(This is an excerpt of the Health Rounds newsletter, where we present latest medical studies on Tuesdays and Thursdays)
By Nancy Lapid
July 10 (Reuters) – We also report on a troubling men’s health trend, and on a discovery that could upend human biology assumptions based on rodent research.
LUNG TRANSPLANTS MAY SAVE SOME TERMINAL CANCER PATIENTS
The long-held guidance that patients with stage IV lung cancer should not be eligible for lung transplants is being challenged by findings from a new study, at least for a subset of patients.
Tracking adults with terminal lung cancer confined to the lungs who were out of treatment options, doctors found lung transplantation was associated with substantially better early survival than medical management alone.
Seventeen such patients underwent lung transplant and 81 received medical management alone, in a study reported in JAMA.
A year later, every transplanted patient was still alive, compared with fewer than half of the similar cancer patients treated with medical therapies.
While stage IV lung cancer has usually spread beyond the lungs, patients in this study belonged to a subset whose cancer remains confined to both lungs even as it progresses to respiratory failure, the researchers noted.
Their immediate cause of death is often not widespread systemic cancer, but progressive failure of cancer-filled lungs.
“This work changes what we can imagine for a highly selected group of patients who were previously considered beyond the reach of curative-intent intervention,” study leader Dr. Ankit Bharat of Northwestern Medicine in Chicago said in a statement.
The 100% one-year survival rate among the cancer patients was also higher than the 88% rate among patients who received lung transplants for traditional reasons, suggesting that giving lungs to certain advanced cancer patients is not a waste of donated organs that are in short supply.
“When the cancer is rigorously proven to be confined to the lungs, when standard therapies have been exhausted, and when the lungs themselves have become the life-limiting organ, transplantation may offer a new path forward,” Bharat said.
CANCER IS FOUND LATER MORE OFTEN IN MEN
Cancer is found at late stages more often in men than in women, according to a U.S. study that may provide insight into gender discrepancies in cancer outcomes since the more advanced the disease at diagnosis, the worse the prognosis tends to be.
Reviewing more than 2.4 million cases diagnosed from 2015 to 2022, researchers identified 16 cancers in which men were significantly more likely than women to be diagnosed after the disease had spread to local lymph nodes.
Such regional-stage diagnoses were 151% more likely in men than in women with tongue cancer, 93% more likely with salivary gland cancer, 80% more likely with oropharyngeal cancer, 74% more likely with thyroid cancer, and 67% more likely with stomach cancer, researchers noted in a report in Cancer Epidemiology, Biomarkers & Prevention.
Late-stage cancers that have spread to other organs were also more common than localized tumors in men versus women for 17 cancer sites, with the largest differences seen in melanoma and cancers of the tongue, thyroid, salivary gland, and stomach.
For a small number of cancer sites – including the larynx and the bladder – men were less likely than women to be diagnosed at later stages.
These patterns persisted across different races, ethnicities and neighborhood income levels.
One explanation could be differences in cancer screening rates, study leader Beth Maclin of the U.S. National Cancer Institute said in a statement.
And women see doctors more often than men, which could mean more opportunities for clinicians to catch cancer symptoms earlier, she noted. Clinicians may also perceive cancer symptoms differently in males and females, leading to different types of diagnostic tests, she added.
BLOOD CELL PRODUCTION IN HUMANS DIFFERS FROM MICE, SURPRISING SCIENTISTS
Manufacturing of red blood cells by the human body works differently than previously thought, scientists have discovered.
The findings overturn decades of assumptions based largely on animal research, according to study leader Dr. Peng Ji of the Feinberg School of Medicine of Northwestern University in Chicago.
Ji’s team used advanced microscopic techniques to directly observe so-called erythroblastic islands, which have long been understood to act as “nurseries” where red blood cells mature.
“For decades, our understanding of these structures has come almost entirely from mouse studies,” Ji said in a statement. “Most experiments relied on isolating cells and studying them in flat, two-dimensional systems, which disrupt their native organization.”
For this study, the researchers were able to preserve the natural structure of erythroblastic islands while comparing mouse and human samples directly.
The findings in mice were unsurprising: the erythroblastic islands formed around a specialized macrophage, or white blood cell, marked by the protein C1q, which sits at the center of clusters of developing red blood cells and helps clean up cellular debris.
In humans, there was no organizing center.
“In humans, the erythroid cells cluster on their own without needing a central macrophage,” Ji said. “That overturns a long-standing assumption that human blood formation mirrors what we see in mice.”
In a report of the findings published in the journal Cell, the researchers say the discovery represents a fundamental shift in understanding how the body produces its most abundant cell type.
“This is essentially a paradigm shift,” Ji said. “Much of biomedical research depends on mouse models. If the underlying biology is different, that affects how we interpret disease mechanisms and develop therapies.”
The findings also raise new questions about how the human body compensates for the absence of a central macrophage. In mice, macrophages play a critical role in clearing the nuclei expelled during red blood cell maturation.
Future research will focus on that and other questions, Ji said.
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(Reporting by Nancy Lapid; Editing by Bill Berkrot)
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