Sequelae of Eating Disorders at Imaging | RadioGraphics

What Causes Lung Cancer? Scientists Are Working To Connect The Dots.

For Sharon Fisher, the lung cancer diagnosis came as a gut punch.

A simple cold had turned into a lingering feeling of congestion, with a dry cough. Eventually diagnosed with pneumonia, a closer look revealed a lesion in the left lobe of her lung. But, how?

After all, she'd never been a smoker, was an avid hiker, was still the same weight she'd been since high school, had no history of illnesses, and was a foodie who ate no processed foods and cooked healthy meals for herself, in spite of her hectic work schedule.

What most people do not realize is that in approximately 15% of lung cancer diagnoses, the patient has never smoked. And, they had no exposure to known carcinogens.

While this fact has baffled the medical community, further exploration revealed that there were many more female never-smokers (as they are referred to) who were contracting this cancer, and at an earlier age, than smokers.

Analyzing the tumors of these never-smokers, a study by the National Cancer Institute revealed that there was an accumulation of genetic mutations within this group. Scientists are still trying to connect the dots to figure out what exposures may have added to the risk. 

For patient Fisher, the lung cancer was already Stage 2 at diagnosis, and required a surgical lobectomy, wherein one of the five lobes of her lungs was removed.

After chemotherapy there was no further evidence of disease. But, the five-year survival rate for stage 2 lung cancer, after treatment, is only 35%.

Over the next few years, Fisher's tumors would return in other areas of her lungs, and despite being a part of clinical trials for her specific cancer mutations and receiving various forms of immunotherapy and targeted treatments, she died of the disease four years later. She was 70 when she passed away, in 2019.

"This is why it is so important to catch lung cancer in its earliest stages," said Ramsy Abdelghani, M.D., Tulane's Director of Interventional Pulmonology. "At stage 1, your 5-year survival rate is 95%. But, in Louisiana, 80% of those diagnosed are either stage 3 or 4. At these advanced stages, survival rates drop precipitously. At stage 4, you're looking at a five-year survival rate of 5%. We're not doing well here with lung cancer screening."

Detecting lung cancer early is easier said than done, and in fact, most people are unaware there is any screening at all for lung cancer.

To receive the low-dose CT scan (10% of the normal radiation) that can detect the earliest of lung cancers, one must meet certain criteria. Patients must be between the ages of 50 and 80, either be a current smoker, or someone who has quit in the last 15 years.

And, the smoking history must be significant — that equates to 20 years of smoking a pack a day, or 10 years of smoking two packs a day. If these criteria are met, patients are entitled to one scan a year, covered by insurance. But, those who have family histories of lung cancer should certainly be in that mix, as they are twice as likely to contract the disease.

Sadly, there are no signs or symptoms in the earliest of stages, so screening is vital. Finding these cancers at stage 2 means there can still be microscopic areas of disease that are present even after surgery, but are not always detectable.

The key is to know your family history, honestly discuss your smoking history with your primary care physician, and take advantage of the ability to screen for this deadly disease. Abdelghany is meeting with primary care physicians to ensure that patients' histories are triggering notifications that will lead to early screening.

Even if you're not a smoker, exposure to radon is the second leading cause of lung cancer. It is a colorless, odorless, radioactive gas that is often found in soil and water.

Although radon decays quickly, it gives off tiny radioactive particles which can leach into buildings and homes and be inhaled. When that happens, it damages the cells that line the lungs. Long-term exposure can lead to lung cancer. According to the National Cancer Institute, it is the only cancer proven to be associated with inhaling radon.

Diagnosis for lung cancer has become far more sophisticated of late. Biopsies are less invasive and pinpointing the exact location of a tumor has become far more accurate.

"I do robotic bronchoscopies by navigating an endoscope through the intricate branches of the bronchi, then do intraoperative imaging to confirm my location," Abdelghany said. "This is a quick, minimally invasive technique to isolate the lesion, and get it analyzed, so treatment can begin."

Major strides are being made in treating all types of lung cancer

Although not technically lung cancer, mesothelioma is a type of cancer that starts in the membranes that cover the lungs. If you didn't know much about this disease prior to the barrage of television ads now asking those with the disease to join class-action lawsuits, you have now probably learned that 80% of these cases are caused by exposure to asbestos — much of it from factories.

Tiny bundles of asbestos fibers which fly through the air can be inhaled. This causes cell turnover, which leads to cancer.

There is a high mortality rate associated with this cancer, as there are no early signs or symptoms that would lead someone to treatment. It is critical that anyone working with asbestos wear a proper mask that filters out all particulate matter.

Major strides have been made over the last decade, relative to all types of lung cancer.

Before these new treatments, the only recourse for treating lung cancer was surgery, chemotherapy or radiation.

Now, by knowing the exact type of cancer you have and determining what stage it is, along with knowing what factors within the tumor can be targeted, precision medicine can go after specific markers within the tumor. As researchers like to say — it is important to know the enemy, so you can find the right tools to fight it.

Lung Cancer Screening Guidelines Perpetuate Racial Disparities, Study Finds

Current national guidelines that rely on age and smoking exposure to recommend people for lung cancer screening are disproportionally failing minority populations including African Americans, according to a new study led by researchers at Stanford Medicine.

An alternative risk-based method that incorporates additional information including family history and other health problems such as previous cancer diagnoses does a better job of eliminating disparities among races, the study found.

The disparities persist despite a revision to the guidelines that was implemented in 2021 to address race-based disparities in screening eligibility.

"Our study shows that these changes to the guidelines are not sufficient to address race-based differences in lung cancer incidence and age at diagnosis," said associate professor of neurosurgery and of biomedical informatics Summer Han, Ph.D. "This is a lost opportunity to detect lung cancers early when cancers are still treatable. Early detection saves lives."

Han is the senior author of the study, which was published Oct. 26 in JAMA Oncology. Neurosurgery instructor Eunji Choi, Ph.D., is the lead author of the research.

Lung cancer is the leading cause of cancer death in the United States, killing about 127,000 people annually, but it can be treatable if detected early.

Low-dose computed tomography, or CT scan, has been shown to significantly reduce the number of lung cancer deaths. But because the radiation delivered by the scans can be harmful (they use on average about 10 times the radiation of standard X-rays), only those people at relatively high risk for lung cancer should be screened. The two biggest risk factors for lung cancer are exposure to tobacco smoke and age.

Screening guidelines

In 2013, the United States Preventive Services Task Force issued guidelines recommending annual low-dose CT scans for people aged 55 to 80 who had a minimum cumulative smoking exposure of 30 pack years (a pack year is the number of packs of 20 cigarettes smoked each day multiplied by the number of years the person has smoked) and who were still smoking or who had stopped smoking within the previous 15 years. Someone who smoked three packs per day for 10 years would have an exposure of 30 pack years, for example.

The task force is an independent panel of national experts in disease prevention and evidence-based medicine. Although doctors can make their own decisions about who should and should not be screened, they generally follow the task force's guidelines.

In 2021, the task force revised these guidelines—lowering the starting age for screening to 50 years and the exposure levels to 20 pack years—to address the fact that African Americans tend to develop lung cancers at a younger age and after less smoking exposure than other racial groups.

"Many studies have found that only about 32% of African Americans with lung cancer, versus 56% of white people, were eligible for screening under the 2013 guidelines," Han said.

Choi, Han and their colleagues analyzed a multi-ethnic group of 105,261 people 45 to 75 years old with a history of smoking who enrolled in a research study between 1993 and 1996. Participants were African American, Japanese American, Latino, Native Hawaiian and other Pacific Islander, or white.

When they enrolled, the participants filled out a questionnaire about their smoking history, sociodemographic factors such as education level and body mass index, and their medical background, including a personal history of cancer or a family history of lung cancer.

The researchers used a national cancer registry to identify which participants were diagnosed with lung cancer within six years of their enrollment in the study.

Using the answers to the questionnaire, the researchers assessed which of the participants would have been eligible for lung cancer screening under either the updated Preventive Services Task Force guidelines, which use only age and smoking history, or a risk-based assessment method that also uses information about each person's family history, health background and any previous cancer diagnoses.

They found that overall, 24% of people in the study would have been eligible for screening based on the task force's updated guidelines. But there were differences among the racial and ethnic groups: 30% of white people would have qualified for screening compared with 25.5% of Japanese Americans, 25.1% of Native Hawaiians and other Pacific Islanders, 21.4% of African Americans, and 15.7% of Latinos.

A better measure of disparities

Reduced eligibility doesn't indicate a health inequity on its own. It's possible that one group may have comparatively lower smoke exposure than another, or may be at lower or higher risk biologically, for example.

A more telling measure is a ratio researchers call eligibility-to-incidence rates—or the number of people in a group eligible for screening compared with the number of lung cancer cases found in that group over a certain time. Higher ratios imply adequate screening; lower ratios imply that some lung cancer cases are occurring in people who were not deemed eligible for screening.

When the researchers calculated this ratio using the 2021 task force guidelines, they found that white people in the study had an eligibility-to-incidence ratio of 20.3, while African Americans had a ratio of 9.5. This difference was driven by the fact that fewer African Americans were eligible for screening (21.4% versus 30.2%) and that African Americans had a higher incidence of lung cancer over the subsequent six years (2.2% versus 1.5% of white participants). Native Hawaiians and other Pacific Islanders had an eligibility-to-incidence ratio of 16.8 versus the 20.3 of white participants.

In contrast, the risk-based analysis did a better, but not perfect, job at eliminating disparities. Under this analysis, African Americans had an eligibility-to-incidence ratio of 15.9 versus 18.4 for white participants. The improvement was primarily due to an increase in the number of African Americans who would have been eligible for screening—35.7% versus the 21.4% eligible under the task force guidelines.

The difference in eligibility-to-incidence ratios between Native Hawaiians and other Pacific Islanders and white people also improved to 16.6 versus 18.4. Minimal differences were observed between white people and the other racial groups.

Further analysis showed that selecting people to screen based on the risk-based analysis was more likely than the task force guidelines to accurately identify people with lung cancer—a measure known as sensitivity—and fewer screens were needed to detect one case of lung cancer (26 versus 30).

The researchers hope that their findings will spur a national dialogue about race-based disparities in lung cancer screening recommendations and how to devise more equitable and effective guidelines.

"It's critically important to identify high-risk people across racial and ethnic groups," Han said.

"Our study shows that risk-based screening reduces racial disparities and improves screening efficiency. Disparities evident in the U.S. Preventive Services Task Force's lung cancer screening guidelines may have a significant impact on lung cancer mortality in the United States. We clearly show that a method that incorporates additional information in screening assessments is better at identifying true cases of lung cancer. It also reduces the number of false positives."

More information: Eunji Choi et al, Risk Model–Based Lung Cancer Screening and Racial and Ethnic Disparities in the US, JAMA Oncology (2023). DOI: 10.1001/jamaoncol.2023.4447

Citation: Lung cancer screening guidelines perpetuate racial disparities, study finds (2023, October 27) retrieved 30 October 2023 from https://medicalxpress.Com/news/2023-10-lung-cancer-screening-guidelines-perpetuate.Html

This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.

Iowa's Governor Says Her Husband, Diagnosed With Lung Cancer, 'never Smoked'

Governor Kim Reynolds says her husband's lucky to be getting a break-through drug to treat his recently diagnosed lung cancer.

"He's been in treatment for about a month," Reynolds told reporters late this morning. "I'm happy to say that the radiation has really eliminated and kicked the pain that was in the spine and so that has been a true blessing. It's helped his attitude quite a bit to not be in so much pain. He's on an oral immune therapy drug for the tumor and hopefully, if this works, he won't have to do chemo."

Reynolds issued a written statement last month, announcing that her husband had lung cancer. He went to the doctor because of back pain. "We thought he had a ruptured disc, so it was really was kind of a gut punch," Reynolds said today. "He's not a smoker, never smoked."

Today is the first time the governor has talked publicly about the diagnosis. She grew emotional during a news conference as she thanked Iowans for their messages of support. "Every day we get two or three cards in the mail to say that: 'We're praying for you and keeping you in our prayers,"' Reynolds said. "It's just another reflection of Iowans and who we are and it matters and it makes a difference, so just a heartfelt thank you for that."

Reynolds said she and her husband are grateful and feel lucky to have the medical team at the John Stoddard Center Center in Des Moines and the University of Iowa Hospitals and Clinics who've been working on his case.  "We really are very optimistic and he is a strong dude and we're really feeling the prayers and we're ready to move through this," Reynolds said.

The type of lung cancer Kevin Reynolds has is not considered curable, but with treatment it can go into remission, according to the governor.

---