Calculation of Prescribed Dose for Permanent Implant with Cs-131 Using LQ Equation including Resensitization

PURPOSE

To develop a new biological equivalent dose (BED) formulism that includes repair, repopulation and resensitization (redistribution and reoxygenation), and can be used to calculate prescribed dose for permanent implant with Cs-131.

METHODS

Because of lack of sufficient clinical data, the prescribed dose with new isotopes is usually calculated based on BED compared with other isotopes that have already been used in clinical practice. The current widely used formulism of BED calculation for permanent implant which was given by Dale includes cell repair and repopulation but not resensitization. Resensitization can be included in the extended LQ equation (LQR) proposed by Brenner. Applying Dales formulism to Brenners LQR, we obtained a new BED calculation formula that accounts for resensitization. We used this new formulism to calculate the BED that corresponds to the prescribed dose for cervix (with Au-198) and prostate (with I-125) permanent implant. Then, we obtained the prescribed dose with Cs-131 which has the same BED as Au-198 or I-125.

RESULTS

The new formulism was used for prostate and cervix cancer permanent implant. The prescribed dose with Cs-131 for cervix was 40 Gy (42 Gy without resensitization) and 66 Gy (69 Gy without resensitization) which were equivalent to 35 Gy and 60 Gy with Au-198, respectively. For prostate implant, the prescribed dose with Cs-131 that corresponded to 144 Gy with I-125 was 135 Gy (124 Gy without resensitization).

CONCLUSION

Resensitization led to significant dose correction for permanent implant. The calculation of BED and dose was dependent on dose itself and thus should be patient-specific. Since this calculation relied on many biological parameters, and may not be accurate if the parameters are not accurate. Also, the dose prescription should be adjusted based on clinical outcomes.

Prevention of seizure-induced sudden death in a chronic SUDEP model by semichronic administration of a selective serotonin reuptake inhibitor

DBA/1 mice are a chronically susceptible model of sudden unexpected death in epilepsy (SUDEP) that exhibit chronic audiogenic generalized convulsive seizures (GCSs), leading to death from respiratory arrest (RA) if not resuscitated. Serotonin (5-HT) normally enhances respiration in response to elevated CO(2) levels, which occur during GCSs in humans. Selective serotonin reuptake inhibitors (SSRIs), such as fluoxetine, increase 5-HT availability. We examined whether fluoxetine can block GCS-induced sudden death in DBA/1 mice. Fluoxetine (15-70 mg/kg ip) was administered acutely with seizure induction at 30minutes or semichronically in five daily doses (20mg/kg/day) with induction after 5 days. Acute fluoxetine (45 or 70 mg/kg) significantly reduced the incidence of RA without blocking seizure susceptibility. Semichronic fluoxetine did not block seizures, but significantly reduced seizure-induced RA, which is consistent with effects of SSRIs on respiration in patients with epilepsy [Bateman LM, Li DS,LiN TC, Seyal M. Epilepsia 2010;51:2211-4]. These findings suggest that treatment with SSRIs should be evaluated for reducing the incidence of SUDEP in patients.

Differences in serotonin receptor expression in the brainstem may explain the differential ability of a serotonin agonist to block seizure-induced sudden death in DBA/2 vs. DBA/1 mice

DBA mice are models of sudden unexpected death in epilepsy (SUDEP) that exhibit audiogenic generalized convulsive seizures (GCS), ending in death due to respiratory arrest (RA). Serotonin (5-HT) normally enhances respiration in response to elevated CO(2) levels, which occur during GCS in patients. Fluoxetine, a selective serotonin reuptake inhibitor (SSRI), blocks GCS-induced SUDEP in both DBA/2 and DBA/1 mice. This study examined the effects of a 5-HT(2B/2C) agonist (m-chlorophenylpiperazine, mCPP) to test the generality of serotonergic effects on DBA mice. In DBA/2 mice mCPP pre-treatment [5 or 10 (but not 2) mg/kg, i.p.] significantly reduced RA incidence without blocking seizure susceptibility. However, in DBA/1 mice mCPP in doses up to 40mg/kg was ineffective in blocking seizure-induced RA, and 60mg/kg was toxic. The cause of this strain difference was perplexing. Previous studies showed that brainstem 5-HT receptor protein expression was abnormal in DBA/2 mice. Therefore, expression of 5-HT receptor proteins in the medial-caudal brainstem of DBA/1 mice was evaluated using Western blots. In DBA1/mice 5-HT(2C) and 5-HT(3B) receptor expression levels were significantly reduced, as seen previously in DBA/2 mice. However, 5-HT(2B) receptor expression was also reduced in DBA/1 mice, contrasting with the 5-HT(2B) receptor elevation seen in DBA/2 mice. This difference may explain the differential effects of the 5-HT(2B/2C) agonist in these SUDEP models. mCPP blocked RA in DBA/2 mice and concomitantly reduced tonic seizures, which also occurs. Fluoxetine is the only agent tested that blocks RA selectively in these SUDEP models, which may be clinically relevant.