In a quiet corner of the body where breath meets blood, the lungs of people carrying excess fat around the belly appear to lose some of their guardianship against disease. Researchers in Buffalo, reporting in the Journal of Thoracic Oncology, found that abdominal fat, measured directly rather than inferred from body weight, tracks with a higher chance of non-small cell lung cancer among people already made vulnerable by smoking. The finding complicates an older and more comforting picture in which a higher BMI seemed to offer some protection, and it suggests that the fat we store is not merely
Abdominal Fat Linked to Lung Cancer Risk Through Suppressed Immune Defenses
Obesity impairs the lung's immune defenses before tumors take hold
Mark
Why does this study matter if people already knew obesity raises some cancer risks?
Mimi
Because lung cancer was the odd one out. Earlier work suggested a higher BMI meant lower risk, and this study says that picture was misleading.
Mark
What did they do differently?
Mimi
They measured total fat area in the abdomen from CT scans instead of BMI, and they studied 1,170 current or former smokers.
Luke
Worth noting the design is observational. It shows an association in people who later developed cancer, not proof that fat caused it in humans.
Mark
And the immune explanation?
Mimi
Obese lungs had more regulatory T cells, while other cells that should kill tumor cells looked defective. In preclinical models with excess fat, tumors grew faster.
Luke
The source says tregs appeared to play a key role. That's careful language, and the mechanism is still being worked out. The team says so itself.
Mark
Does it change anything for patients now?
Mimi
Not directly. Yendamuri says correcting obesity's effects on airway immune cells may help prevent or intercept early cancers.
Luke
Note the word may. No intervention is described or tested here, and we don't know yet whether it would work.
El Pulso
- A study of 1,170 smokers has forced a reconsideration of an earlier, reassuring link between higher body mass index and lower lung cancer risk.
- Abdominal fat measured on CT scans now stands as the sharper signal, pointing to the belly rather than overall weight as the troublemaker.
- Inside obese airways, regulatory T cells multiply while the cells built to destroy tumors falter, letting cancer gain ground unnoticed.
- Researchers are tracing the mechanisms behind this immune breakdown and testing whether correcting obesity's effects could intercept early-stage tumors in high-risk people.
In a quiet corner of the body where breath meets blood, the lungs of people carrying excess fat around the belly appear to lose some of their guardianship against disease. Researchers in Buffalo, reporting in the Journal of Thoracic Oncology, found that abdominal fat, measured directly rather than inferred from body weight, tracks with a higher chance of non-small cell lung cancer among people already made vulnerable by smoking. The finding complicates an older and more comforting picture in which a higher BMI seemed to offer some protection, and it suggests that the fat we store is not merely a passive reserve but an active participant in how our immune systems tolerate or resist the beginnings of cancer.
Researchers at Roswell Park Comprehensive Cancer Center in Buffalo have found that excess fat around the abdomen raises the risk of non-small cell lung cancer, and that it does so by weakening the immune defenses of the airways. Their findings, published in the Journal of Thoracic Oncology, contradict earlier studies that suggested people with a high body mass index were at lower risk.
The team, led by thoracic surgeon Sai Yendamuri and immunologist Joseph Barbi, focused on people already at elevated risk because of smoking. They studied 1,170 current or former smokers, including 576 patients treated with surgery for early-stage lung cancer and 576 people screened at the center and followed for at least a year. Instead of relying on BMI, they used CT scans measuring total abdominal fat, a more physiologically meaningful gauge. Among the cancer-free screening group, those with more abdominal fat were more likely to later develop lung cancer.
To explain the link, the researchers examined airway immunity in patients and in laboratory models. The lungs of obese subjects held more regulatory T cells, which seemed to let tumors grow unchecked, while other immune cells that would normally kill tumors appeared defective. In models with excess fat, lung tumors developed faster.
Barbi said obesity impairs the lung's defenses before and during early tumor development, and Yendamuri argued the evidence strongly points to obesity as a driver of lung cancer. Their hope is that correcting obesity's effects on airway immune cells might prevent or intercept early cancers. The team is now working to uncover the other ways obesity weakens the lung's defenses.
Researchers at Roswell Park Comprehensive Cancer Center in Buffalo have reported that excess fat around the abdomen raises the risk of non-small cell lung cancer, and that it does so by weakening the immune defenses in the airways. The findings, published in the Journal of Thoracic Oncology, run against earlier studies that suggested people with a high body mass index, or BMI, were at lower risk of the disease.
The work was led by two senior authors: Sai Yendamuri, MD, MBA, FACS, chair of thoracic surgery, and Joseph Barbi, Ph.D., assistant professor of oncology in the Department of Immunology. Yendamuri is also a senior vice president and chief strategy officer at Roswell Park.
The team focused on people already at elevated risk because of smoking. They analyzed data on 1,170 current or former smokers in an observational case-control study. One group was 576 people diagnosed with stage 1 or 2 non-small cell lung cancer who were treated with surgery at Roswell Park between 2009 and 2020. The other was 576 people who had lung cancer screening at the center between 2015 and 2022. Those in the screening group were followed for at least a year to see whether cancer later appeared.
Rather than relying on BMI, the researchers used CT scans that captured total fat area in the abdominal region. The source describes this as a more accurate and physiologically meaningful measure of overweight and obesity than BMI. Among the high-risk but cancer-free screening group, people with relatively high total fat area were more likely than those with lower totals to go on to develop lung cancer.
To understand why, the researchers examined the airway immune environment in human patients and in laboratory studies. The lungs of obese subjects held higher numbers of regulatory T cells, or tregs, which appeared to play a key role in letting cancer grow unchecked. Meanwhile, other immune cells that would ordinarily be able to kill tumor cells appeared to be defective. In preclinical models with excess fat, lung tumors developed faster.
"Now we know that obesity impairs the lung's immune defenses before and during the early stages of tumor development," Barbi said. Yendamuri said the results offer strong evidence that obesity is a risk factor driving lung cancer, and that strategies to correct obesity's effects on airway immune cells may help prevent or intercept early-stage cancers in people at high risk.
Obesity has been shown to increase the risk of at least 13 types of cancer and to worsen outcomes after diagnosis, but its role in lung cancer has been less clear. The question carries weight because the share of the U.S. population with a BMI over 25 has climbed to 66% over the past 40 years, and more than half of that group falls into the obese category, with a BMI of 30 or higher.
The team is now working to identify other ways obesity compromises the lung's cancer-fighting defenses, and the mechanisms underneath them.
Citas Notables
Now we know that obesity impairs the lung's immune defenses before and during the early stages of tumor development.— Joseph Barbi, Ph.D., Roswell Park
Strategies to correct the effects of obesity on airway immune cells may help prevent or intercept early-stage lung cancers in people at high risk.— Sai Yendamuri, MD, Roswell Park (paraphrased)
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