The study, conducted by researchers at NYU Langone Health and NYC Health + Hospitals, showed that surgery patients lost an average of 58 pounds over two years. In contrast, patients who were prescribed a GLP-1 drug for at least six months lost about 12 pounds. That translates to 24% total weight loss for surgery patients compared with 4.7% for those using medication. Even among patients who stayed on GLP-1 therapy continuously for a full year, average weight loss reached only 7%, still far below the results seen with surgery.

Real-World Results Fall Short of Clinical Trials

“Clinical trials show weight loss between 15% to 21% for GLP-1s, but this study suggests that weight loss in the real world is considerably lower even for patients who have active prescriptions for an entire year. We know as many as 70% of patients may discontinue treatment within one year,” said lead author Avery Brown, MD, a surgical resident at NYU Langone Health. “GLP-1 patients may need to adjust their expectations, adhere more closely to treatment or opt for metabolic and bariatric surgery to achieve desired results.”

The findings highlight a key gap between controlled clinical trials and everyday use, where side effects, costs, and long-term adherence can limit the effectiveness of medication-based weight loss.

How the Study Compared Surgery and GLP-1 Medications

Researchers analyzed electronic medical record data from patients treated between 2018 and 2024 within the NYU Langone Health and NYC Health + Hospitals systems. All participants had a body mass index (BMI) of at least 35 and either underwent bariatric surgery (sleeve gastrectomy or Roux en-Y gastric bypass) or received a prescription for injectable semaglutide or tirzepatide.

After adjusting for factors such as age, BMI, and co-morbidities using average treatment effect weighting, the team compared outcomes for 51,085 patients across both groups. The study was supported by NYU CTSA grant KL2 TR001446 from the National Center for Advancing Translational Sciences at the National Institutes of Health (NIH).

Future Research and Treatment Decisions

“In future studies we will aim to identify what healthcare providers can do to optimize GLP-1 outcomes, identify which patients are better treated with bariatric surgery versus GLP-1s, and determine the role out-of-pocket costs play in treatment success,” said senior author Karan R. Chhabra, MD, MSc, a bariatric surgeon and Assistant Professor of Surgery and Population Health at NYU Grossman School of Medicine.

GLP-1 drugs have gained widespread attention, with about 12% of Americans reporting they have taken one at some point and 6% saying they currently use them. However, persistence remains a major challenge. Recent research shows that 53.6% of patients with overweight or obesity stop GLP-1 therapy within one year (53.6%), and that figure rises to 72.2% by two years.

At the same time, bariatric surgery remains underused. According to the ASMBS, more than 270,000 metabolic and bariatric procedures were performed in 2023, representing only about 1% of people who meet BMI eligibility criteria.

“While both patient groups lose weight, metabolic and bariatric surgery is much more effective and durable,” said ASMBS President Ann M. Rogers, MD, FACS, FASMBS, who was not involved in the study. “Those who get insufficient weight loss with GLP-1s or have challenges complying with treatment due to side effects or costs, should consider bariatric surgery as an option or even in combination.”

Obesity Remains a Major Health Challenge

According to the U.S. Centers for Disease Control and Prevention (CDC), obesity affects 40.3% of adults in the United States, while severe obesity impacts 9.4%. Research shows obesity can impair immune function, drive chronic inflammation, and raise the risk of many serious conditions, including cardiovascular disease, stroke, type 2 diabetes, and certain cancers.

*Semaglutide is the active ingredient in Ozempic and Wegovy and tirzepatide is the active ingredient in Zepbound and Mounjaro.

• New cancer cases worldwide have more than doubled since 1990, reaching 18.5 million in 2023. Over the same period, annual cancer deaths rose by 74 percent to 10.4 million (both excluding non-melanoma skin cancers), with most cases now occurring in low- and middle-income countries.
• More than 40 percent of cancer deaths globally are linked to 44 modifiable risk factors, including tobacco use, unhealthy diets, and high blood sugar. This means a large share of cancer deaths could be prevented through proven public health measures.
• Looking ahead, researchers predict global cancer cases will increase by 61 percent over the next 25 years, reaching 30.5 million new diagnoses a year by 2050. Annual cancer deaths are forecast to rise by nearly 75 percent to 18.6 million, largely driven by population growth and aging populations.
• While age-adjusted cancer death rates have declined worldwide, this progress has not reached everyone. In several low- and middle-income countries, both cancer rates and total deaths continue to rise.
• The researchers stress that responding to this growing cancer burden will require stronger action from governments and policymakers, including expanded prevention efforts, earlier diagnosis, and better access to effective treatment at national, regional, and global levels.

A Rapid Global Rise in Cancer

The global burden of cancer has grown dramatically over the past three decades. Since 1990, the number of newly diagnosed cancer cases worldwide has more than doubled, reaching 18.5 million in 2023. Over the same period, annual cancer deaths rose by 74 percent to 10.4 million (both excluding non-melanoma skin cancers). Most of those affected now live in low- and middle-income countries.

A significant share of this burden is linked to preventable causes. More than 40 percent of cancer deaths worldwide are associated with 44 modifiable risk factors, including tobacco use, poor diet, and high blood sugar. This connection highlights major opportunities to reduce cancer deaths through prevention.

Looking ahead, researchers project that new cancer cases will climb another 61 percent over the next 25 years, reaching 30.5 million annually by 2050. Cancer deaths are forecast to rise by nearly 75 percent over the same period, reaching 18.6 million per year. These increases are largely driven by population growth and the continued aging of populations worldwide.

While age-adjusted global cancer death rates have declined overall, this progress has not been evenly shared. In several low- and middle-income countries, both the number of cancer deaths and the rates themselves are still increasing. The authors stress that meeting this growing challenge will require stronger efforts from governments and policymakers to prevent cancer, expand early diagnosis, and improve treatment access at national, regional, and global levels.

Projections Warn of a Growing Crisis

Between 1990 and 2023, global cancer cases and deaths rose sharply despite advances in treatment and expanded efforts to address cancer risk factors. Without urgent action and increased funding, researchers estimate that by 2050, 30.5 million people will receive a new cancer diagnosis each year and 18.6 million will die from the disease. More than half of new cases and nearly two-thirds of deaths are expected to occur in low- and middle-income countries (LMICs), according to a major analysis by the Global Burden of Disease Study Cancer Collaborators published in The Lancet.

Although the total number of cancer cases and deaths is projected to increase significantly between 2024 and 2050, age-adjusted incidence and mortality rates are not expected to rise globally. This suggests that most of the growth in cancer burden will be driven by demographic changes rather than worsening individual risk.

Even so, the projected improvements fall well short of the United Nations Sustainable Development Goal (SDG) to cut premature deaths from non-communicable diseases, including cancer, by one-third by 2030.

Experts Call for Greater Global Action

“Cancer remains an important contributor to disease burden globally and our study highlights how it is anticipated to grow substantially over the coming decades, with disproportionate growth in countries with limited resources,” said lead author Dr. Lisa Force from the Institute for Health Metrics and Evaluation (IHME), University of Washington, USA. “Despite the clear need for action, cancer control policies and implementation remain underprioritized in global health, and there is insufficient funding to address this challenge in many settings.”

She added, “Ensuring equitable cancer outcomes globally will require greater efforts to reduce disparities in health service delivery such as access to accurate and timely diagnosis, and quality treatment and supportive care.”

The analysis draws on data from population-based cancer registries, vital registration systems, and interviews with family members or caregivers of people who died from cancer. It provides updated global, regional, and national estimates covering 1990 to 2023 across 204 countries and territories, examining 47 cancer types or groupings and 44 attributable risk factors.^[1] The study also projects the global cancer burden through 2050 and evaluates progress toward the UN SDG target for reducing non-communicable disease deaths between 2015 and 2030.

Uneven Cancer Burden Across Countries

In 2023, global cancer deaths reached 10.4 million, while new cases climbed to 18.5 million (both excluding non-melanoma skin cancers). Compared with 1990, this represents increases of 74 percent in deaths and 105 percent in new cases.

Despite an overall 24 percent decline in age-standardized cancer death rates worldwide between 1990 and 2023, this improvement has largely occurred in high- and upper-middle-income countries. In contrast, age-standardized cancer incidence increased by 24 percent in low-income countries and by 29 percent in lower-middle-income countries, highlighting growing disparities in regions with fewer resources (see table 1 in paper).

From 1990 to 2023, Lebanon recorded the largest percentage increase in age-standardized cancer incidence and mortality rates for both sexes combined. Over the same period, the United Arab Emirates experienced the greatest decline in age-standardized incidence, while Kazakhstan saw the largest decrease in age-standardized death rates.

Breast cancer was the most commonly diagnosed cancer worldwide in 2023 for both sexes combined. Tracheal, bronchus, and lung (TBL) cancer remained the leading cause of cancer deaths globally (see table 2 in paper).

Preventable Risks Drive Millions of Deaths

The study estimates that 42 percent (4.3 million) of the 10.4 million cancer deaths in 2023 were linked to 44 modifiable risk factors, pointing to significant opportunities for prevention.

Behavioral risk factors accounted for the largest share of cancer deaths across all income levels in 2023. Tobacco use alone contributed to 21 percent of cancer deaths worldwide. Tobacco was the leading risk factor in every income group except low-income countries, where unsafe sex was the primary risk factor, linked to 12.5 percent of cancer deaths.

Men were more likely than women to die from cancers associated with modifiable risks. In 2023, 46 percent of cancer deaths in men were linked to factors such as tobacco use, unhealthy diet, high alcohol consumption, occupational risks, and air pollution. Among women, 36 percent of cancer deaths were associated with modifiable risks, with tobacco, unsafe sex, unhealthy diet, obesity, and high blood sugar playing the largest roles (see appendix 2 table 6).

“With four in 10 cancer deaths linked to established risk factors, including tobacco, poor diet, and high blood sugar, there are tremendous opportunities for countries to target these risk factors, potentially preventing cases of cancer and saving lives, alongside improving accurate and early diagnosis and treatment to support individuals who develop cancer,” said co-author Dr. Theo Vos from IHME. “Reducing the burden of cancer across countries and worldwide demands both individual action and effective population-level approaches to reduce exposure to known risks.”

Equity and Prevention as Global Priorities

The researchers emphasize that cancer prevention must be integrated into health policies in LMICs and that equitable cancer control efforts are essential to ensure timely and effective care for all patients.

“The rise of cancer in LMICs is an impending disaster,” said co-author Dr. Meghnath Dhimal from the Nepal Health Research Council. “There are cost-effective interventions for cancer in countries at all stages of development. These cancer burden estimates can help broaden the discussion around the importance of cancer and other non-communicable diseases in the global health agenda. To control the growth of non-communicable diseases including cancer in LMICs, an interdisciplinary approach for evidence generation and multi-sectoral collaboration and coordination for implementation are urgently needed.”

Dr. Force noted that the findings can help guide future policy. “These new estimates and forecasts can support governments and the global health community in developing data informed policies and actions to improve cancer control and outcomes around the world. They can also support tracking of progress towards global and regional cancer targets.”

She added, “Our analysis also highlights the need for more data from sources such as cancer and vital registries, particularly in lower resource settings. Supporting cancer surveillance systems is crucial to informing both a local and global understanding of cancer burden.”

Study Limitations and Data Gaps

The authors acknowledge several limitations. The estimates rely on the best available data but are constrained by gaps in high-quality cancer data, especially in resource-limited countries. Current Global Burden of Disease estimates do not account for several infectious diseases known to increase cancer risk in some lower-income regions, including Helicobacter Pylori and Schistosoma haematobium, which may lead to underestimation of cancer deaths linked to modifiable risks.

The projections also do not incorporate the effects of the COVID-19 pandemic, recent conflicts, or future medical breakthroughs that could significantly alter cancer trends.

In a linked Comment, Dr. Qingwei Luo and Dr. David P Smith from The University of Sydney and Cancer Council NSW, who were not involved in the study, wrote: “To ensure meaningful progress in reducing the global cancer burden, it is imperative that governments prioritize funding, strengthen health systems, reduce inequalities, and invest in robust cancer control initiatives and research on prevention, intervention, and implementation — because the future of cancer control depends on decisive, collective action today.”

Notes

1. Modifiable Risk Factors
   • Level 1: Behavioral, Environmental / Occupational, Metabolic
   • Level 2: Air pollution, Dietary risks, Drug use, High alcohol use, High body-mass index, High fasting plasma glucose, Low physical activity, Occupational risks, Other environmental risks, Tobacco, unsafe sex.
   • Level 3: Chewing tobacco, Diet high in processed meat, Diet high in red meat, Diet high in sodium, Diet low in calcium, Diet low in fibre, Diet low in fruits, Diet low in milk, Diet low in vegetables, Diet low in whole grains, Occupational carcinogens, Particulate matter pollution, Residential radon, Second-hand smoke, Smoking
   • Level 4: Ambient particulate matter pollution, Household air pollution from solid fuels, Occupational exposure to arsenic, Occupational exposure to asbestos, Occupational exposure to benzene, Occupational exposure to beryllium, Occupational exposure to cadmium, Occupational exposure to chromium, Occupational exposure to diesel engine exhaust, Occupational exposure to formaldehyde, Occupational exposure to nickel, Occupational exposure to polycyclic aromatic hydrocarbons, Occupational exposure to silica, Occupational exposure to sulfuric acid, Occupational exposure to trichloroethylene

The study was funded by the Gates Foundation, St Jude Children’s Research Hospital, and St Baldrick’s Foundation. It was conducted by the GBD 2023 Cancer Collaborators.

“Our new estimates increase the organic compound emissions from wildland fires by about 21%,” says Lyuyin Huang, the first author of the study. “The inventory provides a foundation for more detailed air-quality modeling, health-risk assessment, and climate-related policy analysis.”

Each year, wildfires burn through vast areas of vegetation, sending a complex mixture of water vapor, ash, and carbon-based chemicals into the atmosphere. Some of these chemicals are volatile organic compounds (VOCs), which readily exist as gases. Others only evaporate and become gases at warmer temperatures and are classified as intermediate- and semi-volatile organic compounds (IVOCs and SVOCs, respectively). Once in the air, these partially volatile compounds more easily form fine particles that can be harmful if breathed in, compared with VOCs.

Overlooked chemicals in wildfire smoke

Despite their importance, IVOCs and SVOCs are often missing from wildfire emission studies. Their large numbers and chemical complexity make them difficult to measure, leading many past assessments to focus mainly on VOCs. Researchers led by Shuxiao Wang aimed to include IVOCs and SVOCs alongside VOCs to better capture how wildland fires affect air quality, human health, and climate.

To do this, the team first examined a global database tracking burned land from forest, grass, and peatland wildland fires between 1997 and 2023. They then gathered information on the VOCs, IVOCs, SVOCs, and other extremely low volatility organic compounds released as different types of vegetation burn. When direct field measurements were not available, the researchers relied on laboratory experiments to estimate the chemicals produced. These data were combined to calculate yearly wildfire emissions worldwide.

Global totals and pollution hotspots

Using this approach, the researchers estimated that wildland fires released an average of 143 million tons of airborne organic compounds each year during the study period. This figure is about 21% higher than previous estimates, indicating that wildfire emissions, particularly IVOCs and SVOCs, contribute more to air pollution than scientists had recognized.

When wildfire emissions were compared with earlier estimates of pollution from human activities, the researchers found that human sources produced more airborne compounds overall. However, both sources released similar amounts of IVOCs and SVOCs. The comparison also revealed shared emission hotspots, including Equatorial Asia, Northern Hemisphere Africa, and Southeast Asia. According to the researchers, air pollution in these regions is especially complex and will require different strategies to reduce emissions from both wildfires and human activities.

The authors acknowledge funding from the National Natural Science Foundation of China, National Key R&D Program of China, the Samsung Advanced Institute of Technology, and the Center of High Performance Computing at Tsinghua University.