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Bacteria in lungs may play role in cancer development, study says

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Lung cancer patients who harbor certain bacteria in the airways may have a poorer prognosis, a new study finds, adding to evidence that the body’s “microbiome” may play a role in cancer patients’ outlook.

The microbiome refers to the trillions of bacteria and other microbes that naturally dwell in the body. Research in recent years has been revealing how important those bugs are to the body’s normal functions, including immune system defenses.

When it comes to cancer, studies have hinted that the microbiome can influence tumor progression, and patients’ likelihood of responding to certain treatments.

For example, a number of cancers can be treated with immunotherapy — various approaches to boosting the immune system’s natural tumor-fighting capacity. Research has found that patients who respond well to immunotherapies tend to have a different makeup in the gut microbiome, compared to patients who do not respond.

The new study, published this week in Cancer Discovery, took a different view. Instead of focusing on the gut microbiome, researchers analyzed lung microbes of patients with newly diagnosed lung cancer.

In microbiome research, “the lung has really been ignored,” said lead researcher Dr. Leopoldo Segal, director of the Lung Microbiome Program and an associate professor at New York University Grossman School of Medicine in New York City.

Traditionally, he explained, the lungs were believed to be “sterile.” But recent research has shown that even in healthy people, the lungs can harbor low amounts of bacteria — drawn in from the air or the mouth.

Segal’s team wanted to see whether lung bacteria corresponded to lung cancer patients’ prognosis.

Looking at tissue samples from 83 patients, the researchers found that those with advanced-stage cancer carried more microbes than patients in the early stage of disease.

And when patients did have “enrichment” with certain bacteria types, their odds of survival were lower — even those with earlier-stage cancer.

Specifically, patients harboring Veillonella, Prevotella and Streptococcus bacteria had a worse prognosis. They also showed signs of an inflammatory immune response that, based on past research, may worsen lung cancer patients’ outlook.

None of that proves the bacteria, themselves, were to blame, Segal said. The cancer itself might make the lungs more “receptive” to being colonized with bacteria.

So the researchers turned to lab mice. They transferred Veillonella bacteria into mice with lung cancer and found that the microbes revved up “bad” inflammation, fed tumor growth and shortened the animals’ survival.

That suggests lung bacteria might modulate the immune response in a way that affects lung cancer progression, according to Segal.

But the microbiome is complicated, and it’s hard to draw conclusions from mouse findings, according to Dr. Thomas Marron of Mount Sinai’s Tisch Cancer Institute in New York City.

Right now, he said, there is a “huge interest” in understanding the microbiome’s influence in cancer.

“Studies like this are really interesting,” said Marron, who was not involved with the research, “but we’re probably a few decades away from being able to alter the microbiome to treat cancer.”

Individuals vary in their microbiome makeup, and that’s determined by things like genetics and the immune system, Marron explained. So even if the body’s microbial communities directly affect cancer prognosis, he said, it will be a long time before researchers can turn that into therapy.

“We still don’t know how we could effectively target the microbiome,” Marron said.

He pointed to one question from the new findings: Is there any link between the lung microbiome and patients’ likelihood of responding to immunotherapy?

Segal said his team plans to study that.

Dr. John Heymach chairs thoracic/head and neck medical oncology at M.D. Anderson Cancer Center in Houston. He called the findings “a compelling starting point,” but also emphasized the long research road ahead.

“At this point, we’re not ready to directly act on this in the clinic, by either trying to kill ‘bad’ bacteria, or add back ‘good’ bacteria,” said Heymach, who was not part of the study.

So far, he noted, studies have reached different conclusions as to exactly which types of bacteria are related to better cancer outcomes — which might be due to differences in how studies look for the microbes.

And like Marron, Heymach pointed to the microbiome’s complexity: It generally differs from one large population to the next and among individuals — based on numerous factors.

Still, Heymach said the recent “explosion” in microbiome research could eventually lead to applications in cancer treatment. Besides the possibility of altering the microbiome, he said doctors might be able to use patients’ microbiome makeup as a “biomarker” of their risk of progression.

More information

The American Cancer Society has more on cancer immunotherapy.

Copyright 2020 HealthDay. All rights reserved.



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‘Green prescriptions’ could cancel mental health benefits for some

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So-called “green prescriptions” may end up being counterproductive for people with mental health conditions, researchers say.

Spending time in nature is believed to benefit mental health, so some doctors are beginning to “prescribe” outdoor time for their patients.

That led researchers to investigate whether being in nature helps actually does help people with issues such as anxiety and depression. They collected data from more than 18,000 people in 18 countries.

The takeaway: Time in nature does provide several benefits for people with mental health conditions, but only if they choose on their own to visit green spaces.

While being advised to spend time outdoors can encourage such activity, it can also undermine the potential emotional benefits, according to the authors of the study published this month in the journal Scientific Reports.

The researchers said they were surprised to find that people with depression were spending time in nature as often as folks with no mental health issues, and that people with anxiety were doing so much more often.

While in nature, those with depression and anxiety tended to feel happy and reported low anxiety. But those benefits appeared to be undermined when the visits were done at others’ urging, the investigators found.

The more external pressure people with depression and anxiety felt to visit nature, the less motivated they were to do so and the more anxious they felt.

“These findings are consistent with wider research that suggests that urban natural environments provide spaces for people to relax and recover from stress,” said study leader Michelle Tester-Jones, a postdoctoral research associate at the University of Exeter in the United Kingdom.

But the findings also show that health care practitioners and loved ones should be sensitive about recommending time in nature for people who have mental health issues.

“It could be helpful to encourage them to spend more time in places that people already enjoy visiting, so they feel comfortable and can make the most of the experience,” Tester-Jones said in a university news release.

More information

For more on the benefits of green spaces, go to the National Recreation and Park Association.

Copyright 2020 HealthDay. All rights reserved.



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Study: Nearly half of ‘essential workers’ in U.S. at risk for severe COVID-19

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Nov. 9 (UPI) — Nearly half of those classified as “essential workers” in the United States are at increased risk for severe COVID-19, according to an analysis published Monday by JAMA Internal Medicine.

This means that more than 74 million workers and those with whom they live could be at risk for serious illness, based on disease risk guidelines developed by the U.S. Centers for Disease Control and Prevention, the researchers said.

“Many parts of the country face high and rising infection rates, [and] we should not think about work exposure and health risks in isolation, given that workers and persons at increased risk often live in the same households,” study co-author Thomas M. Selden told UPI.

“Insofar as we can reduce the prevalence of COVID-19 in our communities, we can reduce the extent to which policymakers have to choose between the economy and keeping the population safe,” said Selden, an economist with the U.S. Department of Health and Human Services’ Agency for Healthcare Research and Quality.

Since the COVID-19 pandemic spread to the United States in March, states and cities across the country have instituted lockdown measures designed to limit the spread of the disease.

Many of these measures entailed closing schools and non-essential businesses, with only banks, grocery stores, pharmacies and other businesses deemed to provide vital services allowed to stay open.

For this study, Selden and his colleagues analyzed data on the U.S. workforce to examine how many people were in essential jobs, how often they were able to work at home, their risk for severe COVID-19 and the potential health risks for their household members.

Of the more than 157 million workers across the country, 72% are in jobs deemed essential — based on U.S. Department of Homeland Security criteria — and more than three-fourths of all essential workers are unable to work at home, Selden said.

Essential workers include those in the medical and healthcare, telecommunications, information technology systems, defense, food and agriculture, transportation and logistics and energy, water and wastewater industries, as well as those in law enforcement and public works, the DHS criteria stipulates.

The study notes that up to 60% of these workers have underlying health issues, placing them at increased risk for severe COVID-19 if they get infected, as defined by U.S. Centers for Disease Control and Prevention guidelines.

Those with diabetes, heart disease, high blood pressure and chronic respiratory conditions like asthma are considered to be at high risk for serious illness, the CDC says.

Based on these findings, between roughly 57 million and 74 million adults working in on-site essential jobs — and their families — are at increased risk for serious illness, Selden and his colleagues estimated.

“Policymakers face important decisions about how to balance the economic benefits of keeping workers employed and the public health benefits of protecting those with increased risk of severe COVID-19,” Selden said.

“These issues arise in the context of decisions to close segments of the economy and decisions about how to distribute vaccines, which will initially be available only with limited supply, [and] become all the more difficult when the prevalence of infection rises in parts of the country,” he said.



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Study: Hydroxychloroquine no better than placebo for hospitalized COVID-19 patients

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Nov. 9 (UPI) — COVID-19 patients treated with hydroxychloroquine showed no signs of significant improvement in “clinical status” compared with those given a placebo, a study published Monday by JAMA found.

Patients given a five-day course of the drug were scored as “category six” based on the World Health Organization’s seven-category COVID Ordinal Outcomes Scale, the same as those given a placebo, the researchers said.

Also, 28 days after they started treatment, 10.4% of those treated with hydroxychloroquine died, just slightly lower than the 10.6% fatality rate in the placebo group.

“The results show that hydroxychloroquine did not help patients recover from COVID-19,” study co-author Dr. Wesley H. Self told UPI.

“In the study, patients treated with hydroxychloroquine and those treated with a placebo had nearly identical outcomes, [so] I do not foresee any role for hydroxychloroquine in acutely ill patients hospitalized with COVID-19,” said Self, an infectious disease specialist at Vanderbilt University Medical Center.

Hydroxychloroquine is an immunosuppressive and anti-parasitic drug that is used to treat malaria.

Early in the COVID-19 pandemic, it was touted by President Donald Trump and others as a potential treatment for the virus, despite the lack of any scientific data supporting its use.

Given its effectiveness helping those sickened with malaria — a mosquito-borne infection — to recover, “there was a strong rationale for why hydroxychloroquine may have been beneficial for patients with COVID-19,” according to Self.

However, in July, the U.S. Food and Drug Administration warned against the drug’s use in the treatment of those infected with the new coronavirus, due to potentially serious heart-related side effects.

For this study, Self and his colleagues treated 433 COVID-19 patients at 34 hospitals across the United States with either the drug or a placebo for a period of five days.

Patients assigned to the hydroxychloroquine group received 400 milligrams of the drug in pill form twice a day for the first two doses and then 200 mg. in pill form twice a day for the next eight doses, for a total of 10 doses over the five days.

All of the patients were then assessed based on the WHO’s COVID Ordinal Outcomes Scale, which categorizes those infected according to disease severity.

Most of the patients in both the hydroxycholorquine group and the placebo group were in “category six,” meaning they were hospitalized and receiving extracorporeal membrane oxygenation or invasive mechanical ventilation to maintain their breathing, the researchers said.

“Our results, especially when combined from other studies conducted in the United Kingdom and Brazil, are good evidence that hydroxychloroquine does not provide benefit for patients hospitalized with COVID-19,” Self said.



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