Lung cancer screening using computed tomography (CT) scans can be effective in high risk populations if it follows a strict clinical protocol supported by a multidisciplinary care team, said University of Cincinnati researchers this week.

The researchers, led by Dr Sandra Starnes, director of thoracic surgery at the University of Cincinnati (UC) College of Medicine and a surgeon with UC Health, came to this conclusion after conducting a clinical trial in a high-risk local population with rates of histoplasmosis three times higher than the national average.

Histoplasmosis is a fungal infection that enters the body through the lungs and increases the likelihood of lung nodules.

A paper on the study is about to appear online ahead of print in the Journal of Thoracic and Cardiovascular Surgery.

Lung cancer is the leading cause of cancer-related death in the US, where the National Cancer Institute estimates that in 2010, more than 220,000 people will have discovered they have the disease.

Research suggests that smoking tobacco, exposure to second hand tobacco smoke, and heavy alcohol consumption, increase people’s risk of developing lung cancer, as does exposure to radon, air pollution, asbestos, chromium, nickel, tar and soot.

While there are currently no nationally recognized medical tools for lung cancer screening, recently reported national and localized trials have shown a measure of success with computed tomography (CT) scans in high risk populations of heavy, long-term smokers.

For example, last month’s preliminary results of the National Cancer Institute’s ongoing randomized National Lung Cancer Screening Trial of 53,000 current and former heavy smokers aged between 55 and 74, showed that screening heavy smokers with low-dose CT scans, as opposed to traditional X-rays, led to 20 per cent fewer deaths.

Starnes and colleagues decided to conduct a trial in a high risk population closer to home.

Cincinnati is a large city in the Ohio River Valley, where there is a high prevalence of histoplasmosis.

The challenge of screening for lung cancer in such a population is that on a CT scan, the histoplasmosis nodules can look like the irregular shapes produced by lung cancer, leading to a high rate of unnecessary biopsies.

However, Starnes said that:

“By using three-dimensional CT imaging, we are able to look more closely at the anatomical structure of these nodules and identify concerning lesions”.

For their study, Starnes and colleagues recruited 132 heavy smoking volunteers aged 50 and over who had smoked at least 20 packs of cigarettes a year.

The volunteers filled in questionnaires about their medical history and smoking habits, and then every year for five years they each had a low-dose CT scan to screen for signs of lung cancer.

The results showed that despite having a 60 per cent histoplasmosis nodule rate, it was possible to avoid unnecessary biopsies and still not miss any lung cancer diagnoses, if the protocol was followed strictly.

Plus, said Starnes:

“No one was diagnosed at a stage where the lung tumor could not be surgically removed.”

She warned that if screening does become standard practice, to be effective it must follow a defined, rigorous protocol, and be supported by a multidisciplinary team.

Otherwise, people will end up having unnecessary tests and biopsies for benign disease, she added, stressing that the collective knowledge of an experienced, multidisciplinary team is critical.

The team at the University of Cincinnati includes among other disciplines, pulmonologists, pathologists, gastroenterologists, respiratory therapists, radiologists, medical oncologists, radiation oncologists, oncology nurses and fellowship-trained surgeons.

Journal of Thoracic and Cardiovascular Surgery

Additional source: UC Health News.

Written by: Catharine Paddock, PhD