Adaptation Strategies In Response Research Articles

Distinct molecular responses of mangrove plants to hypoxia and reoxygenation stresses contribute to their resilience in coastal wetland environment

Mangroves adapt to periodical submergence and constitute resilient ecosystems in coastal environments. The question is whether they can sustain long submergence stress when sea level rises as a consequence of climate change. To address this, seedlings of two representative mangrove species that acclimate to low to mid tide (Avicennia marina) and mid to high tide (Kandelia obovata) conditions were treated with continual submergence for 7 days as extended hypoxia, or semi-diurnal cyclic submergence and reoxygenation for 7 days. At specific time points, leaves were collected to construct RNA-Sequencing libraries for gene expression analysis. Through the lens of transcriptome, the initial response of A. marina to submergence was mild but more dramatic after prolong immersion. However, the initial response of K. obovata was drastic and reduced in latitude later, suggesting distinct species-specific responses. After adapting to diurnal cycles, both species minimized transcriptome fluctuations similarly. Metabolically, during initial response, sucrose and starch were converted into glucose for fermentation to increase glycolytic flux, coupled with regeneration of NAD+. The energy amelioration was accompanied by longer term phytohormone regulations where ethylene signal transduction pathway was enhanced, but abscisic acid biosynthesis was reduced. Notably, gibberellic acids biosynthesis increased in A. marina but decreased in K. obovata as a unique feature. Genomic level analysis indicated that only about 30 % of the conserved plant submergence responsive genes were expressed during submergence in these mangroves. The function of an ethylene responsive gene was validated in transgenic Arabidopsis. This research elucidates distinct molecular mechanisms and metabolic pathways that empower A. marina and K. obovata to endure prolonged submergence and hypoxia. By highlighting their unique adaptive strategies in response to rising sea levels, these findings enhance our understanding of mangrove resilience and provide insights for the conservation and management of these essential coastal ecosystems in the face of climate change.

Changes in the Yield Effect of the Preceding Crop in the US Corn Belt Under a Warming Climate.

Crop rotation has been widely used to enhance crop yields and mitigate adverse climate impacts. The existing research predominantly focuses on the impacts of crop rotation under growing season (GS) climates, neglecting the influences of non-GS (NGS) climates on agroecosystems. This oversight limits our understanding of the comprehensive climatic impacts on crop rotation and, consequently, our ability to devise effective adaptation strategies in response to climate warming. In this study, we examine the impacts of both GS and NGS climate conditions on the yield effect of the preceding crop in corn-soybean rotation systems from 1999 to 2018 in the US Midwest. Using causal forest analysis, we estimate that crop rotation increases corn and soybean yields by 0.96 and 0.22 t/ha on average, respectively. We then employ statistical models to indicate that increasing temperatures and rainfall in the NGS reduce corn rotation benefits, while warming GS enhances rotation benefits for soybeans. By 2051-2070, we project that warming climates will reduce corn rotation benefits by 6.74% under Shared Socioeconomic Pathway (SSP) 1-2.6 and 17.18% under SSP 5-8.5. For soybeans, warming climates are expected to increase rotation benefits by 8.36% under SSP 1-2.6 and 13.83% under SSP 5-8.5. Despite these diverse climate impacts on both crops, increasing crop rotation could still improve county-average yields, as neither corn nor soybean was fully rotated. If we project that all continuous corn and continuous soybeans are rotated by 2051-2070, county-average corn yields will increase by 0.265 t/ha under SSP 1-2.6 and 0.164 t/ha under SSP 5-8.5, while county-average soybean yields will gain 0.064 t/ha under SSP 1-2.6 and 0.076 t/ha under SSP 5-8.5. These findings highlight the effectiveness of crop rotation in the face of warming NGS and GS in the future and can help evaluate opportunities for adaptation.

An improved framework for mapping and assessment of dynamics in cropping pattern and crop calendar from NDVI time series across a heterogeneous agro-climatic region.

The absence of spatial and temporal cropping information in semi-arid regions poses a significant challenge in assessing the dynamics of agricultural systems at river basin scales. Satellite remote sensing provides qualitative and quantitative information to derive vegetation dynamics over extensive areas of inherent complexities due to limitations in the availability of field data and the diverse nature of agricultural cropping practices. Utilizing phenological information derived from MODIS Normalized Difference Vegetation Index (NDVI) time series data from 2003-2004 to 2021-2022, this study derives major crop types, and cropping calendar (sowing, maturity, and harvest dates) for each season and year at 250-m resolution. This study introduces an integrated function-fitting model based on the Fast Fourier Transform (FFT) and a Lagrangian 3-point derivative-based approach to extract phenological events from the NDVI time series automatically. The derived phenological information is used in a hybrid crop classification algorithm that combines a rule-based decision tree approach (using the phenological events/dates) and a random forest classifier (using the phenological metrics) to generate the classified crop map at a river basin scale for multiple seasons and years. The implemented approach successfully captured sowing and harvesting dates for every crop growing season over 19years, with an RMSE of 9days, as observed with the available field survey data from 2015 to 2021. The classification results from this hybrid approach demonstrate an overall 82% accuracy. The proposed method shows a substantial improvement in cropping area estimation with a 60% reduction in MAE and RMSE compared to the existing algorithm. From the long time series of derived seasonal crop data (19-year analysis period), the influence of monsoonal activities and shifts on the spatial and temporal dynamics of sowing time and cropping patterns are assessed for a large river basin, demonstrating the utility of this continuous crop calendar. Further, an extensive analysis of results highlights farmers' adaptive strategies in response to dry and wet years, providing foundational insights for future studies on assessing the impacts of climate change. Hence, the hybrid framework adopted in this study for deriving a continuous crop calendar holds immense relevance for parameterizing and utilizing such information for developing river basin scale hydrologic and crop growth models for water resources planning and assessment.

Assessing Hydrological Response and Resilience of Watersheds as Strategy for Climatic Change Adaptation in Neotropical Region

This study aimed to assess the hydrological response and resilience of watersheds in a neotropical region to identify regions sensitive to climate variations, enabling the development of adaptive strategies in response to global environmental changes. This study applied Budyko’s framework using Fuh’s hydrological model rewritten by Zhou to estimate hydrological response and Budyko’s metrics (deviation and elasticity) to estimate hydrological resilience to climatic changes in 26 watersheds in southeastern Brazil. The proposed modeling was able to capture the differences among the watersheds, with “m” values ranging from 1.79 to 3.63. It was possible to rank the hydrological resilience from low to high across watersheds using Budyko’s metrics, where the highest values of elasticity were found in watersheds with a higher percentage of forest cover. The sensitive analyses showed that watersheds with higher “m” values are more sensitive to changes in precipitation and potential evapotranspiration. The results also demonstrate that mean elevation and stream density were two key variables that influence the “m” value; these physiographic characteristics may alter the water and energy balance of the watershed affecting the water yield. A relationship between watershed’s hydrological response and resilience was proposed to identify critical areas for the stability of water yield in the watersheds, providing a guide for public policy and suggesting ways to help the management of water resources in watersheds.

Using historical catch flexibility and fishing ground mobility as measures of the adaptive capacity of fishing communities to future ocean change

Abstract Changing ocean characteristics, moving species, and competing ocean uses challenge fishing communities reliant on marine resources. Many communities have diversified what they catch, or where they fish to cope with variation in availability of fish. However, we often lack understanding of the frequency of these adaptation strategies in response to historical variability. Here, we quantitatively evaluate catch flexibility, catch switching, and fishing ground mobility of Communities at Sea (CaS) in the Northeast USA. CaS capacity to change catch composition or shift fishing grounds differed by gear type and with regional drivers. Dredge was highly mobile but species selective, and groundfish trawl either altered their catch or shifted fishing grounds. Lobster and shrimp trawl CaS were largely unable to take advantage of either strategy, while fleets using other pots and traps did both. Differences within gear types often reflected distinct regional strategies in dealing with the loss of target species from historical fishing grounds. Overall, adaptive capacity for a port reflects its portfolio of fleets as well as shared constraints and opportunities of their home port. Understanding the degree to which fishing communities have adapted to historical variability can help prioritize efforts to enhance adaptive capacity for future ocean change.

Physical climate change exposure and firms' adaptation strategy

AbstractResearch SummaryThis article examines whether and how firms adapt to physical exposures to climate change. I build a novel dataset that compiles information on the adaptation strategies of publicly traded companies around the globe and merge it with climate science data. I find that firms are sensitive to the nature and level of forecasted climate change exposures, and that they adapt more often and more completely to those most salient to their business. Increased physical climate exposure heightens the perceived impact of climate change, leading to a higher degree of adaptation. Furthermore, the positive relationship between firms' climate change exposure and their adaptation is stronger for firms with greater environmental, social, and corporate governance capabilities and those with longer time horizons.Managerial SummaryCompanies are increasingly exposed to the physical impacts of climate change, yet little is known about how they adapt to these long‐term, systemic, and uncertain changes. This study investigates corporate adaptation strategies in response to climate change. By analyzing climate science data and climate change disclosure information from publicly traded companies worldwide, I find that most firms do not adapt to different physical climate change exposures. They adapt more often and more completely when facing higher forecasted climate exposures. Furthermore, firms' environmental, social, and corporate governance capabilities and their time horizons influence their adaptation to greater climate exposures. These findings suggest that targeted interventions may be necessary to improve corporate adaptation to climate change.

Farm adaptive business strategies in crisis management: COVID-19

The global COVID-19 pandemic significantly impacted businesses worldwide, with rural businesses being no exception. This study examines the effects of the global crisis on upland farmers in England. It builds on the under-researched area of constrained rural entrepreneurship. Institutional theory is applied as a theoretical lens to understand how crisis events shape the constrained institutional contexts in which farm businesses strategically navigate. Using a qualitative, multiple case study approach, we explore how different farmers, traditionalist and entrepreneurial, have strategically responded to the aftermath of crisis-influenced constraints. Our findings highlight the importance of business strategy—particularly farm diversification—in helping farmers navigate these challenges. We provide a conceptual framework, the Farm Crisis Adaptation Framework, (FCAF) that theorizes farmer adaptation strategies in response to crisis situations. Our findings indicate a greater needed for rural policymakers to help develop the strategic entrepreneurship skillsets of farmers—helping farmers to future-proof their businesses against uncertainties. Moreover, investment is needed in the local and regional economy, establishing a conducive environment supportive of farm development strategies.

Analisa Strategis Kesiapan Operasional TNI Angkatan Laut dalam Menghadapi Dinamika Lingkungan Maritim

Indonesia, as the largest archipelagic nation globally, faces significant strategic challenges in its maritime domain. The Indonesian Navy's preparedness is paramount in safeguarding the nation's interests amid evolving geopolitical dynamics, resource competition, and maritime security threats such as piracy and terrorism. This paper examines the role and importance of the Operational Ready Force (ORF) within Indonesia's maritime defence strategy. By employing strategic analysis, the study evaluates the Navy's operational readiness, focusing on resource allocation, technological advancements, and international cooperation necessary to enhance the ORF's effectiveness. The research utilizes a comprehensive methodology, including literature review, official documents, and expert interviews, to provide an in-depth understanding of the Indonesian Navy's readiness to address dynamic maritime environments. The paper also explores the strategic implications of global, regional, and national maritime developments, emphasizing the necessity for an adaptive and resilient maritime strategy. The findings suggest that ORF is crucial in bolstering the Indonesian Navy's capabilities, enabling rapid and effective responses to maritime threats while protecting national sovereignty. The study concludes with recommendations for further development of ORF, ensuring Indonesia's continued maritime security and regional stability through integrated technology, strengthened international collaboration, and adaptive threat response strategies.

3490: Risk-adapted and response-adapted strategies for stage 3 NSCLC

3490: Risk-adapted and response-adapted strategies for stage 3 NSCLC

Assessing the impact of Land Use Land Cover changes on land surface temperature over Kigali, Rwanda in the past three decades

Land use changes and urban activities cause environmental degradation and climate change. This study aims to assess the impacts of Land Use Land Cover (LULC) changes on land surface temperature (LST) in Kigali, Rwanda over the past three decades. The combined techniques of remote sensing and GIS were applied to generate good quality Landsat images, categorize land use classes and retrieve urban indices. The modified Mann-Kendall test and Sen’s slope estimator were used to analyze trends in LST. The results indicate that between 1990 and 2020, the extent of builtup and forest areas have increased at an average rate of 3.39 km2/year and 2.42 km2/year respectively, while open land has decreased at an average rate of 5.81 km2/year. In the same period, water bodies and wetlands showed minimal changes with an increase of 1.56 km2 and a decrease of 1.66 km2 for water bodies and wetlands respectively. The slope magnitudes of LST are predominantly positive (p ≤ 0.05) with a high increase observed in dry seasons (0.51 °C per decade for Tmin in JJA and 0.49 °C per decade for Tmax in JF). The positive correlations between LST and urban indices were observed in all studied subregions (all values are above 0.61, p ≤ 0.05). The findings of this study are useful for the development of future urban land use schemes and the adoption of mitigation and adaptation strategies in response to climate change.

Type 2 diabetes: a sacrifice program handling energy surplus

Abstract Type 2 diabetes mellitus (T2DM) is closely associated with obesity, while interactions between the two diseases remain to be fully elucidated. To this point, we offer this perspective to introduce a set of new insights into the interpretation of T2DM spanning the etiology, pathogenesis, and treatment approaches. These include a definition of T2DM as an energy surplus-induced diabetes characterized by the gradual decline of β cell insulin secretion function, which ultimately aims to prevent the onset of severe obesity through mechanisms of weight loss. The body employs three adaptive strategies in response to energy surplus: the first one is adipose tissue expansion to store the energy for weight gain under normal weight conditions; the second one is insulin resistance to slow down adipose tissue expansion and weight gain under overweight conditions; and the third one is the onset of T2DM following β cell failure to reverse the weight gain in obese conditions. The primary signaling molecules driving the compensatory responses are adenosine derivatives, such as adenosine triphosphate (ATP), acetyl coenzyme A (acetyl-CoA), and reduced nicotinamide adenine dinucleotide (NADH). These molecules exert their effects through allosteric, post-translational, and transcriptional regulation of metabolic pathways. The insights suggest that insulin resistance and T2DM are protective mechanisms in the defense against excessive adiposity to avert severe obesity. The perspective provides a unified framework explaining the interactions between the two diseases and opens new avenues in the study of T2DM.

Insights from local government managers: Navigating crises through organizational capacities and perceptions

AbstractRecent years have shown that strategic responses to crises by local governments (LGs) depend on the type of crisis, the institutional environment, but also internal capacities and sensemaking processes. However, such relationships have not been tested widely yet. Based on a survey of managers (n = 590) from cities with more than 15,000 inhabitants in France, Germany, Italy, and the United Kingdom, this study explores the role played by specific organizational capacities (critical thinking, bricolage, and financial capacities) and crisis perceptions (valence—i.e., threat vs. opportunity; and controllability) in shaping adaptive or regressive response strategies. Results show that these capacities are associated with how LGs' managers perceive crises and the type of responses adopted. Higher financial capacity, bricolage, and critical thinking are associated with stronger sense of organizational controllability, but they have different relationships with threat and opportunity perceptions. The study confirms the importance of distinguishing valence (threat and opportunity) from controllability perceptions.

Nonlinear impacts of climate anomalies on oil palm productivity

Oil palm contributes to various global needs as one of the most productive oil crops, but there exist ongoing concerns regarding its yield reductions and associated environmental impacts resulting from land conversion. This is the first detailed report investigating the nonlinear threats to estate-level oil palm yields posed by El Niño Southern Oscillation (ENSO) in the equatorial Pacific Ocean, a major driver of climate variability. Using the Malaysian Palm Oil Board administrative records on monthly performances reported by oil palm estates through the e-submissions portal spanning from January 2015 to June 2023, we focused on elucidating the impacts of ENSO on fresh fruit bunch yield, oil extraction rate, and oil yield. We found that both El Niño and La Niña conditions, characterized by extreme levels of ENSO indices cumulated over lags of 0–23 months prior to harvest, were associated with statistically significant reductions in yields. Lag association patterns unveiled that production risks were linked to pre-harvest exposure to extreme ENSO indices in various time windows. Subgroup analyses further revealed that the effects were pronounced in labor-intensive estates and those lacking fertilizer investments. This study underscores the necessity for adaptation strategies in response to future climate anomalies.

Water-suitable reclamation can mitigate the amplified agricultural water stress driven by climate change in arid inland basin

The escalation of water scarcity poses a significant challenge to the sustainability of irrigated agriculture in arid regions, with climate change further amplifying the unpredictability of water resources for agricultural purposes. Despite the critical nature of this issue, there is a lack of research identifying effective adaptation strategies and establishing water-suitable thresholds for agricultural development. This study modified a conventional approach for estimating irrigation water use (IWU) in the Heihe agricultural area of Northwest China, integrating the distributed hydrological components of the Soil and Water Assessment Tool (SWAT) model. It modeled IWU and surface water availability across three representative concentration pathways (RCPs) and conducted an extensive analysis of agricultural water scarcity for the period 2021–2050. The study established threshold levels for water-suitable agricultural development based on predicted local water resource conditions. Findings suggested a trend towards warmer and wetter conditions in the Heihe agricultural area over the next three decades. The anticipated average IWU, predicted by five general circulation models (GCMs), was expected to reach 26.785 × 108 m3 (RCP2.6), 26.827 × 108 m3 (RCP4.5), and 26.865 × 108 m3 (RCP8.5). These projections indicated an increase of 0.815 × 108 m3, 0.857 × 108 m3, and 0.895 × 108 m3, respectively, in comparison to the historical period spanning from 1985 to 2014. Streamflow was anticipated to diminish by 0.28 × 108 m3 (RCP2.6), 0.46 × 108 m3 (RCP4.5), and 0.23 × 108 m3 (RCP8.5). The predicted agricultural water scarcity index (WSI) was 1.764 (RCP2.6), 1.789 (RCP4.5), and 1.763 (RCP8.5), indicating a worsening of agricultural water use shortages due to climate change. The study identified controlling the scale of cultivation as the most effective adaptation strategy, recommending that water-suitable agricultural reclamation in the Heihe agricultural area be confined to 25 × 104 ha. This research offers a comprehensive assessment of future water security in an arid inland basin, providing valuable insights into the sustainable development of global irrigated agriculture and adaptation strategies in response to climate change.

Application of Shannon Entropy in Assessing Changes in Precipitation Conditions and Temperature Based on Long-Term Sequences Using the Bootstrap Method

This study delves into the application of Shannon entropy to analyze the long-term variability in climate data, specifically focusing on precipitation and temperature. By employing data from 1901 to 2010 across 377 catchments worldwide, we investigated the dynamics of climate variables using the generalized extreme value (GEV) distribution and Shannon entropy measures. The methodology hinged on the robust bootstrap technique to accommodate the inherent uncertainties in climatic data, enhancing the reliability of our entropy estimates. Our analysis revealed significant trends in entropy values, suggesting variations in the unpredictability and complexity of climate behavior over the past century. These trends were critically assessed using non-parametric tests to discern the underlying patterns and potential shifts in climate extremes. The results underscore the profound implications of entropy trends in understanding climate variability and aiding the prediction of future climatic conditions. This research not only confirms the utility of Shannon entropy in climatological studies but also highlights its potential in enhancing our understanding of complex and chaotic climate systems. The study’s findings are vital for developing adaptive strategies in response to the evolving nature of climate extremes, thus contributing to more informed decision-making in environmental management and policy formulation.

Response-Adapted Ultralow-Dose Radiation Therapy for Orbital Indolent B-Cell Lymphoma

Radiation therapy to doses of 24 to 36 Gy is currently used to treat indolent B-cell lymphoma of the ocular adnexa; however, ocular adverse effects are common. To determine if a response-adapted radiation therapy strategy will result in excellent disease outcomes while reducing orbital morbidity. This single-institution, phase 2 prospective nonrandomized controlled trial of a response-adapted strategy involved 50 evaluable patients with stage I to IV indolent B-cell lymphoma of the ocular adnexa enrolled between July 2015 and January 2021. This treatment approach was also retrospectively evaluated with a separate 55-patient cohort treated between March 2013 and October 2021. All data were analyzed between November 2021 and December 2023. Patients were treated with ultralow-dose radiation therapy to 4 Gy in 2 fractions and assessed for response at 3-month intervals. Patients with persistent orbital lymphoma were offered an additional 20 Gy in 10 fractions to complete the response-adapted treatment. The primary end point was 2-year local orbital control within the irradiated field after response-adapted therapy. Secondary end points included overall survival and complete response rate. The 50 prospective patients were a median (range) of 63 (29-88) years old, and 31 (62%) were female. Among the 50 patients, 32 (64%) had mucosa-associated lymphoid tissue lymphoma, 12 (24%) had follicular lymphoma, and 6 (12%) had unclassifiable low-grade B-cell lymphoma. Thirty-one patients (62%) had stage I disease, and 36 (72%) were newly diagnosed. At a median follow-up of 37.4 (95% CI, 33.7-52.5) months, the 2-year local control rate was 89.4% (95% CI, 81.0%-98.7%), and the 2-year overall survival rate was 98.0% (95% CI, 94.1%-100%); 45 patients (90.0%; 95% CI, 78.2%-96.7%) experienced a complete response to response-adapted radiation, including 44 patients with a complete response to ultralow-dose radiation and 1 patient with a complete response after an additional 20 Gy. No local recurrences were observed among patients with a complete response to response-adapted therapy. No grade 3 or higher toxic effects were observed. In a planned subset analysis of 22 patients with newly diagnosed, untreated stage I mucosa-associated lymphoid tissue lymphoma, the 2-year local control rate was 90.7% (95% CI, 79.2%-100%), and the 2-year freedom from distant relapse rate was 95.2% (95% CI, 86.6%-100%). In this nonrandomized controlled trial, response-adapted ultralow-dose therapy for indolent orbital B-cell lymphoma resulted in reduced radiation exposure, negligible toxic effects, and excellent disease outcomes. ClinicalTrials.gov Identifier: NCT02494700.

Research on Cognition and Adaptation to Climate Risks among Inland Northwest Chinese Residents

Global climate change poses a significant threat to the sustainable development of human society, highlighting the critical importance of developing effective adaptation strategies in response to climate-related disasters. Public awareness and adaptive behaviors towards climate risks serve as crucial indicators of community concerns regarding climate change, laying the foundation for effective adaptation strategy design. For this study, we selected inland northwest Chinese residents, represented by Xi’an City, as the research subjects, to investigate their climate risk cognition and adaptation levels. Based on randomly sampled survey data, descriptive statistical analysis and multiple logistic regression models were used to study the public’s climate change awareness, climate risk sensitivity, and climate risk adaptability, as well as evaluation of climate risk adaptation measures in the public sector, and we also analyzed the impact mechanisms of factors such as gender, age, income, and education level on the related indicators. The study found that with the increasing urban heat island effect, residents of Xi’an are more likely to reach a higher level of belief in climate change regarding long-lasting weather events. However, there is still no collective consensus on the reasons for climate change. Residents are overly optimistic about the future impact of climate disasters, and there is high uncertainty in their ability to adapt to climate change risks. Additionally, specific demands were obtained from different groups of urban residents regarding measures in the public sector for climate risk adaptation.

The role of response adapted therapy in the era of novel agents

The optimal treatment of classic Hodgkin Lymphoma (cHL) requires an individualized approach, with therapy guided by pretreatment clinical risk stratification and interim response assessment with positron emission tomography (PET). The overall goal is to achieve high cure rates while minimizing acute toxicity and late therapy-related effects. Interim PET-adapted strategies (iPET) were initially developed with traditional chemotherapy, reducing intensity after interim complete response and escalating treatment for patients with iPET+ disease. Recently, novel agents including brentuximab vedotin and the checkpoint inhibitor immunotherapies (CPIs) pembrolizumab and nivolumab have been adopted into the front-line treatment of cHL, and PET-adapted approaches may be relevant for these drugs as well. In this review we discuss response-adapted strategies utilizing novel agents, consider challenges including indeterminate radiographic findings with CPIs, and address emerging techniques for response assessment including new PET-based imaging metrics and the role of circulating tumor DNA.

The emerging challenge of FLiRT variants: KP.1.1 and KP.2 in the global pandemic landscape.

The SARS-CoV-2 virus has undergone substantial evolution, leading to emergence of new FLiRT variants characterized by specific spike mutations-F to L at position 456 and R to T at position 346-enhancing their transmissibility and immune evasion capabilities. Particularly, KP.2 shows a significant increase in cases in the USA, indicating a potential shift in the pandemic landscape due to its greater ability to evade vaccine-induced immunity and its higher effective reproduction number compared to JN.1. This evolving scenario underscores the need for continuous monitoring and adaptive response strategies to address the challenges posed by these new variants. This abstract examines the emergence of FLiRT variants KP.2 and KP1.1, descendants of the Omicron JN.1 variant, as they draw global attention amidst the ongoing coronavirus disease-2019 pandemic.

Response-adapted ultra-low-dose 4 Gy radiation as definitive therapy of gastric MALT lymphoma: a single-centre, pilot trial

Given the favourable prognosis of patients with gastric mucosa-associated lymphoid tissue (MALT) lymphoma, treatment-related toxicity should be minimised. We aimed to evaluate the efficacy of 4 Gy radiotherapy given in a response-adapted approach. We conducted a single-centre, single-arm, prospective trial at MD Anderson Cancer Center (Houston, TX, USA) of response-adapted ultra-low-dose radiotherapy. Eligible patients were 18 years or older and had newly diagnosed or relapsed Helicobacter pylori-negative gastric MALT lymphoma, with stage I-IV disease. Given the expected low toxicity profile of treatment, performance status was not an exclusion criterion. Patients received external beam photon-based radiotherapy for a total dose of 4 Gy in two fractions. Patients with a complete response to 4 Gy via endoscopy and imaging at 3-4 months were observed; patients with a partial response were re-evaluated in 6-9 months. Residual disease at 9-13 months or stable or progressive disease at any time required additional treatment with 20 Gy. The primary endpoint was gastric complete response at 1 year (second evaluation timepoint) after 4 Gy treatment. All analyses were performed as intention to treat. This trial is registered at ClinicalTrials.gov (NCT03680586) and is complete and closed to enrolment. Between March 27, 2019, and Oct 12, 2021, we enrolled 24 eligible patients. The median age of participants was 67 years (IQR 58-74; range 40-85); 15 (63%) were female and nine (37%) male; 18 (75%) were White, four (17%) Asian, and two (8%) Hispanic; 20 (83%) had stage I disease, one (4%) stage II, and three (13%) stage IV. Median follow-up time was 36 months (IQR 26-42). 20 patients (83%) had a complete response to 4 Gy (16 at 3-4 months, four at 9-13 months); two patients received 20 Gy for symptomatic stable disease at 3-4 months and two for residual disease at 9-13 months; all had a complete response. The 3-year local control rate was 96% (95% CI 88-100), with one local relapse at 14 months after 4 Gy radiotherapy salvaged successfully with 20 Gy. One patient with stage IV disease had a distant relapse. The most common adverse events were grade 1 nausea (nine [38%] of 24 patients who received 4 Gy and two [50%] of four patients who received 20 Gy) and grade 1 abdominal pain (five [21%] of 24 and zero of four, respectively). No grade 3 or worse adverse events were noted, including no treatment-related deaths. Most patients had a complete response after 4 Gy radiotherapy; all who required an additional 20 Gy had a complete response within 12 months. This response-adapted strategy could be used to select patients who would benefit from additional radiotherapy and spare others potential associated toxicity. National Cancer Institute.